Copyright © 2007 Dorling Kindersley
The word ceramic comes from an ancient Greek word for “burned earth”. Ceramics are made by firing (heating) clay (fine particles of earth) in an oven called a kiln or furnace. China, bricks, and tiles are made from ceramics. Over the past few decades, ADVANCED CERAMICS have been developed with superior or additional properties to traditional ceramics.
Porcelain has the finest texture of all ceramics. It is made from a white clay called kaolin, fired at very high temperatures. Most ceramics let water through until they are glazed, but porcelain is naturally water-resistant already. It is valued for its glassy smoothness and translucency.
Ceramics can be thrown (made) by shaping a lump of wet clay on a wheel (a turning plate). The potter places the clay on the centre of the wheel, then skilfully raises it into shape by hand.
The pot is fired in a kiln. The first firing, called the bisque firing, hardens the clay. A coating called a glaze is painted onto the pot, and the pot is fired again. Glaze waterproofs the pot.
This master potter and industrialist introduced many kinds of coloured pottery. He is best known for his Jasper Ware, with classical designs in white on blue or green. He also invented a pyrometer to measure kiln temperature.
Bio-ceramics now replace teeth and bones. They are one example of advanced ceramics. Each type is made from a particular component of pure clay. It is heated at a specific temperature, sometimes in a specific gas environment, such as nitrogen. This changes the ceramic’s chemical structure and properties.