Preparation Of Nano-MoS₂ And Nano-Al₂O₃ With Different Morphology And Its Effect On The Friction Properties Of EP

Friction and wear have always been the primary issues for solving energy loss.With the rapid development of aerospace,mechanical weapons and other industries and in-depth research on nano-tribology,nano-lubrication and wear-resistant materials have been widely concerned.Based on the study of the influence of the morphology on frictional performance on inorganic nanomaterials,this thesis uses the hydrothermal method to prepare nano-molybdenum disulfide with different morphologies as lubricants and nano-alumina with different crystal forms as wear-resistant.The goal is to prepare the epoxy composite coating materials with good friction properties.On the basis of this,its toughness and temperature resistance of epoxy resins are improved,so that its comprehensive properties are improved.In order to investigate the influence of the morphology of MoS₂ nano-lubricant on friction properties,three different morphology nano MoS₂ were prepared using a one-step hydrothermal method?temperature 180°C,time 24 h?to control different reaction materials and reaction conditions.The product was characterized by SEM,EDS and XRD.The results showed that when the pH of the reaction solution was 6.0,the molybdenum concentration was0.150 mol/L,and the sodium silicate concentration was 0.210 mol/L,the morphology was well-distributed and the particle size was approximately,86 nm flower-like MoS₂;The reaction solution pH 5.5,molybdenum concentration 0.080 mol/L is the optimal conditions for preparation of flake-like nano-MoS₂;Microsphere-like MoS₂ obtained when the solution pH is 6.0 and the ammonium molybdate concentration is 0.016 mol/L.The particle size is about 150 nm and the dispersibility is good.Among them,the spherical nano-MoS₂ has the highest yield and the best morphology.Two-step hydrothermal method and direct precipitation method were used to control the reaction temperature,concentration and calcination temperature,and optimization experiments were conducted to investigate the effect of the anti-wear agent nano-Al₂O₃crystal form on the friction performance.The product was characterized by SEM,EDS and XRD.The results showed that compared with the direct precipitation method,the nano-Al₂O₃prepared by the two-step hydrothermal method has high purity,small particle size,regular morphology,uniform distribution and good dispersion.The optimum reaction conditions were:hydrothermal temperature 180°C,time 24 h,dispersant PEG-6000,Al³⁺concentration 0.150mol/L,and CO?NH₂?₂ concentration 0.750 mol/L.The precursors were calcined at different temperatures to obtain flocculent?-Al₂O₃ and spherical?-Al₂O₃ with a particle size of about200 nm.The effect of MoS₂ and Al₂O₃ on the friction properties of epoxy-based composite coating materials was investigated using a ring-type friction wear tester?MRH-3G?.The results showed that the best lubricants and antiwear agents were spherical nano-MoS₂ and?-Al₂O₃,respectively.The optimum ratio of MoS₂ to Al₂O₃ was 2:3,the total amount of filler was 4wt%of epoxy resin,and the friction coefficient was 0.129,80%reduction compared to pure epoxy resin,the friction properties of the coating material have been improved.On this basis,toughening agent?CTBN?and heat resistance agent?PAI?have been modified to obtain epoxy resin heat resistance,wear resistant composite coating,impact resistance reached 12.13kJ/m²,initial decomposition temperature of 337°C.