(1. 裝甲兵工程學院材料工程系, 北京100072; 2. 西安交通大學材料科學與工程學院, 西安710049)
摘 要: 通過研究含油量低、中、高三種銅石墨自潤滑材料的滑動摩擦過程，發(fā)現(xiàn)摩擦系數(shù)μ與滑動距離n 的關(guān)系曲線由三部分構(gòu)成， 即dμ/dn <0(自潤滑開始工作階段), dμ/dn →+0(自潤滑穩(wěn)態(tài)工作階段),dμ/dn →∞(自潤滑失穩(wěn)向干摩擦過渡階段)。依據(jù)自潤滑材料與潤滑油的特性和摩擦過程的物理變化，確立自潤滑材料滑動摩擦自潤滑機理為：在法向載荷和摩擦熱的作用下，由于油的流動性、孔隙的可壓縮性和油受熱膨脹等特性，使材料內(nèi)部貯油被迫流向摩擦表面起潤滑作用；摩擦熱、出油量、摩擦系數(shù)三者之間具有自反饋調(diào)節(jié)作用，使穩(wěn)態(tài)工作時保持低且穩(wěn)定的摩擦系數(shù); 摩擦面的油在滑動過程中不可避免地有所損耗，在自反饋調(diào)節(jié)作用下，通過提高摩擦面溫度可向摩擦面補充油，待摩擦面溫度達到或高于油的閃點后，摩擦面的油將大量揮發(fā)，摩擦由自潤滑向干摩擦過渡，自潤滑失效。
關(guān)鍵字: 粉末冶金；滑動摩擦；自潤滑；自潤滑材料；自潤滑機理
（1. Department of Materials Engineering, Armored Force Engineering Institute, Beijing 100072, P.R.China
2. Shanghai Silicate Research Institute, CAS, Shanghai 200050, P. R. China
3. The School of Materials Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, P. R. China）
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.
Key words: powder metallurgy; sliding friction; self-lubrication; self-lubrication materials; self-lubrication mechanism
