Synergetic effects of biomimetic microtexture with multi-solid lubricants to improve tribological properties of AISI 4140 steel

Inspired by the ability of tree frog toes to regulate body fluids, this control mechanism is applied to the tooth surface of slewing bearing (AISI 4140 steel (AS)) by adopting the regular hexagonal microtexture. SnAgCu-TiC (SACT) lubricants are filled in the microtextures. Results of two-factor analysis of variance show that there is a significant interaction between the microtexture and lubricants. When the microtextures with 1000 µm side are filled with SnAgCu-4 wt% nano-TiC (AS-SACT410), coefficient of friction (COF) of sample is the lowest. Compared with AS (0.437), COF of AS-SACT410 is reduced to 0.085, decreased by 80.55%. Macroscopic anti-friction originates because SnAgCu wraps around nano-TiC to form tribofilms containing submicron rollers, achieving substantially reduced COF.