Ceramic materials

Ceramic materials

1. HOW CERAMICS MATERIALS ARE MADE

   • Preparation
     • The clay is cleaned to eliminate plant material, such as roots and leaves.
   • Mixing
     • The clay is mixed with water, colouring, temper and flux. With some ceramics, some of the raw materials melt
   • Shaping
     • The clay is shaped into its final form. Factory-made ceramics are typically shaped by moulds, presses or extruding machines.
   • Drying
     • The clay is dried to eliminate water. In factories, this process takes place in heated tunnels, using recirculated air.
   • Decoration
     • After objects have been fired, they can be decorated and finished with different types of glaze
   • Firing
     • This is done in special ovens called kilns at temperatures between 700ºC and 1700ºC, depending on the type of clay that is being used.

2. CLASSIFICATION OF CERAMIC MATERIALS

   • Terracotta
     • is made with ordinary clay that is usually a matte red colour. It is hard, rough and fragile.
   • Earthenware
     • is made from a mixture of white clay, silica and feldspar. It is fine and smooth, as well as hard.
   • Refractory ceramics
     • are made with baked clay and metal oxides. They can resist temperatures up to 3000ºC.
   • Stoneware
     • which is made from refractory clay, has a glass-like appearance. It is very compactable and hard enough to scratch glass
   • Porcelain
     • is made with a special white clay called kaolin. It is transparent, translucent, compact, acid-resistant and hard enough to scratch glass.

3. GENERAL PROPERTIES

   • Ceramic materials are made from clay, which is very abundant in nature. When clay is wet, it is both soft and pliable, so it can be shaped very easily. Once clay dries, it becomes porous and chemically inert, as well as resistant to high temperatures.