中文摘要：

采用激光熔覆技术在45钢基体上制备了不同CeO2含量的镍基纳米Al2O3复合涂层,对熔覆层进行了微观组织分析和显微硬度测试。结果表明,随着CeO2含量的增加,熔覆层组织由亚共晶向共晶组织转变;加入1.0%CeO2对镍基纳米Al2O3熔覆层的组织起到明显的细化和净化作用,枝晶生长的方向性减弱,组织趋向均匀,熔覆涂层的显微硬度值比未加稀土的涂层提高了60-95HV0.2。

英文摘要：

The Ni-based nano-Al2O3 composite coatings with different addition of CeO2 are obtained by laser cladding on the surface of 45 steel.The microstructure of the coatings is investigated and analyzed by scanning electron microscope （SEM） and XRD respectively.The microhardness of the coatings is tested.The results show that the microstructure of the coatings varies continuously from sub-eutectic to eutectic with increase of CeO2.Adding 1.0% CeO2,the microstructure is obviously fined and purified,the growing direction of dendrites becomes weakened,and the microhardness of the coating is increased 60-95HV0.2 compared with that of the coating without CeO2.