A ceramic material is being considered for a high strength and high temperature application. Explain:

1. (i) what the primary types of atomic bonds in ceramics are and how does this affect the thermal properties. (2)

2. (ii) Plastic deformation due to dislocation motion is important in metals. Explain why this is not a very important consideration for the properties of ceramics and glasses. (1)

3. (iii) Why is the tensile strength of ceramics much lower than the compressive strength? (2)

(iv) Define the terms apparent porosity and true porosity. Why are these porosities called apparent and true?

(v) What is meant by Ferroelectricity?