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Barium ferrite

Barium ferrite, chemically designated as BaFe₁₂O₁₉, is an M-type hexaferrite and ferrimagnetic ceramic material characterized by a hexagonal magnetoplumbite crystal structure with space group P6₃/mmc.^[1] This structure consists of alternating spinel (S) and hexagonal (R) blocks, where Fe³⁺ ions occupy five distinct interstitial sites, contributing to its ferrimagnetic ordering. Known for its hard magnetic behavior, barium ferrite exhibits high uniaxial magnetocrystalline anisotropy (K₁ ≈ 3.3 × 10⁵ J/m³),^[2] saturation magnetization ranging from 48 to 71 emu/g depending on synthesis and temperature, coercivity up to 2.4 × 10⁵ A/m, and a Curie temperature around 720 K, rendering it chemically stable and resistant to demagnetization.^[1]^[3] First synthesized in the early 1950s through solid-state reactions of barium carbonate and iron oxide, barium ferrite has evolved from traditional high-temperature sintering (900–1300°C) to advanced methods like microemulsion, sol-gel, and cold sintering at 300°C for denser microstructures.^[3] These techniques allow control over particle size (from nanoparticles ~30 nm to micrometer grains) and morphology, influencing its monodomain nature and tunable properties via doping (e.g., Pb substitution for enhanced coercivity).^[1] Its uniaxial magnetic anisotropy and low raw material costs make it economically viable for large-scale production.^[3] Barium ferrite's defining applications stem from its electromagnetic characteristics, including use in permanent magnets for motors, speakers, and magnetic stripes due to high remanence and coercivity.^[3] In high-density magnetic recording media, it enables perpendicular orientation for increased storage density, while in microwave devices, it serves as an absorber for GHz-range electromagnetic interference shielding and radar attenuation, with reflection losses exceeding 40 dB in composites.^[1] Ongoing research explores its integration in nanocomposites and 4D printing for innovative sensors and energy-efficient technologies.^[1]

Composition and Structure

Chemical Formula

Barium ferrite, commonly referred to as barium hexaferrite, has the chemical formula \ce{BaFe12O19}.^[4] This formula represents the stoichiometric composition of the compound, which can also be written in oxide notation as \ce{BaO \cdot 6Fe2O3}.^[5] The notation BaM is often used to denote this M-type barium hexaferrite, distinguishing it from other ferrite variants such as spinel or garnet structures. The compound consists of barium (Ba), iron (Fe), and oxygen (O) as its constituent elements. Barium adopts the +2 oxidation state, while each of the twelve iron atoms is in the +3 oxidation state, and the nineteen oxygen atoms are in the -2 state, ensuring overall charge balance in the formula unit.^[6] This arrangement reflects the ferrimagnetic nature inherent to hexaferrites, though the focus here is on the elemental makeup. The molar mass of \ce{BaFe12O19} is calculated as 1111.46 g/mol, based on the atomic weights of its elements: barium (137.33 g/mol), iron (55.845 g/mol × 12), and oxygen (16.00 g/mol × 19).^[7] This value underscores the heavy metal composition dominated by iron, which constitutes the majority of the mass.

Crystal Structure

Barium ferrite, with the chemical formula BaFe_{12}O_{19}, crystallizes in a magnetoplumbite-type hexagonal structure belonging to the space group P6_3/mmc (No. 194).^[8] The unit cell is characterized by lattice parameters a \approx 5.89 Å and c \approx 23.2 Å, accommodating two formula units (Z=2).^[9] This structure consists of a close-packed arrangement of oxygen ions forming layers that stack in a specific sequence, defining the M-type hexaferrite architecture.^[10] The layered configuration is described by the repeating sequence RSRS, where S denotes spinel blocks (Fe_6O_8) composed of two oxygen layers with iron ions in interstitial sites, and R represents hexagonal blocks (BaFe_6O_{11}) featuring three oxygen layers with a barium ion substituting for an oxygen in the central layer.^[11] Within these blocks, the 12 Fe^{3+} ions per formula unit occupy five distinct crystallographic sites: three octahedral sites (12k, 4f_{2}, and 2a), one tetrahedral site (4f_{1}), and one trigonal bipyramidal site (2b).^[12] The octahedral sites dominate, hosting the majority of the iron ions and contributing to the structural stability through their coordination with oxygen anions.^[13] The ferrimagnetic nature arises from the antiparallel alignment of magnetic moments in the sublattices: spins at the 12k, 2a, and 2b sites align parallel to the c-axis (up-spin), while those at the 4f_{1} and 4f_{2} sites align antiparallel (down-spin), resulting in a net magnetization from the antiparallel alignment, with 16 up-spins and 8 down-spins per unit cell, yielding 8 uncompensated up-spins.^[14] This collinear ferrimagnetic ordering is intrinsic to the layered arrangement and supports the material's high uniaxial anisotropy along the hexagonal c-axis.^[15] The M-type hexaferrite structure can be visualized as alternating S and R blocks stacked along the c-axis, with barium ions centered in the R blocks and iron ions filling the polyhedral voids in both block types, forming a rigid framework that underpins its magnetic properties.^[16]

Properties

Magnetic Properties

Barium ferrite, or BaFe₁₂O₁₉, displays ferrimagnetic behavior arising from the antiparallel alignment of magnetic moments among Fe³⁺ ions in its hexagonal structure, yielding a net magnetization that persists up to its Curie temperature of approximately 450°C.^[17]^[18] This ferrimagnetism, combined with strong uniaxial magnetocrystalline anisotropy, positions barium ferrite as a classic hard magnetic material, resistant to demagnetization and ideal for permanent magnet applications. The anisotropy constant K \approx 3.3 \times 10^5 J/m³ stems primarily from the crystal field effects on Fe³⁺ ions at specific crystallographic sites, such as the octahedral 12k and bipyramidal 2b positions, which favor magnetization along the c-axis.^[17]^[19] Key magnetic parameters include high coercivity H_c \approx 200{-}400 kA/m and remanence B_r \approx 0.4 T, reflecting its ability to maintain strong magnetic fields once magnetized.^[17] The intrinsic saturation magnetization M_s \approx 380 kA/m (B_s \approx 0.48 T) represents the maximum magnetization achievable in ideal single-domain crystals, independent of microstructure.^[20] In contrast, extrinsic parameters like H_c and B_r are modulated by processing factors; for instance, sintered bulk materials often exhibit lower effective coercivity due to multidomain formation, while optimized nanoparticles approach theoretical limits closer to 600 kA/m. The hysteresis loop of barium ferrite features a wide coercive field and high remanence ratio (B_r / B_s \approx 0.8{-}0.9), indicative of its hard magnetic nature, with the loop's squareness enhanced by the dominant uniaxial anisotropy.^[17]^[21] The demagnetization curve, plotted in the second quadrant of the hysteresis loop, shows a steep initial slope followed by a gentler decline, underscoring the material's stability under reverse fields up to H_c.^[17] Particle size significantly influences magnetic performance, as sizes below approximately 20 nm risk superparamagnetic relaxation at room temperature, reducing effective coercivity, whereas micron-sized particles (around 1 μm) optimize single-domain behavior for maximum H_c.^[22]^[23] Orientation effects further enhance properties; in randomly oriented powders, B_r is limited, but aligned particles in textured magnets can boost remanence by up to 20-30% through coherent c-axis alignment, improving overall energy product.^[24] These microstructural dependencies highlight why barium ferrite's extrinsic properties vary widely (e.g., H_c from 150 to 290 kA/m in commercial forms) despite consistent intrinsic values.^[17]

Chemical and Mechanical Properties

Barium ferrite exhibits a density of approximately 5.28 g/cm³, which contributes to its suitability for compact applications in magnetic devices.^[25] This material demonstrates a Mohs hardness in the range of 5-6, reflecting its relatively hard yet brittle nature as a ceramic, which influences machining and handling processes.^[26] Chemically, barium ferrite is insoluble in water and maintains stability in the +3 oxidation state for iron, owing to its robust oxide structure that resists degradation under ambient conditions.^[25] It shows resistance to most acids and bases, with excellent overall chemical stability that prevents reactivity in typical environmental exposures.^[27]^[28] As a ceramic material, barium ferrite possesses compressive strength on the order of 700 MPa and a Young's modulus of approximately 150 GPa, indicating high stiffness but inherent brittleness that limits tensile performance to around 50 MPa.^[29] The hexagonal crystal structure imparts mechanical anisotropy, with properties varying along different crystallographic directions.^[30] Thermally, barium ferrite has a low linear thermal expansion coefficient of about 10 × 10⁻⁶ /K and a melting point of 1316 °C, enabling reliable performance in elevated-temperature environments without significant dimensional changes or phase instability.^[31]^[25] Electrically, it behaves as an insulator with resistivity exceeding 10⁴ Ω·m, which minimizes eddy current losses in high-frequency applications.^[29] Barium ferrite offers strong corrosion resistance in humid environments, attributed to its oxide composition that forms a passive layer against moisture-induced degradation.^[32]^[27]

Synthesis and Production

Historical Development

The development of ferrite materials began in the 1930s with the invention of spinel ferrites by Japanese researchers Yogoro Kato and Takeshi Takei at the Tokyo Institute of Technology, using ceramic synthesis methods involving iron oxide and other metal oxides to create magnetically soft materials for early electronic applications.^[33] These initial ferrites laid the groundwork for subsequent hard magnetic variants, though barium-specific compositions were not explored until later.^[34] In the early 1950s, researchers at Philips Laboratories in the Netherlands, including J.J. Went, G.W. Rathenau, and E.W. Gorter, discovered the hard magnetic properties of barium hexaferrite (BaFe₁₂O₁₉) while seeking cost-effective alternatives to expensive Alnico magnets, which relied on scarce metals like cobalt. This material, a hexagonal ferrite or hexaferrite, exhibited high coercivity and stability, leading to its patenting in 1952 and initial commercialization under the trade name Ferroxdure for isotropic permanent magnets.^[35] By the mid-1950s, barium ferrite magnets were widely adopted in consumer electronics, particularly for loudspeaker drivers, where their low cost and corrosion resistance displaced Alnico, enabling mass production of affordable audio devices.^[36] Advancements continued with the development of anisotropic forms in the 1950s, such as Philips' Magnadur trademarked variant around 1954, which aligned crystal domains during sintering to enhance remanence and energy product.^[37] By the 1970s, research focused on textured magnets through oriented sintering and particle alignment techniques, improving performance for demanding applications by increasing magnetic anisotropy and overall efficiency.^[38] These innovations built on foundational theoretical work in ferrimagnetism by Louis Néel, whose 1948 model explaining antiparallel spin arrangements in ferrites like hexaferrites enabled precise prediction of their magnetic behavior, earning him the 1970 Nobel Prize in Physics.^[39]

Manufacturing Methods

The conventional ceramic process remains the primary industrial method for producing barium ferrite due to its simplicity, cost-effectiveness, and scalability for large-scale production. This process begins with the intimate mixing of barium carbonate (BaCO₃) and iron oxide (Fe₂O₃) in a molar ratio of approximately 1:6, followed by calcination at temperatures between 900°C and 1200°C to form the hexagonal ferrite phase. The calcined material is then wet-milled to achieve a fine particle size, typically 1-5 μm, mixed with binders and lubricants, pressed into green compacts under high pressure, and finally sintered at 1200-1300°C to densify the structure and enhance magnetic properties.^[40]^[41] Wet chemical methods, such as co-precipitation and sol-gel techniques, offer greater control over particle size and morphology, enabling the synthesis of nanoscale barium ferrite powders for specialized applications. In co-precipitation, aqueous solutions of barium and iron salts (e.g., BaCl₂ and FeCl₃) are mixed and precipitated using a base like NaOH, followed by washing, drying, and annealing at 800-1000°C to yield particles with sizes around 50-100 nm and high coercivity. The sol-gel method involves forming a gel from metal nitrates or alkoxides with chelating agents like citric acid, followed by drying and calcination, which produces ultrafine powders (20-50 nm) with uniform composition and reduced aggregation.^[42]^[43]^[41] Hydrothermal synthesis provides an alternative route for obtaining high-purity, crystalline barium ferrite particles under mild conditions. This method entails reacting barium and iron precursors in an aqueous medium within a sealed autoclave at 150-250°C and elevated pressure for several hours, resulting in well-formed hexagonal platelets with minimal impurities and particle sizes of 100-500 nm.^[44] Microemulsion synthesis utilizes water-in-oil microemulsions as nanoreactors to produce ultrafine barium ferrite particles. The process involves precipitating barium and iron carbonates within aqueous cores (10-25 nm) of the microemulsion, followed by separation, drying, and calcination at around 950°C to form the hexagonal phase, yielding particles of 5-15 nm precursors that develop into nanoparticles with intrinsic coercivity up to 5089 Oe and saturation magnetization of 60.1 emu/g.^[45] Cold sintering enables low-temperature densification of barium ferrite powders at 300°C, promoting energy-efficient production and denser microstructures. The method mixes pre-synthesized BaFe₁₂O₁₉ powder with a transient liquid phase (e.g., 5-15 vol.% eutectic NaOH:KOH and water) in a die, applies high pressure (530-1230 MPa) for 30 minutes under uniaxial compression, achieving relative densities of 89-93%, saturation magnetization of 64-93 emu/g, and coercivity of 1427-1789 Oe with minimal secondary phases.^[3] Doping with elements such as cobalt (Co) and titanium (Ti) is commonly incorporated during synthesis to tailor the magnetic properties, particularly coercivity, by substituting iron sites in the crystal lattice. For instance, Co²⁺-Ti⁴⁺ co-doping at levels of 0.2-0.5 mol% reduces anisotropy while maintaining high remanence, allowing coercivity adjustments from 2000 Oe to 4000 Oe depending on the substitution ratio and processing temperature. These dopants are added as salts during the initial mixing stage in ceramic or chemical routes.^[46]^[47] Shaping methods are applied post-powder synthesis to form finished magnets with desired orientations and geometries. Extrusion is used for anisotropic barium ferrite magnets, where the powder-binder mixture is aligned in a magnetic field during extrusion to achieve preferred c-axis orientation along the length. Injection molding, suitable for complex shapes, involves compounding the powder with polymers, injecting into molds under pressure, and subsequent debinding and sintering to produce isotropic or semi-anisotropic components.^[48]^[49] Quality control in barium ferrite manufacturing focuses on ensuring phase purity and consistent particle characteristics to meet performance specifications. X-ray diffraction (XRD) analysis verifies the formation of the pure magnetoplumbite phase (BaFe₁₂O₁₉) by identifying characteristic peaks and detecting secondary phases like hematite or spinel. Particle size distribution is assessed via laser diffraction or scanning electron microscopy (SEM), targeting a narrow range (e.g., D₅₀ of 0.5-2 μm for magnets) to optimize packing density and magnetic alignment.^[50]^[51] Early scale-up of barium ferrite production was enabled by patents in the 1950s, such as those describing optimized calcination and sintering for commercial magnets.^[52]

Occurrence

Natural Occurrence

Barium ferrite occurs naturally in exceedingly rare quantities as the mineral barioferrite (BaFe₁₂O₁₉), a member of the magnetoplumbite group, primarily in pyrometamorphic environments.^[53] This mineral was first identified in 2008 and approved by the International Mineralogical Association in 2009, marking it as a natural analogue of the widely synthesized barium hexaferrite used in industrial applications.^[54] Barioferrite forms tiny platy crystals, typically up to 3 × 15 × 15 μm in size, appearing black with a sub-metallic luster and a calculated density of 5.31 g/cm³.^[53] The type locality for barioferrite is the Hatrurim Basin in the Negev Desert of Israel, specifically within metamorphosed barite nodules in bituminous calcium-rich rocks of the spurrite-merwinite and pyroxene-hornfels facies.^[55] Formation occurs under high-temperature conditions exceeding 750°C in an oxygen-rich environment, likely resulting from the natural ignition of barite (BaSO₄) combined with iron oxides or hydroxides, leading to the reduction of sulfate and incorporation of iron into the hexaferrite structure.^[54] Associated minerals include barite, calcite, magnetite, maghemite, and other ferrites such as magnesioferrite, with barioferrite often appearing in small segregations intergrown with these phases.^[56] Additional occurrences have been reported in the Czech Republic (Zabrušany deposit), Palestine (Jabel Harmun in the Hatrurim Complex), and Russia (Chelyabinsk Oblast), all linked to similar pyrometamorphic processes in altered barite-bearing rocks.^[53] Despite these natural formations, pure barioferrite remains anthropogenic in practice, with no significant commercial sources due to its rarity and the dominance of synthetic production methods that replicate its hexagonal crystal structure (space group P6₃/mmc).^[53] Related minerals like franklinite or maghemite may incorporate trace barium impurities in iron-rich settings, but they do not form the pure BaFe₁₂O₁₉ composition observed in barioferrite.^[56] Laboratory simulations have explored its geological formation by mimicking high-temperature, oxidizing conditions, confirming the mineral's stability in such alkaline-influenced, calcium-rich pyrometamorphic contexts.^[54]

Commercial Production

Barium ferrite, a key component of permanent magnets, is produced on a large industrial scale, with global annual output exceeding 300,000 tons, primarily serving the magnet industry.^[57] Major production occurs in China, Japan, and various European countries, where established manufacturing infrastructure supports high-volume output for electronics, automotive, and energy sectors.^[58] The supply chain for barium ferrite relies on abundant raw materials, including iron oxide (Fe₂O₃) derived from widespread iron ore mining and barium carbonate (BaCO₃) sourced from barite (barium sulfate) deposits processed through reduction and carbonation.^[59] Iron ore, the primary source of Fe₂O₃, is cheaply available globally due to extensive mining operations, while BaCO₃ prices fluctuate based on barite supply from major producers like China and India.^[60] Production costs are influenced by these raw materials, with Fe₂O₃ remaining low-cost, but the energy-intensive sintering process—requiring high temperatures for densification—accounts for a significant portion of expenses, often amplified by electricity and fuel demands.^[61] Additionally, recycling of ferrite scraps from manufacturing and end-of-life products integrates into the supply chain, helping to recover valuable materials and reduce dependency on virgin ores.^[62] Environmental considerations in commercial production include managing dust emissions during raw material milling and grinding, typically through enclosed systems and filtration to minimize airborne particulates.^[63] Calcination steps, involving the decomposition of carbonates, generate CO₂ emissions, contributing to the process's carbon footprint, though efforts to optimize energy use aim to mitigate this. Recycling initiatives achieve high recovery rates for production scraps, often exceeding 90% in integrated facilities, promoting sustainability in the supply chain.^[62] Market trends for barium ferrite reflect shifting demands, with a decline in traditional audio applications such as magnetic recording tapes due to digital alternatives, contrasted by robust growth in automotive components like motors and sensors, as well as renewable energy systems including wind turbine generators where low-cost ferrite magnets serve as viable options.^[64] This expansion in automotive and renewables is driven by the material's cost-effectiveness and reliability, supporting global ferrite magnet market growth projected at a CAGR of around 7% through 2032.^[65]

Applications

Permanent Magnets

Barium ferrite, a type of ceramic permanent magnet, plays a significant role in direct current (DC) motors, loudspeakers, and relays owing to its high coercivity, which provides resistance to demagnetization, and its low production cost compared to rare-earth alternatives.^[36]^[66] In DC motors, particularly those in automotive and industrial applications, barium ferrite enables reliable operation under varying loads without significant magnetic loss.^[33] Similarly, in loudspeakers, it forms the core of the magnetic circuit, converting electrical signals into mechanical vibrations efficiently while maintaining stability.^[67] Relays benefit from its demagnetization resistance, ensuring consistent switching performance in electrical circuits.^[68] Barium ferrite magnets are produced in both anisotropic and isotropic grades, with the anisotropic variety featuring aligned crystal structures that yield higher remanence for enhanced magnetic performance.^[69] In automotive alternators, textured anisotropic barium ferrite is preferred to achieve greater magnetic flux density, supporting efficient power generation under high-speed conditions.^[70] Isotropic grades, lacking this orientation, offer more uniform but lower magnetic properties, suitable for less demanding applications.^[71] Ferrite magnets, including those based on barium ferrite, hold approximately 47% of the global permanent magnet market by revenue as of 2024, valued for their superior high-temperature stability over neodymium-iron-boron (NdFeB) magnets, which can lose coercivity above 150°C while barium ferrite remains effective up to 250°C.^[72]^[73]^[74] Key advantages include inherent corrosion resistance, eliminating the need for protective coatings, and affordability for mass production.^[75] However, their energy product (BH_max) is lower, typically ranging from 20 to 40 kJ/m³, limiting use in high-performance scenarios requiring compact designs.^[76] Practical examples include small DC motors in household appliances like washing machines and fans, where cost and durability outweigh the need for maximum strength.^[77] Barium ferrite also serves as holding magnets in sensors, providing stable attachment and magnetic fields for position detection in automotive and industrial systems.^[78]

Data Storage and Security

Barium ferrite particles, known for their plate-like hexagonal structure, have been incorporated into magnetic tapes as a recording medium to enable high-density data storage. These particles allow for smaller sizes compared to traditional metal particles, reducing spacing losses and improving signal-to-noise ratios without significant thermal instability, which is crucial for archival applications.^[79] In data backup systems, such as Linear Tape-Open (LTO) formats, barium ferrite has become the standard since around 2010, supporting capacities up to 30 TB uncompressed in LTO-10 as of 2025 and facilitating reliable long-term storage for enterprise data.^[80] For consumer audio applications, barium ferrite was occasionally used in cassette tapes alongside iron oxide and chromium dioxide formulations, particularly in higher-end or experimental variants during the 1980s and 1990s, to enhance recording performance.^[81] In magnetic stripes for credit cards and identification documents, barium ferrite powder is embedded in a polymer matrix to achieve high coercivity levels, typically ranging from 2100 to 4000 oersteds, which matches the capabilities of standard read/write heads while providing resistance to accidental demagnetization from everyday magnetic fields.^[82] This material's platelet-shaped particles are aligned during manufacturing to optimize magnetic orientation, ensuring consistent data encoding and readability in swipe-based systems.^[83] The high coercivity makes these stripes suitable for secure, durable applications like access control cards, where data integrity is essential over repeated use.^[82] Barium ferrite is also utilized in security inks for banknotes and official documents, where fine particles are oriented within the ink formulation to create machine-readable magnetic patterns for authentication.^[84] These oriented particles, aligned via application of an external magnetic field during the printing and coating process, produce detectable magnetic signatures that verify document genuineness without visible alterations. Such techniques enhance anti-counterfeiting measures by allowing automated readers to confirm the unique alignment and coercivity properties of the embedded ferrite. Despite the shift toward solid-state and cloud-based digital storage, the use of barium ferrite in recording media has declined in consumer sectors like audio cassettes, which peaked in the late 20th century before obsolescence.^[85] However, it maintains a legacy role in archival storage, where its chemical stability—showing only 1% degradation in magnetization after simulated decades of exposure—ensures data longevity exceeding 30 years under ambient conditions, outperforming metal particulate alternatives.^[32]

Other Uses

Barium ferrite is employed in microwave absorbers for stealth technology and electromagnetic interference (EMI) shielding, leveraging its natural ferromagnetic resonance in the 40-60 GHz range to effectively attenuate radar signals and mitigate high-frequency noise.^[86]^[87] In composite forms, such as barium ferrite integrated with ceramics or polymers, these materials achieve reflection losses below -13 dB across broad microwave bands, enhancing their utility in military and electronic applications.^[87] Fine powders of barium ferrite are utilized as pigments in paints and plastics, imparting brown to red hues while providing magnetic functionality.^[88] These pigments exhibit excellent UV stability and chemical inertness, enabling durable coloration in exterior coatings and polymer composites exposed to environmental stressors.^[89] In biomedical applications, barium ferrite nanoparticles show potential for magnetic hyperthermia in cancer treatment, where alternating magnetic fields induce localized heating to 43-46°C, selectively damaging tumor cells without affecting healthy tissue.^[90] Surface-modified variants, such as those conjugated with targeting ligands like trastuzumab, enhance specificity for breast cancer cells, combining hyperthermia with imaging and radiotherapy.^[90] Emerging uses include barium ferrite-based nanocomposites for flexible magnets and sensors, where integration with polymers like natural rubber or bacterial cellulose yields lightweight, bendable materials with tunable magnetic properties.^[91] These composites enable applications in wearable sensors for magnetic field detection, offering high sensitivity and mechanical flexibility for strain-responsive devices.^[92]

References

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[PDF] Cold sintering of magnetic BaFe12O19 and other ferrites at 300ºC
BaFe12O19, or barium hexaferrite, is one such material of particular interest due to its high saturation magnetization, good chemical stability, oxidation and ...
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Barium hexaferrite ; Molecular Formula. BaFe12O ; Synonyms. Ferroxdure; Barium hexaferrite; 12047-11-9; Ferotop GP 500; 4HT629NL8B ; Molecular Weight. 1111.5 g/mol.
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Jul 4, 2025 · Chemical Name: BARIUM FERRITE ; CBNumber: CB4173463 ; Molecular Formula: BaO.6Fe2O3 ; Molecular Weight: 1111.45 ; MDL Number: MFCD00197996.
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https://www.chemicalbook.com/ChemicalProductProperty_EN_CB4173463.htm
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Barium ferrite nanopowder, particle size 97 trace metals 12047-11-9
### Summary of Barium Ferrite (637602)
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[PDF] The crystal structure and refinement offerrimagnetic barium ferrite ...
The crystal structure and refinement offerrimagnetic barium ferrite, BaFe12019*. By W. D. TOWNES, J. H. FANG ** and A. J. PERROTTA. Institute for Exploratory.
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The crystal structure and refinement of ferrimagnetic barium ferrite ...
The symmetry is P63/mmc; the unit cell whose dimensions are a = 5.893 Aand c = 23.194 A, contains two formula units. The structure is built up of ten close ...Missing: space parameters
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Investigation of crystal structure, microstructure and low temperature ...
The unit cell of BaFe12O19 is arranged by stacking R (BaFe6O11) and S (Fe6O8) blocks in RSR*S* sequence where '*' denotes rotation of block along c-direction of ...
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Aug 5, 2021 · The spiraled MWCNTs/BaFe 12 O 19 hybrid showed the highest microwave absorption of more than 99.9%, with a minimum reflection loss of − 43.99 dB and an ...
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a Crystal structure of M-type barium hexaferrite BaFe12O19. Red ...
The chemical formula of M-type barium ferrite is BaFe 12 O 19 , and BaFe12O19 exhibits a symmetric hexagonal crystal structure with a space group of P63/mmc [11] ...
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Three of the Fe3+ sites are octahedral (12k, 4f2, 2a); one is tetrahedral (4f1), and one is trigonal bipyramidal (2b). A suitable characterization technique ...
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[PDF] Room-Temperature Ferrimagnet with Frustrated Antiferroelectricity
In BaFe12O19, the high-spin Fe3+ ions (S = 5/2) order ferrimagnetically below 450 °C with 16 up-spin and eight down-spin Fe3+ ions per unit cell, resulting in a ...Missing: sublattices | Show results with:sublattices
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The crystal structure of BaFe 12 O 19 unit cell in 3D. - ResearchGate
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[PDF] Review of Magnetic Materials Along With a Study of the ... - DiVA portal
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Jun 26, 2023 · The magnetic anisotropy in BaM ferrite is influenced by the. Fe3+ ions distribution in five crystallographic sites: three octahedral sites 12k (. ) ...
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Apr 15, 1985 · This result can be explained with the existence of a nonmagnetic thin layer, several angstroms in thickness, on the surface of the particles.
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Barium Ferrite | AMERICAN ELEMENTS ®
Density, 5.28 g/cm3. Solubility in H2O, Insoluble. Exact Mass, 1113.027924. Monoisotopic Mass, 1113.027924. BaFe, BaM, barium ferrate, Barium dodecairon ...
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Chemical Resistance ; Largely Resistant. Tartaric acid. Citric acid. Alcohols. Inorganic acids. Gasoline ; Conditionally Resistant. Uric acid > 10%. Sulfruric ...
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Hardness approx. Mohs. 6-7. HV. 500-600. Elasticity modulus approx. 103N/mm2. 150. Compressive strength approx. N/mm2. 700. Tensile strength approx. N/mm2. 50.
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The thermal expansion coefficients along the a axis (αa) and c axis (αc) of barium hexaferrite were measured from room temperature to 850 °C. The thermal ...
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Linear thermal expansion coefficients of common materials, including metals, plastics, and composites. ; Barium, 20.6 ; Barium ferrite, 10 ; Benzocyclobutene, 42.Missing: melting | Show results with:melting<|separator|>
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This study experimentally compared barium ferrite with conventional metal particulate media in terms of their chemical corrosion resistance and thermal ...<|control11|><|separator|>
[31]
Ferrite World｜Learn about Technology with TDK
Ferrite is Japan's original magnetic material that was invented by Dr. Yogoro Kato and Dr. Takeshi Takei at Tokyo Institute of Technology in 1930.Missing: isotropic | Show results with:isotropic
[32]
Recent advances in U-type hexagonal ferrites - ScienceDirect.com
Ferrites were first invented by Prof, Yogoro Kato and Prof. Takeshi Takei in 1930 at the well-known institute Tokyo Institute of Technology in Japan [17].Review Article · 3. Crystal Structure Of... · 6. Result And Discussion<|control11|><|separator|>
[33]
Manufacturing Processes for Permanent Magnets: Part I—Sintering ...
Feb 2, 2022 · Barium hexaferrite (BaFe12O19) was discovered in 1952 at the Philips Physics Laboratory and was marketed under the trade name Ferroxdure.<|separator|>
[34]
How Are Ferrite Magnets Applied in Motors and Speakers, and What ...
Applications in Audio Speakers. Historical Context. Ferrite magnets revolutionized speaker design in the 1950s and 1960s by displacing Alnico alloys, which ...
[35]
[PDF] Philips Technical Review - World Radio History
The use of artificially prepared radioactive elements (radio -isotopes) for biological and medical purposes as well as in industry and in many branches of ...
[36]
Characterization and Sintering Behavior of Ba and Sr Ferrites - 1973
Compacts formed by mechanical pressure filtration in a magnetic field are characterized by oriented aggregates of platy particles with planar faces and planar ...
[37]
[PDF] Louis Néel - Magnetism and the local molecular field - Nobel Prize
16. 1970 LOUIS NÉEL. The theory of ferrimagnetism also makes it possible to explain the behav- iour of composite ferrites ...Missing: research | Show results with:research
[38]
(PDF) Synthesis of dense, fine‐grained hexagonal barium ferrite ...
Jan 3, 2018 · Generally, most permanent ferrites are produced by the conventional ceramic process in industry due to its easy operation, low cost, and large ...
[39]
Synthesis of barium ferrite ultrafine powders by a sol–gel ...
Jan 15, 2014 · The ultrafine powders of barium ferrite (BaFe12O19) were synthesized by a sol–gel combustion technique using glycine gels prepared from ...Missing: manufacturing | Show results with:manufacturing
[40]
A study on barium ferrite particles prepared by chemical ...
Aug 6, 2025 · In view of ferrite's excellent magnetic properties and chemical stability, ferrite is commonly used as permanent magnets and in magnetic ...Missing: solubility | Show results with:solubility
[41]
Synthesis and properties of barium ferrite nano-powders by ...
Mar 1, 2019 · The chemical co-precipitation method involves the following reaction: 12FeCl3 + BaCl2 + 38NaOH = 12Fe (OH)3 + 38NaCl + Ba (OH)2, through which ...
[42]
A novel hydrothermal synthesis method for barium ferrite
Aug 6, 2025 · This modified sol–gel method produced pure and highly crystalline ferrite ... Barium hexaferrite powders have been prepared by sol-gel technique.
[43]
https://www.sciencedirect.com/science/article/abs/pii/S0304885318316949
[44]
Co–Ti co-substitution of M-type hexagonal barium ferrite - IOPscience
Apr 8, 2015 · Co–Ti substitution reduced the coercivity whilst increased magnetic permeability. These improvements in magnetic properties are attributed to Co ...
[45]
Ferrite-based soft and hard magnetic structures by extrusion free ...
May 22, 2017 · Ceramic extrusion free-forming (EFF), commonly known as the robocasting process, allows the computer-controlled deposition of highly dispersed ...
[46]
Paste-Injection of Low-Density Barium Hexaferrite Magnets with Soft ...
Facile paste-injection molding produced hard/soft magnetic composites with reproducible density and magnetic properties. The paste was prepared from BaCO3 and ...
[47]
The magnetic property alterations due to transition from barium ...
The particle size for barium ferrite nanoparticles is around 31.97 nm. Fig. 1. Download: Download full-size image. Fig.
[48]
Effect of Particle Size and Its Distribution on the Fabrication and ...
Aug 6, 2025 · Magnetic properties of the bonded barium ferrite magnet were measured at different temperatures. The results were found to be fairly close ...<|control11|><|separator|>
[49]
Ferrite Magnets: The Ultimate Guide - Newland
Jun 9, 2025 · These magnets are primarily made from iron oxide and a combination of either barium or strontium carbonate, making them inexpensive, plus ...
[50]
Barioferrite: Mineral information, data and localities.
Well-studied ceramic phase in materials science ("barium hexaferrite", strongly magnetic). The synthetic Sr-analogue is sometimes sold as "magnetic hematite".
[51]
A new mineral species of the magnetoplumbite group from the ...
Jan 6, 2012 · A new mineral barioferrite—a natural analogue of synthetic barium ferrite Ba Fe 12 3+ O19—has been identified in the central part of a ...
[52]
[PDF] Barioferrite BaFe12O19
Barioferrite, a new mineral of the magnetoplum bite group, was found in one of numerous barite nod ules abundant in rocks of the Haturim Formation in. Israel.<|control11|><|separator|>
[53]
Dynamic Disorder of Fe 3+ Ions in the Crystal Structure of Natural ...
The tetrahedral Fe3 and octahedral Fe4 sites have admixtures of Mg and Ti, respectively. Their mean Fe–O bond lengths are 1.915 and 2.022 Å (at 100 K) and ...
[54]
Study of the sintering temperature and the sintering time period ...
Mar 30, 2018 · The hexagonal ferrite BaFe12O19 (BaM) has been prepared by the citrate precursor method. The synthesized sample has been sintered at 1000, ...
[55]
Ferrite Magnet Manufacturers - TOPMAG
Jun 8, 2024 · The main production bases for ferrite magnets are concentrated in China, Japan, and some European countries, where manufacturers hold a leading ...
[56]
[PDF] Barite (Barium) - USGS Publications Warehouse
Barite (barium sulfate, BaSO4 ) is an industrial mineral commodity that is used primarily in the drilling of oil and gas wells. The mineral commodity is also ...Missing: ferrite chain
[57]
What Affects Ferrite Magnet Price in 2025? A Complete Breakdown
Jun 5, 2025 · The type and purity of raw materials, such as barium ferrite or strontium ferrite, directly affect the cost. Higher purity materials typically ...
[58]
Influence Composition Fe2O3 of Isotropic Magnet BaFe12O19 on ...
Ferrite magnets are nevertheless still produced and applied up to this point, because raw materials cost, the production costs and product prices are cheaper ...
[59]
Recycled magnetic materials (BaFe12O19 and Fe3O4) for the ...
Nov 30, 2023 · ... barium ferrite. ... Currently, the contamination by plastics is major concern because >360 million tons are produced annually worldwide, ...
[60]
Ferrite Market Size Report, 2020-2025 - IndustryARC
Ferrite Market size is valued at $5 billion in 2023 and forecast to reach around $6.38 billion by 2030, after growing at a CAGR of 5% during 2024-2030.Missing: annual tons<|control11|><|separator|>
[61]
Ferrite Magnet Market Size, Share, Trends | Growth [2025-2032]
Oct 20, 2025 · The global ferrite magnet market is projected to grow from $10.0 billion in 2025 to $16.4 billion by 2032, exhibiting a CAGR of 7.3% during ...
[62]
Barium Ferrite - an overview | ScienceDirect Topics
Ferrites are a type of ceramic material made by mixing and firing large portions of Fe (III) oxide with other metallic constituents such as barium (Ba) or ...
[63]
Ferrite Magnets – The Ultimate Guide
Aug 28, 2023 · Cost-Effectiveness: The availability of raw materials combined with a simple manufacturing process makes ferrite magnets cost-effective.<|control11|><|separator|>
[64]
Speaker Magnets: Types, Applications, and Comparison
Apr 2, 2025 · This article will introduce the various types of speaker magnets, their applications, and a detailed comparison between neodymium and ferrite magnets.
[65]
Permanent Magnet Motors | Magnet Applications | Bunting-DuBois
Permanent magnet motors are available in both AC and DC varieties, and may utilize alnico, ferrite, or rare earth magnets. Learn more.
[66]
Ceramic (Hard Ferrite) Magnets - Dexter Magnetic Technologies
Consequently, ceramic ferrite magnets are available in both oriented (anisotropic) and non-oriented (isotropic) grades. Because of its lower magnetic properties ...
[67]
Ferrite Magnets | Dailymag
Ferrite magnets can either be isotropic or anisotropic: Isotropic ... Ferrite magnets are widely used in power generators, alternators, and eddy currents.<|control11|><|separator|>
[68]
Ferrite Magnets - IMA
Ferrite magnets also called black magnets are made of iron oxide and barium or strontium ferrite. Ferrite magnets are highly resistant to corrosion.Missing: motors | Show results with:motors
[69]
Permanent Magnets Market Size & Share Report, 2030
The global permanent magnets market was USD 22.18 billion in 2023 and is projected to reach USD 39.71 billion by 2030, with a CAGR of 8.7%. Asia Pacific had ...Missing: barium coercivity disadvantages
[70]
Permanent Magnet Market Size, Share, Trends & Growth 2032
Ferrite magnets provide high-temperature operations, resistance to demagnetization, and are cost-effective. These properties increase its use in automotive ...
[71]
Ferrite Magnets: Exploring Their Pros and Cons Across Industries
Apr 16, 2024 · Ferrite magnets offer several advantages, including cost-effectiveness, corrosion resistance, and versatility in shape and size.Missing: market coercivity
[72]
Preparation and Properties of Barium Ferrite Using Hot‐Rolled Mill ...
The quality of the isotropic magnets reached coercivity Hc 1750 Oe, remanence Br 2200 G, and maximum energy product (BH)max 1.0 × 106 G · Oe and that of the ...
[73]
https://www.grandviewresearch.com/industry-analysis/permanent-magnets-industry
[74]
Why Ferrite Magnets Are Still Essential in Modern Electronics
Oct 27, 2025 · Sensors and Magnetic Devices. Hall-effect sensors, speed sensors, and encoders depend on ferrite magnets to supply stable magnetic fields.Missing: holding | Show results with:holding
[75]
Barium Ferrite: Overview | Fujifilm [United States]
Barium Ferrite (BaFe) is a new type of magnetic particle which can be greatly reduced in size to improve recording density without magnetic signal loss.Missing: audio | Show results with:audio
[76]
Tape Storage Is Here to Stay - EE Times
Aug 16, 2023 · Barium ferrite is now the default magnetic particle in LTO tape sold by companies like IBM, while epsilon ferrite is being looked at as the ...
[77]
Curious Kids: how does music get onto a cassette tape?
Aug 11, 2021 · The material could be iron oxide, chromium dioxide, or sometimes barium ferrite.
[78]
Technology - AIDC Basics - Mag Stripe FAQ - Compsee
Sep 11, 2025 · Gamma Ferric Oxide will give you a low coercivity stripe, Barium Ferrite will give you a high coercivity stripe. The material alone does not ...
[79]
Explaining the Physics Behind Magstripes/ Experimental Conclusions
Apr 27, 2011 · High coercivity magnetic stripes are usually black and made of barium ferrite. Low coercivity magnetic stripes are usually made of iron oxide.
[80]
Security Ink Technologies for Anti-Counterfeiting Measures
Apr 10, 2024 · Authentication of documents or products containing OVI is typically done by observing the color shift under different lighting conditions or ...
[81]
Study Reveals New Findings on Longevity of Legacy Magnetic ...
Aug 11, 2022 · Findings suggest that polyester-based magnetic audio tapes that are playable today and kept at standard room conditions may remain usable for as long as 100 ...
[82]
Millimeter wave ferromagnetic resonance in gallium-substituted Îµ ...
These ferrites include M-type barium ferrite (BaFe12O19) and strontium ferrite (SrFe12O19), which have natural ferromagnetic resonant frequency range from 40 ...
[83]
Advanced Radar Absorbing Ceramic-Based Materials for ... - NIH
Sep 14, 2018 · A double-layer microwave absorber was achieved by using carbonyl iron and barium ferrite powder: it showed reflection losses below −13 dB within ...
[84]
[PDF] Molecular Beam Epitaxy Integration of Magnetic Ferrites
Barium hexaferrite (BaM,. BaFe12O19) is an ideal candidate for high frequency microwave device applications because of its strong uniaxial anisotropy (HA ~17 ...
[85]
Magneto-active ferrite-based paint pigments - AIP Publishing
Jun 8, 2023 · Ferrite-based paint pigments, nickel ferrite and barium ferrite, are tested as a dispersed phase of a MR fluid in this study.
[86]
(PDF) A method for preparation and application of micronized ferrite ...
Aug 6, 2025 · This work presents a method of preparing single-, double-, and triple-cation ferrite pigments by employing simple chemical techniques to study ...
[87]
Trastuzumab Modified Barium Ferrite Magnetic Nanoparticles ... - NIH
It can be assumed that 223Ra-doped BaFe nanoparticles should be promising candidates for multimodal drug combining localized magnetic hyperthermia with internal ...
[88]
Magnetic and dynamic mechanical properties of barium ferrite ...
Aug 6, 2025 · The physical properties such as Tensile, Elongation, Young Modulus, Compression and (X-Ray) transmission were Studied. View. Show abstract.
[89]
https://www.researchgate.net/publication/304657469_A_method_for_preparation_and_application_of_micronized_ferrite_pigments_in_anticorrosive_solvent-based_paints