Corrosion behaviors and electrochemical mechanisms of laser-cladded NiCrAlMo/nano-CeO2 composite coatings in chloride-enriched environments

Abstract

Q235 steel is a low-cost material widely applied in modern industrial constructions. However, electrochemical degradation is the main drawback for its applications in chloride-enriched environments. To address this problem, NiCrAlMo and NiCrAlMo + 2 wt% nano-CeO2 composite coatings were laser-cladded on Q235 steel substrates. Characterization methods were used to investigate the microstructures, corrosion behaviors, and electrochemical mechanisms of the obtained coatings. The results showed that adding nano-CeO2 is conductive for removing residual gas pores and for refinement of grains, effectively improving the passive and electrochemical properties of the NiCrAlMo coating in both chloride-enriched solutions. Furthermore, the NiCrAlMoCeO2 composite coating exhibits a significantly reduced icorr of 0.4919 µA cm2 and an increased resistance ( Rp) of 175,310 Ω cm2 in a neutral solution, demonstrating the good anti-corrosion properties for its application in marine engineering structures.