Mg_3Sb_2含量对Al-Mg_3Sb_2复相涂层耐磨性的影响

Effect of Mg_3Sb_2 Content on Wear Resistance of Al-Mg_3Sb_2 Composite Coatings

目的研究Mg_3Sb_2含量对Al-Mg_3Sb_2复相涂层的组织、硬度和摩擦学性能的影响,对比分析AZ31B镁合金基体、纯Al涂层和添加不同含量的Mg_3Sb_2之后涂层性能的差异。方法通过火焰喷涂技术在AZ31B镁合金表面制备了Al-Mg_3Sb_2复相涂层。利用扫描电镜(SEM)观察了涂层的截面形貌,利用X射线衍射仪(XRD)分析了涂层的物相组成。通过显微硬度计测试了AZ31B和涂层的硬度,通过摩擦磨损试验仪测试了AZ31B和涂层的摩擦学性能,并通过超景深三维显微镜测试了试样的磨痕宽度、深度及磨损体积。结果经火焰喷涂后可得到组织致密的复相涂层,涂层中的物相主要为Mg_3Sb_2和Al。涂层的平均硬度随Mg_3Sb_2含量的增加而增加,最高可达334.2HV0.025,是AZ31B的4.14倍。摩擦磨损试验中,涂层的摩擦系数随着Mg_3Sb_2含量的增加而减小,但都大于AZ31B的摩擦系数;涂层的磨损率随着Mg_3Sb_2含量的增加而减小,60%Mg_3Sb_2和80%Mg_3Sb_2涂层的磨损率小于AZ31B的磨损率,其他涂层的磨损率大于AZ31B的磨损率,80%Mg_3Sb_2涂层的耐磨性最好,比AZ31B下降了63.26%。随着Mg_3Sb_2含量的增加,Al-Mg_3Sb_2复相涂层的磨痕表面犁沟逐渐变浅并消失。结论 Mg_3Sb_2的加入可以提高涂层的硬度,随着其含量的增加,涂层的耐磨性逐渐提高。

The work aims to study effects of Mg3Sb2 on microstructure, hardness and tribological properties of Al-Mg3Sb2 composite coatings and compare differences in properties of AZ31 B magnesium alloy substrate, pure Al coating and coatings doped with different content of Mg3Sb2. The Al-Mg3Sb2 composite coatings were prepared on the surface of magnesium alloy AZ31 B by flame spraying. Cross sectional morphology of the coatings were observed with SEM. Phase composition of the coatings was analyzed with XRD. Microhardness of AZ31 B and the coatings was tested with microhardness tester. Tribological properties of AZ31 B and the coatings were measured with friction-wear tester. And width, depth and wear volume of grinding cracks were measured with ultra deep field 3 D microscope. Dense composite coatings could be obtained by flame spraying, and phases in the coatings were mainly Mg3Sb2 and Al. Average microhardnesses of the coatings increased with the increase of Mg3Sb2 content, which was up to 334.2 HV0.025, which was 4.14 times that of AZ31 B. In the friction-wear test, friction coefficient of the coatings decreased with the increase of Mg3Sb2 content, which was greater than that of AZ31 B. Wear rate of the coatings decreased with the increase of Mg3Sb2 content. Wear rates of 60% Mg3Sb2 and 80% Mg3Sb2 coatings were less than that of AZ31 B, wear rates of other coatings were more than that of AZ31 B. Compared with AZ31 B, wear rate of the 80%Mg3Sb2 coating decreased by 63.26%. With the increase of Mg3Sb2 content, worn surface furrows on the Al-Mg3Sb2 composite coating become shallow and disappeared gradually. The addition of Mg3Sb2 can improve hardness of the coatings, and wear resistance of the coatings increases gradually with the increase of Mg3Sb2 content.