98/03288 Manufacture of high-strength ceramic composite boards for buildings from fly ash: Ota, K. and Ota, M. Jpn. Kokai Tokkyo Koho JP 10 25, 171 [98 25,171] (Cl. C04B35/74), 27 Jan 1998, Appl. 96/176,947, 5 Jul 1996, 7 pp. (In Japanese)

Abstract

The effects of boron and/or carbon on the densification of AlN were investigated. Sintering was promoted by adding the additives simultaneously. Thermo-chemical analysis indicated that a liquid phase composed of aluminum and boron were formed by the borothermal reduction of Al2O3 and AlN. Liquid phase sintering is believed to be the reason for the enhanced densification of AlN. The present investigation proposes a method to densify AlN using non-oxide sintering additives having high melting temperature (>2000 °C). The deterioration of AlN refractory is expected to be suppressed by preventing the formation of oxide grain boundary network which is vulnerable to corrosion caused by molten metal.