|
| search | sitemap | links | legal | contact us | |||
|
|||
 |
|||
|
|
Glossary of Glass & Ceramic Terms ABS APP Ammonium Poly Phosphate - common phosphate flame retardant also used in intumescent systems. ATH Aluminium Tri-Hydroxide (hydrate) - endothermic flame retardant. ATO/TRIOX Antimony Tri Oxide - halogen synergist. Biscuit Ware Pottery bodies after the first firing stage. Body Stain Colour stains added to a clay body. Bone China A thin and translucent china made from a body containing bone ash, china clay and Cornish stone. Coefficient of Expansion A measure of the reversible change of volume or length of a glass or ceramic material with temperature. Covercoat Often referred to as overprint lacquer, printed onto glass & ceramic decals which when dried creates the vehicle by which the inks can be removed form the decal paper. Acrylic resin and plasticiser in aromatic hydrocarbon solvent. Decal The in-direct printing method for the production of glass or ceramic transfers. Dilatancy The property of a suspension to thicken when stirred and to thin again when stirring is stopped. DINP Di-Iso Nonyl Phthalate - plasticiser widely used for flexible PVC. Earthenware A moderately porous pottery formed from a body containing ball clay, china clay, flint and Cornish stone, which is fired to a temperature somewhat below that required to produce a vitreous article. EMR Excess Metal Release Enamel A fusible vitreous coating for application onto glass & ceramics at low temperatures. Engobe A coloured coating of slip applied to a ceramic body before glazing to improve its appearance. Eutectic A mixture of two or more substances which has the lowest melting point in the whole series of possible compositions. Flux A substance added to a material to enable it to fuse more readily, i.e. at a lower temperature (e.g. alkali oxides). This liquid or cooling forms a glass which binds the grains of the body together. Frit Any fused substance or mixture quenched to a glass Glaze A thin glassy layer formed on the surface of a ceramic product by exposure of the coated article to a high temperature. Usually applied in the form of a suspension of ground glaze in water, to the clay or biscuit surface of the ware. Glaze body Fit Ideally the glaze should have a lower thermal expansion than the body, so that on contraction the body puts the glaze into compression. This avoids the crazing of the glaze due to tensile stresses in it Glaze Stain Colour added to the glaze. HRR Heat Release Rate Intumescence The increase in volume of a material when subjected to heat. IR Infra-Red - IR-Drying or IR-Curing LOI "Loss On Ignition" - The loss in weight of a material expressed as a percentage of its dry weight when heated under specified conditions. Majolica In modern pottery, a soft opaque coloured glaze, temperature approx. 900°C - 1050°c. Originally named from the island of Majorca where it was first made in the 16th century. Basically similar to Delft. MDH Magnesium (Di) Hydroxide (hydrate) - endothermic flame retardant. Moisture Expansion The extent to which a porous ceramic material will expand in size when it absorbs water or water vapour. OPL Over-print Lacquer - see Covercoat Pad Printing A silicone pad is used to draw ink from recesses on a printing plate and then pressed directly onto the product. PE Poly Ethylene - common resin. Porcelain A vitrified and translucent ware made from a body containing china clay, ball clay, quartz and feldspar which is made by one firing only. Porosity The amount of pore space in a ceramic material, which may consist of both open and sealed channels. PP Poly Propylene - common resin. PSD Particle Size Distribution' - For a powder it indicates both the variety of particle sizes and the proportion of particles of each size. PVC Poly-Vinyl Chloride - common resin. Sintering The adhesion and densification of particles of a single phase on heating. SOD Specific Optical Density SSOF Surface Spread of Flame STA Simultaneous Thermal Analysis Thermal Shock The disruption of a ceramic article by stresses set up due to differences in temperature in different parts of the article. Thixotropy The property of a suspension to continue thinning when stirred. TP Thermo-Plastic - a printing media that is solid at room temperature and becomes liquid when heated. Triaxial Refers to the three stain system comprising Zircon-Iron Coral, Zircon-Vanadium Turquoise & Zircon-Praseodymium Yellow. UL94© Underwriters Laboratories 94© - common small-scale ignition test. Underglaze Any method of decoration applied before the glazing process. UV Ultra-Violet - UV-Drying or UV-Curing Viscosity The resistance to flow offered by a liquid. Vitreous As applied to ceramics, means glassy. Having extremely low or no porosity. Vitrification The progressive fusion of a material or body during the firing Wetting Agent A chemical which when added to a liquid reduces its surface tension and causes the liquid to wet solid surfaces more efficiently. ZHS Zinc Hydroxy Stannate - potential ATO replacement. |
||
