Investigation of tribological behavior and failure mechanisms of PEEK-based composites, Babbitt alloy, and CuSn10Pb10 bimetal for wind turbine main shaft sliding bearings under simulated operational conditions

Abstract

As wind turbine capacities increase, the demand for improved stability and reliability has intensified. Traditional rolling bearings used as wind turbine main bearings often prove insufficient under conditions of the low speeds, heavy loads, frequent start-stop cycles, and complex load environments, along with significantly high maintenance costs. Sliding bearings offer a promising alternative, yet research on high-performance materials tailored for Wind Turbine Main Shaft Sliding Bearings (WTMSSB) is limited. This study investigates the tribological behavior and failure mechanisms of several sliding bearing materials under complex operational conditions. Multi-condition friction and wear tests were conducted to evaluate the friction coefficient, friction temperature rise, and volume wear rate of Babbitt alloy (ZChSnSb11–6), bimetal CuSn10Pb10, pure PEEK, and the 10 % PTFE-filled modified PEEK composites. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were employed to analyze the microstructural features and elemental distributions on wear surfaces and wear debris. The 10 % PTFE-filled modified PEEK composite demonstrated superior self-lubricating properties and wear resistance under both lubricated and dry friction conditions, showing strong potential for complex load environments. While Babbitt alloy exhibited low friction under oil lubrication, its high wear rate and susceptibility to adhesive failure under dry conditions limit its applicability. Bimetal CuSn10Pb10 displayed consistently high friction and poor wear resistance across all conditions, with a tendency for seizure. This study provides robust experimental evidence for optimizing sliding bearing materials for WTMSSB and offers guidance for future material development and practical applications.