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US 4,536,452 AGranted
Spontaneously-formed machinable glass-ceramics
AssigneeCorning Glass Works
InventorsJohn L. Stempin, Dale R. Wexell
Life of this patent
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Abstract
This invention is related to the production of machinable glass-ceramic articles which are essentially free from crystals having a mica structure and consist essentially, in weight percent, of SiO.sub.2 : 24-28 Al.sub.2 O.sub.3 : 9-20 MgO: 12-28 SrO: 0-11 BaO: 0-14 CuO: 0-5 Ag.sub.2 O: 0-3.5 NiO: 0-1.5 Cr.sub.2 O.sub.3 : 0.5-6.5 F: 2-9
Claims2
A machinable glass-ceramic article having a crystal content greater than 50% by volume and being essentially free from any mica phase consisting essentially, in weight percent on the oxide basis (fluorine being reported as fluoride), of:
- SiO.sub.2 :
- 24-48
- Al.sub.2 O.sub.3 :
- 9-20
- MgO:
- 12-28
- SrO:
- 8.7-11
- BaO:
- 1.9-14
- CuO:
- 0-5
- Ag.sub.2 O:
- 0-3.5
- NiO:
- 0-1.5
- Cr.sub.2 O.sub.3 :
- 0.5-6.5
- F:
- 2-9.
17 more elements
Dependencies are inferred from the claim text.