激光熔覆NiAl-Mo复合涂层组织结构与高温抗氧化性研究

    Study on Microstructure and High Temperature Oxidation Resistance of Laser Cladding NiAl-Mo Composite Coating

    • 摘要: 采用激光熔覆技术在P92钢表面制备Ni Al-Mo复合涂层,研究了涂层的组织结构与高温抗氧化性。结果表明:采用激光熔覆技术可在P92钢表面制备致密无裂纹的Ni Al-Mo复合涂层。Ni3Al和Ni Al为涂层中的主要相,Fe元素与部分Mo元素溶解于Ni3Al和Ni Al中形成Ni基固溶体,未完全溶解的Mo在涂层上部以富Mo区存在,涂层下部则以微溶Mo颗粒存在。800℃氧化达162 h时,无涂层的P92基体形成了600μm疏松氧化膜,而涂层形成了5μm的致密氧化膜。涂层氧化膜由Ni O、Ni Fe2O4、Al2O3共同组成。在P92钢表面激光熔覆制备Ni Al-Mo复合涂层对解决P92钢高温条件下氧化膜过厚、易剥落问题具有重要意义。

       

      Abstract: NiAl-Mo composite coating was prepared on the surface of P92 steel by laser cladding technology. The microstructure and high temperature oxidation resistance of the coating were studied. The results show that a dense and crack-free NiAl-Mo composite coating can be prepared on the surface of P92 steel by laser cladding technology. Ni3 Al and NiAl are the main phases in the coating. Fe and some Mo elements are dissolved in Ni3 Al and NiAl to form Ni-based solid solution. The incompletely dissolved Mo exists in the Mo-rich region at the upper part of the coating, and the Mo particles are slightly dissolved at the lower part of the coating. When it is oxidized at 800 ℃ for 162 h, a 600 μm loose oxide film is formed on the uncoated P92 substrate, and a 5 μm dense oxide film is formed on the coating. The coating oxide film is composed of Ni O, Ni Fe2 O4 and Al2O3. The preparation of NiAl-Mo composite coating on the surface of P92 steel by laser cladding is of great significance to solve the problems of too thick oxide film and easy spalling of P92 steel under high temperature conditions.

       

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