Coupling hybrid of HBN nanosheets and TiO2 to enhance the mechanical and tribological properties of composite coatings

Epoxy resin (EP) composite coatings enhanced with hexagonal boron nitride (HBN) nano-sheets, TiO 2 particles and HBN-TiO 2 hybrid material were fabricated successfully on the surface of 304L stainless steel. The structural and morphological features of HBN, TiO 2 and HBN-TiO 2 hybrid obtained from mechanical peeling and sol-gel method were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), Raman spectroscopy, XRD patterns, FT-IR spectra and XPS spectra. Moreover, tribological characteristic of composite coatings was investigated by UMT-3 tribometer. Mechanical behavior, worn surface, steel ball surface and debris size distribution of composite coatings were detected to investigate the tribological mechanism. The results demonstrated that HBN/EP, TiO 2 /EP and HBN-TiO 2 /EP composite coatings showed remarked promotion of mechanical behavior compared with the neat EP, especially for the improvement of hardness. The HBN-TiO 2 /EP composite coating, whose wear rate decreased by 65.8 % in comparison with the neat EP, manifested prominent tribological performance ascribed to the load carrying capacity of TiO 2 and the reduction of self-lubricating effect on the size of debris.