Corrosion behaviour of bioinspired laminated Al matrix composite hybrid reinforced with B4C and graphene nanoplatelets

Abstract

ABSTRACT Electrochemical corrosion tests (2500 ppm H3BO3 and 3.5 wt-% NaCl + 2500 ppm H3BO3 solution), salt spray tests and associated microstructure analysis were conducted to investigate the corrosion behaviours of bioinspired Al-xB4C-1GNPs laminated composites. The low porosity, defects and tightly bonded interface contribute to the high corrosion resistance. The increase of B4C content increased the corrosion potential and decreased the corrosion current density. The Al-5B4C-1GNPs has the highest corrosion resistance in NaCl + H3BO3 solution, the corrosion rate is 0.00459 mm/a. The laminated composites have better corrosion resistance in X plane than that in Z plane. The GNPs can prevent the Al matrix underneath it from contacting with solution and O2. The laminated structure and orientation of GNPs can effectively change the corrosion pathway and prevent the corrosion crack propagating longitudinally into the composite.