激光熔覆Ni基WC复合熔覆层组织与性能的研究

通过激光熔覆的方法在Cu-Cr-Zr三元铜合金表面制备Ni60添加不同含量WC颗粒的合金熔覆层。熔覆层的微观组织结构、化学成分、物相组成分别由SEM、EDS、XRD进行表征;显微硬度、耐磨性和耐蚀性也分别由硬度试验机、干滑动摩擦磨损试验机以及电化学工作站进行测试。结果显示,在合适的工艺参数下,可以得到冶金结合良好,没有缺陷,组织均匀且致密的激光熔覆层。含WC的熔覆层组织中,主要含有Cr7C3、Cr23C6、CrB、NiSi3、γ(Ni,Fe)、W2C、Cr2W4C、WC等相。熔覆层平均硬度可达基体的7倍以上,并且随WC含量增加逐渐增加。熔覆层耐磨性随WC含量增加也逐渐提高,摩擦系数和磨损量均下降明显。熔覆层的耐蚀性随WC含量的增加先提高,后降低,其中WC含量为15%时熔覆层的耐蚀性最好。

Study on microstructure and properties of laser cladding Ni-based WC composite coating

Laser clad Ni-based WC composite coating was fabricated on Cu-Cr-Zr ternary copper alloy by using a fiber laser. The microstructure, composition, microhardness, wear resistance and corrosion resistance of the coating with different content of WC particles were researched by means of SEM, EDS and XRD, hardness tester, wear tester and electrochemical workstation, respectively. The results showed that the laser cladding layer with favorable metallurgical bonding, no defect and uniform structure could be obtained under the appropriate process parameters. The main phases of the laser cladding layer were Cr7C3 , Cr23C6 , CrB, NiSi3 ,γ(Ni, Fe)W2C , Ni 2W4C and WC. The average hardness of the composite coating could reach more than 7 times that of the substrate and increase with the increase of WC content. The friction coefficient and wear loss of the cladding layer decreased with the increase of WC content, which indicated that the wear resistance was improved. The corrosion resistance of the cladding layer first increases and then decreases with the increase of WC content and the best corrosion resistance could be obtained when WC content was 15%.