Heat Treatment of Metals ›› 2025, Vol. 50 ›› Issue (3): 284-290.DOI: 10.13251/j.issn.0254-6051.2025.03.045

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Microstructure and wear resistance of Ni-based WC coating prepared by HVOF spraying and vacuum heat treatment

Liu Jun1, Ji Yizhi2, Li Wei3, Liao Bin1, Cao Zhigang2, Huang Xiuxi2, Liu Siye1, Dong Hui4   

  1. 1. National Energy Group Baoqing power generation Co., Ltd., Shaoyang Hunan 422000, China;
    2. East Power Plant, Huaneng Hainan Power generation Co., Ltd., Dongfang Hainan 572633, China;
    3. Xi'an Thermal Engineering Research Institute Co., Ltd., Xi'an Shaanxi 710001, China;
    4. School of Materials Science and Engineering, Xi'an Shiyou University, Xi'an Shaanxi 710065, China
  • Received:2024-10-06 Revised:2025-01-18 Online:2025-03-25 Published:2025-05-14

Abstract: To improve the wear resistance of the thermal power boiler water wall, desulfurization system desulfurization circulation pump and ash removal system pipeline, Ni25WC and Ni35WC coatings were deposited on the surface of 2205 stainless steel by high velocity oxygen fuel (HVOF) spraying and vacuum heat treatment. The microstructure and phase of the coatings, as well as the key properties, such as abrasive wear resistance and erosion wear resistance, were studied. The results show that heat treatment enhances the bonding between the hard phase and the adhesive phase, and the pores change from lamellar shape to spherical shape. The hard phases in Ni25WC and Ni35WC coatings do not flake off during abrasive wear test, and the wear mass loss of the Ni25WC and Ni35WC coatings are 42 mg and 30 mg, respectively, which less than 4% of the mass loss of 2205 stainless steel. Both coatings mainly contain Ni, W2C, Cr3C2 and C. The hardness of Ni25WC and Ni35WC coatings is basically the same, both more than three times that of the 2205 stainless steel. During erosion wear test, the sand repeatedly impacts the surface, causing the hard phase peeling off. As a results, the erosion wear resistance of the two coatings is only about 30% higher than that of 2205 stainless steel. According to results of abrasive wear and erosion wear, the performance of Ni35WC coating is better than that of Ni25WC coating.

Key words: high velocity oxygen fuel, vacuum heat treatment, Ni-based WC coating, microstructure, abrasive wear, erosion wear

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