稀土对6063Al镍基激光熔覆层组织及摩擦磨损性能的影响

Effect of Rare Earth on the Microstructure and Tribological Properties of Laser Cladding Ni- Based Coatings on 6063 Al

利用激光熔覆技术,在6063Al表面制备了添加有La2O3、Y2O3、Ce O2的Ni60合金熔覆层,并通过SEM、XRD、显微硬度计和摩擦磨损试验机等设备的测试分析,研究稀土氧化物对6063Al表面Ni基激光熔覆层组织结构、硬度及摩擦磨损性能的影响.结果表明:不同成分熔覆层的主要相结构均为β-Ni Al(Cr)和少量的Al3Ni、Al Ni3和Al等,但La2O3+Ni60熔覆层中含稀土化合物Al4La,Y2O3+Ni60熔覆层中出现了YAl3、Al Ni Y和Ni17Y2,Ce O2+Ni60熔覆层中检测到了Ce Ni5和Ce3Ni6Si2;添加不同稀土氧化物的Ni60熔覆层呈现细密的、均匀分布的枝晶,无明显气孔,其晶粒较不含稀土的Ni60熔覆层明显细化;加入稀土氧化物的Ni60熔覆层硬度提高HV100~300,且随着深度的增加,硬度值比未加稀土的Ni60熔覆层过渡较平缓;和Ni60熔覆层相比,添加稀土氧化物La2O3、Y2O3和Ce O2的Ni60熔覆层磨损面崩损程度减小了,具有较平整的表面磨痕形貌,磨痕深度和宽度均大幅减小,磨损量减少了一个数量级,摩擦系数也较低,其中加入La2O3和Ce O2的熔覆层磨损量最低,耐磨性最好.

Ni- Based alloy coatings with different rare- earth oxides( La2O3,Y2O3,CeO 2) were prepared on the surface of 6063 aluminum alloy by using laser cladding. The effects of rare earth oxides on the microstructures,phase structures,microhardness and tribological properties of laser cladding Ni- Based alloy coatings on 6063 Al alloys were investigated by means of X- ray diffraction,scanning electron microscopy,micro- hardness tester,friction and wear testing machine. The results show that the main phases of the cladding layers with different contents were β- NiA l( Cr) and a small amount of Al3 Ni,AlN i3 and Al. La2O3+ Ni60 cladding layer contained rare earth compound Al4 La. Y2O3+ Ni60 cladding layer contained YAl3,AlN iY,Ni17Y2,and CeO 2+ Ni60 cladding layer detected CeN i5,Ce3Ni6Si2 in the structures. The Ni60 cladding layers with addition of rare earth oxides exhibited uniform distribution of dendrites,no porosity,and more refined grains than Ni60 cladding layer without rare earth oxides. The increment of microhardness of Ni60 cladding layer was HV100 ~ 300 in the presence of rare earth oxides. And the hardness profile showed a mild transition in comparison with thecladding layer without rare earth oxides. The collapse damage of worn surface of Ni60 cladding layer was alleviated in the presence of rare earth oxides. The depth and width of wear track were greatly reduced and wear volumes were reduced by one order of magnitude. The friction coefficients were reduced. The cladding layers with addition of La2O3,CeO 2had the lowest wear volume,and therefore the best wear resistance.