ME Ceramics, Glasses, and Electronic Materials

Question 1

The primary bonding type in most ceramic materials is:

Accepted Answer

Ionic and/or covalent bonding

Answer

Metallic bonding

Answer

Van der Waals forces

Answer

Hydrogen bonding

Question 2

Which defect in a crystalline ceramic consists of a cation vacancy paired with an anion vacancy to maintain electrical neutrality?

Accepted Answer

Schottky defect

Answer

Frenkel defect

Answer

Interstitial defect

Answer

Edge dislocation

Question 3

The main reason ceramics are brittle compared to metals is:

Accepted Answer

Lack of mobile dislocations due to strong directional bonding and large unit cells

Answer

Higher melting points making plastic deformation impossible

Answer

Lower atomic density

Answer

Presence of large amounts of amorphous phase

Question 4

Silica glass (SiO2) has an amorphous structure because:

Accepted Answer

Rapid cooling from the melt prevents long-range atomic ordering

Answer

Silicon and oxygen have very different atomic radii preventing crystallization

Answer

SiO2 has no preferred bonding angles

Answer

The melt viscosity is too low to allow ordering

Question 5

Partially stabilized zirconia (PSZ) is toughened by which mechanism?

Accepted Answer

Transformation toughening: stress-induced tetragonal-to-monoclinic phase transformation at a crack tip

Answer

Microcrack toughening through grain boundary fracture

Answer

Fiber pullout of zirconia whiskers

Answer

Plastic zone formation ahead of the crack tip

Question 6

In semiconductor materials, the band gap determines:

Accepted Answer

The energy required to excite an electron from the valence band to the conduction band

Answer

The electrical resistivity of the metallic contacts

Answer

The dislocation density of the semiconductor crystal

Answer

The thermal expansion coefficient of the material