纳米CeO2对激光熔覆Ni基合金层组织与性能的影响

为了研究纳米CeO2颗粒对激光熔覆层的组织和性能的影响,在Q235钢基体上制备了加入不同量纳米CeO2的Ni基合金熔覆层,利用OLMPUS PME-3型光学显微镜,XD-3A型X射线衍射仪,HV-1000型显微硬度计,MM-200型环-块磨损试验机和扫描电镜等对激光熔覆层显微组织、相结构、显微硬度、磨损性能和磨损机理进行了研究。结果表明,在激光熔覆层中添加纳米CeO2能够细化组织,改变凝固组织的形态。当加入质量分数为1.5%的纳米CeO2时,熔覆层凝固组织形态为等轴树枝晶;生成了含Ce的新相Ce2Ni21B6,明显提高了熔覆层的显微硬度和耐磨性;熔覆层磨损由严重磨损转化为轻微磨损。但是加入过量的纳米CeO2,硬度反而降低。

Effect of nano-CeO2 on the microstructure and properties of laser clad nickel-based alloy coating

The microstructure and properties of laser clad coating are introduced after adding nano particles.Nickel-based alloy powder with different addition of nano-CeO_2 is laser cladded onto Q235 steel substrate.The coating is examined to reveal the microstructure,phase composition,microhardness and wear resistance using optical microscope(OP),X-ray diffractometer(XRD),microhardness tester,block-on-ring wear tester and scanning electron microscope(SEM) respectively.The results show that fine dendrite and equiaxed dendrite are observed by adding nano-CeO_2.Equiaxed dendrite across the section is obtained when the additive reaches to 1.5%(mass fraction).A new phase(Ce_2Ni_(21)B_6) is found.The microhardness and wear resistance of the coating are much higher than those of the substrate,and further improved by adding nano-CeO_2.But the hardness decreased when the additive amount is much high.The mechanism of these effects is also discussed.