Solid material have been conveniently grouped into three basic classification : metals , ceramics and polymers.This scheme is based primarily on chemical make up and atomic structure and most material fall into one distinct grouping or another , although there are some intermediate.
METALS:Material in this group are composed of one or more metallic elements such as iron, aluminium copper and nickel.In comparison metals are more dense than ceramics and polymers. Metals are ductile and fracture resistant .
CERAMICS:Ceramics are compounds between metallic and polymers they are most frequently oxides , nitrides, and carbides. For example most ceramics are aluminium oxide and silicon nitrides .They are very high resistance power against heating.
POLYMERS: Polymers include the familiar plastics and rubber material.Many of them are organic compounds that are chemically base one hydrogen and carbon and other non metallic elements.