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33 Cards in this Set
- Front
- Back
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high noble
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> 60% noble metal content (gold + platinum + palladium) with at least 40% containing gold
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noble
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is at least 25% noble metal content
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Predominantly base
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is less than 25 % noble metal content
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high noble metals combos
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gold- palt- palladium
gold- pall-silver gold-palladium |
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noble metals combos
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pallad-silver
high palladium |
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predominatly base metal combos
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nickel-chromium
nickle-chromium-beryllium cobalt-chromium |
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define precious alloys
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virtue of their scarcity
ie be, in, Ga |
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semi-precious alloys
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half precious and hald non precious no alloys meet this specific definition, description valueless
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function of constituent of gold
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corrosion and tarnish resistance, workability, burnishability
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function of constituent of platinum-
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increase strength, melting range, hardness, corrosion resistance
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function of constituent of palladium
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increase strength, hardness, corrosion and tarnish resistance, increase melting range, increase sag resistance, affinity to carbon
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function of constituent of silver
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lowers melting point range, increase fluidity, increase CTE, discoloration of porcelain, affinity to )2, poor corronsion and tarnish resistance
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function of constituent of indium, iron
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oxidation protection, strength, increase bonding to porcelain
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function of constituent of Ni
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low cost, strength, increase CTE, increase corrosion, allergen
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function of constituent of Co
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low cost strength, decrease workability, high melting
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function of constituent of Cr
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strength, high melting passivation, decrease corrosion
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function of constituent of Be
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decrease melting range, increase castability, fine grain, Ni-Be
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Au-Pt-Pd 75-88%, 11%, 8%
Adv |
excellent castability
excellent porcelain bondin easy to adjust and to finish excellent resistance to corrosion and tarnish biocompatibility |
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Au-Pt-Pd 75-88%, 11%, 8%
disadv |
high cost
poor sag resistance not for long span FPD low surface hardness high density |
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Au-Pt-Pd 53%, 35%, 22%
adv |
less expensive than high Au of Au-Pt-Pd system
improved rigidity & sag resistance high nobility level excellent resistance to corrosion & tarnish |
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Au-Pt-Pd 53%, 35%, 22%
disadv |
high cost
high CTE high density |
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Au-Pd -55%-40%, indium, tin 8-12%
adv |
excellent castability
improved rigidity good bonding strength good resistance to corrosion and tarnish |
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Au-Pd -55%-40%, indium, tin 8-12%
disadv |
CTE problems
high cost |
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Pd-Ag 60%, 30%, In, Tin < 10%
adv |
low cost, low density
good porcelian bonding easy to adjust and finsih good resistance to corrosino and tarnish easy to adjust and to finish |
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Pd-Ag 60%, 30%, In, Tin < 10%
disadv |
no carbon crucible
porcelain discoloration Pd prone to absorb gases higher CTE |
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Au-Pd-Ag 53%, 35%, 12%
adv |
less expensive than Au-Pt-pd
improved rigidity and sag resistance easy tp adjust and to finish high nobility level |
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Au-Pd-Ag 53%, 35%, 12%
disadv |
porcelain discoloration
hgih cost high CTE |
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Pd-Co 88% 10%, Pd-Cu 80%, 15%
adv |
losw cost,
low density good sag resistance easier to presolder melt and cast easily |
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Pd-Co 88% 10%, Pd-Cu 80%, 15%
disadv |
thick oxides
no carbon crucible not for long span FPD prone to gases absorption high hardness |
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Ni-Cr-Be 75% 20% 2%
ADV |
low cost, low density
high sag resistance can have this casting CAN BE ETCHED- MARYLAND BRIGDE |
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Ni-Cr-Be 75% 20% 2%
dis |
thick oxides
Ni sensitivity Be carcinogenic need induction casting more bond failure technically sensitivity difficult to cut, polish, solder |
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Co-Cr 60% 30%
adv |
do not contain NI
do not contain Be low density , more casting/ounce high sag resistance low cost |
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Co-Cr 60% 30%
disadv |
more difficult to process
high hardness-need induction heavy oxidation technically sensitive |
