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ISSN Печать: 1093-3611
ISSN Онлайн: 1940-4360
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High Temperature Oxidation Morphology of Al-Si Coating on the Superalloy K438
Краткое описание
To increase the time of efficacy of aero engines, the technology of protective coatings is widely used on the aero engine turbine, in order to improve the high temperature oxidation resistance of alloys. This study uses hot diffusion to form Al-Si coating on superalloy K438. According to GB/T13303-91(The Standard of The Public of China: Steels Detemination Method of Oxidation Resistance), high temperature oxidation experiments of Al-Si coating on superalloy K438 were carried out at 1000 °C for 50hr. The surface morphology was studied by using SEM (XL-300FEG).It is concluded that in the process of high temperature oxidation, the Al-Si coating on superalloy K438 has formed continuous and compact oxide scale α-Al2O3 ,which would prevent oxygen permeating to the alloy substrate. This oxide scale α-Al2O3 has no cracks and did not peeled off. The addition of Si to the coating can effectively prevent diffusion between elements of substrate and those of coating. It acts as a diffusion barrier, prolongs the deterioration period of coating and provides excellent high temperature oxidation resistance.