Glossary
Processes
CD Source
Closed Drift ion source. "Closed-Drift" refers to the physics of the ion source operation.
The electrons that maintain the plasma are confined by electric and magnetic fields that interact and capture the electrons in the front of the source. The electrons effectively are forced to "drift" around a circular path.
CIM
Ceramic Injection Moulding. A production technique where ceramic powders are mixed with a plastic into a pliable paste and forced into a mould.
CNC Machining
Computer Numerically Controlled Machining
CVD
Chemical Vapour Deposition A production technique involving the reaction of gaseous chemicals, the product of which will deposit onto a prepared substrate.
Glaze
A surface coating that seals any open porosity of the bare ceramic surface from contamination or moisture pickup
IBS
Ion Beam System. Equipment to apply a coating to a substrate by way of ion beam.
MIM
Metal Injection Moulding, very similar to CIM, this technique uses specially prepared metal powders to make metal components
Piezoelectric
When mechanical pressure is applied to one of these materials, the crystalline structure produces a voltage proportional to the pressure. Conversely, when an electric field is applied, the structure changes shape producing dimensional changes in the material. The amount of deformation is proportional to the applied electric field and the d33 coefficient of the material
Poling
The application of a high electric field resulting in dipole alignment within the material.
Sintering
The heating process that transforms a green ceramic and densifies the material into a stronger state.
Materials Properties
Coefficient of thermal expansion
Either volumetric or linear this describes the expansion that occurs with a change in temperature. Volumetric describes the volume change whereas linear describes the change in dimensions.
Dielectric Constant
The relative permittivity of a material. Indicates the ability of a material to store electrical energy when a voltage is applied to it.
Dielectric Loss
This is the proportion of energy that is dissipated within a dielectric material and lost as heat in an electrostatic field.
Dielectric Strength
The minimum electric field that produces breakdown of the insulating properties of the dielectric.
Dissipation Factor
The dissipation factor is a measure of the loss of power that takes place in virtually all dielectric materials, usually in the form of heat. It is expressed as the ratio of the resistive (loss) component of the current to the capacitive component of current, and is equal to the tangent of the loss angle.
Green Ceramic/ Green Body
A ceramic part in an unfired state
Hermetic Seal
Airtight seal
Loss Factor
This is the product of the Dielectric Loss and the Dielectric Constant of a dielectric material.
Poisson’s Ratio
When a sample of material is stretched in one axis, it tends to get thinner in the other two axes. Poisson's ratio (ν) is a measure of this tendency. It is defined as the ratio of the strain in the direction of the applied load to the strain normal to the load. For a perfectly incompressible material, the Poisson's ratio would be exactly 0.5.
Porosity
The proportion of the non-solid volume to the total volume of material.
Thermal Downshock
Thermal downshock is the name given to cracking resulting from rapid temperature change. It occurs when a thermal gradient causes different parts of an object to expand by different amounts. This differential expansion can be understood in terms of stress or of strain, equivalently. At some point, this stress overcomes the strength of the material, causing a crack to form. If nothing stops this crack from propagating through the material, it will cause the component to catastrophically fail.
Young’s Modulus
Young's modulus (or elastic modulus) is a measure of the stiffness of a given material. It is defined as the limit for small strains of the rate of change of stress with strain. This can be experimentally determined from the slope of a stress-strain curve created during tensile tests conducted on a sample of the material. Young's modulus is named after Thomas Young the English physicist, physician, and Egyptologist
Materials and products
RBSN
Reaction Bonded Silicon Nitride
ZTA
Zirconia Toughened Alumina
PZT
a) Piezoelectric Transducer
b) Lead Zirconate Titanate, Pb(Zr,Ti)O3
