Study On Preparation And Tribological Properties Of Serpentine/ Cu (Ni) Composite Powder

In this paper,based on the composition and the phase of Liaoning Xiuyan serpentine, its thermal phase transition and powder modified method were studied in detail.Then the composite powders were synthesized by liquid-phase method. The tribological properties of the composite power have been studied. And achieved the following key results:The serpentine used in the experiment was almost antigorite, and cell parameters were a₀=0.5444nm,b₀=0.9223nm,c₀=0.7263nm,α=γ=90°,β=91.75°,at about 830℃it totally changed to forsterite.The research used the serpentine of Xiuyan in Liaoning as the raw material.The mineral composition and crystal structure were analyzed by chemical analysis,TG-DTA and XRD. The results showed that the mineral composition of raw materials was antigorite. The physical structure characteristics of serpentine and heat-treatment serpentine were investigated by infrared spectrum and laser Raman spectroscopy.The specific surface area and the pore structure of powders were analyzed by BET.To improve the dispersing stability of serpentine powders in basic oil, many surface modifiers were tested in the research,the results showed that Modification effect of serpentine powders with the mixing of surface modifiers of Span60 and Tween60 were best.The technology operation conditions of the serpentine surface modification were optimized: the Span60 and Tween60 complex ratio were 7:3, the amount of modifier compound were 5%, the optimion modified temperature was 70℃.Analysis indicateed that blends with modifiers not only at the serpentine surface with physical adsorption, but also its silane oxygen radicals can produce chemical reaction with unsaturated hydroxyl of serpentine surface,which showed good modification effect.Copper nanopowders and serpentine / Cu composite powders were prepared by liquid-phase method.The optimion experimental conditions were as follows: the molar ratio of Cu²⁺:KBH4:KOH was 4:3:8, the reaction temperature was 40℃, protective agent and dispersing agent were EDTA and PVP. The results showed that copper powders’average size was 40nm with good distribution.In the preparation of serpentine/Cu composite powders,the copper nanopowders wraped evenly on the surface of serpentine, coating evenly. Nickel nanopowders and serpentine/Ni composite powders were prepared by liquid-phase method. Amorphous nickel coated evenly on the surface of serpentine by SEM analysis.The tribological properties have been evaluated by four-ball friction test,gear friction test and air compressor test. The results showed that the composite powders had good anti-wear and friction-reducing properties as the additive in lubricating oil. In four-ball friction test compared with base oil the friction coefficient of serpentine and serpentine/Cu and serpentine/ Ni composite powders, had good antifriction effect, friction coefficient lower than the basic oil by 36.12%, 40.84% and 26.55%. And scanning electron microscopy analysis showed that serpentine/Ni composite powders showed the least wear worn. The energy consumption of Serpentine/Cu composite powders reduced by about 10%, the temperature reduced by about 17% compared to base oil in gear friction test. In air compressor test compared with base oil the energy consumption of Serpentine/Cu composite powders reduced by 4.47%, the temperature of oil reduced by12.24%。The good abrasion and energy-saving effect coefficient of composite powder are related to microparticles-supporting effects of nanoparticles, and catalysis of metal elements.