自润滑材料滑动摩擦特性与自润滑机理
来源期刊：中国有色金属学报1999年第3期
论文作者：丁华东 韩文政 李雅文 王永兰 金志浩
文章页码：515 - 519
关键词：粉末冶金；滑动摩擦；自润滑；自润滑材料；自润滑机理
Key words：powder metallurgy; sliding friction; self-lubrication; self-lubrication materials; self-lubrication mechanism
摘 要：通过研究含油量低、中、高三种铜石墨自润滑材料的滑动摩擦过程，发现摩擦系数μ与滑动距离n 的关系曲线由三部分构成， 即dμ/dn <0(自润滑开始工作阶段), dμ/dn →+0(自润滑稳态工作阶段),dμ/dn →∞(自润滑失稳向干摩擦过渡阶段)。依据自润滑材料与润滑油的特性和摩擦过程的物理变化，确立自润滑材料滑动摩擦自润滑机理为：在法向载荷和摩擦热的作用下，由于油的流动性、孔隙的可压缩性和油受热膨胀等特性，使材料内部贮油被迫流向摩擦表面起润滑作用；摩擦热、出油量、摩擦系数三者之间具有自反馈调节作用，使稳态工作时保持低且稳定的摩擦系数; 摩擦面的油在滑动过程中不可避免地有所损耗，在自反馈调节作用下，通过提高摩擦面温度可向摩擦面补充油，待摩擦面温度达到或高于油的闪点后，摩擦面的油将大量挥发，摩擦由自润滑向干摩擦过渡，自润滑失效。
Abstract: The whole course friction characteristic curves, friction coefficient μ versus friction distance n , which consisted of three stages, i.e., dμ/dn <0(initial self-lubricating stage), dμ/dn →+0(stable self-lubricating stage) and dμ/dn →∞(failure stage, self-lubrication giving way to dry friction), were obtained for the oily self-lubricating materials. The self-lubricating mechanism in sliding friction was founded by studying the physical changes during friction course and analyzing the properties of material and lubrication oil, and it may be given as follows: under the compressing action of normal load and friction heat, and based upon the fluidity of oil, compressibility of pores and heated expansibility of oil, the oil stored in the pores of material is compelled to flow to the friction surface to lubricate. During friction process, there are self feedback adjusting functions, i.e., HD mechanism, among friction heat, oil quantity and friction coefficient; and it is that which maintains the friction coefficient low and steady. It is unavoidable for oil to waste during friction process, but the wasted oil is able to supply under the HD mechanism by increasing the friction surface temperature. As soon as the friction surface temperature is near or beyond the flash point of oil, the oil between friction surfaces will volatilize greatly, and this makes the friction type transform from self-lubrication friction to dry friction and the self-lubrication fails.
