Study On The Triboelectrification And Friction Transfer Of Ptfe-based Composites With Rare Eeath

In this paper,both the formation of transfer film and the triboelectrification of the addition of rare earth into PTFE-based composites which sliding against 45 steel were studied.The orthogonal experimental design was adopted.The design was combined with the composition of PTFE-based composites:Gr,CF,GF,MoS₂,we selected the gradient experiment and provided data analysis method to obtain the optimal value,in order to provide reference for composition optimization design of high-performance PTFE composite.In this paper,two different additive processes of rare earth were used:1.The matrix was modified only;2.The matrix and the filler were modified together.The addition of rare earth elements was bound to have an impact on the triboelectrification voltage of the composite,because rare earth elements is metallic elements.At the same time,rare earth could effectively improve the interfacial bonding performance between the filler and the matrix,It was expected to promote the formation of transfer film on the surface of 45 steel so that tribological properties of samples was improved.The changes of triboelectrification voltage,friction coefficient,wear and transfer film of PTFE-based composites were studied under different working conditions and different processes.The correlation among tribological properties,triboelectrification voltage and friction transfer during friction was discussed.Analyzing the mechanism of friction and wear of the sample,the formation of the transfer film and friction surface was studied by Optical microscope and thermal field emission scanning electron microscope.The effect of rare earth elements on the formation of transfer film was studied by EDS and Elemental analysis plane scanning.The following research results were obtained in this paper.1.Influence of the addition of rare earth on the triboelectrification of PTFE-based composite materials under different working conditions and process conditions.Under the same addition process and rare earth addition content,with the increased of load or speed,the tribological voltage increased gradually.Under the same conditions of speed,load and fillers content,the average triboelectrification voltage of the composite was LaF₃/PTFE(process 2),LaF₃/PTFE(process 1),YF₃/PTFE(process 2),and YF₃/PTFE(process 1)from high to low.Under the same working condition,process condition,with the increase of LaF₃/PTFE content,the average triboelectrification voltage of the PTFE-based composite increased at first and then decreased with a large downward trend.When LaF₃ was 1.2wt%,the triboelectrification voltage reached the peak.In YF₃/PTFE composite,with the increase of YF₃ content,the average triboelectric voltage of the composite increased slowly at first,and then decreased rapidly.2.Effect of the addition of rare earth on the tribological properties of PTFE-based composites under different working conditions and process conditions.Under the same addition process and rare earth content,the friction coefficient of the PTFE-based composite gradually decreases and the wear loss increases with the increase of load and speed.Under the same working condition,with the increase of LaF₃ content,the friction coefficient of the composite gradually decreased at first,and the friction coefficient was the minimum when the LaF₃ content was 1.2wt%.Later,with the increase of LaF₃content,the wear loss gradually decreased at first and then gradually increased,and the wear loss was the minimum when the LaF₃ content was 1.2wt%.In YF₃/PTFE composite,the friction coefficient of the composite gradually decreased with the increase of YF₃ content at first,and the friction coefficient is the minimum when YF₃content was 1.2wt%,and then increases with the increase of YF₃ content.The wear loss gradually decreased and then gradually increased with the content of YF₃at first,and the wear loss was the minimum when YF₃ content was 1.2wt%.Under the same working condition,the tribological properties of RE-PTFE-based composite with process 1 showed lower than those with process 2,and the friction coefficient of the former increased after a long time experiment.3.Effect of rare earth on transfer film formation of PTFE matrix compositesUnder the same condition,the transfer film formed by the process 2 of PTFE-based composite was better than that of the process 1 of PTFE-based composite,and the stability and continuity of the former's transfer film was higher than that of the latter's transfer film.With the same addition process and rare earth content,the stability and coverage of the transfer film of LaF₃/PTFE composites was better than that of YF₃/PTFE composites.Under the same condition,with the increase of rare earth content,the coverage of PTFE-based composite transfer film increases gradually.When the rare earth content is1.2wt%,the PTFE-based composite transfer film has the best film-forming condition.Later,with the increase of rare earth content,the continuity and coverage of transfer film began to decrease.4.Correlation between triboelectrification and tribological properties of PTFE-based composites added with rare earth elementsThe friction coefficient of composites decreases with the increase of triboelectric voltage.The wear loss of composite increases with the increase of triboelectric voltage.The transfer film thickness increases with the increase of voltage.The triboelectrification voltage increases with the increase of the content of rare earth elements in the transfer film.The distribution of rare earth elements in the transfer film was the same as that of the reinforced-fibre,The interfacial bonding strength between filler and matrix was enhanced.