Development of Tribo-Coating Lubrication Method for the Space Machines and Its Application

新技术-固体润滑剂的摩擦涂层-已经由我们的小组介绍，以便在超高真空中提供持久的低摩擦。根据该方法，固体润滑剂在滑动过程中蒸发并沉积在摩擦表面上。本研究的目的是从低摩擦、稳定摩擦和使用寿命的角度来论证这种方法在高真空中应用的可能性。主要研究结果如下：（1）采用原位沉积法对氮化硅球/不锈钢环和不锈钢保持架的球轴承进行了原位沉积铟，使其摩擦系数保持在0.002以下。该值几乎与常规固体润滑剂如离子镀Ag膜的值相同。(2)在不锈钢滚道和氮化硅球的混合轴承的情况下，使用两次摩擦涂层铟可以保持稳定和0.002的低摩擦直到10^7个循环。(3)陶瓷棒/不锈钢环无保持架轴承的使用寿命是有保持架轴承的10倍。(4)铟的最佳摩擦涂覆速度为6-20 nm/min，在此速度下获得稳定的低摩擦系数（0.002）。(5)在800-1400 MPa的接触压力下，稳定摩擦时最佳涂层厚度为100-400 nm。

New technique - TRIBO-COATING of a solid lubricant - have been introduced by our group in order so provide durable low friction in ultra high vacuum. According to this method solid lubricant is evaporating during the process of sliding and depositing on the friction surfaces. The possibility of this method to decrease friction has been shown using pin-on-disk apparatus.The purpose of this research was so show its possibility so apply rolling bearing in high vacuum from the view points of low and stable friction and its endless life. In addition, optimum-coaling condition to give stable and low friction wan clarified.The following results were mainly obtained:(1) Friction coefficient of a ball bearing, which has silicon nitride balls/stainless steel rings and stainless steel retainer, is kept lower than 0.002 by the in-situ tribo-coating with indium. This value is almost same as that of conventional solid lubricant such as ion-plated Ag film.(2) In the case of hybrid bearing with stainless steel races and silicon nitride balls, stable and low friction of 0.002 could be kept until 10^7 cycles with two times tribo-coating of indium.(3) The ceramic bats/stainless steel rings bearing of no retainer shows ten times longer life than of a retainer.(4) Optimum coating speed of indium for tribo-coating was 6-20 nm/min, in which stable and low friction of 0.002 was obtained.(5) Optimum coating thickness during stable friction was 100-400 nm that was formed under contact pressure of 800-1400 MPa.