Corrosion characteristics of in situ hybrid (Al3Ni + Al2O3)/Al composites synthesized by the solid-state combustion

Abstract In this study, in situ hybrid (Al 3 Ni + Al 2 O 3 )/Al composites were prepared successfully by the solid-state combustion via Al–NiO system. The effects of Al 3 Ni + Al 2 O 3 on the corrosion features of composites were analyzed using potentiodynamic polarization, electrochemical impedance spectroscopy, and immersion corrosion in 3.5 wt% NaCl solution. The results show that with the increase of NiO addition, the corrosion resistance of composites is improved, and the corrosion resistance of 15 % NiO–Al composite is almost comparable to the Al matrix. The increased quantity and dispersive distribution of Al 3 Ni and Al 2 O 3 particles can effectively prevent the occurrence of corrosion and the movement of free electrons. Besides, more fine Al 2 O 3 particles distributed in grain boundaries can increase the impedance and hinder the electrochemical corrosion preferentially starting at the boundary. Also, in the composite with high NiO addition, a better and compact interface bonding can be formed due to reduction of large size Al 3 Ni particles and improvement in the dispersion of particles, thereby inhibiting interface damage. This study has advanced understanding of corrosion.