Discuss the important non-metallic materials of construction used in engineering practice.

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 The commonly used important non-metallic materials are wood, glass, rubber, leather, carbon, plastics etc. which are used in various engineering construction.

  1. Wood: It is a bad conductor of heat and electricity. It is lighter in weight but has sufficient tensile strength. It has less resistance to corrosion. Wood is used in making patterns used in foundry.              
  2. Glass: It is a very brittle and hard material. Glass is used in doors and windows. Glass of special composition is used in various optical instruments.                                                                                 
  3. Rubber: Rubber and similar synthetic materials such as Neoprene have a variety of application in machinery. Rubber should be protected from high temperature, oil and sunlight. It is an excellent material for seats and diaphragms for water lubricated bearing for parts subjected to vibrations.                                                                                                                                             
  4. Leather: Leather is very flexible and has good resistance to wear. Leather is used in making gaskets, belts etc. It is also used as a packing material and in making washers.                                  
  5. Carbon: It has very high compressive strength and high shear strength compared to other non-metallic materials. It has good resistance to corrosion. Carbon is used in electrical insulation. Graphite is a form of carbon which is used in bronze used as a lubricant in bearing material. Diamond is used for drill bits which are used for oil exploration, digging deep wells etc.                 
  6. Plastic: Plastic are lighter in weight but have high strength. It can resist corrosion. Plastics are available in various colors and surface finish of plastic products is very good. There are two types of plastics such as (a) Thermoplastic plastics, (b) Thermosetting plastic.

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