石墨对TA7钛合金微弧氧化涂层组织结构及摩擦磨损行为的影响

为提高TA7钛合金耐磨损关键服役性能,在钛合金表面制备微弧氧化陶瓷涂层。通过厚度、粗糙度、显微硬度测量、X射线衍射、场发射扫描电镜观察、能谱分析、摩擦学性能检测等手段研究了石墨对微弧氧化涂层组织结构及摩擦学行为的影响机制。结果表明:基础电解液中加入石墨颗粒能够显著提高TA7钛合金微弧氧化涂层的厚度,降低微弧氧化涂层的表面粗糙度和显微硬度,且随着石墨浓度的升高,微弧氧化涂层的厚度增大,表面粗糙度和显微硬度减小;微弧氧化涂层降低了TA7钛合金的摩擦系数,显著改善了合金的耐磨性能;石墨颗粒的加入进一步降低了微弧氧化涂层的摩擦系数,当石墨浓度为3 g/L时,涂层摩擦系数保持在0.15以下,表现出良好的减摩特性。

Influence of Graphite on the Microstructure and Tribological Behavior of Microarc Oxidation Coatings Formed on TA7 Alloy

In order to improve the anti-wear properties of TA7 titanium alloy,a microarc oxidation(MAO)coating was fabricated on the surface of alloy.The influences of graphite particles on the microstructure and tribological behavior of MAO coatings were investigated by means of thickness,roughness and microhardness measurement,as well as X-ray diffraction,field emission scanning electron microscopy,energy dispersive spectrum analysis and tribological performance testing.Results showed that the introduction of graphite particles into the base electrolyte increased the coating thickness and decreased the surface roughness and hardness.With the increase of the concentration of graphite particles,the thickness increased while the surface roughness and microhardness decreased.The anti-friction property of TA7 alloy was improved because the friction coefficient was decreased by MAO treatment.The introduction of graphite particles further decreased the friction coefficient of MAO coatings.The friction coefficient of MAO coating fabricated in the electrolyte with 3 g/L graphite remained below 0.15,indicating good friction reduction characteristics.