dr. din 4

Question 1

metals with minimal chemical reactivity, resist oxidation, corrosion, tarnish

Answer 1

noble metals

Question 2

have intrinsic value, noble + silver

Answer 2

precious

Question 3

inexpensive non noble metals

Answer 3

base/non-precious

Question 4

down fall of base metals?

Answer 4

hard to work with

Question 5

pt=?

Answer 5

platinum

Question 6

pd=?

Answer 6

palladium

Question 7

Ir=?

Answer 7

iridium

Question 8

Rh=?

Answer 8

rhodium

Question 9

Os=?

Answer 9

osmium

Question 10

Ru=?

Answer 10

ruthenium

Question 11

Au=?

Answer 11

gold

Question 12

Do we usually use noble or alloys?

Answer 12

alloys

Question 13

problem with gold?

Answer 13

if in contact with an amalgam, can rub the amalgam causing release of mercury which will imbed itself into the gold, making the color become more grey. also causes sensitivity to the patient.

Question 14

characteristics of gold

Answer 14

soft, malleable, primary component in many alloys, resistant to oxidation/corrosion

Question 15

Tm of gold?

Answer 15

1063 celcius

Question 16

pt does what to gold?

Answer 16

increases mechanical properties (strength and hardness)

Question 17

properties of pt

Answer 17

tough, ductile, malleable

Question 18

Pd is used interchangeably with what?

Answer 18

Pt

Question 19

silver alloy allows for what?

Answer 19

inhibition of corrosion

Question 20

iridium (Ir) and ruthenium (Ru) are what?

Answer 20

grain refiners

Question 21

Rhodium (Ru) is an alloy with what?

Answer 21

pt- thermocouples

Question 22

precious metal, malleable, ductile, best electrical, thermal conductor, corrodes with sulfur, chlorine and phosphorous?

Answer 22

silver - Ag

Question 23

two forms of Au-Cu?

Answer 23

solid (>424) or ordered( <424)

Question 24

random arrangement, more flexible

Answer 24

solid

Question 25

stronger and less flexible

Answer 25

ordered

Question 26

single phase, range of compositions, random arrangement of atoms. gold-copper

Answer 26

solid solution

Question 27

single phase, specific composition, ordered arrangement of atoms, stronger but more brittle

Answer 27

inter metallic compound

Question 28

if want material to be softer how do you treat it?

Answer 28

quench in water immediately. solid solution

Question 29

if want material to be harder what do you do

Answer 29

cool for a while then quench. ordered phase

Question 30

hardening effects

Answer 30

increased tensile strength, yield strength, hardness, but decreased elongation

Question 31

as you range from gold types 1-4 what happens to properties?

Answer 31

gold content decreases, hardness increases, strength increases, cu content increases

Question 32

type 1 gold used for what type of gold restorations?

Answer 32

small

Question 33

type 4 gold used for what type of restorations?

Answer 33

larger

Question 34

gold used for class 3 & 5

Answer 34

type 1

Question 35

gold used for inlays and medium hardness

Answer 35

type 2

Question 36

gold used for hard, inlays, inlays, crowns and bridges

Answer 36

3

Question 37

gold used for extra hard, crowns, bridges, partial denture frame work

Answer 37

4

Question 38

as you go up in gold types, what happens to heat hardening?

Answer 38

increases