Structure Of Metal And Ceramics

Most ceramics usually contain both metallic and nonmetallic elements with ionic or covalent bonds.

Structure of metal and ceramics.

Ceramic crystal structures generally more complex than metals because they are composed of at least two elements or more. Sometimes even monocrystalline materials such as diamond and sapphire are erroneously included under the term 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. The properties of ceramics however also depend on their microstructure.

Polycrystalline materials are formed by multiple crystal grains joined together during the production process whereas monocrystalline materials are grown as one three dimensional crystal. Therefore the structure the metallic atoms the structure of the nonmetallic atoms and the balance of charges produced by the valence electrons must be considered. A cermet is a composite material composed of ceramic and metal materials. Generally the metallic elements used are nickel molybdenum and cobalt.

The metal is used as a binder for an oxide boride or carbide. Ceramics are by definition natural or synthetic inorganic non metallic polycrystalline materials. The bonding of atoms together is much stronger in covalent and ionic bonding than in metallic. Charge balances and relative ion size plays key roles in determining structure and properties.

Bonding ranges from ionic to covalent. In atomic structure they are most often crystalline although they also may contain a combination of glassy and crystalline phases. 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. The two most common chemical bonds for ceramic materials are covalent and ionic.