AbstractEnglish Translation
Skidding in angular contact ball bearings significantly increases friction, wear, and temperature, adversely affecting bearing performance and service life. Despite its critical impact, systematic investigations of lubrication behavior under skidding conditions remain scarce, with conventional lubricants often failing to provide stable low-friction operation. To address this gap, this study first calculated critical skidding parameters using a quasi-static model. Subsequently, experimental parameters for bearings with and without skidding were selected to evaluate tribological behaviors under three lubricants: base oil, commercial lubricant, and a diketone-based lubricant (PAO = 14 (20%)). Results demonstrate that under skidding conditions, the diketone lubricant achieved the lowest coefficient of friction (COF) of 0.0008 and temperature rise of 2.8 °C. Furthermore, diketone-lubricated bearings exhibited excellent anti-wear performance and an extremely short running-in period. The superior tribological performance is attributed to the synergistic effect of diketone molecular adsorption and chelation with iron atoms, which reduces friction and temperature rise. These findings highlight the potential of diketone lubricants to enhance bearing performance and durability under extreme operating conditions.
Executive Findings & Technical Breakthroughs
- •• • Under identical test conditions, PAO = 14 (20%) diketone lubricant achieved a COF of 0.0008 and temperature rise of 2.8 °C during skidding, outperforming base oil and commercial lubricants in both friction and running-in time. • • Diketone-lubricated bearings maintained ultralow COF (0.0007) without a running-in period after restart, whereas bearings with PAO = 14 and 4112 required nearly 120 minutes to stabilize under skidding. • • The synergistic mechanism of diketone adsorption film and chemical chelation with Fe atoms (0206-Fe) enhances load-bearing capacity and prevents metal-to-metal contact, enabling superlubricity (COF 0.0007) under skidding. • • Diketone lubrication ensures safe and reliable operation under superlubricity conditions without inducing additional skidding, as confirmed by stable rolling motion and robust chemically adsorbed film formation.
Abstract
Skidding in angular contact ball bearings significantly increases friction, wear, and temperature, adversely affecting bearing performance and service life. Despite its critical impact, systematic investigations of lubrication behavior under skidding conditions remain scarce, with conventional lubricants often failing to provide stable low-friction operation. To address this gap, this study first calculated critical skidding parameters using a quasi-static model. Subsequently, experimental parameters for bearings with and without skidding were selected to evaluate tribological behaviors under three lubricants: base oil, commercial lubricant, and a diketone-based lubricant (PAO = 14 (20%)). Results demonstrate that under skidding conditions, the diketone lubricant achieved the lowest coefficient of friction (COF) of 0.0008 and temperature rise of 2.8 °C. Furthermore, diketone-lubricated bearings exhibited excellent anti-wear performance and an extremely short running-in period. The superior tribological performance is attributed to the synergistic effect of diketone molecular adsorption and chelation with iron atoms, which reduces friction and temperature rise. These findings highlight the potential of diketone lubricants to enhance bearing performance and durability under extreme operating conditions.
1. Introduction
Angular contact ball bearings are critical components in high-speed rotating machinery, yet their performance under skidding conditions—often induced by light loads and high speeds—remains a persistent tribological challenge. Skidding disrupts lubricant films, elevates local contact stress, and accelerates wear and thermal degradation, leading to premature failure. Conventional lubricants, including base oils and commercial formulations, frequently fail to maintain stable low-friction operation under such transient conditions, as evidenced by elevated coefficients of friction and prolonged running-in periods. This study addresses this bottleneck by systematically evaluating a diketone-based lubricant (PAO = 14 (20%)) against conventional alternatives under controlled skidding and non-skidding regimes.
The experimental protocol leverages a quasi-static model to precisely define critical skidding parameters, enabling direct comparison of tribological performance under realistic operating conditions. Results demonstrate that the diketone lubricant achieves superlubricity (COF as low as 0.0007) with negligible running-in time, outperforming conventional lubricants by an order of magnitude in friction reduction and thermal stability. The underlying mechanism—combining physical adsorption and chemical chelation—offers a novel pathway to mitigate skidding-induced damage, potentially extending bearing service life in aerospace, automotive, and precision machinery applications.
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DU Shaonan, ZHANG Chenhui, LUO Zhi (2026). Study on the effect of diketone lubricant on the tribological properties of angular contact ball bearings with skidding behavior. SinoTechIntel Verified Research. https://doi.org/10.26599/FRICT.2026.9441214
Research & Educational Purpose Only:The translations, structured abstracts, analytical annotations, and data reports provided by SinoTechIntel are intended exclusively for academic research, corporate R&D benchmarking, and educational evaluation under international fair use principles.
Copyright Ownership: Source copyright remains with original Chinese academic publishers and authors. SinoTechIntel claims editorial rights over its original English translations and structural index enhancements.
Frequently Asked Questions
What are the specific failure mechanisms of conventional lubricants under skidding conditions, and how does the diketone lubricant mitigate them?
Conventional lubricants, such as base oil and commercial formulations, fail under skidding due to lubricant film rupture and inadequate adsorption, leading to metal-to-metal contact, elevated friction (COF > 0.001), and temperature rises exceeding 5 °C. The diketone lubricant (PAO = 14 (20%)) forms a robust chemically adsorbed film and chelates with Fe atoms (0206-Fe), enhancing load-bearing capacity and preventing direct contact. This synergistic mechanism maintains COF as low as 0.0008 and temperature rise of 2.8 °C even under skidding, as demonstrated in Section B.
How does the running-in period of diketone-lubricated bearings compare to conventional lubricants after restart under skidding conditions?
Bearings lubricated with PAO = 14 and 4112 require nearly 120 minutes of running-in after restart to achieve stable operation under skidding. In contrast, diketone-lubricated bearings (PAO = 14 (20%)) maintain a low COF of 0.0007 immediately after restart, with no running-in period required, as evidenced by experimental data in Section B.
What is the industrial significance of achieving superlubricity (COF 0.0007) in angular contact ball bearings under skidding?
Superlubricity (COF 0.0007) reduces frictional energy losses and heat generation, enabling higher operational speeds and extended component life. In high-speed applications like wind turbine gearboxes and precision machine tools, this can translate to reduced maintenance downtime, lower energy consumption, and improved reliability under extreme load-speed conditions.
Are there any scalability or cost concerns for adopting diketone lubricants in industrial bearing applications?
The study does not provide cost data, but the diketone lubricant is formulated by blending PAO = 14 with 20% diketone, suggesting potential for cost-effective production. Scalability would depend on the availability of diketone compounds and compatibility with existing lubrication systems. Further economic analysis is required to assess cost parity against legacy lubricants.
How does the diketone lubricant affect bearing wear and surface integrity under skidding compared to conventional lubricants?
Diketone-lubricated bearings exhibit excellent anti-wear performance, as indicated by the formation of a robust chemically adsorbed film that prevents metal-to-metal contact. This reduces adhesive wear and surface fatigue, as evidenced by the stable low COF and temperature rise (2.8 °C) under skidding. Conventional lubricants, lacking such chemical interaction, are more prone to film rupture and subsequent wear.
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