Ferrite Ceramics and Ferromagnetic Materials Specifications

Help with Ferrite Ceramics and Ferromagnetic Materials specifications:

Electromagnetic and Magnetic Properties

	Saturation Magnetization (Bs or 4πMs)		Saturation magnetization or flux density (Bs , 4πJs, 4πMs) is the flux density (B) at which saturation of a magnetic material occurs.  Saturation is the point at which the flux density (B) in a material does not increase with further application of increased magnetization force (H).
	Search Logic:		User may specify either, both, or neither of the "At Least" and "No More Than" values. Products returned as matches will meet all specified criteria.
	Permeability (µ)		Permeability is the ability of a material to carry magnetic flux as compared to the permeability of a vacuum, which by definition has a permeability of one.   Initial permeability is determined by the slope or the B-H curve for a given small flux density (< 10 Gauss).  Permeability is the ratio of the flux density to the magnetizing force: µ = B/H where H = magnetic field strength or magnetizing force and B = magnetization induction, moment or flux density in the material (given in flux per unit area). Permeability varies as a function of the applied magnetic field strength (H). A maximum incremental permeability value usually occurs as the applied magnetic field strength is increased.  In the CGS system, permeability has no dimensions.
	Search Logic:		User may specify either, both, or neither of the "At Least" and "No More Than" values. Products returned as matches will meet all specified criteria.
	Coercive Force (Hc)		The coercive force is equal to the demagnetization force required to reduce the residual induction, Br, to zero in a magnetic field after magnetizing to saturation.
	Search Logic:		User may specify either, both, or neither of the "At Least" and "No More Than" values. Products returned as matches will meet all specified criteria.

Back to Top

Material Type

	Ferrite / Garnet
	Your choices are...
	Ferrites and Ferromagnetic Ceramics		Ferrite ceramics and ferromagnetic materials have dielectric and magnetic properties that are suitable for radio frequency (RF) and microwave applications. They provide high electrical resistivity and low magnetic losses. Ferrite ceramics and ferromagnetic materials include a number of crystalline materials that exhibit ferromagnetism (or ferrimagnetism). Ferromagnetism is a phenomenon by which a material can exhibit a spontaneous magnetization. It is one of the strongest forms of magnetism. Each ferromagnetic material has a definite temperature, above which it ceases to exhibit spontaneous magnetization. This is called the Curie temperature.
	Ferrite Ceramic		Ferrites are ferrimagnetic oxides with dielectric and magnetic properties that are useful for RF and microwave applications. Spinel ferrites typically have a general formula of AB2O4.  Iron-based ferrites have the general formula MO-Fe2O3 where M is a divalent ion such as Fe, Ni, Cu, Mg, Mn, Co, Zn, or Li. Hexagonal ferrites, hexaferrites, or materials in the magnetoplumbites group have the general formula AB12O19 and include barium ferrite and strontium ferrites.
	Ferrite - Hexagonal		Ferrites are ferrimagnetic oxides with dielectric and magnetic properties that are useful for radio frequency (RF) and microwave applications. Hexagonal ferrites, hexaferrites, or materials in the magnetoplumbites group have the general formula AB12O19 and include barium ferrite and strontium ferrites. Hexagonal ferrites must be processed under an applied magnetic field due to their high magnetic anisotropy. They provide high-saturation magnetization and are used in devices generating internal-biasing fields. BaFe12O19 and SrFe12O19 Ba ferrites and Sr ferrite are common hexagonal ferrites.
	Ferrite - Spinel		Ferrites are ferrimagnetic oxides with dielectric and magnetic properties that are useful for radio frequency (RF) and microwave applications. Spinel ferrites typically have general formula of AB2O4.
	Garnet (Ferromagnetic)		Ferrogarnets or rare earth iron garnets have a fairly complex structure with the general formula of (3M2O3)C(2Fe2O3)A(3Fe2O3)D where M is yttria or rare earth ion and (A,C,D) are lattice site.  Yttrium aluminum garnet or YIG (Y2Fe5O12) is a common microwave or ferromagnetic garnet.  Magnetization levels are modified by substituting Al for Fe or combinations of Ho, Dy or Gd for Y in microwave or ferromagnetic garnets.
	Search Logic:		All products with ANY of the selected attributes will be returned as matches. Leaving all boxes unchecked will not limit the search criteria for this question; products with all attribute options will be returned as matches.

Back to Top

Shape / Form

	Shape / Form:
	Your choices are...
	Bar Stock		Stock products are available in the form of a bar or rod, usually with a square cross-section. Stock forms can be processed in rectangular, oval, hexagonal, or other shapes.
	Fabricated / Custom Shape		Materials are fabricated in the form of a custom or application-specific shape such as a crucible, valve seat, blade, fired custom shaped brick or block, custom contoured tile, diffuser, furnace lining, degasser, and precast cement or concrete structural shape. The custom shape could be fabricated using pressing, slip casting, firing or sintering, melting, casting, cement form casting, and/or other processing methods.
	Filter / Diffuser		Spargers or diffusers are porous ceramics used to blow fine bubbles of a gas into a metal melt to remove impurities, particulates or other detrimental melt gases, de-oxidize melts, and enable chemical reactions. Filters are porous ceramics are used to remove impurities by passing the molten materials through the filter.
	Plate / Board (e.g., Fiberboard)		Stock products are available in the form of a solid plate, slab, board, or substrate. The board or plate may consist of a ceramic fiberboard product, a dense sintered ceramic plate, or a precast cement bonded slab.
	Rod Stock		Stock products are available in the form of a rod or a bar with a round cross-section.
	Tube Stock		Tube stock has a single, central bore or inner diameter. Tubes are commonly used as heating elements, for thermocouple protection, or channeling molten metal.
	Search Logic:		All products with ANY of the selected attributes will be returned as matches. Leaving all boxes unchecked will not limit the search criteria for this question; products with all attribute options will be returned as matches.
	Hollow Stock / Shape?		Materials are supplied or available as hollow tubes, pipes or other stock with an open internal bore.
	Search Logic:		"Required" and "Must Not Have" criteria limit returned matches as specified. Products with optional attributes will be returned for either choice.

Back to Top

Dimensions

	Length		The length of a stock material such as a bar, rod, plate or tube.
	Search Logic:		User may specify either, both, or neither of the "At Least" and "No More Than" values. Products returned as matches will meet all specified criteria.
	Width / O.D.		The width is the outer diameter (O.D.) of stock shapes such as bars, plates, and tubes; or of fabricated components such as crucibles.
	Search Logic:		User may specify either, both, or neither of the "At Least" and "No More Than" values. Products returned as matches will meet all specified criteria.
	Thickness / Wall Thickness		The thickness of a stock form, tube wall, or other fabricated component. Stock forms include bars, rods, plates and tubes.
	Search Logic:		User may specify either, both, or neither of the "At Least" and "No More Than" values. Products returned as matches will meet all specified criteria.
	Bore Diameter (I.D.)		The bore diameter or inner diameter (ID) is the width at the bottom of fabricated, tapered components such as crucibles.
	Search Logic:		User may specify either, both, or neither of the "At Least" and "No More Than" values. Products returned as matches will meet all specified criteria.

Back to Top

Thermal

	Curie Temperature		This is the maximum temperature that the refractory or ceramic material can be exposed to momentarily without the degradation of structural or other required end-use properties.  The maximum use temperature is usually equal to the melt temperature of the metal, glass, or other material contained by the refractory body in the furnace, boiler or process unit. The Curie point is the temperature above which a material loses its unique magnetic, dielectric or piezoelectric property.  Ferrites or other magnetic materials lose their unique magnetic properties above the Curie temperature. The relative permeability drops to a value below 0.1 above the Curie temperature.  Magnetic susceptibility is inversely proportional to temperature.
	Search Logic:		User may specify either, both, or neither of the "At Least" and "No More Than" values. Products returned as matches will meet all specified criteria.
	Thermal Conductivity		Thermal conductivity is the linear heat transfer per unit area through a material for a given applied temperature gradient. Heat flux (h) = [thermal conductivity (k) ] x [temperature gradient (Δ T)]
	Search Logic:		User may specify either, both, or neither of the "At Least" and "No More Than" values. Products returned as matches will meet all specified criteria.
	Coeff. of Thermal Expansion (CTE)		The coefficient of linear expansion (CTE) is the amount of linear expansion or shrinkage that occurs in a material with a change in temperature.
	Search Logic:		User may specify either, both, or neither of the "At Least" and "No More Than" values. Products returned as matches will meet all specified criteria.

Back to Top

Electrical

	Dielectric Strength		Dielectric strength is the maximum voltage field that the ceramic or material can withstand before electrical breakdown occurs.
	Search Logic:		User may specify either, both, or neither of the "At Least" and "No More Than" values. Products returned as matches will meet all specified criteria.
	Dielectric Constant (Relative Permittivity)		The dielectric constant is the relative permittivity of a material compared to a vacuum or free space.  k = εr = ε / εo= where ε is the absolute permittivity of the material and εo is the absolute permittivity of a vacuum 8.85 x 10-12 F/m.
	Search Logic:		User may specify either, both, or neither of the "At Least" and "No More Than" values. Products returned as matches will meet all specified criteria.
	Loss Tangent (tan δ )		In dielectric materials, the loss tangent or loss coefficient is ratio of the imaginary or loss permittivity to the real permittivity of a material. In a capacitive circuit with a sinusoidal or AC voltage, the loss tangent is equal to the ratio of dissipated or discharged current to the storage current tan δ = | IR / IC | .  The dielectric quality factor (Q) is equal the inverse of the loss tangent. High Q or low loss tangents are required to reduce insertion losses.  Q = (average stored energy per cycle / energy dissipated per cycle) In magnetic materials or ferrites, the loss tangent or loss coefficient is ration of complex imaginary permeability (µ") to real permeability(µ').
	Search Logic:		User may specify either, both, or neither of the "At Least" and "No More Than" values. Products returned as matches will meet all specified criteria.
	Electrical Resistivity		Electrical resistivity is the longitudinal electrical resistance (ohm-cm) of a uniform rod of unit length and unit cross-sectional area. Electrical resistivity is the inverse of conductivity. High resistivity is a defining characteristic of a dielectric material.
	Search Logic:		User may specify either, both, or neither of the "At Least" and "No More Than" values. Products returned as matches will meet all specified criteria.

Back to Top

Physical Properties

	Density		Density is the mass per unit area for a material.  The fired density is dependent on the theoretical density of 100% dense body and the actual porosity retained after processing.
	Search Logic:		User may specify either, both, or neither of the "At Least" and "No More Than" values. Products returned as matches will meet all specified criteria.

Back to Top

Applications

	Applications:
	Your choices are...
	Electrical / HV Parts		Materials are used to fabricate electrical parts for high voltage or power applications. Examples include insulators, igniters or heating elements.
	Electronics / RF-Microwave		Materials are suitable for electronics applications, including RF and microwave. Ferrites, garnets, alumina/sapphire and silicates have sufficient dielectric properties for use in electronic, radio frequency (RF) and microwave devices such as antenna radomes, patch antenna substrates, thin/thick film substrates and resonators. In addition, ceramics, glass and other non-metallic compounds or elemental semiconductors are used as substrates, wafer or dummy wafers in semiconductor manufacturing.  Ceramics are also used for wafer chucks or holders, wafer furnace boats and thin film chamber liners.
	Other		Other unlisted, specialized or proprietary applications.
	Search Logic:		All products with ANY of the selected attributes will be returned as matches. Leaving all boxes unchecked will not limit the search criteria for this question; products with all attribute options will be returned as matches.

Back to Top

Features

	Performance Features:
	Your choices are...
	Coated		Coated materials use or are available with a glaze (fused glass enamel), metallized coating, plastic coating or other protective coating. The coating may seal porosity, improve water or chemical resistance, or enhance joining to metals or other materials. This category also includes glass materials with an organic coating or film, or ceramic frit coating for spandrel applications.
	Machinable		Machinable ceramics can be machined in the green, glass or finished state without excessive chipping. Typically, non-machinable ceramics are ground to finished dimensions, often with super abrasive grinding wheels.
	Modified / Doped		Materials are modified or doped with ions or additions of another ceramic to impart specific properties or improve processing.
	Soft		Soft ferrites have low magnetization and are used in applications where the fields and magnetizations are cycled frequently and hysteresis losses are critical. Soft ferrites exhibit magnetic properties only when they are subject to a magnetizing force such as the magnetic field created when current is passed through wire surrounding a soft magnetic core.  Ceramic ferrites have a distinct advantage in some applications (magnetic cores) over ferromagnetic metals because their highly resistive nature eliminates or minimizes eddy current losses. Soft piezoelectrics are less resistant to stress induced depolarization compared to hard piezoelectrics. High sensitivity or "soft" ceramics feature high sensitivity and permittivity, but if over driven these materials can be damaged due to self-heating beyond their operating temperature range or Curie temperature. Soft piezoelectrics are used in various sensors, low-power motor-type transducers, receivers, and low power generators.
	Hard		Hard ferrites or magnetic materials have high magnetization or remanence (B) and these materials are used as permanent magnets. Hard ferrites retain their magnetization after the applied magnetics is removed. Soft ferrites have low magnetization and are used in applications where the fields and therefore magnetizations are cycled frequently and hysteresis losses are critical. Ceramic ferrites have a distinct advantage in some applications (magnetic cores) over ferromagnetic metals because their highly resistive nature eliminates or minimizes eddy current losses. High power or "hard" piezoelectric ceramics can withstand high levels of electrical excitation and mechanical stress. These materials are suited for high voltage or high power generators and transducers.  Hard piezoelectric ceramics are more resistant to stress induced depolarization compared to soft piezoelectrics.  Hard piezoelectric materials are characterized by a very high load or distortion constant, low hysteresis and high Qm.
	Metallized / Silvered (Electrode, Mirror)		Ceramic surfaces are coated with a thin metal layer applied by plating, thin film, fired-on coating or other process. The coatings maybe continuous or selectively patterned on the surface or thru vias. In addition, float glass sheet or glass plate silvered to produce sheet mirror stock.
	Specialty / Other		Other unlisted, specialized, or proprietary material features.
	Search Logic:		All products with ANY of the selected attributes will be returned as matches. Leaving all boxes unchecked will not limit the search criteria for this question; products with all attribute options will be returned as matches.

Back to Top