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    Tribological properties of tungsten disulfide nano-powder as lithium-based grease additive
    Hits:   Date:2020-06-10  
    With the rapid development of industry, high-speed, heavy-load and high-temperature equipment have been put into use in the industrial sector, but there are currently fewer high-temperature and high-performance grease varieties. As a new type of solid lubricating material, tungsten disulfide has excellent lubricating properties. It has a layered hexagonal crystal structure. The W and S elements in the layer are covalently bonded, and the molecular bond formed by S-S is bonded between the layers. Because the latter has a lower bond energy, slippage easily occurs during friction, so it has a lower coefficient of friction. Studies have shown that the W element in tungsten disulfide has an empty orbit in the 4f electron layer, and the nano tungsten disulfide powder has a large specific surface area. The combination of the two promotes the easier adsorption of tungsten disulfide on the metal surface. Provided favorable conditions for its better performance.

    Tungsten disulfide is suitable for lubricating under various harsh conditions such as high temperature, heavy load, high pressure, high vacuum, high speed, high radiation, strong corrosion and ultra-low temperature. It has important application value in the fields of aviation, aerospace and defense industry. At present, the research on tungsten disulfide is mainly concentrated in the field of lubrication such as material coating and composite materials. Recently, the Military Oil Research Institute of the Logistics Engineering College of the General Armament Department of the Chinese People's Liberation Army released an article on the tungsten disulfide nano powder in lubricating grease. Tribology research paper, the nano tungsten disulfide is produced by Hunan Huajing Powder Material Co., Ltd.

    Studies have shown that at an optimal addition amount of 2% by mass, lithium-based greases exhibit the best tribological properties. The maximum non-seizure load and sintering load are increased by 112.8% and 84.3% respectively compared to the base grease. The average friction Coefficient and wear scar diameter decreased by 17.3% and 46.8%, respectively. During the friction process, part of the tungsten disulfide powder is deposited on the pits of the friction pair due to the nano-scale effect, which plays a role in surface repair; at the same time, under high temperature and high load conditions, a WS2 nanoparticle permeation layer is formed, and the tungsten disulfide nanoparticles The powder reacts chemically with the surface of the friction pair. A chemical reaction film containing Fe2O3, FeSO4, WO3, and Fe3O4 is formed, thereby exerting a good lubricating effect.