Experimental Evaluation of New Alloy Coatings
Abstract
The oxidation behavior of binary iridium aluminum and iridium and hafnium alloys, and ternary iridium aluminum-silicon, rhenium aluminum silicon, tungsten aluminum-silicon and molybdenum aluminum silicon alloys has been investigated in 1 atm oxygen at 1550 C - 1800 C. Iridium-hafnium alloys form a protective hafnia scale at above 50 at % hafnium and iridium-aluminum alloys form a protective alumina scale at above 55% aluminum. Silicon decreases the aluminum concentration necessary for the formation of a protective alumina scale on irridium-aluminum alloys from around 55 to below 30 at %, and remarkably extends the lifetime of the alumina scale. Rhenium-aluminum-silicon, tungsten-aluminum-silicon, and molybdenum-aluminum-silicon alloys also exhibit good oxidation resistance, but the data are too sparse for any definite analysis or conclusions. The iridium-aluminum-silicon alloys with the aluminum concentration from 30 to 50 and the silicon concentration from 8 to 15 at% are proposed to be the best potential coating materials. Keywords: Oxidation; Iridium; Aluminum; Hafnium; Silicon; Rhenium; Tungsten; Molybdenum; Oxidation kinetics. (kt)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 19, 1989
- Accession Number
- ADA214922
Entities
People
- Kang N. Lee
- Wayne L. Worrell
Organizations
- University of Pennsylvania