Glass-ceramic hermetic seals to high thermal expansion metals
A process for forming glass-ceramic materials from an alkaline silica-lithia glass composition comprising 60-72 mole-% SiO/sub 2/, 18-27 mole-% Li/sub 2/O, 0-5 mole-% Al/sub 2/O/sub 3/, 0-6 mole-% K/sub 2/O, 0-3 mole-% B/sub 2/O/sub 3/, and 0.5-2.5 mole-% P/sub 2/O/sub 5/, which comprises heating said glass composition at a first temperature within the 950-1050/degree/C range for 5-60 minutes, and then at a devitrification temperature within the 700-900/degree/C range for about 5-300 minutes to obtain a glass-ceramic having a thermal expansion coefficient of up to 210 x 10/sup /minus/7///degree/C. These ceramics form strong, hermetic seals with high expansion metals such as stainless steel alloys. An intermediate nucleation heating step conducted at a temperature within the range of 675-750/degree/C for 10-120 minutes may be employed between the first stage and the devitrification stage. 1 fig., 2 tabs.
- Research Organization:
- EG and G Mound Applied Technologies, Miamisburg, OH (USA)
- DOE Contract Number:
- AC04-76DP00053
- Assignee:
- TIC; ERA-14-001157; EDB-88-184938
- Patent Number(s):
- PATENTS-US-A6043526
- OSTI ID:
- 6749151
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360601* -- Other Materials-- Preparation & Manufacture
360603 -- Materials-- Properties
ALKALI METAL COMPOUNDS
CERAMICS
CHALCOGENIDES
CHEMICAL COMPOSITION
DESIGN
EXPANSION
GLASS
HEAT TREATMENTS
LITHIUM COMPOUNDS
LITHIUM OXIDES
MINERALS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
SEALS
SILICA
SILICON COMPOUNDS
SILICON OXIDES
THERMAL EXPANSION