Browse Prior Art Database

Liquid-Phase Sintering Pure Cordierite-Type Ceramics

IP.com Disclosure Number: IPCOM000060135D
Original Publication Date: 1986-Mar-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 1 page(s) / 13K

Publishing Venue

IBM

Related People

Giess, EA: AUTHOR [+2]

Abstract

Crystalline powders of pure cordierite are difficult to sinter because of the very narrow sintering range within about 50ŒC of its incongruent melting point of 1468ŒC. Furthermore, high strength cordierite-type glass ceramics have been made by inducing spinel to crystallize. In order to make dense cordierite-type ceramics having high strength at relatively low temperatures, liquid phase sintering can be used.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 51% of the total text.

Page 1 of 1

Liquid-Phase Sintering Pure Cordierite-Type Ceramics

Crystalline powders of pure cordierite are difficult to sinter because of the very narrow sintering range within about 50OEC of its incongruent melting point of 1468OEC. Furthermore, high strength cordierite-type glass ceramics have been made by inducing spinel to crystallize. In order to make dense cordierite-type ceramics having high strength at relatively low temperatures, liquid phase sintering can be used. Liquid-phase sinterable pure cordierite can be made by starting with a fine particle size (<1 mm) MgAl2O4 spinel and coating it with enough colloidal SiO2 to make cordierite by the reaction: 2 MgAl2O4 + 5 SiO2 = Mg2Al4Si5018 The silica coating will induce sintering at low temperatures and after the ceramic compact formed from the powders has sintered (densified by eliminating pores between particles), it can be reacted to form cordierite by the above reaction. Having sintered by the spinel route, these compacts will have high strength, and good density will follow from the relatively low temperatures afforded by liquid phase sintering of the precursor SiO2-coated spinel particles. The preparation of the powder to be used in this liquid phase sintering process is illustrated by the following example. A commercially available magnesium aluminate spinel powder was used, which had properties that were conducive to high sinterability and reactivity. The spinel (Si 20 ppm, Fe 13 ppm, Cu 1 ppm) was crystalline material with a mean particle diameter of 0.6 mm and having a 95% size distribution between 0.2 and 3.0 mm. The shape of the individual particles was nearly spherical, and the bulk powder was non-agglomerated. An aqueous dispersion of 7...