Structure Of Metal And Ceramics

The properties of ceramics however also depend on their microstructure.

Structure of metal and ceramics. A cermet is ideally designed to have the optimal properties of both a ceramic such as high temperature resistance and hardness and those of a metal such as the ability to undergo plastic deformation. Usually they are metal oxides that is compounds of metallic elements and oxygen but many ceramics especially advanced ceramics are compounds of metallic elements and carbon nitrogen or sulfur. Sometimes even monocrystalline materials such as diamond and sapphire are erroneously included under the term ceramics. A cermet is a composite material composed of ceramic and metal materials.

Ceramics are by definition natural or synthetic inorganic non metallic polycrystalline materials. The atoms in ceramic materials are held together by a chemical bond. Polycrystalline materials are formed by multiple crystal grains joined together during the production process whereas monocrystalline materials are grown as one three dimensional crystal. Most ceramics usually contain both metallic and nonmetallic elements with ionic or covalent bonds.

Ceramic crystal structures generally more complex than metals because they are composed of at least two elements or more. Charge balances and relative ion size plays key roles in determining structure and properties. The two most common chemical bonds for ceramic materials are covalent and ionic. Depending on the physical structure of the material cermets can also be metal matrix.

The metal is used as a binder for an oxide boride or carbide. In atomic structure they are most often crystalline although they also may contain a combination of glassy and crystalline phases. Generally the metallic elements used are nickel molybdenum and cobalt. The bonding of atoms together is much stronger in covalent and ionic bonding than in metallic.