颗粒增强铝基涂层的组织结构与摩擦学性能

Microstructure and Tribological Properties of Particle Reinforced Aluminum-based Coatings

选用常规微米尺度Al2O3粉体和纳米结构Al2O3-TiO2粉体作为硬质颗粒,采用等离子喷涂方法在45钢基体上制备了Al2O3/Al2O3-TiO2颗粒增强铝基复合涂层,采用扫描电镜(SEM)、X射线衍射仪(XRD)和维氏硬度计观察和测试涂层的形貌、物相及显微硬度,通过滑动摩擦磨损试验分析涂层的摩擦学性能。结果显示,Al/Al2O3涂层的表面形貌和纯铝涂层非常相似,Al/Al2O3-TiO2涂层表面可以看到未熔、半熔和全熔的增强相存在。Al/Al2O3涂层的主要物相为Al和α-Al2O3,Al/Al2O3-TiO2涂层的主要物相为Al、α-Al2O3和TiO。随着增强相加入量的提高,Al/Al2O3涂层和Al/Al2O3-TiO2涂层的硬度不断提高;当添加量为30%时,硬度分别比未加增强相时提高了67%和76%。加入增强相的涂层的平均摩擦因数都有较大幅度的减小,加入30%Al2O3的Al/Al2O3涂层的磨损量比未加入增强相涂层的磨损量下降85.6%,Al/Al2O3-TiO2涂层的磨损量比未加入增强相涂层的磨损量下降74%左右,表明硬质颗粒Al2O3和Al2O3-TiO2的加入,可显著提高涂层的耐磨性。

Conventional micron Al2O3 powder and nanostructured Al2O3TiO2 powder were selected as strengthening particles for Al. Plasma spraying was used to deposit the Al2O3 and Al2O3TiO2 particle reinforced aluminum composite coatings on 45 steel substrate. Morphology, phase, and micro hardness of the coatings were measured by SEM, XRD and Vickers. Tribological properties of the coatings were analyzed by sliding friction and wear test. The results show that surface morphologies of Al/Al2O3 and Al coatings are similar, but unmelted, half and full melted Al/Al2O3TiO2 particles can be seen on the coating surface. Al/Al2O3 consists of Al and αAl2O3, and Al/Al2O3TiO2 consists of Al, αAl2O3 and TiO. With the increase of reinforcements, the hardness of both Al/Al2O3 and Al/Al2O3TiO2 coatings were continuously improved; when the content of reinforcements were 30%, the hardness for Al/Al2O3 and Al/Al2O3TiO2 coatings were enhanced by 67% and 76%, respectively. The coefficient of friction decreases by adding reinforcements. The weight loss of the Al/30%Al2O3 coating and Al/ 30%（Al2O3TiO2） coating is reduced by 85.6% and 74% repectively, compared with that of pure Al coating, indicating that the hard particles of Al2O3TiO2 and Al2O3 can significantly improve the wear resistance of Al-based coating.