Performance Degradation Mechanism of Polyurea Grease Under Static Thermal-Oxidative Aging Conditions

被引:0
作者
Sha, Guangrong [1 ,2 ]
Lai, Bingbing [2 ,3 ]
Zhao, Qilong [2 ,3 ]
Sun, Yiping [2 ,3 ]
Wang, Xiaobo [2 ,3 ]
Lou, Wenjing [2 ,3 ]
Liu, Xiaoling [1 ]
机构
[1] School of Mechanical and Automotive Engineering, Qingdao University of Technology, Shandong, Qingdao
[2] State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Gansu, Lanzhou
[3] Qingdao Key Laboratory of Lubrication Technology for Advanced Equipment, Qingdao Center of Resource Chemistry & New Materials, Shandong, Qingdao
来源
Mocaxue Xuebao/Tribology | 2024年 / 44卷 / 08期
关键词
FT-IR; microstructure; polyurea grease; rheology; static thermal degradation;
D O I
10.16078/j.tribology.2023092
中图分类号
学科分类号
摘要
Lubricant aging is one of the main causes of rolling bearing failures. Thickener is one of the core components of lubricating greases. Lubricating greases with the different thickeners exit different aging behaviors and mechanisms. Polyurea lubricating grease is commonly used in industrial equipment operating under harsh conditions such as high temperature, high speed, and high load due to its excellent performance. The study of the aging mechanism of polyurea lubricating grease is beneficial for understanding the state of lubricating grease, providing data support and theoretical basis for the practical application and further development of lubricating grease. In this article, the aging behavior of polyurea greases under high temperature conditions were investigated by simulating a static thermal aging circumstance. To investigate the decay process of polyurea grease and the effect of temperature on this process under thermal aging conditions at 160, 180, 200 and 220 ℃, respectively. The aging process of polyurea grease under the thermal aging condition of 180 ℃ was taken as an example. Based on the differences in infrared spectra during the aging process of polyurea lubricating greases, and combined with the microstructures of the thickeners, the oxidation stabilities, thermal stabilities, and rheological properties of the polyurea lubricating greases, their aging and decline mechanism were studied in detailed. The results indicated that in the early stage of thermal aging of polyurea greases, the degree of association between thickener molecules increased with the increasing of aging time which could inhibit the oxidation of the base oil to some extent. With the continuous effect of thermal effect, the microstructures of thickener fibers changed from disordered short fiber structures to spherical particle structures, the base oil precipitated and began to oxidize. At the same time, the structural stabilities of grease became weak and then strengthens, and the structural strength gradually weakened. At the last stage, hydrogen bonds in the microstructures of polyurea greases had begun to be broken and the thickeners undergoes obviously oxidative degradation, which led to a rapid decrease in the oxidation stabilities of polyurea lubricating greases. As a result, there were the loss of a large amount of lubricating oils and hardening of polyurea lubricating greases. It had been found that the aging temperature could change the aging process of lubricating greases, but it would not change their decay law. The higher the temperature was, the faster the aging and deterioration of lubricating grease were, the worse the oxidation stability, the faster the structural change, and the lower the structural strength. © 2024 Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences. All rights reserved.
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页码:1074 / 1083
页数:9
相关论文
共 18 条
[1]  
Sun Hongwei, Liu Dajun, Long Jun, Et al., Test analysis and application of poly-urea grease in bearing, Bearing, 3, pp. 25-28, (2005)
[2]  
Li Zhibin, Dong Luhu, Gao Yanqing, Research status and development trend of polyurea grease, Petroleum Products Application Research, 31, 5, pp. 18-22, (2013)
[3]  
Yuxin Zhou, Bosman R, Lugt P M., A master curve for the shear degradation of lubricating greases with a fibrous structure[J], Tribology Transactions, 62, 1, pp. 78-87, (2019)
[4]  
Couronne I, Vergne P., Rheological behavior of greases: part II —effect of thermal aging, correlation with physico-chemical changes[J], Tribology Transactions, 43, 4, pp. 788-794, (2000)
[5]  
Shen Tiejun, Hu Minghua, Liu Ruigang, Et al., The influence of static thermal degradation on microstructure and rheological properties of lithium-calcium base grease, Tribology, 31, 6, pp. 581-586, (2011)
[6]  
Hu Minghua, Liu Yansheng, Shen Tiejun, Et al., The inflence of static thermal degradation on colloidal performance of lithium-calcium base grease, Lubrication Engineering, 33, 10, pp. 55-57, (2008)
[7]  
Huang Zhenxiong, Hu Ping, Guo Yang, Et al., Aging analysis of bentonite-composite aluminum base lubricating grease, Petrochemical Technology, 47, 7, pp. 696-701, (2018)
[8]  
Wang Chuan, Jiang Mingjun, Guo Xiaochuan, Et al., Study on static thermal aging properties of titanium complex grease, Petroleum Processing and Petrochemicals, 51, 3, pp. 73-79, (2020)
[9]  
Li Xiurong, Pan Jiabao, Wang Lingjuan, Et al., Effect of static thermal ageing on fibrous entanglement and reversibility of lubricating greases, Lubrication Engineering, 41, 12, pp. 93-97, (2016)
[10]  
Hu Jintao, Zhang Ansheng, Zhang Enhui, Et al., Influence of high temperature thermal effect on the properties of complex lithium grease, Tribology, 41, 4, pp. 447-454, (2021)