Ceramics and composites

4 types of ceramics 

Electrical, magnetic, optical, automotive 

Examples of electrical ceramics 

Capacitor dielectrics, superconductors, solid oxide fuel cells 

Example of magnetic ceramics

Recording media

Examples of optical ceramics

Fiber optics, lasers

Examples of automotive ceramics

Spark plugs, oxygen sensor

What is a capacitor

Compounds of metallic and non- metallic elements

What are most of the bonds in ceramics

Totally ionic or majority ionic with some covalent

Why are ceramics not thermally or electrically conductive

Lack of free electrons

4 properties of ceramics

Good insulators, high strength, hard and brittle

3 classes of ceramics

Crystalline, amorphous, partially crystalline

3 typical structures of ceramics

AX, A_mX_p, A_mB_nX_p

What do A and X represent in an AX ceramic

A- cations, X-anions they are equal in an AX ceramic

3 examples of AX ceramics 

Rock salt, cesium chloride structure, zinc blend structure 

What does A_mX_p represent in a ceramic structure 

Different numbers of cations and anions 

Example of A_mX_p structures ceramics

Fluorite structure

What do A B and X represent in A_mB_nX_p structures

A and B are cations, X is anion

What is an example of AX- rock salt structure

Sodium chloride type 

What is a coordination number

Number of anion nearest neighbours for a cation

What is the coordination number for AX- rock salt structure

6

What is AX- rock salt structure in terms of face centers

Two interpenetrating face centered cubic lattices

3 types of defects in ceramics

Atomic point defects, interstitial/ vacancy, Schottky defect

What must be maintained to prevent defects in ceramics 

Electroneutrality or charge balance 

How can solid solutions be formed in impurities 

Substitutionally or interstitially 

What must be relatively similar in impurities in ceramics

Ionic size

In impurities, what is maintained

Electroneutrality