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Use of Phase Separation for Hard Glass Panel Sealing Procedure

IP.com Disclosure Number: IPCOM000089387D
Original Publication Date: 1977-Oct-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 13K

Publishing Venue

IBM

Related People

Landermann, JB: AUTHOR [+2]

Abstract

A hard glass panel sealing procedure is described wherein, prior to the hard glass sealing process in the glass panel manufacture, the hard glass plates, e.g., PYREX* plates, are heat treated to induce phase separation in order to increase their viscosity.

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Use of Phase Separation for Hard Glass Panel Sealing Procedure

A hard glass panel sealing procedure is described wherein, prior to the hard glass sealing process in the glass panel manufacture, the hard glass plates, e.g., PYREX* plates, are heat treated to induce phase separation in order to increase their viscosity.

Currently, soft glass plates, such as soda-lime-silicate glass, are used for gas panels. Thermal shock resistance of soft glasses is relatively low, however, because of their relatively large thermal expansion. This is disadvantageous in using soft glass plates for manufacturing panels of larger sizes. Use of hard glass plates, such as PYREX, has been suggested to replace current soft glasses. However, to seal the hard glass plates with sealing glasses currently available, either commercially or in the laboratory, sealing temperatures have to be raised much higher than those sealing temperatures which are used for the soft glass plates. This is because of the generally accepted rule which indicates that, by lowering the thermal expansion of the glass, the viscosity of the glass is increased. The problem here is that the viscosity of the as-received hard glass is not as high as desired.

The method attempts to solve this problem from a different direction. Most of the commercial hard glasses, including PYREX, are borosilicates, and many of them including PYREX, are phase-separable upon appropriate heat treatment. Upon phase separation, the viscosity of the glass has been reported to increase as much as 2 orders or more of magnitude in some cases [1]. The subject method heat-treats the hard glass plates re...