Comparison on electrochemical corrosion performances of arc and laser thermal sprayed Al-Ti-Ni coatings in marine environment

Al-Ti-Ni coatings were fabricated on S355 structural steel using an arc spraying (AS) and laser thermal spraying (LTS), and their electrochemical corrosion performances in 3.5% NaCl, 0.1 M H2SO4 and 0.1 M NaOH solutions were comparatively investigated. The results show that the obtained coatings are composed of crystalline and amorphous phases, and the metallurgical bonding is formed at the interface of laser thermal sprayed coating. The polarization resistance R-p and charge transfer resistance R-ct of laser thermal sprayed coating are higher than those of arc sprayed coating in 3.5% NaCl, 0.1 M H2SO4 and 0.1 M NaOH solutions, while the corrosion current density j(corr) is opposite, its electrochemical corrosion resistance is better than the arc sprayed coating. The R-p and R-ct of laser thermal sprayed coating in 0.1 M NaOH solution are the highest among the three kinds of solutions, showing the highest electrochemical corrosion resistance.