Nb2O5-Ag纳米复合薄膜的制备及高温摩擦机理研究

Research on Preparation and High Temperature Tribological Mechanism of Nb2O5-Ag Nano-composite Film

针对固体润滑薄膜材料的摩擦磨损及高温摩擦机理问题,用脉冲激光沉积技术制备了不同Ag含量的Nb2O5-Ag复合薄膜。用X射线衍射、扫描电镜、透射电镜和纳米压痕仪表征了薄膜的物相、微观结构及力学性能;用高温摩擦试验机测试了薄膜在25、700℃的摩擦磨损性能,并分析了薄膜的高温摩擦机理。结果表明：复合薄膜中Ag的含量会影响其结构及力学性能。当复合薄膜中Ag的含量为33.66 at%时,其结构变得更加致密且硬度（1.12 GPa）和弹性模量（14.36 GPa）最高。25℃时复合薄膜的摩擦系数随Ag含量的增加逐渐降低至0.38;而在700℃时,其摩擦机理为复合薄膜中不同含量的Ag与Nb2O5发生化学反应生成了Ag2Nb4O11和Ag NbO3,其中Ag NbO3能形成润滑膜,具有良好的高温润滑作用。

Aiming at the problem of friction and wear and high temperature mechanism of solid lubricating films,Nb2O5-Ag nano-composite film with different Ag content was prepared by pulsed laser deposition（PLD）method.The phase composition,microstructure and mechanical properties of the films were investigated by XRD,SEM,TEM and nano-indenter.The tribological properties of the films at 25℃and 700℃were tested by high temperature tribotest machine,and the high temperature wear mechanism of the composite film was analyzed.The results show that the of the Ag contents in composite film can influence the microstructure and mechanical properties of the film.When the content of Ag is 33.66at%in the composite film,the structure becomes more compact and it has the highest hardness（1.12 GPa）and elastic modulus（14.36GPa）.The friction coefficient of the composite film gradually decreases to 0.38 at 25℃with the increase of Ag content.While at 700℃,the wear mechanism is that Ag2Nb4O（11）and Ag NbO3are produced by chemical reaction between different Ag contents and Nb2O5in the composite film,and the lubricating film is formed by Ag NbO3,which has a good high temperature lubrication effect.