纳米CaB/MoDDP复合润滑油添加剂的摩擦学性能

Tribological performance of nano CaB/MoDDP compound lubricant additive

摘要:

为提高润滑油的抗磨减摩性能,提升机械设备在恶劣工况下运行的稳定性和安全性,通过四球机和低速重载摩擦磨损试验机研究纳米硼酸钙（CaB）和二烷基二硫代磷酸钼（MoDDP）复合润滑油添加剂的减摩抗磨性能,期望取得较单一添加剂更优异的润滑效果。研究结果显示:制备的纳米CaB为不规则的纳米薄片状,平均尺寸为50~150 nm,经油酸改性后在基础油中具有良好的分散稳定性；纳米CaB和MoDDP均可显著提高润滑油的润滑效果,随着纳米CaB和MoDDP添加质量分数的增加,摩擦因数和磨斑直径呈现先降低后升高的趋势,纳米CaB和MoDDP的最佳添加质量分数分别为2.0%和1.5%；与单一添加CaB、MoDDP相比,复合CaB/MoDDP可进一步改善润滑油的减摩抗磨性能,MoDDP和CaB的最佳质量配比为1.5%∶3.0%,此时摩擦副的摩擦因数最小,磨痕最浅,磨斑直径最小,最大无卡咬负荷最高,并且在低速重载工况下,显示出优良的润滑效果,表明CaB/MoDDP复合润滑油添加剂具有良好的减摩抗磨效果,可以显著提高润滑油的性能。

Abstract:

To improve the tribological properties of lubricant oil and enhance the stability and security of mechanical equipment under severe working conditions, the friction reduction and anti-wear performance of nano-calcium borate (CaB) and molybdenum dialalkyl dithiophosphates (MoDDP) composite additives were studied using four-ball tester and block on ring tester. The results showed that the prepared nano-CaB was a nanosheet with irregular shape and the average size was 50-150 nm. After oleic acid modification, it showed good dispersion stability in base oil. Both nano-CaB and MoDDP could significantly improve the lubrication effect of lubricant oil. With the increasing of nano-CaB and MoDDP mass fraction, the friction coefficient and grinding spot diameter firstly decreased and then increased. The optimal adding mass fraction of nano-CaB and MoDDP was 2.0% and 1.5%, respectively. Compared with single addition of CaB and MoDDP, compound CaB/MoDDP could further improve the friction reducing and anti-wear performance of lubricant oil. The optimal mass fraction ratio of MoDDP and CaB is 1.5%∶3.0% that showed the smallest friction coefficient and grinding spot diameter, and the highest maximum nonseizure load. It also showed excellent lubrication effect under low speed and heavy load condition.