NITRIC ACID CORROSION AND POLARISATION OF A AUSTENITIC STEEL-EFFECT OF ADDED SPECIES
The effect of added species on the corrosion of 18/ 23/Nb austenitic steel in boiling nitric acid is considered in relation to the oxidation potential of the systems. It is shown that stainless steels corrode at an accelerated rate when the standard oxidation potential of redox species addcd to the solution is between about 1.3 and 1.55. The mechanism of accelerated corrosion involves oxidation of chromium in the oxide film normally present on stainless steels from the Cr-III to Cr-VI oxidation state. This destroys the corrosion resistant properties of the steel. When species which produce accelerated corrosion in nitric acid are present this reaction takes place anodically at a potential of about 1. 15 V and is virtually unpolarized. When accclerated corrosion occurs the cathodic reaction is also depolarized and involves reduction of the species responsible for producing accelerated corrosion. However, when stainless steels do not suffer accelerated corrosion the cathodic reaction is different and involves reduction of nitric acid. This reaction is heavily polarized. (auth)
- Research Organization:
- Gt. Brit. Culcheth Labs., Culcheth, Lancs, England
- NSA Number:
- NSA-13-011828
- OSTI ID:
- 4275089
- Report Number(s):
- IGR-TN/C-419
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
Similar Records
Influence of uranium on corrosion of stainless steel in solutions of fluoride in nitric acid
STUDY OF CORROSION AND ELECTROCHEMICAL BEHAVIOUR OF STAINLESS STEELS IN THE COURSE OF CATHODIC POLARIZATION IN NITRIC ACID SOLUTIONS. 2. CATHODIC PROCESSES DEVELOPING ON THE SURFACES OF STAINLESS STEELS IN NITRIC ACID SOLUTIONS