Abstract
A novel γ-γ'(Ni solid solution—Ni3Al)NiPtAl coating was produced on advanced single-crystal(SC)superalloy N5 by electroplating of a thin Pt coating with~3 μm in thickness followed by heat treatment at 1000 ℃ in vacuum.For comparison,a traditional γ-γ'NiPtAl coating was also produced by electroplating of a thick Pt coating with~6 μm in thickness followed by heat treatment at 1100 ℃ in vacuum.The novel coating has a mass gain of~0.5 mg·cm-2 after 100 h 1-h cyclic oxidation at 1150 ℃,showing better oxidation resistance than the traditional coating.An oxide scale mostly con-sisting of α-Al2O3 grew on the novel coating because the element Cr from the SC alloy substrate contributes to the formation of α-Al2O3.Pt content in the novel coating has significant effect on the oxidation resistance.The opti-mized Pt content in the coating is about 16 at%,which is helpful to reduce the diffusion of harmful elements from the substrate into the coating but also to reduce the cost of the coating.