Corrosion of 304 stainless steel exposed to nitric acid-chloride environments
- Los Alamos National Lab., NM (United States). Materials Corrosion and Environmental Effects Lab.
In an effort to examine the combined effect of HNO{sub 3}, NaCl, and temperature on the general corrosion behavior of 304 stainless steel (SS), electrochemical studies were performed. It was found that the corrosion response of 304 SS was bifurcated: materials were either continuously passive following immersion or spontaneously passivated following a period of active dissolution. Increasing NaCl concentrations promoted pitting, active dissolution upon initial immersion, a smaller potential range for passivity, longer active corrosion periods, larger active anodic charge densities preceding spontaneous passivation, and larger corrosion current and peak current densities. In contrast, intermediate HNO{sub 3} concentrations were found to promote active dissolution, with continuous passivity noted at HNO{sub 3} concentration extremes. During active corrosion, increasing HNO{sub 3} concentration increased anodic charge density, corrosion current density, and peak current density. The time required for spontaneous passivation was found to be maximized at intermediate HNO{sub 3} concentrations. Susceptibility to pitting was found to be highest at intermediate HNO{sub 3} concentrations. The pit initiation and repassivation potentials decreased with increasing HNO{sub 3} until the HNO{sub 3} concentration exceeded a critical concentration where pitting susceptibility was entirely eliminated. No differences between 304 SS, 304 L SS, and sensitized 304 SS were apparent in solutions yielding active dissolution, passive, dissolution or pitting. Increasing solution temperatures increased the susceptibility to both pitting and active dissolution. 53 refs.
- OSTI ID:
- 504793
- Report Number(s):
- CONF-970332-; TRN: 97:013476
- Resource Relation:
- Conference: Corrosion 97. 52. annual corrosion conference of the National Association of Corrosion Engineers: economics and performance - bridging the gap and NACExpo, New Orleans, LA (United States), 9-14 Mar 1997; Other Information: PBD: 1997; Related Information: Is Part Of Corrosion/97 conference papers; PB: [4584] p.
- Country of Publication:
- United States
- Language:
- English
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