A N-Doped FeCrNiMo High-Entropy Alloy with Corrosion Resistance Prepared by Powder Metallurgy
摘要
A novel N-doped FeCrNiMo high-entropy alloy (HEA) was successfully synthesized via powder metallurgy, and its corrosion behavior in 3.5 wt.% NaCl solution was systematically investigated. Electrochemical characterization revealed that the FeCrNiMo HEA demonstrates exceptional corrosion resistance, exhibiting a remarkably low room-temperature current density of 0.022 μA/cm2 and a high pitting potential of 1.03 VSCE. Current density for the FeCrNiMo HEA is an order of magnitude lower than commercial stainless steels (316L and 7-Mo) and nickel-based alloys (Nicrofer 3033 and IN625). As a result, the corrosion resistance of the material is superior to that of the comparison specimens. The corrosion rate of FeCrNiMo HEA was determined to be 1.7 × 10−4 mm/a, representing an order of magnitude improvement over comparison specimens (7-Mo: 1.7 × 10−3 mm/a, 316L: 7.84 × 10−3 mm/a, IN625: 1.45 × 10−3 mm/a). Surface analysis revealed a dual-layer passive film structure: an outer Fe-containing oxide layer and an inner Cr-rich layer predominantly composed of Cr2O3/Cr(OH)3. Notably, Mo distribution throughout the passive film was found to enhance film quality and chloride-induced pitting resistance. The exceptional corrosion performance originates from the alloy's uniform microstructure and supersaturated Cr/Mo composition, which synergistically promote the formation of a highly stable passive film with self-repairing capabilities. This unique combination of structural characteristics and elemental distribution establishes the FeCrNiMo HEA as a promising candidate for marine corrosion applications.