Assessment of the Pitting, Crevice Corrosion, and Mechanical Properties of Low-Temperature Plasma-Nitrided Inconel Alloy 718

A comparative study on the mechanical properties, scratch resistance, and localized corrosion (pitting crevice) of plasma-nitrided Inconel alloy 718 (UNS NO7718: IN 718) was carried out. Thermochemical treatment performed at low temperatures (400 450 °C) for 4 h. The formed layers with thicknesses 7.17 ± 0.89 µm 7.96 0.48 (450 °C). XRD nanohardness analyses indicated formation a hard layer composed expanded austenite phase (γN), CrN 400 °C, + γ maximum indentation hardness 12 12.5 GPa, respectively, when compared to 5 GPa substrate hardness. scratching tests (2–8 N) showed that increasing load, nitrided surfaces had transition from 100% microcutting combination microplowing/cutting, presence cracks. critical load 3 N °C °C. untreated condition maintained crack-free combined mechanism regardless load. For same held lower coefficient friction values higher resistance values, which were more pronounced linear polarization (3.56 wt.% NaCl) pitting in all samples, being less resistant. Nitriding increased crevice Inconel, while it severely damaged it. brought concomitant gains as-received 718.