蓖麻油基含氧化石墨烯润滑脂的制备及其性能研究

以蓖麻油为基础油,以一水氢氧化锂、12-羟基硬脂酸和癸二酸为稠化剂原料,氧化石墨烯(GO)为添加剂,制备3种含GO不同质量分数的混合锂基脂,分别利用锥入度试验器、钢网分油测试仪、滴点试验器、流变仪、热重分析仪、摩擦试验机和三维形貌仪考察其理化性能和润滑性能,探讨GO对蓖麻油基润滑脂的作用机制。结果表明:含GO混合锂基脂的黏度随剪切率和温度的增加均呈非线性减小的变化趋势,但随着剪切速率和温度的升高,GO对蓖麻油基润滑脂的黏度与剪切速率关系和黏温特性影响越来越小;微量的GO能够提高混合脂的热稳定性能;混合锂基脂的平均摩擦因数随GO质量分数的增加呈先减小后增大的变化趋势,适量的GO有助于提高蓖麻油基润滑脂的减摩抗磨性能,这是因为摩擦过程中GO以片层形式进入摩擦副的接触区,能够有效地降低摩擦副表面的直接接触概率,且GO具有自润滑性能,在摩擦副界面上发挥较为有效的润滑作用。

Study on Preparation and Its Performance of Lubrication Grease Containing Graphene Oxide Based on Castor Oil

Three mixed lithium greases with different mass percent of graphene oxide(GO) additive were prepared by using the basic oil of castor oil and the thickening agent including lithium hydroxide monohydrate,12-hydroxy-stearic acid and sebacic acid.The physical-chemical properties and lubricating performance of mixed lithium greases were investigated by means of the penetration tester,the steel mesh oil separator tester,the dropping point tester,the rheometer,the thermogravimetric analyzer,the frictional tester and the three-dimensional surface profilemeter.The mechanism between castor oil-based grease and GO was also discussed.The results show that with the increase of shear rate and temperature,the viscosity of mixed lithium greases containing GO shows a trend of nonlinear reduction,but the GO plays a smaller and smaller role on the relation between the viscosity and shear rate of castor oil-based greases and the viscosity-temperature characteristics.The moderate amount of GO can improve the thermal stability of mixed lithium greases.With the increase of the GO mass percent,the average coefficient of friction of the mixed lithium base grease is decreased first and then increased.The moderate amount of GO is helpful to improve the friction reducing and anti-wear ability of castor oil-based grease,this is because GO enters the contact area of the friction pair in the form of sheet layer,which can effectively reduce the direct contact probability of the friction pair surface,and GO has the self-lubricating property,which plays a more effective lubrication role on the interface of the friction pair.