METHOD FOR PREPARING CONFIGURED SILICON CARBIDE WHISKER-REINFORCED ALUMINA CERAMIC ARTICLES

摘要

METHOD FOR PREPARING CONFIGURED SILICON CARBIDEWHISKER-REINFORCED ALUMINA CERAMIC ARTICLESAbstract of the DisclosureA ceramic article of alumina reinforced with silicon carbidewhiskers suitable for the fabrication into articles of complexgeometry are provided by pressureless sintering and hot isostaticpressing steps. In accordance with the method of the invention amixture of 5 to 10 vol.% silicon carbide whiskers 0.5 to 5 wt.% of asintering aid such as yttria and the balance alumina powders is ball-milled and pressureless sintered in the desired configurationan inert atmosphere at a temperature of about1800°C to provide a self-supporting configured composite of a densityof at least about 94% theoretical density. The composite is then hotisostatically pressed at a temperature and pressure adequate to provideconfigured articles of at least about 98% of theoretical density whichis sufficient to provide the article with sufficient strength and frac-ture toughness for use in most structural applications such as gasturbine blades, cylinders, and other components of advanced heat engines.