Ceramics are usually inorganic materials consisting of metal and non-metallic elements are ionic compounds. Some ceramics partially ionic, covalent bond may partially. Structure and properties of complex compounds containing different types of elements are different, some are amorphous, some are crystalline. Melting temperatures are high, chemically stable and resistant to external influences.
Although the compression strength with high tensile strength is very low. They are brittle internal structure defects, dents, scratches and microcracks cause stress concentration, therefore the drawing effect on brittle. The average compressive strength of the ceramic is eight times the tensile strength. The resistance to tensile stresses on the surface creating a residual pressure can be increased through thermal treatment. The slip resistance of ceramic is very high, plastic deformation without substitution break off. In addition, some widely used as they are very hard abrasive materials.
Ceramics are generally insulating and dielectric materials. Electrical conductors but react in an electiric field. Ceramic with a high dielectric are used in production of capacitors. Quartz crystal and barium titanate turn mechanical effect to the electrical response, the electrical response to the mechanical response. It has this feature called piezoelectric ceramics are used in the electronics industry.
|Unit||Al O - 99%23||Al O2 3|
|Modulus of Elasticity||GPa||330||280|
|Thermal Expansion||-610 / K||8,2||8|
|Thermal Conducitivity||W / (m-K)||30||26|