Ceramics exhibit good strength under compression; however, they exhibit virtually no ductility under tension.
Ceramics家族包括polycrystalline and single-crystal inorganic materials, inorganic glasses, and glass-ceramics.
Classification
一般我们不以chemical compounds分类，而是以major function分类。
- electrical
- magnetic
- optical
- automotive
- mechanical/structural
- biomedical
- construction
- others
- chemical
- domestic
Structure
有amorphous但主要是crystalline:
- Sodium chloride
- Diamond cubic
- Cubic zincblende(ZnS) (sphalerite)
- Fluorite(CaF2)
- Hexagonal zincblende(ZnS) (wurtzite)
Applications (重点)
- Alumina (Al2O3)
- Diamond (C)
- Silica (SiO2)
- Silicon carbide (SiC)
- Silicon nitride (Si3N4)
- Titanium dioxide (TiO2)
- Zirconia (ZrO2)
Bonding
Ceramics由primary bonds组成，这些bonds主要是ionic or covalent还有少量的metallic bonding.
A large amount of thermal energy must be provided to cause atoms or ions to separate to larger interatomic or interionic distances, thereby leading to melting.
High melting point materials also tend to have high elastic moduli (弹性模量), meaning that the bonds are stiff (high stiffness).
Materials that have predominantly ionic or covalent bonds lack free electrons to conduct electricity.所以它是good thermal insulators.
例外就是diamond, since diamond has extraordinarily stiff bonds that efficiently transport heat.
