Effect of annealing treatment on microstructures, mechanical properties and cavitation erosion performance of high velocity oxy-fuel sprayed NiCoCrAlYTa coating

Enkang Hao^1,2，Yulong An^1,2，Xia Liu³，Yijing Wang^1,2，Huidi Zhou^1,2，Fengyuan Yan^1,2

1. State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences2. Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences3. Research Center of Modern Surface and Interface Engineering, Anhui University of Technology

摘 要：The mechanical parts serving in the marine environment are up against the dual damage of corrosion and cavitation erosion, so the Ni Co Cr Al YTa coating with excellent corrosion resistance is successfully prepared by high velocity oxy-fuel（HVOF） sprayed technology to protect the equipment from deterioration. The chemical composition and mechanical properties as well as the microstructure evolution of the coating before and after annealing treatment are studied. At the same time, the influence of annealing treatment on the corrosion and cavitation erosion behaviors of the coating is investigated, as well. The NiCoCrAlYTa coating mainly contains γ-Ni, β-Ni Al, and γ’-Ni₃Al phases. During the deposition, the microcrystals or incomplete crystals generate in the interior of the coating because of the large temperature difference and impact force. Meanwhile, there is twin crystal structure in the as-spayed coating. After annealing treatment, the growth of grains and the segregation of reactive elements improve interface strength and inhibit the formation of micro-defects in the coating. The annealing temperature is of significance to the microstructure, mechanical properties, anti-corrosion and cavitation erosion resistance of the coating. This study provides a combined approach toward improving the corrosion and cavitation erosion resistance of NiCoCrAlYTa coatings.

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