改性纳米h-BN润滑油添加剂对缸套-活塞环摩擦学性能的影响

Effect of Modified Nano h-BN Lubricating Oil Additive on Tribological Properties of Cylinder Liner-Piston Ring

在缸套-活塞环摩擦副中,当活塞在上、下止点处为零速,难以形成油膜,且在气缸的高温工况下,其他部位的油膜也会被破坏,从而造成缸套-活塞环的摩擦功耗增加和磨损加剧。采用优质润滑油是提高缸套-活塞环润滑与摩擦特性的重要手段。制备改性纳米六方氮化硼(h-BN)颗粒并将其按不同质量分数分散至聚α-烯烃(PAO10)基础油中,使用R-tec摩擦磨损试验机开展不同载荷下的往复摩擦试验,通过观测摩擦因数、磨损体积和缸套磨损表面、磨损元素及三维形貌参数,研究改性纳米h-BN添加剂对缸套材料摩擦学性能的影响以及减摩抗磨润滑机制。结果表明:加入改性纳米h-BN添加剂可以显著降低缸套-活塞环摩擦副的摩擦因数,减少磨损量,加入质量分数0.25%的添加剂在50 N、3 Hz工况下可使摩擦因数降低33.87%,磨损体积降低23.32%;在载荷及摩擦热作用下纳米h-BN添加剂可以在磨损表面形成摩擦保护膜,可以改善缸套的表面粗糙度,创造优良的润滑环境,提升其摩擦学性能。

In the cylinder liner-piston ring friction pair,when the piston is zero speed at the top and bottom dead cen⁃ter,it is difficult to form an oil film,and under the high temperature working condition of the cylinder,the oil film in other parts will also be destroyed,resulting in increased friction power consumption and wear of the cylinder liner-piston ring.The use of high quality lubricating oil is an important means to improve the lubrication and friction characteristics of cylin⁃der liner-piston ring.Modified nano-hexagonal boron nitride(h-BN)particles were prepared and dispersed of them in different mass fraction into polyα-olefin(PAO10)base oil.R-tec friction and wear testing machine was used to carry out reciprocating friction tests under different loads,and the friction coefficient,wear volume,wear surface of cylinder liner,wear elements and three-dimensional morphology parameters were observed.The influence of modified nano h-BN additive on tribological properties of cylinder liner materials and the friction reducing and anti-wear lubrication mechanism were studied.The results show that the addition of modified nano h-BN additive can significantly reduce the friction coefficient of cylinder liner-piston ring friction pair and reduce the wear amount.Under the working condition of 50 N and 3 Hz,the addition of 0.25%mass fraction additive can reduce the friction coefficient by 33.87%and the wear volume by 23.32%.Under the action of load and friction heat,nano h-BN additive can form a friction protective film on the wear surface,im⁃prove the surface roughness of the cylinder liner,create an excellent lubrication environment,and enhance its tribological properties.