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Enhanced Sintering of Cordierite-type Glass Powder

IP.com Disclosure Number: IPCOM000060628D
Original Publication Date: 1986-Mar-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Giess, EA: AUTHOR [+2]

Abstract

Glass powders must be sintered before they crystallize in order to eliminate pores which otherwise would be left. The presence of such pores decreases the product strength. In order to enhance the sintering of cordierite glass particles, a layer of MgO is applied to the cordierite particles prior to sintering.

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Enhanced Sintering of Cordierite-type Glass Powder

Glass powders must be sintered before they crystallize in order to eliminate pores which otherwise would be left. The presence of such pores decreases the product strength. In order to enhance the sintering of cordierite glass particles, a layer of MgO is applied to the cordierite particles prior to sintering.

Sintering of powder glass ceramics is realized by viscous flow driven by surface energy, which in turn is the result of additive contributions from each of the glass constituents. MgO contributes twice as much to surface energy as other constituents in the cordierite-type oxide glass.

In an example, cordierite-type oxide glasses having an average particle size of approximately 3.5 micrometers undergo enhanced sintering (densification) when these glass powders are surface-coated with a thin layer of MgO. A Mg salt (e.g., nitrate or acetate) is dissolved in alcohol (methanol) mix with and dried onto the powder. One gram of MgO coats 1000 grams of 3.5 micrometer diameter spheres with a layer that is 4.2 ~ thick, about a monolayer. The MgO- coated powders have improved flow when dry, and experience an increase in shrinkage rate in comparison to the glass powders which are uncoa

The addition of Al2O3 and SiO2 has relatively little effect on sintering. However, P2O5 enhances sintering more than MgO does, while B2O3 retards sintering. Chemical surface treatments affect sintering in a way which suggests that viscos...