| In this dissertation, preparation and tribology properties of metal nanoparticles were chiefly investigated. Copper and bismuth were chosen as raw materials to research in preparing metal nanoparticles. Appropriate modifier was applicated with in-situ modification and dry grinding followed by wet grinding.The copper nanoparticles and bismuth nanoparticles have homogeneous size distribution and excellent dispersing stability.Lubricant additives of copper and bismuth nanoparticles were prepared. MMW-1 friction wear testing machine was adopted to test lubricating properties of copper nanoparticles, bismuth nanoparticles and copper-bismuth mixed particles.Relationship between wear scar diameter, friction coefficient and quantity of metal nanoparticles in lubricant were tested under long time and different burden, Mechanism of antiwear and antifrication was also investigated. The conclusions of experimental research are as following:(1) The influence of technology parameters on particles size of bismuth nanoparticles was researched, and the optimized programme of preparing bismuth nanoparticles in dry grinding was obtained. The rotation speed is 400r/min, the mass ratio of modifying reagent and bismuth is 1:4, the mass of bismuth is 25g, and the time is 8h. For the optimized sample treated by wet grinding, the rotational speed is 350r/min and the time is 4h. The size of bismuth particle was changed from maximum size 630μm to average size 300nm after dry grinding, and then decreased to 200nm after wet grinding, the average diameter of particles in liquor medium is 170nm.(2) The influence of ball milling technology parameter on particle size of copper nanoparticles was also researched, and the optimized scheme of preparing copper nanoparticles in dry grinding was obtained. The rotation speed is 400r/min, the mass ratio of modifying reagent and copper grains is 1:6, the mass of copper is 25g,... |
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