Low-Temperature Transient Glass-Phase Processing of Monoclinic SrAl2Si2O8

• Published in: Journal of the American Ceramic Society 1998-09, Vol.81 (9), p.2285-2293
• Main Authors: Chinn, Richard E., Haun, Michael J., Kim, Chan Young, Price, David B.
• Format: Article
• Language: English
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Chemical industry and chemicals; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Glass-ceramics; Glasses; Growth from solid phases (including multiphase diffusion and recrystallization); Materials science; Methods of crystal growth; physics of crystal growth; Physics
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/j.1151-2916.1998.tb02623.x

The use of transient glass‐phase processing to lower the glass‐melting temperature and subsequent heat‐treatment temperature of stoichiometric SrAl2Si2O8 to produce the stable monoclinic form has been described. Two nonstoichiometric, low‐melting, alumina‐deficient, strontium aluminosilicate compositions were melted, quenched, and milled into glass powders. B2O3 was dissolved into one of the glass compositions to control the crystallization behavior. The glass powders were then wet‐mixed with enough alpha‐Al2O3 powder so that the overall composition was that of stoichiometric SrAl2Si2O8 (B2O3 neglected). The four compositions were dry‐pressed into pellets and sintered in three processes. Glass‐alumina pellets with dissolved B2O3 were densified via viscous‐phase sintering at 1100°C, followed by complete dissolution of the alumina and crystallization to ~100% monoclinic SrAl2Si2O8. Pellets without dissolved B2O3 required considerably higher temperatures to form ~100% monoclinic SrAl2Si2O8 in a modified process.