Basic classification of Materials

Solid materials have been conveniently grouped into three basic categories. Metals, ceramics and polymers. This scheme is based primarily on chemical makeup and atomic structure, and most materials fall into one distinct grouping or another. Another category is advanced materials-those used in high technology applications, such as semiconductors, biomaterials, smart materials, and nanoengineered materials. Let's discuss about the basic first and another one we can discuss on next article.

Metals. Materials in this group are composed of one or more metallic elements (e.g., iron, alumunium, copper, titanium, gold and nickel), and often also nonmetallic elements like carbon, nitrogen, and oxygen in relatively small amounts. Atoms in metals and their alloys are arranged in a very orderly manner, and in comparison to ceramics and polymers, are relatively dense. regard to mechanical characteristics, these materials are relatively stiff and strong, yet are ductile, and are resistant to fracture, which accounts for their widespread use in structural applications.

Ceramics. Ceramics are compound between metallic and non-metallic elements; they are most frequently oxides, nitrides, and carbides. For example, common ceramic materials include alumunum oxide or alumina, silicon dioxide or silica, Silicon carbida, silicon nitride, and, in addition, what some refer to as the traditional ceramics-those composed of clay minerals, as well as cement and glass.

Polymers. Polymers include the familiar plastic and rubber materials. Many of them are organic compounds that are chemically based on carbon, hydrogen, and other non metallic elements. Furthermore, they have very large molecular structures, often chainlike in nature, that often have a backbone of carbon atoms. Some of the common and familiar polymers are polyethylene, nylon, poly vinyl chloride, polycarbonate, polystyrene, and silicone rubber.