Tribological performances of epoxy resin composite coatings using hexagonal boron nitride and cubic boron nitride nanoparticles as additives

[Display omitted] •HBN and CBN were added to the epoxy resin as binary nanofillers.•The BN nanoparticles modified by polydopamine displayed great dispersibility.•The tribological mechanisms of HBN and CBN were systematically studied. Hexagonal boron nitride and cubic boron nitride were modified by polydopamine to improve dispersion in epoxy resin (EP). The average coefficient of friction (COF) of EP-HBN@PDA coating decreased under dry and seawater condition compared to EP indicating BN possessed self-lubricating effect. COF decreased with CBN content raising in seawater, because seawater removed debris including BN particles and CBN with high hardness improved rigidity of coatings. Wear rates of EP-CBN@PDA coating decreased by 68.88% and 97.95% compared to EP-HBN@PDA, and binary-filled coating performed excellently under seawater, it revealed CBN was more effective than HBN in improving load carrying capacity of coatings.