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Title: Method of processing "BPS" glass ceramic and seals made therewith

Abstract

A glass ceramic composition, a glass ceramic-to-metal seal, and more specifically a hermetic glass ceramic-to-metal seal prepared by subjecting a glass composition comprising, by weight percent, SiO.sub.2 (65-80%), LiO.sub.2 (8-16%), Al.sub.2 O.sub.3 (2-8%), K.sub.2 O (1-8%), P.sub.2 O.sub.5 (1-5%), B.sub.2 O.sub.3 (0.5-7%), and ZnO (0-5%) to the following processing steps: 1) heating the glass composition in a belt furnace to a temperature sufficient to melt the glass and crystallize lithium phosphate, 2) holding at a temperature and for a time sufficient to create cristobalite nuclei, 3) cooling at a controlled rate and to a temperature to cause crystallization of lithium silicates and growth of cristobalite, and 4) still further cooling in stages to ambient temperature. This process produces a glass ceramic whose high coefficient of thermal expansion (up to 200.times.10.sup.-7 in/in/.degree.C.) permits the fabrication of glass ceramic-to-metal seals, and particularly hermetic glass ceramic seals to nickel-based and stainless steel alloys and copper.

Inventors:
 [1];  [1];  [1];  [2]
  1. Albuquerque, NM
  2. (late of Albuquerque, NM)
Issue Date:
Research Org.:
AT&T Corp., Albuquerque, NM (United States)
OSTI Identifier:
871891
Patent Number(s):
5820989
Assignee:
Sandia Corporation (Albuquerque, NM)
Patent Classifications (CPCs):
C - CHEMISTRY C03 - GLASS C03C - CHEMICAL COMPOSITION OF GLASSES, GLAZES, OR VITREOUS ENAMELS
Y - NEW / CROSS SECTIONAL TECHNOLOGIES Y10 - TECHNICAL SUBJECTS COVERED BY FORMER USPC Y10T - TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
DOE Contract Number:  
AC04-76DP00789
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
method; processing; bps; glass; ceramic; seals; therewith; composition; ceramic-to-metal; seal; specifically; hermetic; prepared; subjecting; comprising; weight; percent; sio; 65-80; lio; 8-16; 2-8; 1-8; 1-5; 5-7; zno; 0-5; following; steps; heating; belt; furnace; temperature; sufficient; melt; crystallize; lithium; phosphate; holding; time; create; cristobalite; nuclei; cooling; controlled; rate; crystallization; silicates; growth; stages; ambient; process; produces; coefficient; thermal; expansion; 200; times; 10; -7; degree; permits; fabrication; particularly; nickel-based; stainless; steel; alloys; copper; steel alloy; ceramic seals; controlled rate; glass ceramic; ceramic composition; composition comprising; time sufficient; thermal expansion; weight percent; stainless steel; ambient temperature; temperature sufficient; glass composition; processing steps; process produces; steel alloys; metal seal; processing step; ceramic-to-metal seal; glass ceramic-to-metal; hermetic glass; metal seals; ceramic seal; /428/

Citation Formats

Reed, Scott T, Stone, Ronald G, McCollister, Howard L, and Wengert, deceased, Paul R. Method of processing "BPS" glass ceramic and seals made therewith. United States: N. p., 1998. Web.
Reed, Scott T, Stone, Ronald G, McCollister, Howard L, & Wengert, deceased, Paul R. Method of processing "BPS" glass ceramic and seals made therewith. United States.
Reed, Scott T, Stone, Ronald G, McCollister, Howard L, and Wengert, deceased, Paul R. Thu . "Method of processing "BPS" glass ceramic and seals made therewith". United States. https://www.osti.gov/servlets/purl/871891.
@article{osti_871891,
title = {Method of processing "BPS" glass ceramic and seals made therewith},
author = {Reed, Scott T and Stone, Ronald G and McCollister, Howard L and Wengert, deceased, Paul R.},
abstractNote = {A glass ceramic composition, a glass ceramic-to-metal seal, and more specifically a hermetic glass ceramic-to-metal seal prepared by subjecting a glass composition comprising, by weight percent, SiO.sub.2 (65-80%), LiO.sub.2 (8-16%), Al.sub.2 O.sub.3 (2-8%), K.sub.2 O (1-8%), P.sub.2 O.sub.5 (1-5%), B.sub.2 O.sub.3 (0.5-7%), and ZnO (0-5%) to the following processing steps: 1) heating the glass composition in a belt furnace to a temperature sufficient to melt the glass and crystallize lithium phosphate, 2) holding at a temperature and for a time sufficient to create cristobalite nuclei, 3) cooling at a controlled rate and to a temperature to cause crystallization of lithium silicates and growth of cristobalite, and 4) still further cooling in stages to ambient temperature. This process produces a glass ceramic whose high coefficient of thermal expansion (up to 200.times.10.sup.-7 in/in/.degree.C.) permits the fabrication of glass ceramic-to-metal seals, and particularly hermetic glass ceramic seals to nickel-based and stainless steel alloys and copper.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1998},
month = {1}
}

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