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The Nature of Ceramics

One of the first solid materials, if not the very first, that man learned to use was ceramic natural stone. It was used in a variety of applications because of its characteristic properties such as hardness, strength to chemical attack which make it comparatively easy to shape. Thus natural ceramics provided man with tools, durable containers and even a roof. It is not surprising that man got greatly interested in ceramics and tried to create ceramics such as: pottery, bricks, concrete, glass. These products are spoken of as main industrial products to this day.

Ceramic material have been extended greatly. They range from dull clay to lustrous ruby, from the refractory linings to electronic control devices.

What is ceramics? Can this question be answered? Essentially it is defined as a combination of one or more definite metals with a non-metallic element, usually oxygen. The comparatively large oxygen atoms serve as a matrix with the small metal atoms. The main characteristic of the construction of ceramic crystals is that the atoms are linked by bonds that are primarily ionic but also to a significant extend covalent. These bonds are responsible for the stability and strength of ceramic materials. In the combination of oxygen atoms with metal atoms the ionic bonds are particularly strong. It should be noted that each oxygen atom with two electronic vacancies in its outer shell borrows two electrons from its metal neighbors, thus both kinds of atom become highly ionized – one negatively, the other positively.

As highly oxidized compounds the ceramics are strongly resistant to attack by nearly all chemicals. This accounts for many of their uses, even the making of steel depends on the use of ceramics.

A lot of analyses have been made by chemists. They found that the principal elements, for instance, in natural clays were oxygen, silicon and aluminium. They form the compounds known as aluminosilicates.

But a giant step forward in ceramic science came when crystal structures were analysed by means of X-ray diffraction. It has been found out that in the construction of ceramic materials much depends on how the atoms are stacked.



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Many scientists both in Soviet Union and abroad work at the investigation of the properties of ceramic products. Many ceramic materials are being mass-produced now. They can be drawn into rods, cast or pressed. These ceramics are light in weight, but very strong. Some of tem are so hard that they can cut steel. You can hardly find any branch of industry where ceramic products are not used.

 


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