Question

For each of the following material properties, mark whether metals or ceramics would typically have a higher value (mark both if its not clear).

Ceramics Metals

Maximum Tensile Strength (Ideal) _______ ______

Maximum Tensile Strength (in practice) _______ ______

Elastic Modulus _______ ______

Ductility _______ ______

Thermal Conductivity _______ ______

Corrosion Resistance _______ ______

Impact Toughness _______ ______

Scratch Resistance _______ ______

Ease of Manufacture _______ ______

Cost _______ ______

Prove the minimum ratio of the ionic radii in an octahedral pair (coordination # = 6) is 0.414. (Hint: Draw a picture of what a coordination number = 6 would look like)

Describe the difference in the atomic behaviors (specifically viscosity) of crystalline and amorphous ceramics as they heat up.

Determine the coordination number for the following pairs:

MgO

Al₂S₃

BaO

NiS

Which of the following is not an advantage of powder sintering

Faster processing

Ease of final shape processing

High Strength

Lower temperature/energy requirements

Assume you make a semi-conductor out of germanium, and dope it with nitrogen. What type of semi-conductor is the result?

N-Type -or- P-Type

Match the form of carbon to its description

Graphite	sp2 bonding, but folded on itself to get strength and 3-D stability together. Expensive to make, but promising properties.
Diamond	Single plane of extremely strong bonds, excellent conductivity.
Graphene	Planar structure of sp2 bonding, stacked in layers. Extremely strong in plane, weak between layers. Used as a lubricant.
Fullerenes/nanotubes	3-D crystalline structure of sp3 bonds. Extremely stable, so very hard