Tribological performances of hexagonal boron nitride nanosheets via surface modification with silane coupling agent

Abstract

Hexagonal boron nitride (h-BN) is a promising lubricant additive for decreasing wear and friction. However, the poor dispersion stability and bulky size of h-BN restricted its lubrication application. In this paper, bulk h-BN was exfoliated into h-BN nanosheets (h-BNNSs), and then the self-made h-BNNSs were chemically modified with silane coupling agent via a facile and scalable reaction method. The morphology and structure of surface-functionalized h-BNNSs (m-BNNSs) were certified using a series of characterizations. Results revealed that h-BNNSs could be chemically well capped by surface modifier and the lipophilic groups were covalently attached to h-BNNSs surfaces. The m-BNNSs composite possessed long-term dispersion in liquid paraffin (LP). At the optimal adding content of 0.6 wt%, coefficient of friction and wear volume of m-BNNSs composite were decreased by about 31.9% and 53.8% compared with those of LP, respectively. Therefore, m-BNNSs composite as a lubricating oil additive has high research value and good prospects of lubrication applications.