Processing and oxidation behavior of Pt-diffused coatings

摘要

Pt-diffused coatings were synthesized on Ni10 Al alloy by electroplating a thin layer of Pt(1-5μm)followed by a diffusion treatment in vacuum at 1000-1100℃.Effects of processing parameters(Pt thickness and vacuum diffusion temperature)on the microstructures and chemical composition of Pt-diffused coatings were investigated.Also,the oxidation behavior of the coatings was studied at1100℃.Pt film reveals nano-sized grain size of 93-113 nm.Vacuum diffusion treatment leads to the grain growth.1-μm Pt film with 1000℃/1 h vacuum diffusion fabricates nano-sized Pt-diffused coating which exhibits the best oxidation resistance.And a single continuous Al2O3 scale forms on the coating with low Al(~9 at%)and Pt(~6 at%)contents.Increasing initial Pt thickness would introduce more defects and cracks,leading to a duplex scale and decreasing the oxidation resistance of Ptdiffused coatings.