Self-repair technology of wear metals is an innovative technology in the field of surface engineering.This technology can evidently improve the physic-chemical and mechanical properties of friction pairs and reduce the wear loss by selectely repairing the worn surface.It can repair the worn surface of various metals without machinery disassembly,and significantly reduce friction shock,then reduce energy consumption greatly and extend service life of the devices.In this paper,the heat treatment process, preparation,and its suspension property in lubricant of the serpentine are explored.The formation mechanism of the self-repairing protective coating,and the antiwear property of a mixed powders as lubricant additive have been systematically studied.The main conclusions are reached as follow:1.The heat treated serpentine at different temperature was examined by using Xray Diffraction apparatus,differential thermal(DTA) and thermogravimetric(TG) analyser and infrared spectrometric analyzer.The results indicated that the phase transformation of serpentine can take place at 800℃.Its chemical transformation equation can be shown as follow:Mg_3Si_2O_5(OH)_4→Mg_2SiO_4+MgSiO_3+2H_2OThe serpentine powder was prepared by using a QM planetary ball milling machine at different conditions.The dispersive property of the serpentine powder in the lubricant was investigated by using different dispersants.The results indicated that the size of the prepared powder was less than 10μm.The serpentine powder can well suspended in the lubricant by using oil acid and titanate coupling agent as dispersants.2.The film formation process of the additive on the surface of the metal friction pairs using self-repairing materials as oil additive was conducted by MM-200 friction and wear tester.The surface topography and components of protective film on the worn surface of 45~# steel rings were analyzed by SEM and EDAX.The experimental results indicated that wear and formation of the self-repairing film on the metal friction pairs are concurrence in the initial stage.As the time increases,the formation of the self-repairing film generated gradually.The self-repairing film fully covered on the worn surface of the metal in the end of the test.3.The formation of the self-repairing film were studied systemically at different experimental conditions.The results indicated that the self-repairing film formation process is faster obviously when the load is relatively higher(600N and higher than 600N).The optimal content of the serpentine particulates in the lubricant is 2 wt%.The addition of the graphite particulate in lubricant can effectively diminished the friction coefficient of the friction pairs,but it has no effect on the formation of the protecting film.The powder heat treated at 550℃and 900℃as lubricant additives can form a protective film on the metal surface with a large number of micro-holes.The smooth self-repairing film can be generated on the worn steel surface of carbonized steel pairs lubricated with additive oil during friction and wear,and the protective film can prohibit the crack or void nucleation and initiation in the deformed layers.Therefore,this avoids the occurrence of delamination wear.4.Composite powder using as lubricant additive was investigated in order to enhance the friction-reducing effect of the additive.The experimental results show that the composite additive can achieve an ultra-low friction coefficient of 0.007 for the 45~# steel friction pairs.The worn surface is smooth with only a small amount of scratches on the local area of the metal surface.The XPS result after 100h test shows the carbon was concentrated on the worn surface besides of Fe,O,Si and Mg.The existence of the carbon-rich surface layer is the main reason for the superlubricity characteristics.5.The additive powder directly takes part in the formation process of the self-repairing film and constitutes the main component of the film.The mechanism of self-repairing film(ⅰ)The serpentine powder can be ground into smaller size in the friction process by the surface asperities of the two contacting surfaces.There are a large number of surface dangling bonds on the powder surface after ground.At the same time,the friction produces fresh surfaces of the steel where the activity of friction pairs and the grindings is enhanced. (ⅱ) The serpentine powder with activated surface interacts with the fresh surface. The activated powder can adhere on the steel surface.The activated powder can adhere to each other,and deposit on the pits and scratches of the friction pairs surface.At thesame time,some bigger powder can also deposit on the pits and scratches of the friction pairs surface.(ⅲ) The fine powder adhered on the activatory surface and deposited on the pits and scratches can interact under high contacting stress,high transcient temperature. Then a self-repairing film formed in the local area on the friction pairs surface.(ⅳ) The powder continually spread on the friction pairs surface under the process of the mechano-chemistry,tribo-chemistry,triboheat and load until the self-repairing film covers fully on the friction pairs surface.Afterward,the wear and the self-repairing film formation process reaches dynamic balance.