Study on the high-temperature tribological performance of biodegradable ultrafine β-tricalcium phosphate reinforced barium complex grease

Lubricating additives are essential for enhancing the tribological properties of grease. The development of low-cost lubricant additives with excellent biodegradability is expected to be the prevailing trend for future advancements. In this study, biodegradable ultrafine β-tricalcium phosphate (β-TCP) was utilized to enhance the friction reduction, anti-wear and extreme pressure properties of barium complex greases at high temperatures. At 150 °C and a load of 150 N, compared to the base grease, the average friction coefficient (AFC) of barium complex grease with 4.5% β-TCP was reduced by 21.82%. Meanwhile, the wear volume was reduced by 88.43%. Moreover, the extreme pressure properties of the barium complex grease were increased by 3.75 times. The lubrication mechanism of β-TCP is the formation of a protective film of P and Ca compounds on the surface of the friction partner.