摘要
目的探究片层状的二硫化钨(WS_(2))和六方氮化硼(h-BN)纳米添加剂对00#锂基润滑脂极压性能和抗磨性能的影响,对比2种纳米材料润滑性能的差异。方法分别配制出含WS_(2)和h-BN纳米添加剂的00#半流体锂基润滑脂,对润滑脂的滴点以及锥入度理化指标进行了测定,然后使用MRS10A四球磨损试验机对润滑脂的极压抗磨性能进行考察。通过扫描电子显微镜(SEM)和光学显微镜(OM)观察磨斑磨损的形貌特征,并使用光电子能谱仪(XPS)对磨斑表面的元素进行检测与分析,探讨WS_(2)和h-BN纳米添加剂的作用机理。结果与基础脂相比,含WS_(2)纳米添加剂的润滑脂在质量分数为0.5%时摩擦因数最大可降低12.7%,磨斑直径可降低10.5%;含h-BN纳米添加剂的润滑脂在质量分数为0.25%时摩擦因数降低了4.2%,在质量分数为0.5%时磨斑直径最大降低22.1%;2种纳米添加剂的加入均使润滑脂的最大无卡咬负荷提高了40.0%。通过SEM和OM观察的形貌及轮廓特征可以看出,WS_(2)与h-BN纳米添加剂可以有效地改善磨斑表面质量,降低磨斑表面粗糙度,对磨损表面起到一定的修复作用。XPS元素结果分析显示,WS_(2)纳米添加剂在摩擦表面会发生摩擦化学反应生成Fe_(2)O_(3)、FeO和FeS_(2)等反应薄膜,而在h-BN磨斑表面则主要会反应生成B_(2)O_(3)、Fe_(2)O_(3)、FeO等反应膜。摩擦反应膜的生成可以起到提高润滑脂极压抗磨性能的作用,而粒子片层间发生滑移时剪切作用力相对较低则是纳米添加剂可以起到降低摩擦因数的主要原因。以WS_(2)和h-BN纳米添加剂复配的铁路机车牵引齿轮脂按Q/CR762-2020《铁路机车牵引齿轮脂》技术指标进行理化性能检测,测定结果完全满足该标准。结论WS_(2)和h-BN都具有明显改善润滑脂润滑性能的作用,WS_(2)对降低摩擦因数的作用好于h-BN,但h-BN可以更好地降低磨损量,两者都可以有效提高润滑脂的极压性能。
As a new type of lubrication additive,nanomaterial can significantly improve the lubrication characteristics of the lubricant,which can effectively reduce the friction and wear between two moving surfaces and maintain a good lubrication effect to protect and repair the damaged surface under some special working conditions.In this article,the effects of two kinds of lamellar nano-additives disulfide(WS_(2))and hexagonal boron nitride(h-BN)on the extreme pressure and anti-wear properties of lithium-based grease were studied,and the differences in lubrication properties between the two kinds of nanomaterials were compared.With WS_(2)and h-BN nanomaterial as additives,100SN and KH150BS oil were uniformly mixed in a ratio of 3:1 as base oil,and 2#lithium grease as soap source,00#lithium grease containing WS_(2) and h-BN nano-additives was prepared by the high-speed agitator and three-roll grinder respectively.At first,the dropping point and cone penetration of grease were measured,and then the long-wear and extreme pressure tests were carried out by using the MRS10A four-ball wear tester.In order to discuss the mechanism of action of WS_(2)and h-BN nano-additives,the scanning electron microscope(SEM)and optical microscope(OM)were used to observe the morphological characteristics of wear spots,and the elements on the wear spot surface were detected and analyzed by X-ray photon-electron spectroscopy(XPS).The results show that compared with base grease,the friction coefficient and wear spot diameter of grease containing WS_(2) nano additive can be reduced by 12.7%and 10.5%at the concentration of 0.5wt.%.The grease containing h-BN nano-additive can reduce the friction coefficient by 4.2%at the concentration of 0.25wt.%,and the wear spot diameter can be reduced by 22.14%at the concentration of 0.5wt.%;The addition of two kinds of nano-additives increased the maximum non-seizure load of grease by 40%.The morphology and contour characteristics observed by SEM and OM can show that WS_(2) and h-BN nano additives can effectively improve the surface quality of the wear spot,reduce the surface roughness of the wear spot,and play a certain role in repairing the worn surface.XPS element analysis shows that the WS_(2) nano additive will undergo tribo-chemical reaction on the friction surface to form Fe_(2)O_(3),FeO,and FeS_(2)reaction films,while on the h-BN wear surface,it will mainly react to form B_(2)O_(3),Fe_(2)O_(3),FeO,and other reaction films.The formation of friction reaction film can improve the extreme pressure and anti-wear performance of lubricating grease,and the relatively low shear force in the case of interlamellar slip is the main reason why nano-additives can reduce the friction coefficient.The railway locomotive traction gear grease compounded with WS_(2)and h-BN nano additives is tested for physical and chemical performance according to the technical indicators of Q/CR762—2020"Railway Locomotive Traction Gear Grease",and the measurement results fully meet Q/CR762—2020"Railway Locomotive Traction Gear"Grease"standard.The film formation and slip effect of WS_(2)and h-BN nano-additives on the wear spot surface are the main reason for improving the lubrication performance of the grease.WS_(2) can better reduce the friction coefficient compared with h-BN,while h-BN can better reduce the wear,and both can effectively improve the extreme pressure performance of the grease.
作者
关强
张绪伟
何娇
李征
魏云玲
任付娥
龚楠
丁昊昊
王文健
GUAN Qiang;ZHANG Xu-wei;HE Jiao;LI Zheng;WEI Yun-ling;REN Fu-e;GONG Nan;DING Hao-hao;WANG Wen-jian(School of Mechanical Engineering,Southwest Jiaotong University,Chengdu 610031,China;Chengdu Shuguang Petrochemical Petrochemicals Co.,Ltd.,Chengdu 610083,China;Department of Mechanical and Electrical Engineering,Qingdao University of Technology,Shandong Linyi 273400,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2022年第8期233-242,共10页
Surface Technology
基金
国家重点研发计划政府间国际科技创新合作重点专项(2018YFE0109400)
青岛理工大学临沂校区自然科学重点培育科研项目(2019ZRZD001)。
