Recently, the aluminizing of MCrA
lY coatings sprayed by a low-pressure-plasma spray (LPPS) process is used for improving the high temperature oxidation resistance. However, the aluminizing properties of plasma-sprayed MCrA
lY coatings, which have an important effect on coating performance, have not alway been clarified. In this study, five kinds of as-sprayed MCrA
lY (CoCrA
lY, CoNiCrA
lY, CoNiCrA
lY+Ta, NiCrA
lY, NiCoCrA
lY) coatings were selected for the aluminizing test. The pack-aluminizing was conducted at 1173, 1223 and 1273K for 5, 10 and 20h, respectively.
The experimental results showed that the aluminum rich layers of NiA
l or CoA
l phase were formed by the aluminizing process. It also indicated that the thickness of the aluminum rich layers could be determined, by the parabolic time dependence. There is a tendency that the reaction diffusion rate by the aluminizing increases with increasing nickel content in MCrA
lY coatings and the reaction diffusion rate of as-sprayd MCrA
lYs is faster than that of the heat treated MCrA
lY
s (1393K, 2h, Ar atmosphere) in all cases.
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