New series of high expansion coefficient glasses can be sealed by fusion onto hot surfaces of metals and alloys. Glasses have relatively low working temperatures, good chemical durability, and can be used in electrical insulators and feedthroughs to fluid or vacuum systems

Camp, F. E.

Champman, J. W.

Hirayama, C.

English

NASA Technical Reports Server

December 1970	 Brief 70-10429 
NASA TECH BRIEF . 
i:ii . .-------
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage commercial 
application. Tech Briefs are available on a subscription basis from the National Technical Information Service, Springfield, 
Virginia 22151. Requests for individual copies or questions relating to the Tech Brief progam may be directed to the Tech-
nology Utilization Division, NASA, Code UT, Washington, D.C. 20546. 
High Expansion Coefficient Glasses Can be Sealed to Common Metals 
A new series of high expansion coefficient glasses 
can be sealed by fusion onto the hot surface of metals 
and alloys. Glass-to-metal seals are used extensively 
in the electronic and electrical industries. The kinds 
of metals involved vary from the low expansion coef-
ficient alloys such as kovar (iron-nickel-cobalt), cold 
rolled steels and nickel, to the high expansion coeffi-
Notes: 
1. The following documentation may be obtained 
from: 
National Technical Information Service 
Springfield, Virginia 22151 
Single document price $3.00 
(or microfiche $0.60) 
Sample Glasses, Their Sag Points and Expansion Coefficients

Composition (Wt %) 
	
Glass	 Expansion 
Sample	 Sag	 Coefficient 
No.	 SiO,	 Na,O	 Al,03	 K,O	 MgO	 CaO	 TiO,	 BaO NaF Point 'C	 x 106 (inch/inch/CC) 
	
53	 39.6	 11.6	 18.4	 ---	 ---	 18.4	 6.9	 ---	 5.1	 593	 11.1 
	
54	 37.3	 11.8	 22.4	 ---	 ---	 14.0	 4.7	 4.7	 5.1	 602	 9.4 
	
6	 64.8	 9.6	 9.4	 13.1	 3.1	 ----	 ---	 ---	 ---	 530	 13.1 
Notes:
1. Sag Point is the temperature at which glass begins to soften or flow. 
2. An example of an application for the sample 6 composition is to seal the ends of a conventional electrical heating 
element where the high-expansion coefficient and good electrical and chemical properties of this glass are a 
distinct advantage. 
cient metals such as copper, stainless steel, and alumi-
num. 
The glasses developed have relatively low working 
temperatures and good chemical durability, and can be 
used in electrical insulators and feedthroughs to fluid 
or vacuum systems. Other applications include oxi-
dation resistant or protective coatings on certain metal 
alloys for high temperature applications. Some repre-
sentative samples of these glasses and certain selected 
properties appear in Table 1.
Reference: 
NASA-CR-72520 (N70-14570), Development 
and Evaluation of Controlled Viscosity 
Coatings for Superalloys 
2. Technical questions may be directed to: 
Technology Utilization Officer 
Lewis Research Center 
21000 Brookpark Road 
Cleveland, Ohio 44135 
Reference: B70-10429
(continued overkaf) 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned.rights.
https://ntrs.nasa.gov/search.jsp?R=19700000414 2020-03-17T00:45:37+00:00Z
Patent status: 
No patent action is contemplated by NASA. 
Source: C. l-lirayama, F. E. Camp, and 
J. W. Chapman of 
Westinghouse Electric Corp. 
under contract to 
Lewis Research Center 
(LEW- 10698) 
Brief 70-10429	 Category 08


High expansion coefficient glasses can be sealed to common metals

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