Hamlin's Fixed Lecture

Question 1

High noble metals? (7)

Answer 1

Au (Gold)
Pt (Platinum)
Pd (Palladium)
Rh (Rhodium)
Ru (Ruthenium)
Os (Osmium)
Ir (Iridium)

Question 2

What are properties of gold?

Answer 2

Corrosion and oxidation resistance

Increases ductility and malleability

Question 3

Properties of copper?

Answer 3

Principal hardener and heat treatment

Question 4

Principles of silver?

Answer 4

Adjust red color of gold and copper and reduces melting temperature

Increases ductility and malleability

Question 5

Platnium

Answer 5

Raises melting temperature and increases tensile strength. Decreases CTE and reduces tarnish and corrosion

Question 6

Palladium

Answer 6

Oxygen scavenger, raises melting temp and increases hardness

Question 7

Zinc

Answer 7

Oxygen scavenger, increases fluidity and reduces surface temperature

Question 8

Nickel

Answer 8

Increases CTE, anticorrosion

Question 9

Chromium

Answer 9

Corrosion resistance

Question 10

What are principle grain refiners? (2)

Answer 10

Ruthenium and iridium. This increases tensile strength and ductility

Question 11

What is the solidification sequence for a metal?

Answer 11

Liquid -> Embryos -> dendrites -> Grains

Question 12

Ceramic - General characteristics

Answer 12

Brittle
Inert
Good thermal and electric insulation
Hard
High elastic modulus
refractory

Question 13

Why is leucite added to ceramics?

Answer 13

Leucite increases CTE, enabling it to be fired alongside metal alloys and inhibits crack propagation

Question 14

How is porcelain bonded to metal?

Answer 14

1. Compression (CTE of metal should be greater)
2. Chemical Covalent bonding (porcelain to metal oxides)
3. Van der waal forces
4. Mechanical

Question 15

What category is eMax lithium disilicate and what is its composition?

Answer 15

Category 2 - Particle filled glasses

Lithium disilicate crystal particles in a glassy matrix

(Crystal particles impart strength, opacity, color, CTE whereas glass gives it translucency)