Effect of ammonium ions on the corrosion behaviors of high-manganese austenitic steel

The increasing demand for reducing greenhouse gas emissions from shipping has driven global research into new low-carbon fuels such as liquified natural gas and ammonia. High-manganese austenitic steel (HMAS) shows great potential for constructing liquid ammonia storage and transportation containers. However, little so far has been known about the service performance of the HMAS under synergistic effects of ammonia and marine atmospheric environment. Herein, we investigate the corrosion behaviors and mechanisms of the HMAS in three corrosion media including a 3.5 wt.% NaCl solution, an NH 4 + ions-containing NaCl solution, and ammonia solution. The effect of the NH 4 + ions on the corrosion behaviors of the HMAS was explored. Results showed that ignorable corrosion of the HMAS occurred in NH4+ ions-containing NaCl solution, while the corrosion rate of the HMAS in the NaCl solution increased firstly and then decreased with increasing immersion time. In the NH 4 + ions-containing NaCl solution, the NH 4 + ions could interact with the corrosion products of the HMAS and accelerate the corrosion rate. This work provides valuable insights into the combined effects of ammonia and the marine environment on the corrosion behaviors of the HMAS.