镍基固体润滑复合镀层制备及摩擦学性能研究

发布时间：2018-04-02 13:15

  本文选题：电化学沉积法　切入点：自润滑镀层　出处：《兰州理工大学》2017年硕士论文

【摘要】：真空,高速,强辐射,强腐蚀以及高温等极端摩擦环境条件,不仅限制了液体润滑剂的使用,还对我国航空航天领域高精密仪器如人造卫星、火箭等服役寿命带来了巨大的挑战。本论文针对在上述极端摩擦环境条件下,如何提高工作机械零部件之间润滑效果,保持咬合部件之间低摩擦系数,提高航天仪器使用寿命而展开。选取具有良好润滑性能的MoS_2、WS_2固体润滑剂来取代液体润滑剂。通过电化学沉积法,实现MoS_2、WS_2与金属镍的共沉积,弥补了单一固体润滑剂镀层硬度低、单一金属镍镀层摩擦系数高等缺点。研究了不同浓度MoS_2、WS_2对Ni-MoS_2、Ni-WS_2复合镀层形貌、物相以及摩擦学性能影响,并确定了MoS_2、WS_2最佳使用浓度;考察了在最佳浓度下的Ni-MoS_2、Ni-WS_2复合镀层高温摩擦性能,确定了复合镀层最佳使用温度。综合上述实验数据,得出以下结论:1.在对偶件GCr15、20 N载荷条件下,Ni-WS_2复合镀层室温摩擦系数优于Ni-MoS_2复合镀层室温摩擦系数,但润滑效果均优于纯镍镀层。两种复合镀层最佳使用浓度均在30 g/L时,Ni-30 g/L MoS_2复合镀层室温摩擦系数最低为0.02~0.03;Ni-30 g/L WS_2复合镀层室温摩擦系数最低为0.01~0.02。2.高温摩擦条件下,Ni-WS_2复合镀层使用温度要高于Ni-MoS_2复合镀层。Ni-MoS_2复合镀层最佳使用温度在300℃以下,摩擦系数保持在0.02~0.05之间,在400℃环境下,Ni-MoS_2复合镀层摩擦系数接近0.15,因为MoS_2颗粒在325℃以上被氧化成MoO_3,失去润滑作用;Ni-WS_2复合镀层最佳使用温度在400℃以下,摩擦系数维持在0.01~0.05之间,在500℃环境下,Ni-WS_2复合镀层摩擦系数接近0.12,因为WS_2颗粒在425℃以上逐渐被氧化成WO3,失去润滑作用。3.镀液中添加MoS_2、WS_2能够使得Ni离子还原电位负移,且随着MoS_2、WS_2固体润滑剂浓度的增加,Ni离子还原电位负移程度增加,反映了MoS_2、WS_2颗粒促进了阴极极化,在复合沉积体系中阻碍镍的沉积,可以进一步提高镀层结晶细致程度。
[Abstract]:Extreme frictional environmental conditions such as vacuum, high speed, strong radiation, strong corrosion and high temperature not only restrict the use of liquid lubricants, but also limit the use of high-precision instruments such as artificial satellites in the field of aerospace in China. The service life of rocket and so on brings great challenge. This paper aims at how to improve lubricating effect between parts of working machinery and keep low friction coefficient between bite parts under the condition of extreme friction environment mentioned above. In order to improve the service life of spaceflight instruments, the solid lubricant MoS _ S _ 2W _ W _ 2 was selected to replace the liquid lubricant. By electrochemical deposition, the co-deposition of MoS2S / WS2 and nickel was realized, which made up for the low hardness of the single solid lubricant coating. The effects of different concentration of MoSs _ 2S _ 2S _ 2 on the morphology, phase and tribological properties of Ni-MoS _ 2 / Ni-WSS _ 2 composite coating were studied, and the optimum use concentration of MoS _ S _ 2W _ (2) W _ (2) was determined. The high temperature friction properties of Ni-MoSSP _ 2Si _ W _ W _ 2 composite coating at the optimum concentration were investigated, and the optimum operating temperature of the composite coating was determined. The following conclusions are drawn: 1. The friction coefficient of Ni-WS2 composite coating is better than that of Ni-MoS_2 composite coating at room temperature under the condition of GCr1520 N load on the dual part, and the friction coefficient of Ni-WS2 composite coating is better than that of Ni-MoS_2 composite coating at room temperature. But the lubricating effect was better than that of pure nickel coating. The lowest room temperature friction coefficient of Ni-30 g / L MoS_2 composite coating was 0.02 0. 03% Ni-30 g / L WS_2 composite coating at 30 g / L at 30 g / L, the lowest room temperature friction coefficient was 0. 01% 0. 02.2 under high temperature friction condition. The optimum service temperature of Ni-WS2 composite coating is higher than that of Ni-MoS_2 composite coating. The friction coefficient of Ni-MoS2 composite coating is close to 0.15 at 400 鈩，

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