What is China clay and Ceramics?
China Clay:
Ceramics is derived from the Greek words "Keramos' which means potter's clay. Ceramics is a type of clay which contains the compound of carbon, hydrogen, nitrogen, oxygen and silica. It is used to make cups, plate, dishes etc. The clay contains mainly hydrated alumina silicate (AL2O3.SiO3.2H2O). This may also contain other substances like limestone, magnesium carbonate, oxides of manganese and iron. The pure white clay is called kaolin, or China clay. It is used for making cups, plates, dishes, etc.
In order to make ceramic materials, the clay is crushed, ground
and sieved to obtain fine clay. The clay is mixed with water to make a paste
and then cast into different shapes.
The objects of various shapes are allowed
to dry in sunlight for several days. After drying, the products are heated in furnace.
At high temperature, the soil hardens due to chemical reaction and becomes
porous.
A little amount of salt is added to make the objects shiny. Some
objects of ceramics are coated with oxides of tin or lead and are heated again.
The coat of tin oxide or lead oxides melts and forms a thin layer over their
surface. This process is called glazing. Glazing makes the articles smooth,
attractive and waterproof. Color and polish are also added in order to make the
ceramic items more attractive. Ceramics are poor conductor of heat and
electricity, it is used in an electrical appliances. Ceramics is used in making
crockery like cups, bowls, plates, dishes, etc. Ceramics is resistance to the
chemical reactions. So it is also used to make the laboratory apparatus.
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