Class discussions Name two ionic crystals. Name two engineering materials that are joined by covalent bonding. Covalent Ionic

Name a few industrial items made from carbon-graphite. Compare the weight of a 1cm3 of carbon-graphite to the same shape made from steel.

2 indicate whether statement is ture or false Most monolithic technical ceramics are processed in a similar manner to metals, namely melting and casting.

3. Some of our modern kitchen cookware is made of ceramic, metal and plastic materials. (a) list at least three important characteristics required of a materials to be used for this application (b) make a comparison of three ceramic materials as to their relative properties and ,in additional, to cost. (c) on the basis of this comparison, select the material most suitable for the cookware.

Cite the two desirable characteristics of glasses. (a) What is crystallization? (b) cite a property that may be improved by crystallization. What is the distinction between glass transition temperature and melting temperature? Some ceramic materials are fabricated by hot isostatic pressing. Cite some of the limitations and difficulties associated with this technique. Compare the temperatures at which sodalime, borosilicate, 96% silica, and fused silica may be annealed? Compare the softening points for 96% silica, borosilicate and sodalime glasses.

Class Exercise Compare following items for the metal (alloy), plastic polymer (thermoplastics) and ceramic materials Atomic bonding Crystalline structure Mechanical properties Work temperature (high or low) Give examples in their applications