Preparation And Tribological Properties Of Nano-carbon Hybrid Reinforced Epoxy Resin Composite Coatings

With the vigorous development of industries such as aerospace,transportation and machinery manufacturing,higher requirements are placed on the reliability and life of mechanical transmission components.Especially under severe frictional operating conditions,the surface of the material is highly susceptible to corrosion,oxidation and wear,etc.,causing failure of friction components.Polymer nanocomposite coatings are widely used in the surface of bearings,gears and other components to improve their tribological properties due to their excellent corrosion resistance,chemical stability and outstanding friction and wear resistance.Among them,nano-carbon materials have become the“star materials”for improving the anti-friction and wear-resistance of polymer composite coatings due to their microstructure,good mechanics and tribological properties.However,the problem of easy agglomeration and difficult dispersion of nano-carbon materials often affects their performance.Based on this,this paper focuses on the introduction of nano-carbon materials with different dimensions?zero-dimensional,one-dimensional and two-dimensional?and self-lubricating on the surface of nano-carbon materials to solve the agglomeration problem and better play.The synergistic effect between the two ultimately improves the tribological properties of the composite coating.On this basis,the enhancement mechanism of the tribological properties of the polymer composite coatings by different nano-carbon hybrid materials is studied in detail.The specific research contents are as follows:?1?The synergistic enhancement mechanism of 1D CNT and 0D ZnS on EP composite coating was studied.The CNT/ZnS hybrid material was prepared by in-situ synthesis of ZnS on the surface of CNT by one-step hydrothermal method.The microstructure and phase structure of hybrid materials were characterized and analyzed by XRD,Raman and TEM.The formation mechanism of hybrid materials was explored.The results show that compared with CNT and acid-CNT,CNT/ZnS hybrid materials have the best enhancement effect on the tribological properties of EP composite coatings.Due to the formation of a lubricating layer composed of CNT and ZnS,that is,due to the presence of the lubricating layer,there is a weak shear stress between the worn surface and the dual surface,resulting in a decrease in the friction coefficient and wear rate of the composite coating,has the best anti-friction and anti-wear properties.Moreover,with the increase of the content of CNT/ZnS hybrid materials,the friction coefficient and wear rate of EP-CNT/ZnS composite coatings first decreased and then increased.When the content of the CNT/ZnS hybrid material is 1.25wt.%,the corresponding composite coating has the lowest friction coefficient and wear rate.?2?Based on the research in the second chapter,the synergistic enhancement mechanism of1D CNTs with 2D GO nanosheets and 3D MoS₂ nanoflowers on EP composite coatings was studied.CNT/GO,CNT/MoS₂ and CNT/GO/MoS₂ hybrid materials were prepared by simple hydrothermal method.The results show that the EP-CNT/GO/MoS₂ composite coating has lower friction coefficient and wear rate than CNT,GO,MoS₂,CNT/GO and CNT/MoS₂ reinforced EP composite coatings.Compared with EP,the friction coefficient and wear rate of EP-CNT/GO/MoS₂ composite coatings were reduced by nearly 90%and 95%,respectively.This is mainly because CNT and GO with high mechanical strength can withstand the load applied to the worn surface,inhibit further wear of the EP,and MoS₂ can exert its self-lubricating effect.More importantly,the transfer film is formed on the surface of the opposite surface,thereby converting the wear between the metal and the polymer into the wear of the polymer and the polymer,reducing the friction coefficient and the wear rate of the composite coating.?3?CNF,which is one of the nano-carbon materials,has similar structure and properties to CNT.For this reason,we studied the synergistic enhancement mechanism of CNF and MoS₂.CNF/MoS₂ hybrid materials with core-shell structure were successfully prepared by one-step hydrothermal method.The effects of different mass ratios of CNF and MoS₂ on hybrid materials were also studied.The microstructure and phase composition were studied in detail.The results show that the tribological properties of EP-CNF/MoS₂ composite coatings are significantly better than that of EP,EP-CNF and EP-MoS₂,and the friction coefficient and wear rate are 0.075 and8.6×10^-5mm³/Nm,respectively.This is mainly because CNF/MoS₂ is exposed to the worn surface and acts as a“micro-roller”to reduce friction and wear of the material.The ultra-thin MoS₂ nanosheet coated on the surface of CNF is easy to enter the micro-groove to repair the damaged surface.Under repeated stress,a dense and tough transfer film is easily formed on the surface of the dual surface,so that friction and wear mainly occur in the polymer and polymer.The tribological properties of the EP composite coating are improved.