Industrial Ceramics

Industrial ceramics are inorganic materials obtained from mixtures of fine powders of crushed mineral raw materials, compacted and fired at high temperatures, generally between 800 and 1500°C. The majority of ceramics manufactured worldwide are silicate ceramics (the term "silicate ceramics" is generally accepted). They are usually referred to as "traditional ceramics" because of the very long history of these techniques, but recent and significant developments in the scientific and technological aspects contributed by numerous research laboratories around the world and applied to industrial processes mean that these ceramics are now modern, high-tech materials.

Industrial ceramics are predominantly hard, tough and relatively refractory materials. Their mechanical properties are specifically those of materials with brittle behavior, although their mechanical strength is often high. Their thermal conductivity is low, and they are good electrical insulators. Their surface is often rough and sometimes porous, requiring the use of a vitrified enamel-type surface finishing material, which is also a good support for decoration.

They are used in everyday applications, i.e. building (bricks, tiles, etc.), cladding and decoration (floor and wall tiles), tableware (plates, bowls, cups, etc.) and sanitaryware (sinks, trays, etc.). These widely distributed materials are manufactured in very large quantities around the world, in response to large and constant demand, which explains the continued existence of a large industrial sector comprising companies producing mineral raw materials, ceramic products and industrial and laboratory equipment. Over the last few decades, this industrial sector has undergone major scientific and technological changes to enhance its competitiveness and modernity.

Industrial ceramics are either porous or vitrified. Porous ceramics include terracotta, earthenware and some common stoneware, while vitrified ceramics include vitrified stoneware, also known as "vitréous", and porcelain. Porous materials have a highly heterogeneous microstructure at the grain and pore scale (a few μm to a few 10 μm), making these materials opaque, permeable to water and not very mechanically resistant. Vitrified materials have a homogeneous, impermeable microstructure, with crystallized phases distributed in a vitrified phase serving as matrix. In the case of porcelain, the nature and quantity of the crystallized and vitrified phases mean that the materials are more mechanically resistant and translucent.

The compositions from which these ceramics are made are a blend of three main groups of mineral raw materials:

• plastic raw materials, clays and kaolins ;

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