超音速等离子喷涂WC-10Co4Cr涂层的力学性能及冲蚀磨损失效分析
Analysis on Mechanical Properties and Erosion Failure Mechanism of Supersonic Plasma Sprayed WC-10Co4Cr Coating
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摘要: 为改善水轮机表面的抗冲蚀磨损性能,采用超音速等离子喷涂微米WC-10Co4Cr粉末制备碳化物金属陶瓷涂层。对涂层的显微硬度、孔隙率、结合强度、抗冲蚀性能进行了测试,通过X射线衍射仪(XRD)和扫描电子显微镜(SEM)表征和分析了WC-10Co4Cr涂层的物相组成、微观组织结构,并探讨了涂层在含沙水流中的冲蚀磨损失效机制。结果表明:获得的WC-10Co4Cr涂层的孔隙率为0.5%,平均显微硬度达1 226 HV0.2,结合强度为70 MPa,涂层的抗冲蚀磨损性能是基体的2.46倍,可有效提高基体的抗冲蚀性能,在含沙水流作用下的冲蚀磨损失效以犁削和剥落磨损为主。Abstract: In order to improve the anti-erosion property of turbine surface, WC-10Co4Cr cermet coating was prepared by supersonic plasma spraying system. The micro-hardness, porosity, bond strength and anti-erosion performance were measured. Phase composition and microstructure were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Erosion failure mechanism in the sandy stream was analyzed as well. The results indicated that the coatings had 0.5% porosity, the average micro-hardness reached to 1 226 HV0.2 and the bond strength was reached to 70 MPa. The anti-erosion property of the coating was 2.46 times to the matrix, which effectively improved the anti-erosion performance of the matrix. In the sandy stream, the erosion was most caused by the sand plowing wear and flaking erosion.