Abrasive: A hard material used to grind, cut or wear.
Absorption: The inclusion of the energy of a photon within a substance.
Amorphous: A noncrystalline substance, atoms lack long range order.
Annealing: Heat treatment to alter properties.
Annealing point (glass): Temperature at which stresses are removed.
Atomic vibration: Movement of an atom within a substance.
Band gap energy: Energy difference between the valence and conduction bands.
Brittle fracture: A break that occurs by rapid crack propagation.
Capacitance (C): Charge storing capability.
Cement: A material that binds particles together in a mixture.
Ceramic: A compound of metallic and nonmetallic elements.
Color: Wavelengths of light perceived by the eye.
Component: A part, or device. Conduction band: Carries the excited conduction electrons.
Conductivity: The ability to carry an electric current (electricity) or thermal energy (heat).
Covalent bond: Bonding by sharing electrons.
Crystalline: A solid with a repeating three-dimensional unit cell.
Crystal structure: The orderly arrangement of the atoms or ions within a crystal.
Diamagnetism: Weakly repelled from a magnetic field.
Dielectric: An insulator.
Dielectric constant: Relative electrical permittivity of a material as compared to a perfect vacuum.
Dielectric (breakdown) strength: The amount of electricity needed to start an electric current flow in a dielectric material.
Ductile fracture: Break accompanied by large plastic deformation.
Elastic deformation: Change in shape that returns when a stress is removed.
Elastic Modulus: Ratio of stress to strain in elastic deformation, measure of elasticity.
Electric field: The gradient of voltage.
Electronegativity: The attraction of an atom for shared electrons.
Electron volt (eV): Unit of energy equivalent to the energy gained by an electron when it falls through an electric potential of one volt.
Excited state: An energy state to which an electron may move by the absorption of energy.
Fiber Optics: The technology of transferring information as light pulses through long thin fibers, usually made of glass.
Firing: High temperature processing to increase densification in a product.
Fluorescence: Light that is emitted a short period of time after an electron has been excited.
Fracture toughness (Kc): Measure of a material's resistance to crack propagation.
Glass: An amorphous solid showing characteristic specific volume behavior over a certain temperature range.
Glass - ceramic: Crystalline ceramic material that was formed by heat treating glass.
Glass transition temperature (Tg): Temperature at which a glass changes from a supercooled liquid into a solid.
Grain: Individual crystal in a polycrystalline material.
Grain boundary: The boundary between grains (or crystals) that are misoriented with respect to one another.
Green ceramic body: Ceramic object that is dried but not fired.
Ground state: Lowest electron energy state.
Hardness: Resistance to deformation.
Heat capacity: Heat required to produce a unit increase in temperature per quantity of material.
Imperfection: Flaw, any deviation from perfection, as in a crystal.
Index of refraction: Ratio of the speed of light in a vacuum to the speed of light in a medium.
Insulator: Material that does not conduct electricity (electrical) or heat (thermal).
Ionic bond: Electrostatic force between oppositely charged ions.
Laser: Source of coherent light (Light Amplification by Stimulated Emission of Radiation).
Lattice: The regular arrangement of points in a crystal.
Luminescence: Emission of visible light when an electron returns to the ground state from an excited state.
Magnetic field strength: Intensity of an applied magnetic field.
Microstructure: Structural features that can be observed with a microscope.
Noncrystalline: Amorphous, with no long-range atomic order.
Opaque: Material that does not transmit light.
Phonon: Quantum of vibrational energy.
Phosphorescence: Luminescence that lasts for more than one second.
Photovoltaic cells: A device capable of converting light energy to electricity.
Photoconductivity: Electrical conductivity induced by light.
Photon: Quantum of electromagnetic energy.
Piezoelectric: Material that produces an electrical response to a mechanical force.
Plastic deformation: Permanent deformation, change of shape.
Polycrystalline: Composed of more than one crystal or grain.
Porcelain: A durable ceramic composite made by firing clay, feldspar and quartz together.
Reflection: Deflection of light at the interface between two materials.
Refraction: Bending of light as it passes from one medium into another.
Refractory: Material that can be exposed to high temperature without deterioration.
Resistivity: Measure of resistance to passage of electrical current (reciprocal of conductivity).
Semiconductor: Nonmetallic material that has a relatively narrow energy band gap.
Sintering: Coalescence of individual ceramic particles into a continuous solid phase at a high temperature.
Slip: Mixture of clay with water that can be poured into a mold.
Slip casting: Method of making ceramic objects by pouring slip into a mold.
Softening point (glass): Maximum temperature a glass can be heated before it permanently deforms.
Smart materials: Materials able to detect a change in the environment and react to it.
Specific volume: Volume per unit mass, reciprocal of density.
Strain: Change in length of a sample in the direction of an applied stress.
Stress: Force applied to a sample divided by its cross-sectional area.
Structural clay products: Ceramic objects made mainly of clay and used in structural applications.
Structure: Arrangement of internal components.
Superconductivity: Disappearance of electrical resistivity at low temperatures.
Supercooling: Cooling below the normal temperature for a phase change, without the change occurring.
Tensile strength: Maximum stress without fracture.
Thermal expansion coefficient, linear: Fractional change in length divided by change in temperature, a measure of a materials tendency to expand when heated.
Thermal stress: Residual stress caused by a change in temperature.
Thermal tempering: The introduction of residual compressive stresses to increase the strength of glass.
Toughness: Energy absorbed by a material as it fractures, a measure of its resistance to fracture.
Transgranular fracture: Fracture by crack propagation through the grains.
Translucent: Transmits light diffusely.
Transparent: Transmits light clearly.
Unit cell: The basic repeating unit in a crystal.
Whiteware: Clay-based ceramic that turns white after firing.