Question

Consider the following statements regarding the electrical properties of ceramic materials:

1. They are practically non-conductors at a lower temperature.

2. Ordinary glass and silicates in the molten state are dependable as electrical non-conductors.

3. They offer high resistance to the current transmission and get heated soon when conducting electric currents.

Which of the above statements are correct?

1. 1 and 2 only
2. 1 and 3 only
3. 2 and 3 only
4. 1, 2 and 3

Answer 1

Correct Answer - Option 2 : 1 and 3 only

Electrical properties of ceramic materials include:

• Very high electrical resistance at a low temperature which results in low conductivity and it, therefore, behaves as an insulator i.e. non-conductor. (Statement 1 is Correct)
• High dielectric constant
• High dielectric strength
• Low dielectric loss

Variation of ceramic materials with Temperature:

At low Temperature: Ceramic remains in solid form due to no band break and acts as an insulator and no current conduction is possible.

At High Temperature:

• Weaker bonds of ceramic start breaking and due to this ceramic converted into solid to liquid (i.e. molten) state.
• Because of this, some of the free movable ions are generated that can capable to conduct current, and due to current conduction it get heated soon.
• So at high temperature, ceramic is in the molten state and behaves like an electrical conductor.

∴ Statement – 2 is incorrect and Statement 3 is correct.

Note: Some important ceramic materials are glass, silicates, zinc sulfide, yttrium garnet, Alumina, porcelain, etc.