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Alumina Volatility in Water Vapor at Elevated TemperaturesThe volatility of alumina in high temperature water vapor was determined by a weight loss technique. Sapphire coupons were exposed at temperatures between 1250 and 1500 C, water partial pressures between 0.15 and 0.68 atm in oxygen, total pressure of 1 atm, and flowing gas velocities of 4.4 cm/s. The pressure dependence of sapphire volatility was consistent with AI(OH)3(g) formation. The enthalpy of reaction to form Al(OH)3(g) from sapphire and water vapor was determined to be 210 +/- 20 kJ/mol, comparing favorably to other studies. Microstructural examination of tested sapphire coupons revealed surface etching features consistent with a volatilization process.
Document ID
20030025295
Acquisition Source
Glenn Research Center
Document Type
Preprint (Draft being sent to journal)
Authors
Opila, Elizabeth J.
(Cleveland State Univ. Cleveland, OH, United States)
Myers, Dwight L.
(NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2003
Subject Category
Metals And Metallic Materials
Report/Patent Number
E-13870
Funding Number(s)
WBS: WBS 22-896-50-01
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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