Experimental investigation on corrosion behavior of Fe-C- Mn –Cr P/M steels

Abstract

Abstract The corrosion behavior of Fe–C–Mn–Cr powder metallurgy (P/M) steels containing chromium contents of 5 wt%, 10 wt%, and 15 wt% was systematically investigated in acidic environments through the weight loss method. Steel specimens were fabricated via compaction at 1.0 GPa and sintering at 1050 ± 5 °C, then immersed for up to 72 h in sulfuric acid (H2SO4), hydrochloric acid (HCl), and nitric acid (HNO3), each at three normality levels (1N, 2N, and 3N). Results showed that increasing chromium content significantly reduced corrosion rates across all test conditions. Specifically, in 1N sulfuric acid, weight loss decreased from 1.39 g (5 wt% Cr) to 0.98 g (15 wt% Cr) after three days. A similar trend was observed in HCl (0.61 g to 0.41 g) and HNO3 (0.37 g to 0.07 g). These findings confirm the protective role of chromium, which enhances the formation and stability of passive oxide layers, particularly in aggressive acidic media. Sulfuric acid was identified as the most corrosive environment, while nitric acid exhibited the strongest passivation effect. The study provides valuable quantitative insight into the time-dependent corrosion behavior of Cr-alloyed P/M steels and underscores the effectiveness of chromium additions in enhancing long-term corrosion resistance under industrially relevant acidic conditions.