Glass-to-Metal Seals

Glass-to-Metal Seals

Author: Ian W. Donald

Publisher: Society of Glass Technology

Published: 2021-10-10

Total Pages: 294

ISBN-13: 9780900682889

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Although many new innovations have been made in the commercial exploitation of glass-to-metal seals and related components, and the science underpinning these systems is now more thoroughly understood, many of the topics covered in Partridge's original monograph on glass-to-metal seals are still highly relevant today. This is particularly true in the areas of underlying technology, including metal and glass preparation prior to sealing, and certain aspects of stress analysis. The original monograph also continues to provide an excellent introduction to the general area of glass-to-metal systems, as well as providing an historical overview of the early work and technology in this area, particularly in relation to archaic electrical components. The primary purpose of this new monograph is to provide a thorough review of glass-to-metal seals, with particular reference to the more recent developments in the scientific, technical and commercial fields. Current applications for glass-to-metal seals are extraordinarily diverse, ranging from the humble, taken-for-granted light bulb to complex aerospace and military components developed within the last few years. New applications also continue to emerge where the unique properties of these systems can be exploited, thus making a monograph of this nature timely. It is therefore also the purpose of this monograph to highlight new and emerging fields which are benefiting from the application of glass-to-metal seal and related technologies. In this respect, the scope of the monograph has been broadened to include the related topic of glass-to-metal coatings, coatings in general having found many applications in areas ranging from domestic paraphernalia to the aerospace industry. In addition, the more recent and highly versatile glass-ceramic-to-metal systems are reviewed, glass-ceramics not, of course, having been invented in Partridge's day. Some of the newer ceramic-to-metal, glass-to-glass, glass-to-ceramic and ceramic-to-ceramic systems are also covered briefly, areas very much in their infancy in 1949.


Alternative Method for the Evaluation of Fused Glass-to-Metal Seals

Alternative Method for the Evaluation of Fused Glass-to-Metal Seals

Author:

Publisher:

Published: 1979

Total Pages: 51

ISBN-13:

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Glass-to-metal seals on electronic component packages make it possible to obtain electrical feed-thru while maintaining hermeticity throughout severe environmental exposure. As a result of this study, it was determined that sealed sub-assemblies will generally pass the least severe thermal shock requirement of MIL-STD-883, but that the same (previously accepted) lots will exhibit a 6%, or higher, failure rate as a result of manufacturing stresses imposed by cover welding, delidding, and thermal bakes or soaks. During this study, the use of tighter controls on the more critical glass sealing processes was shown to reduce the reject rate to less than 1%. Success in matched glass- seal making depends on the use of three thermal treatments for Kovar: de- carburizing, pre-oxidation and sealing. This report deals specifically with pre- oxidation and sealing. An oxide film on Kovar, prior to sealing, promotes glass wetting and provides for the development of a chemical-mechanical bond at the glass-metal interface. A determination for residual intergranular oxide is useful for judging the quality of a matched glass-to-metal seal where pre- oxidation is a requisite for sealing. Residual oxides can be detected by metallographic techniques, and the range of 2.0 - 6.5 micrometers is appropriate for high quality glass seals. Other effects are also detectable by the evaluation of metallographic cross-sections of sealed packages. These include volume fraction of bubble formation, bubble size, bubble distribution, glas- metal separation and other interface criteria.


Production of Glass Or Glass-ceramic to Metal Seals with the Application of Pressure

Production of Glass Or Glass-ceramic to Metal Seals with the Application of Pressure

Author:

Publisher:

Published: 1987

Total Pages:

ISBN-13:

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In a process for preparing a glass or glass-ceramic to metal seal comprising contacting the glass with the metal and heat-treating the glass and metal under conditions whereby the glass to metal seal is effected and, optionally, the glass is converted to a glass-ceramic, an improvement comprises carrying out the heat-treating step using hot isostatic pressing.


Method for Forming Glass-to-metal Seals

Method for Forming Glass-to-metal Seals

Author:

Publisher:

Published: 1986

Total Pages:

ISBN-13:

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A method for forming a glass-to-metal seal in which the glass has a higher melting point than the metal. The molten glass is vacuum injection molded onto the metal, thus melting a very thin layer of the surface of the metal long enough to form a seal, but not long enough to cause a distortion in the shape of the metal component.