What is Ceramics?

According to the definition, ceramics are inorganic, non-metallic solid materials, which during manufacture are heat treated at temperatures above 600°C. The latter is to leave out naturally occurring stones. technical ceramics- ceramic knife Ceramics are divided in traditional ceramics (porcelain, ceramic ware, pottery, refractories, enamel and glass) and in technical ceramics (for instance pure aluminium oxide and silicon nitride). While traditional ceramics are well known to most of us, technical ceramics are not as apparent at first glance. Technical ceramics are serving particular purposes in a vast number of industrial applications and are often hidden inside the final products and thus "invisible" to us. There are of course exceptions such as the common ceramic cutting knives, which are made of zirconium dioxide (zirconia).

The market for technical ceramics is growing steadily. This is because of their exceptional material properties, which are taken advantage of in applications where other materials do not perform as well or do not work at all. Technical ceramics are divided into two sub-groups: engineering ceramics and functional ceramics. Engineering ceramics are used primarily because of their favourable mechanical properties, often in combination with other useful physical properties such as chemical inertness and electrical resistivity. For functional ceramics, there are mainly inherent specific physical properties (such as conductivity, dielectricity, piezoelectricity, ferroelectricity, ferromagnetism and permeability) that are of interest for certain applications. In this case, the mechanical properties come second in terms of importance.

Ceramic materials can have a fully or partly crystalline structure or in some cases be totally amorphous, such as common glass. One example of a usual technical ceramic material that is crystalline is aluminium oxide (alumina). This material consists of tightly joined micrometer- sized crystals of the atomic elements aluminium and oxygen. The image to the left shows the microstructure of high-purity aluminium oxide.


Writing in progress. If you understand Swedish, please read on at "Om keramer".

technical ceramics - alumina al2o3 structure