Effect Of Laser-Induced Counterface Texture On Wear Of PTFE-Al₂O₃ Composites

Laser induced counterface texture under fluid lubrication can effectively reduce interfacial friction and wear by storing lubricant and hydrodynamic pressure effects.At present,there have been attempts to use solid lubricants on the textured surfaces to reduce friction and wear under dry friction conditions.However,they are limited to the use of powdery lubricants such as molybdenum disulfide,and their anti-friction and anti-wear effects are not significant.In addition,the current literature also lacks a simpler and faster method for optimizing the texture design.The polymer solid self-lubricating material can improve the film forming ability and the quality of the transfer film by storing the debris when it is dry-friction,thus reducing the friction and wear resistance.This study focus on the effect of micro-pit textures produced by laser etching on the wear of a notable alumina PTFE nanocomposite and uses the Taguchi method and“Simplex Method”to find the micro-pits parameters producing the lowest wear of the composite material.To improve the efficiency of the experiment,a multiple execution unit linear reciprocating friction and wear tester was designed and fabricated in this thesis,and 17 groups of wear tests were completed using the tester.The results show that the optimal texture parameters are diameter D=600?m,depth d=5?m,and area distribution ratio f=0.02,and the corresponding composite wear rate is 1.6×10^-7 mm³/Nm.This value is identical to the material's wear rate against untextured counterface.However,when slid against freshly replaced composite pin,the existing transfer film on the B₃ texture reduces composite's wear volume at low wear transition by 90%and yields a steady state wear rate of 3.9×10^-7 mm³/Nm.On the contrary,pre-existing low wear transfer film on untextured counterface increases wear of the newly replaced pin by 3×and yields a wear rate of 4.4×10^-6 mm³/Nm.The study shows that when the texture parameter range is D>600?m,f<0.02,d<5?m,it is more favorable for debris entrapment,transfer film formation and wear reduction when slid against polymeric solid lubricants,and B₃ texture does not need to consume large amounts of run-in wear volume of bulk solid lubricants.This thesis also proposes a new laser-induced counterface texture optimization design method that can be used to improve the texture design efficiency.