氧化铈对激光熔覆制备碳化钛涂层显微组织及显微硬度的影响

Influence of CeO₂ on Microstructure and Microhardness of TiC₄ Coating Produced by Laser-Cladding

摘要: 采用激光熔覆法在45钢基体上制备了氧化铈改性的TiC4复合陶瓷涂层;用XRD、SEM及显微硬度计对涂层的相组成、显微组织及显微硬度进行了分析.结果表明:激光熔覆法制备的TiC4陶瓷涂层具有典型的包覆相和硬质点相结构,加入适量(0.3%~1.0%)的氧化铈可改善涂层相对密度,TiC4颗粒尺寸小于1 μm,平均显微硬度达到700 MPa;添加过量(≥1.5%)的氧化铈对陶瓷涂层硬度反而不利,涂层组织中包覆相比例增多,TiC4晶粒尺寸变大,呈柳叶状,显微硬度下降至450 MPa.

Abstract: TiC4 ceramic layer modified by CeO2 was deposited on 45 steel substrate by laser-cladding technique.The phase composition,microstructure and microhardness of the clad coating were analyzed by SEM,XRD and micro-hardness tester.The results show that the TiC4 ceramic coating prepared by laser-cladding method had typical surrounding phase and hard spot phase structure.Density of the coating was improved,TiC4 particle size was less than 1 μm and the average micro-hardness increased to 700 MPa when 0.3wt%-1.0wt% CeO2 was added.Adding exccess (≥1.5wt%) CeO2 would make adverse effect on the coating micro-hardness,i.e.,the surrounding phase content and TiC4 particle size increased,and the TiC4 grain was lance-shaped and the micro-hardness decrased to 450 MPa.