Wet-jet milling exfoliated hexagonal boron nitride as industrial anticorrosive pigment for polymeric coatings

Abstract The incorporation of inorganic nanofillers into polymeric matrices represents an effective strategy for the development of smart coatings for corrosion protection of metallic substrates. In this work, wet-jet milling exfoliation was used to massively produce few-layer hexagonal boron nitride (h-BN) flakes as a corrosion-protection pigment in polyisobutylene (PIB)-based composite coatings for marine applications. This approach represents an innovative advance in the application of two-dimensional (2D) material-based composites as corrosion protection systems at the industrial scale. Although rarely used as an organic coating, PIB was selected as a ground-breaking polymeric matrix for our h-BN-based composite coating thanks to its excellent barrier properties. The optimization of the coating indicates that 5 wt.% is the most effective h-BN content, yielding a corrosion rate of the protected structural steel as low as 7.4 × 10⁻⁶ mm yr⁻¹. The 2D morphology and hydrophobicity of the h-BN flakes, together with the capability of PIB to act as a physical barrier against corrosive species, are the main reasons behind the excellent anticorrosion performance of our composite coating.