镁合金表面不同掺杂类石墨镀层的界面研究

Interface of Graphite-Like Coating Doped with Different Elements on Magnesium Alloy Surface

摘要:

利用非平衡磁控溅射技术分别在镁合金基体上制备了以Al、Zr、W为过渡层的类石墨镀层。使用透射电子显微镜(TEM)对镀层的截面微观结构及相组成进行分析；使用划痕仪与摩擦磨损机测试镀层的膜基结合强度和摩擦性能。结果表明，镁基体-铝过渡层界面形成了镁和β-Mg17Al12相混合的合金相分层界面；镁基体-锆过渡底层界面形成了较好的局部连续界面；镁基体-钨过渡底层界面为钨粒子对镁合金基体注入形成约20 nm的镁-钨团簇混合界面层。镁基体表面铝、锆、钨掺杂碳镀层的膜基结合力分别为10.2、11.0、4.8 N。掺杂碳镀层工作层成分及结合力的不同，导致镀层耐磨减摩性能差异较大：掺铝碳镀层有较小摩擦系数，在0.1~0.18之间，且耐磨性较好，在球-盘实验结束后镀层依然没有失效；掺锆碳镀层大约在1600 s失效，摩擦系数急剧增大，失效前的摩擦系数在0.08~0.18之间，具有良好的减磨耐磨效果；掺钨碳镀层从一开始摩擦系数就急剧增加，在250 s左右完全失效，出现大面积剥落，在3种镀层中耐磨减摩效果最差

Abstract:

Using the unbalanced magnetron sputter ion plating technique graphite-like coatings with Al, Zr and W as transition layers on the surface of magnesium substrate were prepared. The section microstructure and phase composition of the coatings were analyzed by TEM and the binding force and tribological performance were tested by a scratch tester and a wear machine. The results show that a mixing layer with magnesium and β-Mg17Al12 phase is formed in the interface between Al transition layer and magnesium substrate; there is a partial continuous interface between Zr transition layer and magnesium substrate; the interface between W transition layer and magnesium substrate is a mixed interface layer with magnesium phase and tungsten clusters of about 20nm because of the implantation of tungsten particles into magnesium substrate. The binding force of the three kinds of doped (aluminum, zirconium, tungsten) carbon coatings on the surface of magnesium substrate is 10.2, 11.0 and 4.8 N, respectively. The different work layers of three kinds of doped carbon coatings result in different wear-resistant and anti-friction performances. The Al-doped carbon coating has low friction between 0.1~0.18, so its wear resistance is good and the coating will not fail even after the ball-disc experiment. The work layer of zirconium-doped carbon coating fails around 1600 s when the friction coefficient begins to increase sharply. Its friction coefficient is between 0.08~0.18 before the failure, and it has good wear-resistant and anti-friction performance. The friction coefficient of the tungsten doped carbon coating increases dramatically from the beginning and the coating fails completely in 250 s with a large area of spalling; therefore its wear and friction reducing effect among the three coatings is the worst