Refractory materials are special products that retain their strength at high temperatures. They are used to make crucibles and to make refractory linings, which line furnaces, kilns and incinerators. The refractory material is the surface in the vessel or furnace that comes in direct contact with the extremely hot metal, glass or other material being processed. Thus, refractory materials must be strong at high temperatures, resistant to thermal shock, chemically inert, and have low thermal conductivities and coefficients of expansion. Refractories must be chosen according to the conditions they will face in service. Alumina, the oxide of aluminum, is an important refractory material used globally in a wide variety of industries, including steel production, cement production, petrochemicals, non-ferrous metal production, and glass production. Alumina-based refractories are valued, particularly by the world's steelmakers, for their superior mechanical strength and thermal shock resistance at the extreme temperatures used in materials production.
Ceramics are inorganic non-metallic materials whose formation is due to the action of heat. Up until the 1950s the most important ceramics were the traditional clays—made into pottery, bricks, tiles—along with cements and glass.
Technical ceramics have long been an important feature in our lives. Many household appliances would not be able to function without ceramic insulating elements. Insulators, fuses and circuit-breaker components made of technical ceramics are essential to a safe and reliable power supply. Ceramic substrates and components form the basis for a broad range of devices and subassemblies in all fields of electronics, while ceramic seals and regulator discs ensure a wear-free operation and proper sealing in many valves and household water taps. These few examples illustrate the important role played by technical ceramics in the world today. Since these ceramic components are parts of larger functional units in plant and equipment, machinery and motor vehicles, they are not usually highly visible. As a result, we rely on technical ceramics in our everyday life but are rarely aware of their presence.
Polishing is the process of creating a smooth surface. Often the objective is to create a shiny surface that looks very appealing, as in the metal polishing of a motorbike or a cooking pot. For metallic medical instruments the polished surface removes any minute grooves or surface imperfections where bacteria could easily grow. Household cleaners are formulated to remove stains from porcelain or other materials, while automotive polishes return a finish to its original luster. Stones are polished to enhance their natural beauty, while our teeth are polished to give them a whiter appearance. And for all these needs, Polishing Aluminas are widely utilized and valued. Alumina, with a Mohs' hardness of 9, is second only to diamond on the hardness scale, and is able to polish many softer materials.
Flame retardants are materials that inhibit or resist the spread of fire. Flame retardant chemicals are added to polymeric materials to reduce the flammability. The flame retardant chemical is mixed into the polymeric material during its compounding prior to manufacturing. The flame retarded polymer is then processed into an industrial or consumer product, such as carpeting for your workplace. Aluminum trihydroxide, or Al(OH)33, is an effective flame retardant and also a smoke suppressant because it is composed of 34% water, which is released when heated over 200C. This endothermic reaction cools the polymer material to reduce flame spread and smoke generation.