Study on Solid Lubricant Films adapted for Both Environment of Vacuum and Air Atmosphere by Prevention of Galvanic Corrosion and Strengthening of Bonding Layer

采用射频溅射沉积技术在SUS440C钢基体上制备了不同密度的二硫化钼薄膜。薄膜储存在相对湿度为30%的空气中。采用新研制的试验装置，研究了在相对湿度为9%的空气环境中，储存期对磨损寿命的影响。磨损寿命的变化根据密度分为两种模式。密度在3.7g/cm^3以下的薄膜，其磨损寿命随贮存时间的延长而降低。随着密度的减小，直至磨损寿命开始下降的贮存期也随之缩短。另一方面，对于密度为4.3g/cm^3的薄膜，由于在空气中存放，其磨损寿命先增加后降低。SIMS分析发现，薄膜/衬底界面附近的氧随着贮存时间的延长而增加。研究还发现，溅射二硫化钼的晶向决定了其磨损寿命与膜厚之间的关系。当膜的密度大于3.7g/cm^3时，膜的厚度对其磨损寿命影响不大，因为膜容易脱落；二硫化钼晶体C轴与衬底表面垂直或斜向快速取向。而对于密度在2.7g/cm^3以下的薄膜，其磨损寿命随薄膜厚度的增加而增加；C轴弱取向于基材表面垂直或斜向。也就是说，薄膜的粘附强度与溅射二硫化钼的结晶取向密切相关。在上述研究结果的基础上，提出了一种新的薄膜结构，以承受空气中的储存，并具有更长的磨损寿命。

Molybdenum disulfide films with various densities have been prepared on SUS440C steel substrate by radio frequency sputter deposition. Films were stored in air atmospheres of 30% relative humidity. The effects of storage period on the wear life in air atmospheres of 9% relative humidity have been investigated using newly developed testing device. The variety in the wear life was divided into two patterns for density. The wear life of films with the density under 3.7g/cm^3 decreases with the storage period. As the density was smaller, the storage period until the wear life began to drop became shorter. On the other hand, for the film with a density of 4.3g/cm^3, the wear life increases and then decreases by the storage in air. It was found by the SIMS analysis that the oxygen in the film near film/substrate interface increases as the storage period extends.It was also found that the relationship between the wear life and film thickness depends on the crystalline orientation of sputtered molybdenum disulfide. In the case for the films with the density over 3.7g/cm^3, the wear life is scarcely influenced by the film thickness since the detachment of the film occurs readily ; the C axis of molybdenum disulfide crystal is fast oriented perpendicular or oblique direction to the substrate surface. On the other hand, for the film with a density under 2.7g/cm^3, the wear life increases with the film thickness ; the C axis is weakly oriented perpendicular or oblique direction to the substrate surface. That is, the adhesion strength of the film is strongly related to the crystalline orientation of sputtered molybdenum disulfide.On the basis of the results mentioned above, new film structure to endure the storage in air atmospheres and having a longer wear life was proposed.