Wear mechanism and evolution of tribofilm of ceramic on steel pairs under ester oil lubrication in wide temperature range
Lvzhou Li, Pengpeng Bai, Xiangli Wen, Xue Zhou, Kai Ma, Yonggang Meng, Jianning Ding, Yu Tian
Abstract
The ceramic-steel-pentaerythritol ester system has a broad application prospect under high temperature conditions, which are respectively in the fields of aviation, aerospace and advanced equipment manufacturing. However, a comprehensive understanding of the friction and wear mechanisms of this system across a broad temperature range remains elusive. The tribological properties of the system at 25–475 °C were studied. With the increase of temperature, the evolution of the tribofilm follows the sequence: discontinuous tribofilm → uniform tribofilm → tribofilm removal. At 200–300 °C, an approximately 100 nm thick amorphous PxOy compound tribofilm is formed, and its nanohardness and modulus are reduced by 81.33 % and 54.02 %, respectively, compared with base steel. The tribofilm effectively reduces shear resistance by blocking friction pair contact. When the temperature exceeds 300 °C, it will lead to high-temperature coking, which adversely affects the lubrication performance. It is worth noting that the system can endure short-term service at a maximum temperature of 475 °C. Therefore, this research can help achieve continuous, stable operation of high-temperature resistant systems, as well as short-term use under extreme conditions encountered by complex equipment.