Difficulty of dislocation motion
high yield stress
are non-metallic inorganic compounds formed from metallic (Al, Mg, Na, Ti, W) or
semi-metallic (Si, B) and non-metallic (O, N, C) elements.
Atoms of the elements are held
together in a ceramic structure by one of the following bonding mechanism: IonicBonding, Covalent Bonding, Mixed Bonding (Ionic-Covalent).
Most of ceramic materials have
a mixed bonding structure with various ratios between Ionic and Covalent
components. This ratio is dependent on the difference in the electro_ negativities
of the elements and determines which of the bonding mechanisms is dominating
ionic or covalent.
component fractures before it can deform
low toughness
susceptible to thermal shock
often combined with other materials ( composite)
to improve overall toughness
Toughness of ceramics