Glossary

Acid Refractories

• Refractories containing a high proportion of silica, which may react with basic refractories, slags or fluxes at high temperatures.

Anorthite

• Also known as Calcium Feldspar; a low thermal-expansion aluminosilicate.

Automotive Components

• Gears, tappets, complex shapes, fixings, manifold parts, wear parts etc, which are often metallic and produced by the Powder Metallurgy method.

Batts

• Refractory tiles or slabs that are typically used as part of the kiln car superstructure and which also in certain applications actually support ware directly during the kiln firing cycle.

Bending Resistance

• Resistance to transverse or cross-bending caused by load at high temperatures.

Bung

• A stack of Saggars or Cranks.

Carbon-Ceramic Refractory

• A combination of carbon/graphite with one or more refractory ceramics, e.g. Silicon Carbide (SiC). Also called Plumbago, it is often used to make Crucibles.

Cast Refractories

• At IPS, these are our refractory products which are formed by slip-casting rather than by pressing or extrusion. These items have a low coefficient of thermal-expansion giving good thermal shock resistance, good bending strength and a wear-resistant surface. Working temperatures can be up to 1280°C.

Cordierite

• A magnesium aluminosilicate exhibiting very low and uniform thermal-expansion.

Cranks

• Particular types of refractory supports, most often used in the glost and decoration firings of tableware and also tiles. Cranks are generally built up into stacks separated by fixed legs or by refractory distance pieces known as dots.

Crucibles

• Refractory containers, often round but also square/boxed, which are used for the melting or calcination of materials such as minerals, glass and metals.

Crystallised Glass Panel

• Man-made building materials which are designed to mimic (but are less environmentally damaging than) naturally-occurring products such as granite and marble.

Devitrified Glass

• An older name for Glass-Ceramic.

Dots

• Refractory distance-pieces which are placed between Cranks to form a Bung.

Fast Firing

• Refers to the firing of ceramics where the firing cycle is measured in hours and minutes rather than days. Made possible by Low Thermal Mass (LTM) kilns, modern bodies, single-layer setting etc. Possible in both continuous and intermittent systems.

Ferrous Metals

• Metals such as steel that contain iron (Fe).

Frit

• A glass/ceramic composition that is melted, quenched and then granulated to be used in the production of glazes or porcelain enamels.

Fused Silica

• High-purity silica sand, electrically or flame-fused to form non-crystalline silica, which has good thermal-shock resistance. Can also be formed by the flame hydrolysis of silicon tetrachloride.

Glass-Ceramic

• Suitable for high-temperature applications, a glassy product containing a crystalline phase produced by incorporating small amounts of a nucleating agent into molten glass and then processing by heat treating.

Graphite Refractory

• Refractory product made substantially from graphite (a crystalline form of carbon).

H-Cassette

• An ‘H’ shaped Crank, which when stacked supports Heavy Clay items such as roof tiles; there are no posts and pins required. A camber often forms part of the cassette shape to control the final shape of the tile during firing.

Heat Treatment

• Where a material or component is heated and cooled in a particular way to develop specific properties such as strength, thermal-shock resistance etc.

Heavy Clay Products

• Generally taken to mean clay building components such as bricks, pavers, roof tiles, hollow blocks, chimneys and specials, as well as clay drainage pipes and tiles.

Hydrogen Atmosphere

• Sintering in a hydrogen atmosphere acts to reduce surface oxides on Powder Metal components, which improves the strength particle-to-particle sinter.

Insulating Refractory

• Refractory components (such as firebrick) which have a low Thermal Conductivity, reducing or slowing down the transfer of heat.

Isostatic Powder Compacting

• Where special powders are held in an impermeable membrane and subjected to hydrostatic pressure on all sides to create a compacted shape with uniform density.

Low Thermal Mass (LTM)

• By using stronger or lighter refractory materials, perforations, single layers etc, LTM kilns and furnaces require less heat input per degree of temperature increase. LTM components and design facilitate Fast Firing and enhanced fuel efficiency.

Machinable Ceramics/Refractories

• Fired ceramic components which will withstand such as CNC routing and other high-speed profiling methods without cracking or shattering – giving an end product to engineering tolerances.

Machining

• Shaping of a fired/sintered piece by mechanical removal of material, i.e. cutting, drilling, grinding or abrading.

Magnets

• Materials which produce a magnetic field external to themselves – often produced by Powder Metallurgy route.

Mullite

• A simple compound of alumina and silica that is strong at high temperatures due to a ‘needle-like’ crystal matrix.

Non-Ferrous Metals

• Metals such as aluminium, copper, brass, silver and lead which do not contain iron (Fe).

Oxidising Atmosphere

• A kiln or furnace atmosphere with partial oxygen pressure, allowing oxidation reactions to take place during firing/sintering.

Oxidation

• Chemical reaction where the oxygen content of a compound is increased.

Pinless Cranks

• Similar to T-supports/Cranks, but made using a high glaze-resistant material, and incorporating integral ridges on the placing surface, which preclude the need for separate pins.

Plaque

• Flat refractory piece, often used to carry pyrometric cones through a kiln or furnace.

Plumbago

• Same as Carbon-Ceramic Refractory.

Powder Metallurgy (PM)

• A process of pressing metal-containing powders and then sintering to form a metallic component.

Rapid Prototyping

• At IPS, this involves using a CNC routing machine to rapidly produce a sample setter, which has surface features equivalent to what would be produced by a metal die (to engineering tolerances), allowing the end-user to quickly approve designs without the need for a lengthy and expensive tool-making process.

Refractories

• Inorganic non-metallic materials or products with melting points above 1200°C and which therefore prove themselves ideal in high temperature processing.

Saggar

• A protective refractory box in which ceramic ware (usually electronic ceramics or tableware) can be placed for either its biscuit or glost firing. The saggar prevents contamination of the ware and physical damage as well as aiding in even heating. Also used for powder calcination.

Setters

• Special items of kiln furniture shaped (generally on their upper surface) to conform with the undersurface of plates and dishes, and which serve to support the ware and maintain its shape in the kiln during firing.

Sheet Glass

• Flat, transparent glass, produced by blowing, drawing or by the Float Glass process.

Silicon Carbide Refractories

• Non-oxide ceramics made from Silicon Infiltrated Reaction Bonded Silicon Carbide (SCS/SiSiC), Recrystallised Silicon Carbide (SCR/RSiC) and Nitride or Oxide-bonded Silicon Carbide (NSiC/SCO). These refractories exhibit high thermal-shock resistance, high bending strength, good wear resistance and also chemical resistance.

Sintering Plate

• In Powder Metallurgy, a refractory plate for carrying powder compacts through the furnace during component sintering.

Slabs

• Cordierite-mullite pieces of varying thicknesses, often used on roller kilns and a wide range of ovens – exhibiting excellent thermal shock resistance.

Stained Glass

• Coloured glass – where either colours are put in at the batch stage or are fired on to the surface of a hardened glass product.

Technical Ceramics

• A wide group of high-temperature products, including steatites, electro-porcelains (insulators etc), ferrites, engineering ceramics, etc.

Thermal Conductivity

• Rate of heat flow through a material in unit time per unit temperature gradient along direction of flow per unit of cross-sectional area.

Thermal-Shock

• Sudden and severe changes in temperature.

Thermal-Shock Resistance

• Ability to withstand Thermal Shock without fracture.

Time Compression Technologies

• Another term for Rapid Prototyping.

T-Supports / Cranks

• Designed to support the ware at three points around the foot during glost firing.

U-Cassette

• A ‘U’ shaped Crank made from a special refractory material and which when stacked supports, typically, Heavy Clay items such as roof tiles; there are no posts and pins required.

Y-Supports

• A type of Crank, they are designed to provide the maximum amount of support during glost firing; the legs of the crank radiate at 120° to each other and the crank has an integral leg.