Oxidation behaviour of sputter-deposited Ni-Cr-Al micro-crystalline coatings

摘要

Unblanced magnetron sputter deposition was used to produce Ni-20Cr-xAl(x=2, 3, 5wt/100) coatings on the substrates of the same materials. The effects of coating grain size and Al content on oxi- dation behavior at 1000 deg.c have been studied. It was found that the oxidation products were determined by both grain size and Al content. α-Al_2O_3 scales formed on the coatings containing as little as 2.4 wt/100 Al when the coating grain size was < 100 um. The oxidation behaviour was described using Wagner's theory to include short-circuit diffusion.