Study On Tribology Performance Of Micro Composite Powder And Binder On Cylinder Liner Surface

With the development of diesel engine toward high strength and high power density,the internal friction loss of diesel engine tends to be serious.Among all kinds of friction losses,the mechanical wear between cylinder liner and piston ring accounts for a large proportion.Therefore,it is important to study the friction and wear of cylinder liner piston rings.In this paper,micro-dimple arrays were fabricated on the surface of cylinder liner,and mixed powders of molybdenum disulfide and graphite were filled in different proportions.The friction and wear laws under different parameters were obtained by friction and wear tester.Scanning electron microscopy(SEM),energy dispersive spectrometer(EDS),X-ray diffraction(XRD),three-dimensional confocal microscopy were used to detect the wear surface and micro-dimple internal morphology of the cylinder liner.The mechanism of friction reduction and scuffing resistance performance of micro-nano powder composite binder was analyzed.The following results were obtained:(1)In the case of non-composite binder,composite binder a and composite binder b,the friction and wear properties of cylinder liner specimens filled with graphene in micro-dimple are better than those filled with molybdenum disulfide in micro-dimple and without filling in micro-dimple.Compared with the case without filling in the micro-dimple,the friction coefficient of molybdenum disulfide and graphene filled in the micro-dimple decreased by 8.7%and 27.1%without composite binder,13.1%and 25.4%with composite binder a,and 8.3%and 16.6%with composite binder b.Compared with the case without filling in the micro-dimple,the time of filling molybdenum disulfide and graphene in the micro-dimple increased by 85%and 111%,the time of filling in the composite binder a increased by 31%and 33%,and the time of filling in the composite binder B increased by 58%and 74%.(2)In the absence of binder,composite binder a and composite binder b,the powder release of graphene-filled cylinder liner samples in the micro-dimple during the test time was higher than that of molybdenum disulfide-filled cylinder liner samples in the micro-dimple,which increased by 37%,15%and 40%in turn.The releases of molybdenum disulfide and graphene decreased by 41%and 67%in compound binder a and 50%and 66%in compound binder b.The existence of binder reduces the amount of powder released.(3)Mixed powders with molybdenum disulfide and graphene ratios of 1:4,2:3,3:2 and 4:1 were filled in the micro-dimple respectively.It was found that the mixed powders with molybdenum disulfide and graphene ratios of 4:1 in the micro-dimple had the best scuffing resistance performance.In the absence of binder,composite binder a and composite binder b,the ratio of molybdenum disulfide to graphene in the micro-dimple is 4:1.Compared with that in the micro-dimple,the time of cylinder drawing increases by 29%,26%and 23%,respectively.Binder improves the anti-pull cylinder performance of powder.