Structure Of Metal And Ceramics

The atoms in ceramic materials are held together by a chemical bond.

Structure of metal and ceramics.

The two most common chemical bonds for ceramic materials are covalent and ionic. Polycrystalline materials are formed by multiple crystal grains joined together during the production process whereas monocrystalline materials are grown as one three dimensional crystal. Bonding ranges from ionic to covalent. Most ceramics usually contain both metallic and nonmetallic elements with ionic or covalent bonds.

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. A cermet is a composite material composed of ceramic and metal materials. Ceramic crystal structures generally more complex than metals because they are composed of at least two elements or more. 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. 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. The bonding of atoms together is much stronger in covalent and ionic bonding than in metallic. In atomic structure they are most often crystalline although they also may contain a combination of glassy and crystalline phases.

Charge balances and relative ion size plays key roles in determining structure and properties. Generally the metallic elements used are nickel molybdenum and cobalt. The properties of ceramics however also depend on their microstructure. For metals the chemical bond is called the metallic bond.