Development, Growth and Adhesion of Al2O3 on Platinum-Aluminum Alloys.
Final rept. 1 Apr 73-31 Dec 75,
PRATT AND WHITNEY AIRCRAFT MIDDLETOWN CONN MATERIALS ENGINEERING AND RESEARCH LAB
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The development, growth and adhesion of alpha-Al2O3 scales on platinum-aluminum alloys containing between 0.5 and 10 weight percent aluminum and on Ni-Al and Ni-Cr-Al alloys containing platinum have been studied at temperatures in the interval between 1000 and 1450C. The morphologies and microstructures of the alpha-Al2O3 scales were found to be influenced by the temperature, oxygen pressure and the microstructures of the alloys. The oxidation rates of the alloys appeared to be controlled by transport of oxygen along grain boundaries in the alpha-Al2O3 scales. The Al2O3 scales were very adherent to the platinum-aluminum alloys containing up to 6 weight percent aluminum even after extensive periods of cyclic oxidation. The alpha-Al2O3 scale formed on the alloy containing 10 weight percent aluminum was less adherent during cyclic oxidation. Platinum also improved the adhesion of Al2O3 on the Ni-Al and Ni-Cr-Al alloys.
- Properties of Metals and Alloys