高分散稳定纳米金刚石润滑油的制备及其摩擦学性能

Synthesis and tribological properties of lubricant oil with highly dispersed and stable nanodiamond

为了改善纳米金刚石颗粒(NDPs)在抗磨液压油(AHO)中的分散性,制备了酸氧化-高温热处理的NDPs(T-NDPs),将其与添加剂(油胺、聚异丁烯丁二酰亚胺T154和高碱值合成磺酸钙T106)混合后加入AHO中,制得含T-NDPs的AHO。用FESEM及Zeta电位仪、FT-IR和静态沉降法对其分散性进行表征,用四球摩擦磨损试验机、3D激光扫描显微镜和SEM/EDS对含T-NDPs的AHO的摩擦学性能和磨痕区域进行了分析。结果表明,酸氧化-高温热处理后,NDPs的平均粒径从270.2 nm降至153.5 nm,吸附添加剂后的T-NDPs的平均粒径为101.5nm,添加剂可提高T-NDPs的油溶性并抑制其团聚,因而含T-NDPs的AHO具有良好的分散稳定性;T-NDPs含量为0.04wt%时,AHO的摩擦系数和磨斑直径比不加T-NDPs时分别降低13.2%和17.8%;T-NDPs作为润滑添加剂的减摩抗磨功效归因于其在摩擦界面起到支撑和滚动轴承的作用及在摩擦副表面参与润滑膜形成。

In mechanical systems, high-efficiency and environmentally friendly lubricant oilis demanded for extension of the equipment service life and energy saving demand highly efficient and environmentally friendly lubricating oil.Over last few decades, more attention have been paid to the addition of carbon nanoparticles, such as graphite, graphene and carbon nanotubes etc., in order to reduce the friction and wear in lubricating oil.At present, nanodiamond particles(NDPs) have been considered to be one of the most promising candidates for enhancing the friction reduction and anti-wear properties of lubricating oil effectively and economically due to its excellent properties of hardness, chemical stability, thermal stability and high thermal conductivity. Although NDPs as lubricant additives in lubricating oil have been reported, its dispersity in lubricating oil has not been well investigated. NDPs are easy to agglomerate in many media and have poor dispersive capacity in lubricating oil.In this work,in order to improve the dispersity of NDPs in anti-wearhydraulicoil(AHO), acidified and heat-treated NDPs(T-NDPs) were prepared and mixed with a variety of additives [oleylamine, polyisobutylenesuccinimide(T154) and high alkaline calcium sulfonate(T106)], then the mixture was added into AHO to prepare AHO containing T-NDPs. The materials and dispersity were characterized by FESEM, a Zeta potentiostat, FT-IR and static sedimentation experiment. The tribological property of AHO with T-NDPs and worn surfaces were investigated by the four-ball tribometer, 3D laser scanning microscopy and SEM/EDS. The results showed that the average diameter of NDPs decreased from 270.2 nm to 153.5 nm after acidified and heat-treatment. The average diameter of T-NDPs after adsorption additives was 101.5 nm. Additives could increase oil solubility of T-NDPs and imped their aggregation. Hence, AHO with T-NDPs possessed good dispersion stability. Particularly, the friction coefficient and wear scar diameter of AHO containing 0.04wt% of T-NDPs were reduced 13.2% and 17.8% compared with AHO without T-NDPs. We can analysed the friction reduction and anti-wear mechanism of T-NDPs as lubricant additives from two aspects,one is that the T-NDPs could support the load and act as roll bearing between the friction interfaces, and the other one is that the T-NDPs participated in the lubricating film formation between the friction surfaces.