Purity on Rare Earth Oxide Basis.
In rare earth industry, chemical purities of rare earth oxides and compounds are often presented on rare earth oxide basis (REO basis), i.e., content of a specific rare earth oxide in comparison to total rare earth oxides (TREO) present: REO/TREO. The statement of “Yb2O3 > 99%”, often means Yb2O3/TREO > 99%. To obtain its absolute purity of a specific oxide, you can use formula: REO/TREO x Percentage of TREO in the material.


Purity on Rare Earth Metal Basis.
In rare earth industry, chemical purities of rare earth metals are often presented on rare earth metal basis (REM basis)), i.e., content of a specific rare earth metal in comparison to total rare earth metals (TREM) present: REM/TREM. The statement of “Yb> 99%” often means Yb/TREM > 99%. To obtain its absolute purity of a specific metal, you can use formula: REM/TREM X Percentage of TREM in the material.



Hard substances (such as fused alumina) that are used for polishing, cutting, or grinding.



The ability and capability of a material to soak up a liquid. In pottery and ceramics, this would relate to a glaze prior to firing.

Alumina – Alumina is a technical ceramic commonly used in engineering owing to its outstanding electrical insulation properties combined with rigidity and resistance to corrosion.


Advanced Ceramics

These types of ceramics are known as technical ceramics, high-tech ceramics, and high-performance ceramics. They are for industrial and commercial applications demanding high mechanical strength, abrasion and chemical resistance, electrical insulation, or resistance to high temperatures.



A method where slip is poured into a mould to create more complex ceramic forms. Examples include sanitary ware, figurines, and teapots.

Ceramics – This is a term that covers a broad range of clay-based products from bricks to tableware. The name originates from the Greek ‘Keramos’ which relates to the potter, pottery, or earthen vessel.



Lowest melting compound in a glaze, such as lead, borax, soda ash, or lime, and including the potash or soda contained in the feldspar. The flux combines easily with silica and thereby helps higher-melting alumina-silica compounds to form a glass.


Hot Face

The internal refractory surface area of the kiln.



Used to describe how capable a material is of withstanding high temperatures. This is usually related to kiln shelves, cones, or stilts. 


Tensile Strength

How strong, or resistant, a material is against being torn apart by tension. 


Thermal Conductivity

How effective a material is at letting heat pass through it. 


Thermal Shock

How prone to damage a material is when exposed to changes in temperature.



The way in which materials fuse during firing. 



An instrument for measuring heat at high temperatures.



The pyrolysis (or devolatilization) process is the thermal decomposition of materials at elevated temperatures in an inert atmosphere. It involves a change of chemical composition.


Hot pressing

A high-pressure, low-strain-rate powder metallurgy process for forming of a powder or powder compact at a temperature high enough to induce sintering and creep processes. This is achieved by the simultaneous application of heat and pressure.


Reaction Sintered Silicon Carbide (RBSiC)

Reaction sintering SIC is a reaction of silicon that is uniformly mixed and infiltrated with fine particles -Sic, carbon powder and additives in proportion to generate -Sic and combine with -Sic, and excess silicon is filled into the voids, thereby obtaining a highly dense ceramic material.


Pressureless Sintered Silicon Carbide (SSIC)

The material is a dense SIC ceramic product made by pressureless sintering of high-performance sub-micron SIC powder. It does not contain free silicon and has fine grains. It has excellent properties such as high temperature resistance, high strength, high hardness, high corrosion resistance, and oxidation resistance. It is the preferred general material for domestic and international manufacturing of mechanical seal rings, sandblasting nozzles, bulletproof armor, magnetic pumps, and canned pump components. It is especially suitable for conveying corrosive media such as strong acid and alkali.


Pressureless Sintered Silicon Carbide Plus Graphite (SSiC + G)

Pressureless graphite products are made by adding fine graphite particles and sintering at high temperature on the basis of pressureless sintering SIC. The material not only has the excellent properties of SSIC, but also improves the self-moisturizing slipperiness and dry friction resistance of the material due to the presence of graphite particles. It is suitable for use in working conditions with strong corrosion, high load, dry friction, hard-hard combination, such as sliding bearings.


Microporous Pressureless Sintered Silicon Carbide (Microporous SSiC)

This material is a special pressureless sintering SIC that optimizes the friction performance of the sealing surface. It forms uniformly distributed and independent spherical micropores that are not connected to each other during the sintering process. When the friction pair contacts the fluid medium, the spherical microporous The hole will act as the reservoir of the fluid medium, so that the medium can fully lubricate, thereby reducing the friction coefficient and the friction heat of the end face; when the fluid medium is insufficient, the fluid storage effect of the micropores will improve the lubrication conditions and help promote A fluid film is maintained at the sliding interface. This microporous lubrication mechanism makes the microporous SSIC superior to conventional reaction sintered and pressureless sintered silicon carbide under many working conditions, and is used in limited lubrication conditions and harsh application environments with hard-to-hard grinding surface combinations. Suitable for making water pump seals, sliding bearings, etc.


Anisotropic Magnet

A magnet having a preferred direction of magnetic orientation, so that the magnetic characteristics are optimum in that direction.


Coercive force, Hc

The demagnetizing force, measured in Oersted, necessary to reduce observed induction, B to zero after the magnet has previously been brought to saturation.


Curie temperature, Tc

The temperature at which the parallel alignment of elementary magnetic moments completely disappears, and the materials is no longer able to hold magnetization.


Intrinsic Coercive Force, Hci

An intrinsic ability of a material to resist demagnetization. Its value is measured in Oersted and corresponds to zero intrinsic induction in the material after saturation. Permanent magnets with high intrinsic coercive force are referred as “Hard” permanent magnets, which usually associated with high temperature stability.


Gauss, Gs

A unit of magnetic flux density in the GCS system; the lines of magnetic flux per square inch. 1 Gauss equals 0.0001 Tesla in the SI system.



The condition existing in a medium subjected to a magnetizing force. This quantity is characterized by the fact that an electromotive force is induced in a conductor surrounding the flux at any time the flux changes in magnitude. The unit of flux in the GCS system is Maxwell. One Maxwell equals one volt x seconds.


Oersted, Oe

A unit of magnetizing force in GCS system. 1 Oersted equals 79.58 A/m in SI system.


Hysteresis Loop

A closed curve obtained for a material by plotting corresponding values off magnetic induction, B (on the abscissa), against magnetizing force, H (on the ordinate).


Induction, B

The magnetic flux per unit area of a section normal to the direction of flux. The unit of induction is Gauss in the GCS system Intrinsic Coercive Force, Hci: An intrinsic ability of a material to resist demagnetization. Its value is measured in Oersted and corresponds to zero intrinsic induction in the material after saturation. Permanent magnets with high intrinsic coercive force are referred as “Hard” permanent magnets, which usually associated with high temperature stability.


Irreversible Loss

Defined as the partial demagnetization of a magnet caused by external fields or other factors. These losses are only recoverable by remagnetization. Magnets can be stabilized to prevent the variation of performance caused by irreversible losses.


Isotropic Magnets

A magnet material whose magnetic properties are the same in any direction, and which can therefore be magnetized in any direction without loss of magnetic characteristics.


Magnetic Flex

The total magnetic induction over a given area.


Magnetizing Force

The magnetomotive force per unit length at any point in a magnetic circuit. The unit of the magnetizing force is Oersted in the GCS system.


Maximum Energy Product, (BH)max

There is a point at the Hysteresis Loop at which the product of magnetizing force H and induction B reaches a maximum. The maximum value is called the Maximum Energy Product. At this point, the volume of magnet material required to project a given energy into its surrounding is a minimum. This parameter is generally used to describe how “strong” this permanent magnet material is. Its unit is Gauss Oersted. One MGOe means 1,000,000 Gauss Oersted.


Permeability, Recoil

The Average slope of the minor hysteresis loop.


Remenance, Bd

The magnetic induction which remains in a magnetic circuit after the removal of an applied magnetizing force. If there is an air gap in the circuit, the remenance will be less than the residual induction, Br.


Reversible Temperature Coefficient

A measure of the reversible changes in flux caused by temperature variations.


Residual Induction, Br

A value of induction at the point at Hysteresis Loop, at which Hysteresis loop crosses the B axis at zero magnetizing force. The Br represents the maximum magnetic flux density output of this material without an external magnetic field.



A condition under which induction of a ferromagnetic material has reach its maximum value with the increase of applied magnetizing force. All elementary magnetic moments have become oriented in one direction at the saturation status.



The bonding of powder compacts by the application of heat to enable one or more of several mechanisms of atom movement into the particle contact interfaces to occur; the mechanisms are: viscous flow, liquid phase solution-precipitation, surface diffusion, bulk diffusion, and evaporation-condensation. Densification is a usual result of sintering.


Surface Coatings

Unlike Samarium Cobalt, Alnico and ceramic materials, which are corrosion resistant, Neodymium Iron Boron magnets are susceptible to corrosion. Base upon of magnets’ applications, following coatings can be chosen to apply on surfaces of Neodymium Iron Boron magnets.



An ability to resist to demagnetizing influences expected to be encountered in operation. These demagnetizing influences can be caused by high or low temperatures or by external magnetic fields.



The S.I. unit for magnetic induction (flux density). One Tesla equals 10,000 Gauss.