Ceramics Flashcards
Talk about Feldspar
unhydrated aluminaum silcate=potassium feldspar
when subjceted to high temp.–>crystalline form
crytsalline form is leucite
High strength
High thermal expansion
diff. shades of opacity
forms a glassy phase but dont affect esthetics
main bulk of ceramic as it presents with high %
75-85 %
Silica
12-22
act as strengthening & esthetic agent
Kaolin
act as binder form workable mass increase modulability increase sever opacity--> decrease eastheics modern ceramics are free from kaolin 3-5 %
what are other ingredients
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talk about fluxes
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talk about glass modifiers
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talk about sugar & starch
1
talk about coloring pigments
1
talk about lanthamide earth
provide fluroscnece
Talk about vitrification
1
Talk about devitrification
1
What are the things that decrease during devitrfication
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what is the main disadvantage of ceramic
1
what are factors of crack propagation
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what is compaction
1
what is firing
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what is the alternative step to firing
slip casting technique
what is the step of glazing
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what are 2 types of glaze
auto (self) internal glaze
external (added) glaze
what are the disadvtanges of external glaze
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what is the cooling
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what are properties of porcelin
shrinkage porosity chmecial biological inert mechanical esthetics
why poreclin should be about 13% oversized
to prodce minimum shrinkage & less porosity
How to strength ceramic materials or increase fracture toughness
Design components in restoration
Decrease number or size of stress raisers
Usage of diff.phases of diff. materials to X crack prop.
Relie on toughness of crystals : cystalline phases of leucite & lithium disilicate
Relie on transforming toughness of crystalls
Devolpment of compression stresses
What are classification of ceramic
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