Engineering ceramics

From ArticleWorld

Engineering ceramics are those ceramic products which are used in high performance applications under harsh industrial environments. These materials are used to further develop more sophisticated equipment used in engineering fields.

Need for engineering ceramics

Engineering systems have constantly been undergoing improvements, especially since the Industrial Revolution days. The tasks that they are required to perform are increasing in complexity. This has brought about the need to develop new materials that can support new technology. The study of engineering ceramics is therefore carried out in conjunction with other important fields like engineering metallurgy.

Engineering ceramics are known to possess the following basic properties, which make them suitable to use as alternatives in situations where metals fail to withstand harsh conditions:

• High resistance to wear and tear.
• High mechanical strength, even at extremely high temperatures.
• High level of hardness.
• High level of stiffness.
• Excellent resistance to corrosion due to agents like acids, alkalis and organic solvents.

Engineering ceramics – Their development and application

The word 'ceramic' is derived from the Greek word which refers to pottery. Ceramics are formed in the wet plastic state and then allowed to dry, after which they are subjected to high temperature. The final heat treatment which is imparted to the ceramics gives them the high hardness and superior mechanical strength that they require for use in harsh engineering environments.

Engineering ceramics are mainly obtained from inorganic substances and are invariably non-metallic in their physical and chemical nature. They are good insulators of both heat and electricity, which makes them the right choice for use in high temperature furnaces. Materials such as alumina are suitable for such applications. With the use of ceramic-based furnaces, it has become possible to extract metals such as cast iron from its ore.

Though at normal temperatures ceramics are bad conductors of electricity, under sufficiently low temperatures superconductivity has been observed in some ceramic materials. This is a major breakthrough in modern technology and is under deep research to improve its feasibility.

Many active machine parts are made up of ceramics instead of metals. This is because of the high durability of ceramics and better resistance to wear. Ceramic blades, for instance, are far more durable than steel blades and do not require frequent sharpening.

Metals are known to weaken at high temperatures; this is when ceramics become the right alternative. Examples of such high-temperature resistant materials are zirconia, alumina, diamond and silicon carbide. These materials can withstand temperatures well above 1500°C, unlike most metals, which fail at such high temperatures.