Study On Tribological Properties Of Aluminum Alloy With Rectangular Microtexture Surface

In recent years,surface micro-texture technology has been widely used to reduce friction and wear,improve the bearing capacity of mechanical equipment.Reasonable micro-texture design can significantly enhance the friction reduction and wear resistance of the friction pair.In this paper,SiO2 was coated by laser surface micro-texturing technique and sol-gel method to prepare rectangular micro-textured surfaces with different wettability.The effects of micro-texture size,sliding direction,lubricant concentration,rotating speed and surface wettability on the tribological properties of silicon nitride/aluminium alloy friction pairs were studied under water-based solution lubrication of polyvinyl pyrrolidone.The purpose of the study was to optimize the design of surface micro-texture and expand the practical application of micro-texture technology in mechanical equipment.The main research contents of the thesis are as follows:(1)Aluminum alloy surfaces with different wettability were prepared by constructing rectangular micro-textures of different sizes,combining with low surface energy solution and SiO2 modification.The effects of the size and wettability of micro-textures on the tribological properties of silicon nitride/aluminum alloy friction pairs were studied.The results show that,in the hydrophobic state,the water contact angle of the surface increases with the increase of the length of the rectangular micro-texture.Enhanced hydrophobicity can reduce friction and wear of friction pairs.The water contact angle and rolling angle of SiO2 modified 190×90 ?m rectangular micro-textured specimens can reach 161.2°and 2.4° respectively,which have the best friction reduction and wear resistance.(2)The effects of wettability and sliding direction on the tribological properties of the friction pairs were studied for 190×90 ?m rectangular micro-textured specimens.When sliding along the direction of 0°,the tribological properties of the specimen are the best.The friction reduction and wear resistance of the sample surface can be enhanced by SiO2 modification.Compared with the sliding direction,the wettability has more significant effect on the tribological properties of micro-textured surfaces.(3)The effect of the wettability of the sample and the concentration of PVP water-based lubricating solution on the tribological properties of the friction pair was investigated under sliding conditions along the 0° direction.When the concentration of PVP solution is 15 wt.%,its lubrication effect is the strongest.After SiO2 modification,the friction coefficient and wear loss of the specimen surface further decreased.Compared with the effect of wettability on the tribological properties of micro-textured surfaces,the effect of lubricant concentration is more significant.(4)The effects of wettability and rotational speed on the tribological properties of firiction pairs were studied under the lubrication condition of 15 wt.%PVP solution.With the increase of rotational speed,the friction coefficient of the friction pair decreases and the wear loss increases.The effect of wettability on the tribological properties of micro-textured surfaces is weakened when the rotational speed is greater than 500 r/min.