An investigation on high temperature corrosion behavior of FeCr0.5NiCu0.5 high-entropy alloy in waste incineration environments

Purpose This study aims to address high-temperature corrosion in waste-to-energy (WTE) superheater tubes by developing a FeCr0.5NiCu0.5 high-entropy alloy (HEA) coating via laser cladding. It evaluates the coating’s resistance to chloride-sulfate molten salts at 650 °C, filling a gap in HEA applications for WTE environments. Design/methodology/approach A FeCr0.5NiCu0.5 HEA coating was fabricated on 12Cr1MoV steel using laser cladding. High-temperature corrosion tests in KCl/NaCl/K2SO4/Na2SO4 molten salts were conducted. Microstructural analysis (scanning electron microscope, X-ray diffractometer, energy-dispersive spectrometer) and thermodynamic calculations were used to study corrosion mechanisms, with comparisons to Inconel 625 and substrate materials. Findings The HEA coating showed a dense, single face-centered cubic phase structure with strong substrate bonding. After 168 h, mass loss was 1965 g·m-2, 50% lower than the substrate (4082 g·m-2). Corrosion involved oxidation, sulfidation and chlorination, with Cr-rich oxides suppressing chloride penetration. Originality/value This study pioneers HEA coatings in WTE environments, offering a cost-effective alternative to nickel-based alloys. It reveals Cr’s role in corrosion inhibition and advances material design for harsh energy systems, providing a sustainable solution for WTE infrastructure.