Effect of solution temperature on corrosion behavior of AlCoCrFeNi(Ti) high entropy alloy coatings

Purpose The purpose of this paper is to investigate the corrosion behavior of AlCoCrFeNi and AlCoCrFeNiTi high-entropy alloy (HEA) coatings deposited on AH40 marine steel, with a focus on the effects of temperature variations and corrosive marine environments. Design/methodology/approach Laser cladding was utilized to deposit the coatings, and the corrosion performance was evaluated in a 3.5 Wt.% NaCl solution across a temperature range of 0°C–60°C. Electrochemical performance, passivation film structure, corrosion morphology and corrosion products were characterized using linear sweep voltammetry, electrochemical impedance spectroscopy, scanning electron microscopy and X-ray photoelectron spectroscopy. Findings The results show that both coatings exhibit excellent corrosion resistance at 0°C and 20°C, with the AlCoCrFeNi coating demonstrating particularly high charge transfer impedance and stable passivation. However, as temperature increases, corrosion resistance declines for both coatings, indicated by higher corrosion current density, unstable passivation and increased corrosion pits. The AlCoCrFeNiTi coating displayed greater corrosion sensitivity at 40°C and 60°C, attributed to the instability of the passivation film due to Ti doping at elevated temperatures. This study emphasizes the significant effect of temperature on the stability of HEA passivation films and corrosion behavior. Originality/value This study provides critical insights into the temperature-dependent corrosion behavior of HEA coatings, which can guide the design of new adaptive coatings capable of withstanding multiple environmental conditions, enhancing marine corrosion resistance.