Structure Of Metal And Ceramics

The two most common chemical bonds for ceramic materials are covalent and ionic.

Structure of metal and ceramics.

Ceramics are by definition natural or synthetic inorganic non metallic polycrystalline materials. Bonding ranges from ionic to covalent. A cermet is a composite material composed of ceramic and metal materials. The metal is used as a binder for an oxide boride or carbide.

Charge balances and relative ion size plays key roles in determining structure and properties. For metals the chemical bond is called the metallic 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. Generally the metallic elements used are nickel molybdenum and cobalt.

In atomic structure they are most often crystalline although they also may contain a combination of glassy and crystalline phases. 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. Depending on the physical structure of the material cermets can also be metal matrix. Ceramic crystal structures generally more complex than metals because they are composed of at least two elements or more.

Most ceramics usually contain both metallic and nonmetallic elements with ionic or covalent bonds. The atoms in ceramic materials are held together by a chemical bond. The properties of ceramics however also depend on their microstructure. Sometimes even monocrystalline materials such as diamond and sapphire are erroneously included under the term ceramics.