Important explorations of the sliding tribological performances of micro/nano-structural interfaces: Cross-shaped microconcave and the nanoNb2AlC-Sn

•Sintering and SPS were used to successfully prepare CC-NS-W interface.•Massive NS migration to rational square convex for forming lubrication film.•Excellent lubrication ascribed to sufficient enrichment of NS in nanocrystalline film.•Low-hardness film on a hard convex reduced sliding damages to maintain good lubrication.•W, Nb2AlC, oxides resisted the scrapping damage of film to enable tribological behaviors. Cross-shaped microconcave (CC) cooperated with the Nb2AlC-Sn (NS) to enhance their collaboration lubrications, thereby extended W alloy-base application scope while retaining their longevity and high accuracy. On sliding tribo-pair systems, tribological behavior of 0.5CC-NS was more excellent than those of another CC-NS. This was mainly attributed to the following reasons: (1) enough NS in the 0.5CC-NS helped a lubrication film formation; high bearing abilities of convex squares accepted massive loads to reduce film damage. (2) Convexity of 13.26 ± 0.52 GPa nano-hardness supported the low-hardness film (1.41 ± 0.19 GPa), made Nb2AlC and Sn produce nanocrystallines to maintain excellent lubrication. (3) W-alloys, Nb2AlC and metallic oxides appeared in the film to assist the convex square for an effective resisting to the damages. (4) sliding wear of the films avoided their direct contacts of matching pair, facilitated excellent tribological behaviors of the 0.5CC-NS-W. 0.5CC-NS interfaces were helpful in providing important references for construction of friction interfaces of power-driven gears for arresting enhancements of tribological abilities.