A sustainable interlayer slip leads to the excellent tribological behaviour of hexagonal boron nitride microsheets

Abstract

Here, we first reported the effect of the sheet thickness on the tribological property of h-BN (hexagonal boron nitride) as a lubricant additive and revealed the micro-mechanism. h-BN microsheets with different thicknesses were prepared using molten alkali-assisted method exfoliation. Then, the tribological behaviours were investigated in the present study. The h-BN microsheet with a thickness of approximately 45 nm exhibits the lowest friction coefficient (COF) (decreased by 34.89%) and the best wear-resistance (reduced by 94.74%) compared with pure oil, while h-BN sheets with thicknesses of approximately 200 nm and 2-3 nm displayed poor tribological behaviours. These differences might mainly result from the sustainable formation of a friction film during friction sliding. This tribological behaviour makes h-BN a promising candidate as an advanced lubricant additive in practical applications. In addition, this study is the first to describe the detailed design and highly efficient use of h-BN, and might significantly increase the utilization ratio of h-BN.