Study on the effect of diketone lubricant on the tribological properties of angular contact ball bearings with skidding behavior

• • 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.