화학공학소재연구정보센터
Materials Science Forum, Vol.369-3, 295-302, 2001
Oxidation behaviour of beta-FeAlCr coating produced by close-field unbalanced magnetron sputter deposition
beta -FeAl coatings containing 5.7at.% Cr were produced with a close-field unbalanced magnetron sputter (CFUMS) deposition technique. Cyclic oxidation test at 1100 degreesC in air for 100 1-h cycles and isothermal exposures from 1000 degreesC through 1200 degreesC in pure O-2 for 100 hours were carried out with the coatings. The coating showed better scale spallation resistance during cyclic oxidation test than the cast FeAl. After the isothermal oxidation at 1000 degreesC and 1100 degreesC, fine-grained ridge-type oxide scales were formed on the coatings, while at 1000 degreesC, the oxide scale formed on the cast FeAl showed a large quantity of theta -Al2O3 blades, and big interfacial voids on the base alloy surface were observed. The transformation from theta to alpha -Al2O3 was accelerated due to the presence of Cr in the coatings, and suppressed the fast outward Al diffusion for the growth of theta -Al2O3 scale and eliminated the formation of interfacial voids that deteriorated the oxide scale spallation resistance. After the isothermal exposure at 1200 degreesC, however, the oxide scale on the coating was greatly buckled and spalled, and did not show much improvement over the cast FeAl.