镍基合金激光熔覆-离子渗硫复合改性层组织性能

Microstructure and properties of Ni based alloy composite coating by laser cladding-ion sulfurizing process

利用激光熔覆和离子渗硫技术在45钢表面制备复合改性层,采用SEM,EPMA,XRD等手段对比研究激光熔覆层和渗硫层的组织形貌、成分分布及相组成;并测试渗硫前后涂层的耐磨性和耐蚀性.结果表明,镍基合金涂层主要由γ-(Fe,Ni),Fe_(0.64)Ni_(0.36),M_(23)C_6,WC,M_7C_3和Fe_2B等物相组成,显微硬度达到740 HV0.2.渗硫后在激光熔覆层表面形成了以Fe S为主的渗硫层,表面疏松多孔,由微纳米级的尖岛状颗粒堆砌而成.与熔覆层相比,复合改性层的摩擦系数和磨损量都显著降低,减摩和耐磨效果明显.渗硫后镍基合金激光熔覆层自腐蚀电位下降,腐蚀电流密度增大,耐蚀性略微降低.

The composite layer was produced on 45 steel substrate by laser cladding and low temperature ion sulfurizing process. The microstructure and phase composition of laser cladding layer and sulfurizing layer were studied by the means of SEM,EMPA and XRD. The wear resistance and corrosion resistance of the layer by laser cladding and laser cladding and sulfurizing were also studied. The results showed that phase composition of Ni-based alloy laser cladding coating mainly includes γ-( Fe,Ni),Fe_(0. 64)Ni_(0. 36),M_(23)C_6,WC,M_7C_3 and Fe_2B and so on,and its microstructure hardness is up to 740 HV0. 2. Sulfide layer was produced on the Ni-based alloy coating with low temperature ion sulfurizing process,which is loose and porous,is piled up by the sharp island micro nan-scale particles. Compared with Ni-based alloy laser cladding layer,the friction coefficient and the wear loss of the modified composite layer decrease significantly,excellent antifriction and wear resistance can be obtained. After low temperature ion sulfurizing treatment,the corrosion potential decreases,and the corrosion current density increases and the corrosion resistance of Ni-based alloy laser cladding layer decreases slightly.