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激光熔覆Ni-WC/Cr3C2涂层组织及性能

Study on microstructure and property of laser cladded Ni-WC/Cr3C2 coating

  • 摘要: 采用激光技术在45钢表面熔覆Ni-WC/Cr3C2涂层,采用SEM,XRD等手段进行熔覆层的显微组织、相组成及成分分析,并测试熔覆层的耐蚀性和耐磨性能.结果表明,Ni-WC/Cr3C2熔覆层底部生成方向性较强的胞状树枝晶,中上部组织为细小的树枝晶.涂层主要是由γ-(Fe, Ni),M23C6型碳化物以及未熔的WC颗粒组成.细晶强化、合金元素固溶强化以及碳化物强化的共同作用,使熔覆层的显微硬度提高至711HV0.1.熔覆层耐蚀性明显改善,腐蚀电流密度约为45钢的1/4.随着摩擦速度的增大,激光熔覆Ni-WC/Cr3C2涂层和45钢磨损量增加,且熔覆层的磨损量低于45钢,表明其耐磨性能明显提高.

     

    Abstract: Ni-WC/Cr3C2 coating was prepared on 45# steel surface by laser cladding technology, and the microstructure, phase and composition were studied by means of SEM and XRD, while the corrosion resistance and wear resistance were also studied. The results show that cellular dendrites were formed at the bottom of the laser cladding Ni-WC/Cr3C2 coating, while fine dendrites were at the middle and upper region of the coating. The cladding coating is mainly composed of γ-(Fe, Ni), M23C6 type carbides and undissolved WC particles. The microhardness is increased to 711HV0.1 due to the synergetic effect of fine grain strengthening, solid solution strengthening and carbides. Moreover, a reduction of the corrosion current density of about four times compared with 45# steel indicating the improved corrosion resistance. In addition, the weight loss of both the laser cladding coating and 45# steel was increased with the increase of wearing speed, and the weight loss of cladding coating is lower than that of 45# steel.

     

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