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Solid

A solid is one of the states of , characterized by particles—such as atoms, molecules, or ions—that are tightly packed together and held in relatively fixed positions by strong intermolecular forces. This arrangement gives solids a definite and , distinguishing them from liquids and gases, which can flow and conform to their containers. Solids typically resist deformation, compression, and expansion under normal conditions. Solids can be classified into crystalline forms, with ordered, repeating structures, or amorphous forms, lacking long-range order. Their properties, including strength, , and electrical behavior, form the basis for fields like , , and chemistry.

Definition and Basic Characteristics

Atomic and Molecular Structure

Solids represent a in which constituent particles, such as atoms, ions, or molecules, are tightly packed together with minimal vibrational motion relative to one another, conferring a definite volume and shape to the material. This rigidity arises from strong interparticle forces that restrict translational and rotational freedom, distinguishing solids from more fluid phases. The specific atomic and molecular structure of a solid is governed by the nature of the chemical bonds holding the particles together, which fall into several primary categories: ionic, covalent, metallic, van der Waals (including London dispersion forces), and hydrogen bonding. Ionic bonds, characterized by electrostatic attractions between oppositely charged ions, predominate in salts like (NaCl), where sodium cations and chloride anions form a stable lattice. Covalent bonds involve the sharing of electron pairs between atoms, as seen in , where carbon atoms are linked in a tetrahedral , yielding exceptional . Metallic bonds feature delocalized electrons surrounding positively charged metal ions, enabling high electrical in materials like . Weaker van der Waals forces, arising from temporary dipoles, bind noble gas solids such as , while hydrogen bonds, involving partial charges on hydrogen and electronegative atoms, stabilize structures like . In crystalline solids, these bonded units arrange into highly ordered, repeating three-dimensional that define the material's and properties. Common lattice types include the simple cubic () structure with a coordination number of 6 and packing efficiency of 52%, the body-centered cubic (BCC) with coordination number 8 and 68% efficiency, the face-centered cubic (FCC) with coordination number 12 and 74% efficiency, and the hexagonal close-packed (HCP) structure, which also achieves 74% packing efficiency through its ABAB layering. These efficiencies reflect the fraction of space occupied by atoms, assuming hard-sphere models, and influence and stability. Real solids deviate from ideal s due to structural defects, which occur inevitably and profoundly affect macroscopic properties. Point defects, zero-dimensional imperfections, encompass vacancies (empty sites) and interstitials (atoms occupying non- positions), facilitating processes like and altering electrical . Line defects, or one-dimensional dislocations, include edge and screw types that enable slip during deformation, thereby controlling and mechanical strength without fracturing the material. In contrast to crystalline solids, amorphous solids exhibit no long-range periodic at the level, instead displaying only short-range where neighboring atoms maintain local bonding similar to that in the liquid state from which they often solidify. This disordered, isotropic arrangement results in gradual softening upon heating rather than sharp melting, as seen in like silica-based materials.

Phase Distinction from Liquids and Gases

The solid phase of matter is defined by its definite shape and volume, maintained by strong intermolecular forces that predominate over thermal energy, constraining constituent particles to fixed positions within a rigid structure. This contrasts with liquids, where particles can slide past one another while retaining a fixed volume, and gases, where particles are widely separated and fill their container dynamically. In terms of particle dynamics, solids exhibit only vibrational motion, with atoms or molecules oscillating around equilibrium sites in a lattice, unlike the translational diffusion in liquids that enables flow or the rapid, random translational and rotational movements in gases. This restricted motion in solids arises from the close atomic packing that resists shear forces, distinguishing the phase from the more disordered arrangements in fluids. Thermodynamically, the phase is delineated by the , the temperature at which and coexist in under a given , marking the transition where overcomes stability. The slope of the in a is given by the Clausius-Clapeyron equation: \frac{dP}{dT} = \frac{\Delta H}{T \Delta V} where \Delta H is the enthalpy of fusion, T is the equilibrium temperature, and \Delta V is the change in molar volume between phases; for most substances, \Delta V > 0, so melting points increase with pressure. In phase diagrams, the triple point represents the unique conditions where solid, liquid, and gas phases coexist in equilibrium, serving as a reference for solid stability; for water, this occurs at 0.01°C and 611.657 Pa, below which the solid phase dominates. The critical point, by contrast, ends the liquid-gas distinction at high temperatures and pressures (e.g., 374°C and 22.064 MPa for water), but solids persist beyond this under sufficient pressure, as seen in water's multiple ice phases like ice VII, which form under gigapascal pressures and maintain solidity where liquids would otherwise prevail. Metastable solids occur when a material adopts a higher-energy that is locally but not the global minimum, such as persisting despite being thermodynamically favored under ambient conditions. Supercooling phenomena, often observed in liquids but relevant to solid formation, involve cooling below the without , creating a metastable supercooled state that can rapidly solidify upon ; this is exemplified in supercooled to -40°C before forming .

Classification of Solids

Crystalline Solids

Crystalline solids are defined by their long-range, periodic arrangement of atoms, ions, or molecules, which form repeating unit cells that extend throughout the material. This ordered structure distinguishes them from amorphous solids, which lack such periodicity. The arrangement is categorized into seven crystal systems based on and parameters: triclinic, monoclinic, orthorhombic, tetragonal, trigonal (or rhombohedral), hexagonal, and cubic. In metals, crystalline solids are stabilized by , where valence electrons are delocalized in a "sea" around positively charged metal ions, enabling high electrical and thermal conductivity as well as due to the ability of layers to slide without breaking bonds. For example, alpha-iron adopts a body-centered cubic (BCC) structure, with atoms at each corner and one in the center of the unit cell, contributing to its strength and magnetic properties. Copper, in contrast, forms a face-centered cubic (FCC) , with atoms at the corners and face centers, which enhances its malleability and use in wiring. Natural minerals often exhibit crystalline structures with ionic or covalent network bonding, leading to high hardness and stability. Quartz, composed of SiO₂, crystallizes in a trigonal system with helical chains of SiO₄ tetrahedra linked by shared oxygen atoms, resulting in its piezoelectric properties. , a form of carbon, features a covalent in a lattice, where each carbon atom bonds tetrahedrally to four others, making it the hardest known natural material. Crystalline semiconductors, such as , possess a structure identical to that of but with a band gap of approximately 1.12 eV between the , allowing tunable electrical through doping. This ordered atomic arrangement enables the formation of precise electronic devices. A key feature of crystalline solids is the of their properties, arising from the directional and , which causes variations in , thermal, and electrical behaviors depending on the crystallographic direction. For instance, cleavage planes align with weak directions, influencing how the material fractures.

Amorphous Solids

Amorphous solids, also known as glassy solids, are non-crystalline materials characterized by the absence of long-range atomic or molecular order, featuring only short-range order without a repeating structure. In these materials, atoms or molecules are arranged in a disordered fashion similar to that in a , yet they maintain rigidity due to limited mobility at low temperatures. This structural disorder distinguishes them from crystalline solids, which exhibit periodic arrangements, and results in isotropic properties and often lower packing efficiency. Common examples of amorphous solids include inorganic glasses, such as silica-based materials like soda-lime , which constitutes a vitreous in ceramics and glass ceramics used in windows and containers. Organic amorphous solids encompass non-crystalline polymers, such as and acrylics, which form rigid yet disordered structures in applications like and optical lenses. These materials are typically produced by rapid cooling of melts to suppress , preserving the liquid-like arrangement in a solid state. A defining feature of amorphous solids is the glass transition temperature, denoted as T_g, which marks the temperature at which the material's viscosity reaches approximately $10^{12} Pa·s, transitioning from a hard, glassy state to a more rubbery one without a distinct melting point. Unlike crystalline solids, this gradual transition reflects the kinetic arrest of molecular motion rather than a thermodynamic phase change. The value of T_g varies with composition; for example, it is around 1200 °C for pure silica glass but lower, near 100 °C, for polystyrene. Amorphous solids exhibit relaxation processes, where structural rearrangements occur over time to approach a lower-energy , leading to physical aging that manifests as changes in , , and mechanical properties. During aging below T_g, the material's volume decreases and its increases, enhancing but improving dimensional , as observed in pharmaceutical glasses and polymers stored for extended periods. These slow, non-exponential relaxations, often spanning hours to years, arise from the broad distribution of barriers in the disordered .

Composite and Hybrid Solids

Composite and hybrid solids are engineered materials composed of two or more distinct phases or constituents with different physical or chemical properties, combined to produce enhanced overall performance that surpasses the individual components. These materials are typically multiphase systems where the phases are macroscopically separable and artificially assembled, distinguishing them from naturally occurring multiphase solids. Common examples include fiber-reinforced composites and particle-filled matrices, where the reinforcement phase provides strength or stiffness while the matrix binds the structure together. In composite materials, such as , high-strength are embedded in a polymer matrix like to achieve a high strength-to-weight ratio, making them ideal for and automotive applications. Another classic example is , a composite consisting of a cement-based matrix reinforced with aggregates and often bars, which leverages the of the matrix and tensile for structural durability. These combinations exploit the complementary properties of the phases to optimize mechanical behavior. Hybrid solids, particularly in biomaterials, integrate and inorganic components for biological compatibility and functionality, as seen in , a natural of fibers (about 90% ) and nanocrystals (about 70% inorganic by weight). This hierarchical structure provides with a balance of flexibility from and rigidity from , enabling it to withstand both compressive and tensile loads while supporting osteoconduction and remodeling. Synthetic analogs, such as - scaffolds, mimic this design to promote regeneration in . Nanocomposites represent an advanced class of hybrid solids where nanoscale reinforcements, such as carbon nanotubes (CNTs) or quantum dots, are dispersed in a matrix to yield size-dependent properties. For instance, CNTs in polymer matrices enhance stiffness, strength, and due to their exceptional tensile strength (up to 100 GPa) and high , often improving matrix-dominated properties by 20-50% at low loadings (1-5 wt%). Quantum dots, semiconductor nanoparticles typically 2-10 nm in size, exhibit tunable when embedded in composites; their emission wavelength shifts with particle size due to quantum confinement, enabling applications in and sensors. These introduce synergistic effects at the interface, altering properties like thermal conductivity or beyond simple additive contributions. The synergistic effects in composites arise from interactions between phases, often modeled by the for predictive purposes. For the longitudinal in unidirectional fiber-reinforced composites under isostrain conditions, it is given by E_c = V_f E_f + V_m E_m where E_c is the composite , V_f and V_m are the volume fractions of the and (with V_f + V_m = 1), and E_f and E_m are the respective moduli of the and . This assumes perfect bonding and uniform distribution, providing a baseline for understanding how phase fractions influence overall , though real systems may deviate due to interfacial effects.

Key Physical Properties

Mechanical Properties

Mechanical properties of solids describe their response to applied forces, encompassing deformation, strength, and failure mechanisms under various loading conditions. These properties are fundamental to , as they determine a solid's suitability for structural applications, where resistance to without excessive or rupture is essential. Solids exhibit a range of behaviors depending on their atomic structure and , from recovery in metals to brittle shattering in ceramics. The - curve illustrates a solid's response during tensile loading, plotting (σ, force per unit area) against (ε, deformation per unit length). In the elastic region, deformation is reversible, governed by , which states that is directly proportional to : σ = E ε, where E is the representing the material's stiffness. Beyond the elastic limit, plastic deformation occurs, involving permanent shape change due to movement in crystalline solids. The strength marks the transition to this irreversible regime, while the indicates the maximum the material can withstand before necking and failure. For example, mild has a strength of approximately 250 MPa and of 400-550 MPa. Hardness quantifies a solid's resistance to surface indentation or scratching, serving as a proxy for strength and wear resistance. Common scales include the Mohs scale, an ordinal measure primarily for minerals and ceramics (e.g., quartz at 7, diamond at 10), the Brinell scale using a steel ball indenter for softer metals (e.g., aluminum around 15-30 HB), and the Vickers scale employing a diamond pyramid for both metals and harder ceramics (e.g., steel up to 600 HV, alumina ceramics exceeding 1500 HV). Metals generally exhibit lower hardness than ceramics due to their ductility, allowing plastic flow under load, whereas ceramics' ionic or covalent bonds confer higher resistance but increased brittleness. Fracture mechanics analyzes propagation and modes in solids, distinguishing brittle —characterized by sudden, low-energy without significant deformation, as in —from ductile , where extensive yielding and necking precede rupture, typical of metals. The Griffith provides a foundational model for brittle , predicting the critical (σ_f) for growth in a plate with a through-thickness of 2a: \sigma_f = \sqrt{\frac{2 E \gamma}{\pi a}} where E is and γ is the surface energy required to create new crack surfaces. This equation highlights how flaw size inversely affects strength, explaining why seemingly strong materials fail catastrophically from microscopic defects. combines viscous and responses, prominent in polymers and composites, where deformation under load is time-dependent due to molecular chain entanglements and relaxation processes. Unlike purely solids, viscoelastic materials show (gradual increase under constant stress) and (decreasing stress under fixed ), with behavior modeled by elements like springs () and dashpots (viscous) in series or parallel. In polymer-matrix composites, this property enhances energy dissipation for applications but requires careful consideration for long-term structural integrity. Under sustained or cyclic loads, solids can fail through or , distinct from monotonic loading. involves progressive crack initiation and growth under repeated cycles below the strength, leading to sudden after many cycles (e.g., 10^6 cycles for high-cycle fatigue in alloys). , conversely, is time-dependent deformation under constant , particularly at elevated temperatures, progressing through primary (decreasing rate), secondary (steady-state), and tertiary (accelerating to rupture) stages, as observed in turbine blades. These mechanisms underscore the importance of load duration and cycling in design.

Thermal Properties

Thermal properties of solids describe how these materials conduct, store, and respond to , influencing their behavior under variations. Thermal conductivity, denoted by k, quantifies the ability of a solid to transfer and is governed by Fourier's , which states that the \mathbf{q} is proportional to the negative gradient of : \mathbf{q} = -k \nabla T. In metals, conduction is primarily electron-mediated, where free electrons carry thermal energy efficiently, leading to high k values often exceeding 100 W/m· at . Conversely, in insulators and semiconductors, phonon-mediated conduction dominates, involving lattice vibrations that scatter more readily, resulting in lower k typically below 10 W/m·K. Specific heat capacity, often C_p at constant pressure or C_v at constant volume, measures the heat required to raise the temperature of a unit mass of solid by one degree. The Debye model explains low-temperature behavior, predicting C_v \propto T^3 due to the freezing out of low-frequency phonon modes as temperature decreases. At high temperatures, the Dulong-Petit law applies, stating that C_v \approx 3R per mole of atoms, where R is the gas constant, reflecting the equipartition of energy among vibrational degrees of freedom. This high-temperature limit, approximately 25 J/mol·K, holds for many elemental solids like copper and diamond above room temperature. Thermal expansion characterizes the dimensional changes in solids with temperature, quantified by the linear \alpha, defined as \alpha = \frac{1}{L} \frac{dL}{dT}, where L is . The volumetric \beta relates as \beta = 3\alpha for isotropic materials, though crystals often exhibit , with \alpha varying by direction due to —for instance, up to 50% differences along principal axes in hexagonal crystals. Values of \alpha range from low (e.g., 0.5 × 10^{-6} K^{-1} for alloys) to high (e.g., 25 × 10^{-6} K^{-1} for aluminum). Melting in solids involves absorbing the of to overcome intermolecular forces, transitioning from ordered to disordered without change; typical values are around 100-400 kJ/kg for metals like iron (247 kJ/kg). , the direct solid-to-gas transition, requires the of , which equals the sum of and heats, such as 571 kJ/kg for (CO₂). These latent heats determine the energy barriers for phase changes, affecting processes like and freeze-drying. Certain solids, particularly metallic alloys and compounds, exhibit below a critical T_c, where electrical vanishes and shift dramatically, including a jump in specific heat at T_c. Conventional superconductors have T_c up to about 23 , as in niobium-tin alloys, while high-temperature cuprates reach above 90 under . This threshold arises from electron-phonon interactions forming pairs, enabling zero resistivity in the superconducting state.

Electrical and Magnetic Properties

The electrical properties of solids are fundamentally described by band theory, which arises from the quantum mechanical treatment of electrons in a periodic potential. In this framework, the allowed energy levels for electrons form continuous bands: the valence band, filled with electrons at , and the conduction band, which is empty or partially filled. The region between these bands, known as the E_g, determines the material's conductivity. Insulators possess a large (E_g > 5 eV), preventing electron excitation from the valence to the conduction band under typical conditions, resulting in negligible conductivity. Semiconductors have a smaller ($0.1 < E_g < 3 eV), allowing thermal or optical excitation of electrons across the gap, while conductors (metals) feature overlapping bands or a partially filled conduction band with no significant gap, enabling free electron movement. The Fermi level, the highest occupied energy at , lies within the conduction band for conductors, in the for insulators and semiconductors, and influences charge carrier availability. The density of states, denoting the number of electronic states per energy interval, varies across bands and is crucial for understanding carrier populations in these materials. Electrical conductivity \sigma in solids, particularly metals, is modeled by the Drude theory, which treats electrons as a classical gas scattered by lattice ions. The conductivity is given by \sigma = n e \mu, where n is the carrier density (number of free electrons per unit volume), e is the elementary charge, and \mu is the electron mobility, defined as the drift velocity per unit electric field. In metals, n is on the order of $10^{28} to $10^{29} m^{-3}, leading to high \sigma values around $10^7 S/m at room temperature, though mobility \mu decreases with temperature due to increased scattering. This model explains in solids but overestimates specific heat; quantum refinements, like the , address such limitations while retaining the core expression for \sigma. Semiconductors exhibit tunable conductivity through doping, the intentional introduction of impurities to alter carrier density. In n-type doping, donor atoms (e.g., phosphorus in silicon) add extra electrons to the conduction band, increasing electron concentration n while keeping hole density low. Conversely, p-type doping with acceptors (e.g., boron in silicon) creates vacancies in the valence band, generating holes as majority carriers. The Hall effect provides a method to identify carrier type and measure properties: applying a magnetic field perpendicular to current flow induces a transverse voltage proportional to the carrier charge sign and density, with negative Hall coefficient for n-type (electron-dominated) and positive for p-type (hole-dominated) materials. This effect confirms, for instance, that electrons are the primary carriers in n-type germanium with doping densities around $10^{16} cm^{-3}. Magnetic properties of solids stem from atomic magnetic moments due to electron spin and orbital motion, leading to distinct behaviors under applied fields. Diamagnetism occurs in all materials as a weak, induced repulsion from the field, arising from Lenz's law-like orbital currents that oppose the field, with susceptibility \chi \approx -10^{-5}. Paramagnetism appears in materials with unpaired electrons, where thermal disorder aligns moments weakly with the field (\chi > 0, small), following \chi \propto 1/T. These effects are present in insulators and semiconductors without cooperative interactions. Ferromagnetism represents a strong, spontaneous alignment of moments below the T_C, resulting from exchange interactions that favor parallel spins in lattice sites. In ferromagnets like iron, magnetic —regions of uniform —form to minimize demagnetizing fields, with domain walls allowing reorientation under external fields for . Iron, a body-centered cubic metal, exhibits up to T_C = 1043 K, with saturation around 1.7 T due to its five unpaired d-electrons per atom. Above T_C, thermal agitation disrupts alignment, transitioning the material to . Certain non-centrosymmetric crystals display , an electromechanical coupling where mechanical induces electric polarization, or vice versa. The d quantifies this, defined as d = /voltage, linking applied voltage to generated in actuators or stress to voltage in sensors. This effect requires a lack of inversion in the , as in or , enabling charge separation under deformation. Applications rely on d values up to $500 pm/V in ceramics.

Optical and Other Properties

Optical Properties

Optical properties of solids describe their interaction with , particularly in the visible, (UV), and (IR) regions, governing phenomena such as , , , and of . The n, defined as the ratio of the in to that in the material, quantifies how much bends upon entering a solid and varies with , leading to . In solids like or , causes white to separate into colors, as shorter s (e.g., ) experience higher n than longer ones (e.g., ). in solids follows , n_1 \sin \theta_1 = n_2 \sin \theta_2, where n_1 and n_2 are the refractive indices of the incident and transmitting media, and \theta_1, \theta_2 are the angles of incidence and , respectively; this law applies to interfaces involving solids, enabling applications in lenses and prisms. Absorption and transmission in solids occur when photons are captured by electrons, converting light energy into heat or other forms, with transmission being the fraction of light that passes through. The Beer-Lambert law models this attenuation: I = I_0 e^{-\alpha x}, where I is the transmitted intensity, I_0 the incident intensity, \alpha the absorption coefficient, and x the path length; in solids, \alpha depends on material composition and wavelength. Chromophores—specific molecular groups or defects within the solid—act as primary absorbers, responsible for color in materials like dyes embedded in polymers or impurities in crystals, where they excite electrons to higher energy states upon photon absorption. Reflection at solid surfaces follows , but in anisotropic crystals, it couples with , where the differs for polarized in different directions, splitting a single beam into two orthogonally polarized rays with distinct velocities. (CaCO₃), a classic uniaxial crystal, exhibits strong negative (\Delta n \approx 0.17), producing double images of objects viewed through it due to the ordinary ray (o-ray) following and the extraordinary ray (e-ray) deviating based on its angle to the optic axis. This property arises from the non-cubic lattice structure, enabling polarization-dependent reflection and refraction essential for optical isolators and waveplates. Luminescence in solids involves following , with occurring via rapid radiative decay (nanoseconds) from excited states and from slower triplet states (milliseconds to seconds), often at in doped or organic solids. In crystalline hosts like ZnS or organic matrices, persistent persists after ceases due to trapped charges, while dominates in wide-bandgap semiconductors. These processes enable applications in displays and sensors, with efficiency influenced by host-guest interactions in solid matrices. Opto-electronic effects in semiconductors link light absorption to electrical changes, notably photoconductivity, where illumination generates electron-hole pairs that increase conductivity; in materials like GaN, this is quantified by persistent photoconductivity lasting seconds due to defect trapping. Light-emitting diodes (LEDs) exploit the reverse: injecting carriers into p-n junctions of direct-bandgap semiconductors like AlGaInP or InGaN recombines them, emitting photons at energies matching the bandgap (E_g \approx 1.8-3.1 eV for visible light). Band structure plays a key role, as direct bandgaps in these solids allow efficient momentum-conserving recombination, unlike indirect gaps in silicon.

Chemical and Surface Properties

The of solids, particularly metallic ones, is closely tied to their oxidation states and position in the . Metals exhibit varying oxidation states depending on their and bonding environment, with metals often displaying multiple stable states that influence their resistance to oxidation or . For instance, heavier metals like and tend to form stable higher oxidation states, such as +8 in tetroxides, enhancing their chemical inertness under oxidative conditions. The ranks metals by their tendency to lose electrons and form positive ions, with highly reactive metals like and at the top, readily undergoing oxidation in air or water, while noble metals like remain stable due to low reactivity. This series predicts displacement reactions and overall stability, where metals higher in the series displace those below them from compounds, reflecting inherent thermodynamic favorability for oxidation. Corrosion in solids, especially metals, proceeds via electrochemical mechanisms involving anodic and cathodic reactions at . In anodic regions, metal atoms oxidize to ions (e.g., → Fe²⁺ + 2e⁻), releasing electrons that drive cathodic reactions such as evolution or oxygen (e.g., O₂ + 4H⁺ + 4e⁻ → 2H₂O) in acidic or environments. Passivation enhances resistance by forming a thin, protective layer, as seen in stainless steels where content above 12% promotes a Cr₂O₃ that inhibits further anodic dissolution. This layer acts as a barrier, reducing the and shifting the corrosion potential to more noble values, thereby minimizing uniform or in chloride-containing media. Surface energy in solids quantifies the excess per unit area due to unbalanced intermolecular forces at the , driving phenomena like adsorption and . Adsorption of gases or solutes on solid surfaces lowers this energy, with the Langmuir isotherm modeling coverage under conditions. The fractional surface coverage θ is given by \theta = \frac{K P}{1 + K P} where K is the adsorption and P is the of the adsorbate; this assumes uniform sites with no lateral interactions, predicting at high pressures. Such adsorption is crucial for surface modification and reactivity, as it influences the energetics of subsequent chemical processes. Solid surfaces facilitate by providing active sites for reactant adsorption and reaction, exemplified by the Haber-Bosch process for synthesis. In this process, N₂ and H₂ adsorb dissociatively on iron-based catalysts promoted with and alumina, forming surface intermediates like adsorbed atoms that recombine with to yield NH₃, enabling high-pressure, high-temperature conversion of atmospheric . The solid catalyst's surface defects and electronic structure lower the activation barrier for N≡N bond cleavage, a rate-limiting step, achieving yields through optimized adsorption . Solubility of solids refers to the maximum concentration of solute in with undissolved solid, governed by and interactions, while dissolution describe the rate of this process. For many solids, solubility increases with if dissolution is endothermic, as higher overcomes binding. often follow a shrinking-core model for spherical particles, where the rate is limited by either surface reaction or through a , expressed as proportional to surface area and undersaturation. Aggregation of particles can reduce effective surface area, slowing and altering in applications like pharmaceuticals.

Formation and Synthesis

Natural Formation Processes

Natural solids form through a variety of geological and biological processes that have shaped and over billions of years. The planet's solid originated approximately 4.5 billion years ago during the accretion of planetesimals in the early solar nebula, where of dust and gas led to the into , , and crust as the proto-Earth cooled from a molten state. This foundational event set the stage for subsequent natural formation mechanisms, primarily driven by thermal, pressure, and chemical dynamics in the and . Igneous processes represent one primary pathway for solid formation, occurring when molten cools and solidifies to produce crystalline rocks. As ascends or resides within the , it undergoes progressive , with high- minerals forming first, followed by lower- ones as the melt drops below 1300°C. For instance, magmas rich in iron and magnesium yield rocks like upon rapid cooling at the surface, incorporating minerals such as and that define their dark, dense composition. Slower cooling in plutonic environments produces coarser-grained equivalents like , allowing larger . Sedimentary formation involves the accumulation, compaction, and of particles or chemical precipitates at or near Earth's surface, often in environments. Chemical occurs when dissolved minerals supersaturate and crystallize from water, as seen in deposits or biogenic sources. A prominent example is , formed primarily from the compaction of (CaCO₃) shells and skeletal remains of marine organisms, which accumulate as and harden over time through diagenetic processes. Clastic sediments, derived from weathered rock fragments, further compact under burial pressure to form sandstones or shales, contributing to vast layered sequences that record environmental histories. Metamorphic transformations alter pre-existing rocks into new solids under elevated temperatures and pressures without melting, typically in tectonic settings like zones or mountain belts. These conditions, exceeding 200°C and 300 , induce recrystallization and reconfiguration, enhancing and altering textures. For example, subjected to such recrystallizes into , where grains grow larger and interlock, often preserving faint fossils but losing original . This process exemplifies how regional or contact recycles crustal materials, forming durable solids like or from diverse protoliths. Biological processes contribute to natural solid formation through , where organisms synthesize minerals to construct structural components like shells and s. In such as mollusks, precipitates within organic matrices to form or shells, providing protection and support via controlled and growth. In vertebrates, mineralization involves the deposition of (Ca₁₀(PO₄)₆(OH)₂) crystals along , creating a composite solid that balances rigidity and toughness. These biogenic solids, often incorporating amorphous precursors that transform into crystalline phases, integrate into sedimentary cycles upon organism death, influencing global carbon and nutrient dynamics. structures in these minerals, such as the rhombohedral of , underpin their mechanical properties.

Artificial Synthesis Methods

Artificial synthesis methods enable the controlled of solids with precise microstructures, compositions, and , distinguishing them from naturally occurring formations by allowing tailoring for specific applications in , , and beyond. These techniques, developed primarily in the , leverage thermodynamic and kinetic principles to assemble atoms, molecules, or particles into ordered solid structures under or conditions. Unlike natural mineralization processes that occur over geological timescales, artificial methods accelerate to hours or days, often mimicking seen in minerals but with enhanced purity and uniformity. The Czochralski process, invented in 1915 by , is a cornerstone for growing single-crystal ingots of semiconductors such as , which forms the basis for integrated circuits. In this method, a is dipped into a molten material contained in a and slowly pulled upward while rotating, allowing the melt to solidify around the seed and form a cylindrical with diameters up to 300 mm and lengths exceeding 2 meters. This technique produces dislocation densities as low as 10^3 cm⁻², critical for high-performance electronics, and accounts for over 90% of global wafer production. Powder metallurgy involves compacting and fine metal powders to create dense alloys and composites, offering advantages in shaping complex geometries and incorporating hard inclusions like carbides. The process begins with or milling to produce powders with particle sizes typically 10-100 μm, followed by cold pressing at pressures of 200-800 to form green compacts, and then at temperatures 70-90% of the (e.g., 1100-1300°C for iron-based alloys) to achieve densities up to 99% of theoretical via diffusion-driven necking and . This method is widely used for tool steels and superalloys, enabling properties like tensile strengths over 1000 in nickel-based components for blades. Chemical vapor deposition (CVD) deposits thin films of solids from gaseous precursors onto substrates, ideal for coatings with atomic-level control. In thermal CVD, reactants like and are heated to 800-1000°C, decomposing to form films with growth rates of 1-10 μm/hour and matching natural (Knoop hardness ~70 GPa). Variants such as plasma-enhanced CVD lower temperatures to 200-400°C for applications, producing films for high-temperature electronics with thermal conductivities up to 490 W/m·K. This technique has revolutionized production since the 1980s, yielding gem-quality crystals indistinguishable from natural ones. The sol-gel process synthesizes ceramics and through and of metal alkoxides in solution, forming s that are dried and calcined into monolithic solids. Starting with precursors like () for silica, the sol phase evolves into a gel network via such as Si(OR)₄ + 2H₂O → SiO₂ + 4ROH, followed by aging, drying at 100-200°C, and at 500-1200°C to densify the structure. This method produces optically transparent with porosities controllable from 0-90% and is pivotal for bioactive in medical implants, achieving bioactivity indices where 90% surface coverage by occurs within 7 days in simulated . Additive manufacturing, or , fabricates solid composites layer-by-layer from digital models, emerging in the 1980s with and expanding to metals and polymers by the 2010s. Techniques like fuse metal powders (e.g., ) with laser powers of 200-500 , achieving resolutions down to 20 μm and mechanical properties rivaling wrought materials, such as yield strengths of 900 in parts. This enables of intricate lattice structures for lightweight aerospace components, reducing material waste by up to 90% compared to subtractive methods.

Applications and Fields of Study

Materials Science and Engineering

Materials science and engineering is an field that leverages the inherent properties of solid materials to design, process, and manufacture advanced substances optimized for specific applications. At its core lies the structure-property-processing-performance () paradigm, which establishes causal relationships among these elements: processing techniques dictate the material's microstructure (structure), which in turn governs its mechanical, , and other properties, ultimately determining its real-world performance under load or environmental . This framework, often visualized as a , enables systematic innovation by allowing engineers to predict and tailor material behavior through controlled variations in composition and fabrication methods. In alloy design, a cornerstone of the field, engineers exploit the relationships to create high-performance metals by adjusting elemental compositions and heat treatments. A landmark achievement occurred in the when British metallurgist developed the first modern by incorporating about 12.8% into molten iron, enhancing corrosion resistance while maintaining strength; this innovation, initially aimed at improving rifle barrel durability, transformed industries from to by preventing oxidation in harsh environments. Subsequent steel variants, such as those with added for austenitic structures, further exemplify how targeted alloying refines properties like and to meet demands. Polymer engineering similarly applies PSPP principles to organic solids, distinguishing between thermoplastics—which soften reversibly upon heating due to linear or branched chain structures, enabling efficient molding and —and thermosets, which form rigid, cross-linked networks during curing for superior heat resistance and dimensional stability but complicate end-of-life processing. Thermoplastics like dominate and automotive parts for their processability, while thermosets such as resins excel in composites; however, thermosets remains challenging, often requiring energy-intensive chemical breakdown to recover monomers and avoid accumulation. These distinctions guide , balancing performance with lifecycle . Failure analysis is a critical practice in materials engineering, employing techniques like and to diagnose root causes of structural breakdowns and prevent recurrence. For instance, the 1967 collapse of the in , which claimed 46 lives, was traced to in a high-stress eyebar chain link of the , exacerbated by and undetected over decades of service; this incident spurred rigorous standards for non-destructive testing and monitoring in civil infrastructure. Such analyses not only reveal vulnerabilities in material-environment interactions but also inform PSPP-based redesigns, enhancing safety in bridges, aircraft, and pipelines. Sustainability drives contemporary materials engineering toward eco-friendly solids that minimize environmental impact throughout their lifecycle, with biodegradable polymers emerging as key solutions to . Derived from renewable sources like or , polymers such as () exhibit tunable mechanical properties comparable to petroleum-based alternatives while fully degrading via microbial action in industrial composting facilities, reducing microplastic persistence in ecosystems. highlights their integration into and biomedical applications, where they achieve up to 90% within months under optimal conditions, fostering a by replacing non-degradable thermosets and thermoplastics.

Solid-State Physics and Chemistry

Solid-state physics applies to the behavior of electrons and atoms within crystalline lattices, providing the foundational understanding of electronic and vibrational properties in solids. In periodic lattices, electrons do not behave as free particles but are influenced by the periodic potential of the atomic array, leading to the formation of energy bands that determine electrical conductivity and other properties. A key principle in this field is the Bloch theorem, which describes the wavefunctions of electrons in such potentials. The Bloch theorem, formulated by in 1928, states that the eigenfunctions of an electron in a periodic potential can be expressed as a modulated by a with the same periodicity as the . Mathematically, this is given by \psi_{\mathbf{k}}(\mathbf{r}) = u_{\mathbf{k}}(\mathbf{r}) e^{i \mathbf{k} \cdot \mathbf{r}}, where u_{\mathbf{k}}(\mathbf{r}) is periodic, \mathbf{k} is the wavevector in the , and \mathbf{r} is the position vector. This form implies that electrons propagate as Bloch waves, enabling the band structure theory that explains insulators, semiconductors, and metals. The theorem's implications extend to nearly free electron models and tight-binding approximations, which approximate the periodic potential to compute band gaps and densities of states. Lattice vibrations in solids are quantized as phonons, which are collective excitations arising from the harmonic oscillations of atoms around their equilibrium positions in the . These vibrations follow dispersion relations that relate phonon frequency \omega to wavevector \mathbf{q}, often linear at long wavelengths (\omega = v_s q, where v_s is the ) and more complex near zone boundaries due to interactions. Phonons contribute significantly to the specific of solids; at high temperatures, the classical Dulong-Petit law predicts a constant value, but quantum effects dominate at low temperatures. Albert Einstein's 1907 model treated vibrations as independent harmonic oscillators, yielding a specific heat C_V = 3Nk_B ( \theta_E / T )^2 e^{-\theta_E / T} / (e^{-\theta_E / T} - 1)^2, where \theta_E is the Einstein temperature, which underestimates low-temperature behavior. Peter Debye's 1912 refinement modeled the lattice as a of acoustic modes up to a , producing C_V \propto T^3 at low T, aligning closely with experiments for many materials. Solid-state chemistry focuses on the synthesis and properties of extended solid structures, emphasizing the design and preparation of new compounds with tailored compositions and phases. Methods such as solid-state reactions, where precursors are heated to promote and reaction, enable the formation of inorganic materials like perovskites or superconductors, often requiring high temperatures to overcome kinetic barriers. This field integrates and to predict stable phases and reaction pathways, facilitating the discovery of novel materials with unique electronic or magnetic properties. Phase diagrams in map the equilibrium phases of systems as functions of , composition, and pressure, guiding the synthesis of compounds or alloys. For systems, common features include eutectic points where ifies into two phases, peritectic reactions forming a new from and , and solutions with varying solubility limits. These diagrams, constructed from experimental data like or , reveal phase boundaries and reactions, such as in the Cu-Ni system exhibiting complete solubility or the Pb-Sn system showing a eutectic at 61.9% Sn. Defects in solids, including vacancies, interstitials, and dislocations, play a crucial role in atomic , which governs processes like and doping. Diffusion occurs via random atomic jumps mediated by these defects, described phenomenologically by Fick's laws; the first law states that the \mathbf{J} is proportional to the concentration gradient, \mathbf{J} = -D \nabla C, where D is the diffusion coefficient and C is concentration. The second law, \partial C / \partial t = D \nabla^2 C, predicts how concentration profiles evolve over time. Formulated by Adolf Fick in , these laws apply to both self-diffusion in pure solids and diffusion, with activation energies reflecting defect formation and migration barriers. A pivotal historical milestone in solid-state physics was the derivation of Bragg's law in 1913 by William Henry Bragg and William Lawrence Bragg, which established X-ray diffraction as a probe for atomic structure. The law relates the wavelength \lambda of X-rays to the spacing d of crystal planes and scattering angle \theta via n \lambda = 2 d \sin \theta, where n is an integer order, enabling the determination of lattice parameters from diffraction patterns. This breakthrough, building on Max von Laue's 1912 experiments, founded X-ray crystallography and confirmed the wave nature of X-rays while revealing atomic arrangements in solids like NaCl.

Emerging Applications in Technology

In , the development of using doped marked a pivotal advancement, enabling the miniaturization and efficiency of modern devices. In 1947, and Walter Brattain at Bell Laboratories demonstrated the first , a that amplified electrical signals, which subsequently refined into the junction transistor for practical use. This innovation laid the foundation for integrated circuits, independently conceived by at in 1958 and at in 1959, allowing multiple to be fabricated on a single chip and revolutionizing and . In the energy sector, solid-state batteries represent a promising evolution of lithium-ion technology, replacing flammable liquid electrolytes with solid ones to enhance safety and . Post-2010 advancements have focused on materials like sulfide-based and oxide-based solid electrolytes, achieving ionic conductivities approaching those of liquids while improving stability and cycle life; for instance, developments in garnet-type Li7La3Zr2O12 electrolytes have enabled prototypes with energy densities exceeding 300 Wh/kg. demonstrated over 1000 charging cycles with more than 95% capacity retention in prototypes by 2023, while shipped first A-sample cells for automotive qualification in late 2023. As of 2025, has begun shipping Cobra-based B1 samples and entered baseline production for its separator process, advancing toward commercialization by 2026. Nanotechnology applications of solids, particularly and other two-dimensional (2D) materials, have opened avenues for due to their exceptional mechanical strength and conductivity. , isolated in 2004 by and , earned the 2010 for revealing its two-dimensional structure and properties, including high and flexibility, making it ideal for bendable circuits and displays. In , graphene-based composites serve as transparent electrodes in organic light-emitting diodes (OLEDs) and touch sensors, with prototypes achieving bending radii under 1 mm without performance degradation; extensions to 2D materials like transition metal dichalcogenides further enable stretchable wearables and foldable screens. In , solid biomaterials facilitate advanced implants and systems, leveraging to integrate with human s. Polymeric biomaterials, such as poly(lactic-co-glycolic acid) (), are used in resorbable implants for orthopedic applications, providing mechanical support while degrading over time to avoid secondary surgeries; these have shown success in regeneration scaffolds with over 90% integration in clinical trials. For drug delivery, nanoparticle-embedded biomaterials enable controlled release, as in implants coated with for localized delivery, which can reduce postoperative infection risk; recent hydrogel-based systems further allow on-demand release via external stimuli like . Quantum computing harnesses solid-state qubits in superconducting materials to perform computations unattainable by classical systems, with rapid progress in and correction. Superconducting qubits, fabricated from materials like and aluminum, operate at cryogenic temperatures to maintain quantum coherence; IBM's 2023 milestones include with 133 qubits achieving rates below 0.1% per and the demonstration of utility-scale algorithms outperforming supercomputers in -mitigated . The 1,121-qubit , also unveiled in 2023, advances toward fault-tolerant systems, enabling applications in materials and optimization problems. As of November 2025, has introduced the with 120 qubits and enhanced connectivity for 30% more computational complexity at low rates, alongside the experimental Loon processor paving the way for fault-tolerant quantum computing by 2029.

References

  1. [1]
    Solid: Your data, your choice - Solid Project
    Read about Solid. Solid is an evolution of the web by its creator Sir Tim Berners-Lee realizing his original vision for the Web. About Solid.Solid Team · Solid Applications · Solid Community Forum · About
  2. [2]
    About Solid Project | Tim Berners-Lee - Inrupt
    Inspired by Tim Berners-Lee, Solid is a technology for organizing data, applications, and identities on the web and is built on existing web standards.
  3. [3]
    Solid Protocol
    ### Summary of the Solid Protocol
  4. [4]
    A Short History of the Solid Protocol - W3C
    On 27 July 2022, Tim met physically with the W3C TAG to discuss Solid, during the day and the dinner after. See a list of talks and articles on the SolidProject ...
  5. [5]
    Tim Berners-Lee's Solid explained: What you need to know
    Apr 7, 2023 · Solid, or social linked data, is a project Berners-Lee designed to decentralize the web and put data ownership back in the hands of its creators.<|control11|><|separator|>
  6. [6]
    Solid Notifications Protocol - Solid Project
    The Solid Notification Protocol is an HTTP-based framework for clients to receive notifications of HTTP resource changes and discover notification services.
  7. [7]
    [PDF] Ch. 12.1: Bonding in solids
    Covalent bond is quite strong—diamond, for example. • Very hard, high bond energies, melting points. • Good insulators, tightly bound electrons in- teract less ...
  8. [8]
    Bonding and Bonding Type - Material Correlations | MATSE 81
    As you've recently read, there are four principal bonding types: ionic, covalent, metallic, and van der Waals. Ionic bonding involves the exchange of electrons ...
  9. [9]
    [PDF] Lecture 5: Bonding Models
    Van der Waals bonds are the bonds between layers of carbon atoms in graphite. Hydrogen Bonds. A hydrogen bond is a special type of dipole-dipole bond between a ...
  10. [10]
    11.7 Lattice Structures in Crystalline Solids – Chemistry Fundamentals
    Atoms in BCC arrangements are much more efficiently packed than in a simple cubic structure, occupying about 68% of the total volume. Isomorphous metals with a ...
  11. [11]
    The Arrangement of Atoms in Crystalline Solids
    The hcp and ccp structures differ only in the way their layers are stacked. Both structures have an overall packing efficiency of 74%, and in both each atom ...
  12. [12]
    19. Point & Line Defects | Introduction to Solid State Chemistry
    This page contains materials for the session on point and line defects in crystals. It features a 1-hour lecture video, and also presents the prerequisites, ...
  13. [13]
    Properties of solids
    Amorphous solids do not have much order in their structures. Though their molecules are close together and have little freedom to move, they are not arranged ...
  14. [14]
    11.6 The Solid State of Matter – Chemistry Fundamentals
    Solids can be crystalline (ordered) or amorphous (randomly arranged). Crystalline solids include ionic, metallic, covalent network, and molecular types.
  15. [15]
    Phases of Matter - NASA Glenn Research Center
    In the solid phase the molecules are closely bound to one another by molecular forces. A solid holds its shape and the volume of a solid is fixed by the shape ...
  16. [16]
    3.3: Classifying Matter According to Its State—Solid, Liquid, and Gas
    Jul 28, 2025 · Three states of matter exist—solid, liquid, and gas. Solids have a definite shape and volume. Liquids have a definite volume, ...
  17. [17]
    Molecular Motion: Types, Examples & Concepts Explained - Vedantu
    Rating 4.2 (373,000) Thus, solids show the least molecular randomness. On the other hand, liquids exhibit vibrational motion along with the rotational and translational motion.
  18. [18]
  19. [19]
    23.4: The Clausius-Clapeyron Equation - Chemistry LibreTexts
    Mar 4, 2025 · Evaporation. In Section 23.3, the Clapeyron Equation was derived for melting points. d ⁢ P d ⁢ T = Δ ⁢ H m ⁢ o ⁢ l ⁢ a ⁢ r T ⁢ Δ ⁢ V m ⁢ o ...Evaporation · The Clapeyron Equation · Example 23.4.1 · Learning Objectives
  20. [20]
    12.4: Phase Diagrams - Chemistry LibreTexts
    Jul 12, 2023 · The triple point also represents the lowest pressure at which a liquid phase can exist in equilibrium with the solid or vapor. At pressures less ...
  21. [21]
    Water vs. Steam - Critical and Triple Points - The Engineering ToolBox
    Critical point is where vapor and liquid are indistinguishable and triple point is where ice, water and vapor coexist in thermodynamic equilibrium.
  22. [22]
    Phase diagram of water and ice - Statistical Physics Group
    Where three lines join, there is a 'triple point' when three phases coexist but may abruptly and totally change into each other given a change in temperature or ...
  23. [23]
    A metastable liquid melted from a crystalline solid under ... - Nature
    Jan 23, 2017 · A metastable liquid may exist under supercooling, sustaining the liquid below the melting point such as supercooled water and silicon.
  24. [24]
    Supercooled and glassy water: Metastable liquid(s), amorphous ...
    Nov 13, 2017 · We review the recent research on supercooled and glassy water, focusing on the possible origins of its complex behavior.
  25. [25]
    Science is cool... supercool – scienceinschool.org
    Dec 7, 2010 · We say that the liquid is supercooled. This state of matter is said to be metastable (Figure 3). How can we explain supercooling? The first ...
  26. [26]
    [PDF] The Crystalline Solid State
    Oct 19, 2015 · Crystalline solids have atoms/ions/molecules arranged in regular, repeating patterns. They possess long-range periodicity.
  27. [27]
    CES Information Guide - Materials Science Engineering
    A crystalline material consists of primarily organized crystal structure. A crystal is a solid composed of atoms, ions, or molecules arranged in a pattern that ...
  28. [28]
    [PDF] Crystal Math - Physics Courses
    In three dimensions, there are seven lattice systems: triclinic, monoclinic, orthorhombic, tetragonal, trig- onal, hexagonal, and cubic5. Of these ...
  29. [29]
    Scientific Principles
    Metals are composed of atoms. The strength of metals suggests that these atoms are held together by strong bonds. These bonds must also allow atoms to move.
  30. [30]
    Body-Centered Cubic Structure (BCC) | MATSE 81
    Some examples of metals that possess this crystalline structure include the α phase of iron, chromium, tungsten, tantalum, and molybdenum.
  31. [31]
    Structures of Metals
    The BCC unit cell consists of a net total of two atoms, the one in the center and eight eighths from the corners. In the FCC arrangement, again there are eight ...
  32. [32]
    [PDF] Elasticity of single‑crystal quartz to 10 GPa
    Sep 26, 2014 · α-Quartz is the stable polymorph of SiO2 at ambient conditions and has trigonal symmetry (space group P3121 or P3221). The structure of quartz ...
  33. [33]
    Diamond - The Chemistry of Art
    Diamond is a naturally-occurring form of carbon in which every carbon atom is bound to four other carbon atoms in a tetrahedral array with covalent single ...
  34. [34]
    [PDF] Silicon Crystal Structure
    Feb 26, 2022 · • Lowest energy state is the Diamond Lattice. • 4 electrons are ... – semiconductor band gap energy in eV k – Boltzmann's constant ...
  35. [35]
    [PDF] Lecture Outline Crystallography
    -Metallic bonding is not directional. -Nearest neighbor distances tend to be small in order to lower bond energy. • have the simplest crystal structures. We ...
  36. [36]
    Categories of Solids
    Amorphous solids (literally, "solids without form") have a random structure, with little if any long-range order. Polycrystalline solids are an aggregate of a ...
  37. [37]
    Amorphous materials - UCSB Physics
    Amorphous solids are comprised of particles (atoms, grains, bubbles, molecules) arranged so that the locations of their centers of mass are disordered.
  38. [38]
    Amorphous - CES Information Guide - Materials Science Engineering
    An amorphous structure has no organization (not a crystalline structure), and the atomic structure resembles that of a liquid. Commonly, amorphous materials ...
  39. [39]
    Crystalline and Amorphous Solids
    Crystalline solids have regular structures, sharp melting points, and well-defined edges. Amorphous solids have irregular surfaces, no regular patterns, and ...
  40. [40]
    [PDF] IMI-NFG Course on Processing in Glass Lecture 1
    batch is about 1170 to 1190 kg per 1000 kg molten glass. • For soda-lime-silica float glass, about 1200 -1220 kg dry normal batch is needed to melt 1000 kg ...
  41. [41]
    Polymeric Solid State: Amorphous and Crystalline - EdTech Books
    Some of the most common amorphous polymers are polystyrene, acrylic, polycarbonate, and most copolymers. Approximately half of the most common commercial ...
  42. [42]
    Machine-Learning-Based Prediction of the Glass Transition ...
    Mar 22, 2023 · Kinetically, the glass transition temperature Tg is defined as the temperature ... viscosity of a substance reaches a value of about 1012 Pa s.
  43. [43]
    [PDF] A Simple Theory of Viscosity in Liquids - OSTI
    Viscosity, η, of a liquid near the melting point is of the order of 10-3 Pa.s, whereas the glass transition is defined by η reaching 1012 Pa.s [1]. The ...
  44. [44]
    [PDF] Relaxation in glassforming liquids and amorphous solids
    Sep 15, 2000 · The field of viscous liquid and glassy solid dynamics is reviewed by a process of posing the key questions that need to be answered, ...
  45. [45]
    [PDF] Physical Aging of Amorphous Pen: Isothermal, Isochronal and ...
    When the aging experiments are performed at 90 °C, the R relaxation process dominates the relaxation response in the experimental time range (Figure 14). For ...
  46. [46]
    Physical Ageing of Amorphous Indapamide Characterised by ... - NIH
    Aug 25, 2020 · The calculated enthalpy relaxation as a function of the ageing time for amorphous IND aged at 65, 75 and 85 °C are shown in Figure 7. Data were ...
  47. [47]
    [PDF] Structures and Materials: Composites, Grades K-12 - NASA
    A composite is an engineered material made from two or more ingredients with significantly differing properties, either physical or chemical.
  48. [48]
    [PDF] Composite Materials, Manufacturing, and Mechanics: A Short Course
    A composite is a multiphase material that is artificially made, as opposed to one that occurs or forms naturally. In addition, the constituent phases must ...
  49. [49]
    EP 342: Materials Science: Composites
    Sep 4, 2025 · Carbon-fiber-reinforced composites consist of two parts: a matrix and a reinforcement. In CFRP the reinforcement is carbon fiber, which provides the strength.
  50. [50]
    Biologically Inspired Collagen/Apatite Composite Biomaterials for ...
    A combination of collagen and hydroxyapatite is used, which provides good mechanical properties with high biocompatibility and osteoinduction.
  51. [51]
    A review of the interfacial characteristics of polymer nanocomposites ...
    The advantages of carbon nanotube–polymer composites include improved stiffness, strength, and fracture toughness. Unfortunately, the expected improvement in ...
  52. [52]
    Synthesis and characterization of quantum dot–polymer composites
    The emission properties of these QDs can be easily tuned through their particle size, shape and chemical composition. QDs with different particle sizes can be ...
  53. [53]
    Derivation of the rule of mixtures and inverse rule of ... - DoITPoMS
    Derivation of the rule of mixtures and inverse rule of mixtures ; ε · = εf = εm (i) ; σ E · (ii) ; σ · = f σf + (1 - f) σm (iv) ; E · εax = f Ef εf + (1 - f) Em εm (v).
  54. [54]
    Rule-of-Mixture Equation - an overview | ScienceDirect Topics
    The rule of mixtures equation refers to a set of equations used to predict the properties, such as modulus and strength, of fiber-reinforced composites ...
  55. [55]
    Mechanical Properties of Materials | MechaniCalc
    The engineering stress-strain curve drops after the ultimate strength is reached because the force that can be supported by the material drops as it begins to ...
  56. [56]
    Stress and Strain - BYJU'S
    Hooke's Law states that the strain of the material is proportional to the applied stress within the elastic limit of that material.
  57. [57]
    Stress-Strain Curve | How to Read the Graph? - Fractory
    Jun 3, 2020 · Ultimate tensile strength shows the maximum amount of stress a material can handle. Reaching this value pushes the material towards failure and ...
  58. [58]
    Properties of Metals | Engineering Library
    It is the numerical evaluation of Hooke's Law, namely the ratio of stress to strain (the measure of resistance to elastic deformation). To calculate Young's ...<|separator|>
  59. [59]
    Metal Hardness Testing: Methods & Scales
    Jul 27, 2022 · The Brinell hardness scale is a widely accepted measure of hardness in materials. It involves pressing a ball of steel (or tungsten carbide for ...
  60. [60]
    Hardness - Nondestructive Evaluation Physics : Materials
    The Vickers and Knoop Hardness Tests are a modification of the Brinell test and are used to measure the hardness of thin film coatings or the surface hardness ...
  61. [61]
    Hardness Comparison Chart of Metals, Alloys, and Ceramics
    Aug 28, 2025 · This article provides a clear guide on the hardness scales used to measure metals, alloys, and ceramics. It covers the Mohs hardness scale, ...
  62. [62]
    Griffith Theory - an overview | ScienceDirect Topics
    2 Theoretical fracture initiation: background. 2.1 Griffith tensile theory. Griffith (1921) proposed that tensile failure in brittle materials such as glass ...
  63. [63]
    [PDF] 1 CHAPTER 11 FRACTURE OF MATERIALS 11.1 Brittle vs. Ductile ...
    using theses materials must employ fracture mechanics methods of analysis to insure against failure by brittle fracture. Using the Griffith formulation, we ...
  64. [64]
    Viscoelastic Properties of Polymers and Plastics
    Oct 21, 2019 · Materials that exhibit both viscous and elastic characteristics when deformed under stress are known to be viscoelastic. And this would include any polymeric ...
  65. [65]
    [PDF] ENGINEERING VISCOELASTICITY - MIT
    Oct 24, 2001 · Viscoelastic response is often used as a probe in polymer science, since it is sensitive to the material's chemistry and microstructure. The ...
  66. [66]
    Viscoelasticity and Composite Materials - A356
    Apr 4, 2024 · Polymer matrix composites exhibit viscoelastic behaviour that may affect the long-term performance of the composite structure.
  67. [67]
    Creep-Fatigue - an overview | ScienceDirect Topics
    Fatigue is characterized by the failure of a material subjected to cyclic loading (in stress or strain control) which occurs after a given number of load cycles ...
  68. [68]
    Creep Failure vs. Fatigue in Metals: Differences and Testing Methods
    Both creep failure and fatigue occur due to applied loads, or pressure, and can result in the failure of the material.
  69. [69]
    Low-dimensional heat conduction in surface phonon polariton ... - NIH
    Dec 12, 2023 · Heat conduction in solids is typically governed by the Fourier's law describing a diffusion process due to the short wavelength and mean ...
  70. [70]
    [PDF] Introduction to Thermal Transport
    Electronic Conductivity and Wiedemann-Franz Law k/σT= L. 0 k – thermal ... Thermal Conductivity. •Use of Simulation to Develop Understanding of. Phonon-mediated ...
  71. [71]
    Molecular dynamics simulations of thermal transport in metals
    Jul 26, 2025 · We found that inclusion of an electronic transport pathway reduces the phonon-only thermal conductivity because of electron–phonon scattering.
  72. [72]
    Debye Theory of Specific Heat - HyperPhysics
    The Einstein-Debye phonon model produced agreement with the low-temperature cubic dependence of specific heat upon temperature.<|control11|><|separator|>
  73. [73]
    Law of Dulong and Petit - HyperPhysics
    Law of Dulong and Petit. The specific heat of copper is 0.093 cal/gm K (.389 J/gm K) and that of lead is only 0.031 cal/gm K(.13 J/gm K). Why are they so ...Missing: model | Show results with:model
  74. [74]
    Heat capacity estimation of complex materials for energy technologies
    Dulong and Petit made the empirical observation (ca. 1819) that solids have a heat capacity of ∼ 3 k B per atom near ...
  75. [75]
    [PDF] Thermal Expansion - Rice University
    THE COEFFICIENT OF LINEAR thermal expansion (CTE, α, or α1) is a material property that is indicative of the extent to which a mate- rial expands upon heating. ...Missing: volumetric | Show results with:volumetric
  76. [76]
    [PDF] High pressure thermal expansion - SE
    Feb 11, 2014 · 2.1 Thermal expansion coefficient based on a linear elastic Hookian solid ... and the volumetric, thermal expansion coefficient, β β ≡. 1 ν. ∂ν.
  77. [77]
    [PDF] Idaho National Laboratory
    Mean linear thermal expansion coefficient for polycrystalline β-Zr (α in units of ... The thermal expansion of single crystals of α-Np is anisotropic.
  78. [78]
    14.3 Phase Change and Latent Heat – College Physics chapters 1-17
    In the case of direct solid-vapor transitions, the energy required is given by the equation Q = m L s , where L s is the heat of sublimation, which is the ...
  79. [79]
    Phase Changes - Chembook
    The value (under standard conditions) of the heat of sublimation of a substance is equal to the sum of the heats of fusion and vaporization (ΔHsub = ΔHfus + ΔH ...Missing: latent | Show results with:latent
  80. [80]
    Superconductivity - HyperPhysics
    Several materials exhibit superconducting phase transitions at low temperatures. The highest critical temperature was about 23 K until the discovery in 1986 ...
  81. [81]
    DOE Explains...Superconductivity - Department of Energy
    Superconductivity is the property of certain materials to conduct direct current (DC) electricity without energy loss when they are cooled below a critical ...
  82. [82]
    6.8B: Band Theory of Metals and Insulators - Chemistry LibreTexts
    Feb 3, 2021 · Semiconductors have a small energy gap between the valence band and the conduction band. Electrons can make the jump up to the conduction band, ...Missing: density authoritative sources
  83. [83]
    Band Theory for Solids - HyperPhysics
    A useful way to visualize the difference between conductors, insulators and semiconductors is to plot the available energies for electrons in the materials.Missing: density authoritative sources
  84. [84]
    Drude model - Open Solid State Notes
    From solving this equation in the steady state, we found the Drude conductivity σ = n e 2 τ m \sigma = \frac{ne^2\tau}{m} σ=mne2τ. Discuss if its scaling with ...
  85. [85]
    Metals: the Drude model of electrical conduction - DoITPoMS
    The Drude model is a simplistic model for conduction. It uses classical mechanics, and treats the solid as a fixed array of ions, with electrons not bound.Missing: ne | Show results with:ne
  86. [86]
    Semiconductors and Doping – University Physics Volume 3
    Semiconductor p-type doping creates new energy levels just above the valence band. The Hall effect can be used to determine charge, drift velocity, and charge ...
  87. [87]
    The Feynman Lectures on Physics Vol. III Ch. 14: Semiconductors
    Some of the electrons of the n-type material will, therefore, tend to diffuse over into the p-type material where there are fewer electrons. This cannot go on ...
  88. [88]
    14.2: Magnetic Properties of Materials - Chemistry LibreTexts
    Oct 9, 2020 · There are many different magnetic forms: including paramagnetism, and diamagnetism, ferromagnetism, and anti-ferromagnetism. Only the first two ...Missing: authoritative | Show results with:authoritative
  89. [89]
    Magnetic Properties of Solids - HyperPhysics
    Magnetic Susceptibilities of Paramagnetic and Diamagnetic Materials at 20°C ; Iron oxide (FeO). 720 ; Iron amonium alum. 66 ; Uranium. 40 ; Platinum. 26 ; Tungsten ...
  90. [90]
    2. Classes of Magnetic Materials | College of Science and Engineering
    Oct 14, 2025 · This occurs at a particular temperature called the Curie temperature (TC). Below the Curie temperature, the ferromagnet is ordered and above it, ...Missing: solids authoritative
  91. [91]
    Piezoelectricity - Engineering LibreTexts
    Jul 5, 2021 · Piezoelectricity is the effect of mechanical strain and electric fields on a material; mechanical strain on piezoelectric materials will produce a polarity in ...
  92. [92]
    [PDF] 1 Fundamentals of Piezoelectricity - Wiley-VCH
    The g-constants are calculated from the piezoelectric charge (strain) constant (d) and relative permittivity (𝜀) from the equation: g = d. 𝜀. (Vm∕N). (1.9).
  93. [93]
    [PDF] TIE-29: Refractive Index and Dispersion
    Refractive index (n) is the ratio of light speed in vacuum to a medium, measured relative to air. Dispersion is the change of refractive index with wavelength.Missing: solids | Show results with:solids
  94. [94]
    [PDF] Basic Geometrical Optics
    2. Snell's law. Snell's law of refraction relates the sines of the angles of incidence and refraction at an interface between two optical media to the indexes ...
  95. [95]
    [PDF] Two Photon Absorption in Chromophore Doped Solid Matrices
    Two-photon absorption (TPA) offers the advantage of very high transmission at ... The Beer-Lambert law can be derived from an approximation for the absorption.
  96. [96]
    Absorption Spectra for Disordered Aggregates of Chromophores ...
    Optimizing the optical properties of large chromophore aggregates and molecular solids for applications in photovoltaics and nonlinear optics is an ...
  97. [97]
    Principles of Birefringence | Nikon's MicroscopyU
    Uniaxial crystals have a single optical axis and comprise the largest family of common birefringent specimens, including calcite, quartz, and ordered synthetic ...
  98. [98]
    Interplay of Fluorescence and Phosphorescence in Organic ...
    Jun 21, 2017 · Biluminescent organic emitters show simultaneous fluorescence and phosphorescence at room temperature.
  99. [99]
    [PDF] Molecular fluorescence, phosphorescence, and chemiluminescence ...
    Jun 15, 2006 · SOLID SURFACE LUMINESCENCE. Hurtubise et al. published a recent review of solid-phase, room-temperature phosphorescence as applied to both ...
  100. [100]
    [PDF] Optical characterization of compound semiconductors using ...
    Photoconductivity spectroscopy was used to characterize various epitaxially grown GaN samples via studying defects and imperfections present in the material.
  101. [101]
    Physics of Light and Color - Introduction to Light Emitting Diodes
    Nov 13, 2015 · The choice of materials for LED fabrication relies upon an understanding of semiconductor band structure and the means by which the energy ...
  102. [102]
    [PDF] SOLID STATE PHYSICS PART II Optical Properties of Solids - MIT
    6.2 Optical Properties and Band Structure . ... density can be achieved in indirect band gap semiconductors such as silicon and germanium.
  103. [103]
    23.1 General Trends among the Transition Metals
    Because the heavier transition metals tend to be stable in higher oxidation states, we expect Ru and Os to form the most stable tetroxides.
  104. [104]
    [PDF] Developing the Activity Series | Crisp
    Metals prefer to be oxidized. Metals obtain a stable number of electrons in their outermost shell (achieve the octet) when they are oxidized. Metals have an ...
  105. [105]
    Anodic Passivation Studies⋆ | CORROSION
    A brief review of the present theories of passivity indicates that corrosion can be completely stopped by formation of a very thin oxygen containing film.
  106. [106]
    [PDF] ON THE PASSIVATION AND CORROSION RESISTANCE OF ... - DTIC
    Causes for the resistance to corrosion of stainless steels. Mechanisms of electrochemical passivation. Passivation diagram. Effect of material structure.
  107. [107]
    An effective scheme to determine surface energy and its relation ...
    Jun 15, 2021 · Surface energy is fundamental in controlling surface properties and surface-driven processes like heterogeneous catalysis, as adsorption ...
  108. [108]
    THE ADSORPTION OF GASES ON PLANE SURFACES OF GLASS ...
    ACS Applied Energy Materials 2025, 8 (13) , 9530-9537. https ... Replacing the Langmuir Isotherm with the Statistical Thermodynamic Fluctuation Theory.
  109. [109]
    5.2: The Haber-Bosch Process - Chemistry LibreTexts
    Jun 10, 2021 · The Haber-Bosch Process is an example of heterogeneous catalysis. ... In this case, the two phases are the gas phase and the solid phase.
  110. [110]
    Biochemistry, Dissolution and Solubility - StatPearls - NCBI Bookshelf
    As temperature increases, the solubility of a solid or liquid can fluctuate depending on whether the dissolution reaction is exothermic or endothermic.
  111. [111]
    Dissolution Kinetics of Solid Particles and the Role of Aggregation
    Mar 25, 2025 · The dissolution rate of a single particle is determined by an interplay of interfacial kinetics and mass transport giving two limiting cases of ...
  112. [112]
    [PDF] Precambrian Time— The Story of the Early Earth
    Crustal rocks probably formed soon after the molten Earth solidified more than 4.4 billion years ago, but the only evidence for their existence comes from the ...
  113. [113]
    How the Earth and moon formed, explained - UChicago News
    The Earth formed over 4.6 billion years ago out of a mixture of dust and gas around the young sun. It grew larger thanks to countless collisions.
  114. [114]
    Magmas and Igneous Rocks - Tulane University
    Sep 3, 2015 · Igneous Rocks are formed by crystallization from a liquid, or magma. They include two types. Magma is a mixture of liquid rock, crystals, and gas.
  115. [115]
    7. 4.2 Crystallization of Magma - Maricopa Open Digital Press
    As a magma cools below 1300°C, minerals start to crystallize within it. If that magma is then involved in a volcanic eruption, the rest of the liquid will cool ...
  116. [116]
    Igneous Rocks - Geology (U.S. National Park Service)
    Nov 8, 2023 · Igneous rocks are “fire-born,” meaning that they are formed from the cooling and solidification of molten (melted) rock.
  117. [117]
    Volcanism & igneous rocks - Geological Sciences 101
    Mafic minerals combine to form mafic igneous rocks; basalt if quickly cooled, gabbro if slowly cooled. Intermediate minerals combine to form the intermediate ...
  118. [118]
    Sedimentary Rocks
    They precipitate calcite (calcium carbonate, CaCO3) or other similar carbonate minerals directly from the dissolved chemicals in the water to create their ...
  119. [119]
    Sedimentary Rocks Lesson #13 - Volcano World
    Limestone is produced from the mineral calcite (calcium carbonate) and sediment. The main source of limestone is the limy ooze formed in the ocean. The ...
  120. [120]
    Chapter 10 - Sedimentary Rocks - GotBooks.MiraCosta.edu
    Limestone is a sedimentary rock consisting predominantly of calcium carbonate (CaCO3) derived from the skeletal remains of marine microorganisms, including ...Missing: CaCO3 | Show results with:CaCO3
  121. [121]
    [PDF] Sediments and Sedimentary Rocks!
    Sedimentary Rock: forms at or near the surface of the Earth by precipitation of minerals from water, by growth of skeletal material in organisms, or by the.
  122. [122]
    Metamorphic Rocks - Tulane University
    Sep 25, 2017 · Metamorphism therefore occurs at temperatures and pressures higher than 200oC and 300 MPa. Rocks can be subjected to these higher temperatures ...
  123. [123]
    What are metamorphic rocks? | U.S. Geological Survey - USGS.gov
    Metamorphic rocks form when rocks are subjected to high heat, high pressure, hot mineral-rich fluids or, more commonly, some combination of these factors.
  124. [124]
    Geology - Glacier National Park (U.S. National Park Service)
    Sep 17, 2024 · Usually, over time and with heat and pressure, sedimentary rock becomes metamorphic rock. For example, limestone becomes marble. It is quite ...
  125. [125]
    Metamorphic Rocks Lesson #14 | Volcano World
    Metamorphic rocks form from heat and pressure changing the original or parent rock into a completely new rock. The parent rock can be either sedimentary, ...
  126. [126]
    Biomineralization-Driven Advances in Materials Science and ...
    Aug 18, 2025 · Biomineralization is an extremely unique process in which living organisms can precisely control the formation of highly ordered mineral ...
  127. [127]
    [PDF] Biomineralization: Bones and Teeth
    In the solid gel form, the structure is fibrous, like that of collagen. Mineralization on these scaffolds leads to formation of hydroxyapatite plates similar to ...
  128. [128]
    Making biominerals: nature's recipe is old, evolved more than once
    Aug 19, 2019 · The recipe for making shells, spines, and coral skeletons is not only the same across many modern animal lineages, but is ancient – dating back 550 million ...
  129. [129]
    The materials tetrahedron has a “digital twin” - PMC - NIH
    Feb 1, 2022 · These four elements—processing, structure, properties, and performance—have also been arranged linearly as a three-link chain to highlight the ...
  130. [130]
    The History of Stainless Steel – Celebrating 100 Years - AZoM
    He had added chromium to molten iron to produce a metal that did not rust. Chromium is a key ingredient, as it provides the resistance to corrosion. After this ...
  131. [131]
    Thermoplastics vs Thermosetting Polymers? - AZoM
    May 31, 2023 · Thermoplastic fabrication techniques are more adaptable for generating complicated shapes, whereas thermosetting polymer manufacturing ...
  132. [132]
    Famous Failures: Stress Corrosion and the Silver Bridge Failure
    Mar 24, 2021 · Stress corrosion cracking is a progressive cracking mechanism that can often lead to catastrophic failure. There have been several notable ...
  133. [133]
    Recent advances in biodegradable polymers for sustainable ...
    Aug 19, 2022 · Biodegradable polymers are being developed to be used as an alternative for non-biodegradable polymer materials in a variety of applications.Missing: authoritative | Show results with:authoritative
  134. [134]
    [PDF] About the Quantum Mechanics of the Electrons in Crystal Lattices
    Nov 29, 2018 · Felix Bloch. 1929. Abstract: This article aims to review Felix Bloch theorem of electron motion in a crystal lattice through his seminal paper ...
  135. [135]
    Electrical conduction in metals - AIP Publishing
    The modern theory was created fifty years ago by Felix Bloch; it still provides the basis for understanding conduction, but many challenges remain. Philip B.<|separator|>
  136. [136]
    Introduction to the theory of lattice dynamics
    At the same time Debye introduced a model for the specific heat of a material that extended Einstein's approach by formulating the lattice dynamics in terms of.
  137. [137]
    [PDF] General Discussion of Phase Diagrams
    If in the diagram of a ternary system, all of the Alke- made lines (see (2)) be constructed, the ternary dia- gram will be divided into a number of composition.
  138. [138]
    [PDF] Lecture 19: 11.23.05 Binary phase diagrams
    These binary systems, with unlimited liquid state miscibility and low or negligible solid state miscibility, are referred to as eutectic systems. X. B. ➞. T. L.
  139. [139]
    [PDF] solid-state sciences
    The atomic mechanisms of diffusion in crystalline solids are closely connected with defects. ... Fick (1829–1901). He was born in Kassel, Germany, as the youngest ...
  140. [140]
    The reflection of X-rays by crystals - Journals
    Cite this article. Bragg William Henry and; Bragg William Lawrence. 1913The reflection of X-rays by crystalsProc. R. Soc. Lond. A88428–438http://doi.org ...
  141. [141]
    William B. Shockley – Facts - NobelPrize.org
    In 1947 John Bardeen and Walter Brattain produced a semiconductor amplifier, which was further developed by William Shockley. The component was named a ...
  142. [142]
    Jack Kilby - Magnet Academy - National MagLab
    An American engineer, Jack Kilby, invented the integrated circuit in 1958, shortly after he began working at Texas Instruments.
  143. [143]
    1959: Practical Monolithic Integrated Circuit Concept Patented
    Noyce filed his "Semiconductor device-and-lead structure" patent in July 1959 and a team of Fairchild engineers produced the first working monolithic ICs in May ...
  144. [144]
    Technological Advances and Market Developments of Solid-State ...
    Jan 1, 2024 · This paper reviews current state-of-the-art SSB electrolyte and electrode materials, as well as global SSB market trends and key industry players.Missing: advancements | Show results with:advancements
  145. [145]
    Solid-State lithium-ion battery electrolytes: Revolutionizing energy ...
    This review explores a variety of solid electrolytes, including oxide, sulfide, perovskite, anti-perovskite, NASICON, and LISICON-based materials.
  146. [146]
    [PDF] GRAPHENE - Nobel Prize
    Oct 5, 2010 · The thermal and electrical conductivity is very high and it can be used as a flexible conductor. The Nobel Prize in Physics 2010 honours two ...
  147. [147]
    Fabrication of High-resolution Graphene-based Flexible Electronics ...
    Jul 22, 2019 · Graphene-based flexible electronics can also be fabricated through various printing techniques such as inkjet printing, gravure printing, screen ...
  148. [148]
    Graphene-based flexible electronic devices - ScienceDirect.com
    Therefore, graphene has been widely used in flexible electronic devices including light-emitting diodes (LEDs), solar cells (SCs), and field-effect transistors ...
  149. [149]
    Biomaterials for Drug Delivery and Human Applications - MDPI
    This work serves as a comprehensive overview of biomaterials, with a particular emphasis on their pivotal role in drug delivery.Biomaterials For Drug... · 2. Biomaterials · 2.2. Tissue Engineering<|control11|><|separator|>
  150. [150]
    Biomaterials for Drug Delivery and Human Applications - PMC
    Jan 18, 2024 · This work serves as a comprehensive overview of biomaterials, with a particular emphasis on their pivotal role in drug delivery.
  151. [151]
    Polymeric biomaterials: Advanced drug delivery systems in ...
    Polymeric implants offer several advantages in OA treatment [67]. These implants offer localized and targeted drug delivery, thereby minimizing the systemic ...
  152. [152]
    IBM Quantum Computer Demonstrates Next Step Towards Moving ...
    Jun 14, 2023 · The IBM team demonstrates that it is possible for a quantum computer to outperform leading classical simulations by learning and mitigating errors in the ...
  153. [153]
    The hardware and software for the era of quantum utility is here - IBM
    Dec 4, 2023 · At the 2023 IBM Quantum Summit, IBM debuted IBM Quantum Heron, IBM Quantum System Two, and extended its roadmap.
  154. [154]
    IBM quantum computers: evolution, performance, and future directions
    Apr 1, 2025 · In 2023, IBM has introduced its latest quantum computing milestone with the unveiling of Condor, a quantum processor featuring 1121 ...