Preparation And Tribological Properties Of Textured UHMWPE/SiC Composites

Ultra high molecular weight polyethylene(UHMWPE)has excellent wear resistance,impact resistance,self lubrication,corrosion resistance and so on.However,single UHMWPE has low hardness,poor abrasive wear resistance,poor tensile property and poor flame retardant property,which greatly limits its application in tribology.Therefore,in practical application,it is necessary to modify UHMWPE to improve its comprehensive performance,so as to adapt to harsher friction conditions.In this paper,nano-sic was used to modify and texturize UHMWPE,and the tribological properties of the composites were analyzed.The research contents are as follows:(1)Four kinds of UHMWPE/SiC composites with different SiC contents were prepared by hot pressing method,and the effects of SiC content on the density and functional groups of UHMWPE were studied.The results show that the density of the sample increases with the increase of SiC content.The mixing of SiC and UHMWPE is physical and does not change the chemical properties of UHMWPE.(2)The surface of UHMWPE/SiC composites with SiC content of 1% was etched by nanosecond laser with different linear spacing and etching times.The effects of etching times and etching intervals on the surface morphology and wettability of UHMWPE/SiC composites were investigated.The results show that the surface of UHMWPE/SiC composites is torn and small pieces fall off due to laser etching,resulting in the formation of multiple holes.With the increase of etching times,the contact Angle of the sample increases.The contact Angle of the sample decreases with the increase of etching distance.(3)The effects of SiC content on tribological properties of UHMWPE under different working conditions were studied.The results show that when the friction velocity is high,the addition of SiC can reduce the friction coefficient of UHMWPE under the conditions of low water load lubrication,high dry load friction and high water load lubrication,but the average friction coefficient of UHMWPE/SiC composites with different SiC content under the same working condition is not much different.The friction coefficient of UHMWPE/SiC composites under low load dry friction is not much different from that of pure UHMWPE.When the friction velocity is low,the friction coefficient of the sample decreases first and then increases with the increase of SiC content.When the SiC content is the middle value(1%,2%),the average friction coefficient is the minimum.The wear of the sample decreases first and then increases with the increase of SiC content.When the SiC content is 1%,the wear of the sample is the minimum.Therefore,when the SiC content is 1%,the minimum average friction coefficient of UHMWPE/SiC composites has a good correspondence with the minimum wear amount.The wear mechanism of UHMWPE/SiC composites is mainly adhesive wear,abrasive wear and fatigue wear.However,under high speed and high load dry friction condition,the sample surface is fused,and the wear mechanism is mainly adhesive wear.(4)The effects of etching times and spacing on the tribological properties of UHMWPE/SiC composites under different working conditions were studied.Under dry friction conditions,with the increase of etching distance,the friction coefficient of the sample first decreases and then increases,and the wear of the sample first decreases and then increases.When the etching interval is 100μm,the friction coefficient of the sample is the minimum.When the etching interval is 900μm,the wear amount of the sample is the minimum.At low load,increasing etching times can reduce the friction coefficient of 300μm and 500μm samples,but has little effect on the wear of samples.Therefore,under dry friction conditions,the surface texture can improve the friction coefficient of UHMWPE/SiC composites and effectively reduce the wear amount when the etching interval is 900μm and the etching times is 1 or 3.Under water lubrication condition,the average friction coefficient and wear amount of textured UHMWPE/SiC composites decrease first,then increase and then decrease with the increase of etching distance.When the etching spacing is 300μm and500μm,the friction coefficient of the sample is relatively stable,and the friction coefficient and wear amount are smaller than other samples.Increasing the number of etchings will make the stability of the friction coefficient of the sample deteriorate,but it has little effect on the wear amount.Therefore,under the condition of water lubrication,the minimum average friction coefficient has a good correspondence with the minimum wear amount when the etchings distance is 300μm or 500μm and the number of etchings is 1.The friction coefficient of textured SUHMWPE/SiC composites is affected by the friction condition,and the friction coefficient of the same textured sample is lower under water lubrication and high speed.In the process of friction,the surface texture can avoid abrasive wear.The main wear mechanisms of samples are adhesive wear and fatigue wear.