Year: 1999
Type: article
Abstract: The high‐temperature stability of alumina (Al 2 O 3 ) in argon and argon/water‐vapor (Ar/H 2 O) environments has been investigated. Samples were exposed at temperatures of 1300°C–1700°C for 10 h. The microstructure, flexural strength, and volume all showed significant changes in the Ar/H 2 O environment at 1700°C. Samples also became whiter, because of the oxidation of graphite impurities that had diffused from the hot‐processing dies. In the Ar/H 2 O environment at 1700°C, grain‐boundary etching occurred and was much more severe than in the pure‐argon environment, which was very likely caused by the enhanced formation of gaseous Al(OH) 3 and Al(OH) 2 along grain boundaries. In addition, in the Ar/H 2 O environment, substantial grain growth occurred in the surface vicinity. This grain growth, together with grain‐boundary etching, led to a decrease in flexural strength.
Institutions: American Ceramic Society, Glenn Research Center
Language: English
Subfield: Ceramics and Composites
Field: Materials Science
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2103013138