THE EFFECT OF DISSOLVED CHROMIUM ON THE CORROSION RATE OF TWO CHROMIUM- NICKEL-AUSTENITIC STEELS IN BOILING NITRIC ACID

Technical Report · Thu Nov 01 04:00:00 EST 1951

OSTI ID:4278069

McIntosh, A B; Jones, H N; Mowat, J A.S.

The rate of corrosion of chromium-nickel austenitic steels in boiling 70% nitric acid is greatly influenced by the frequency with which the nitric acid is renewed, the ratio of specimen surface area to volume of nitric acids and the type of condenser employed. lt is shown that these factors all operate by modifying the concentration of hexavalent chromium which tends to build up in the corroding solution and rapidly accelerates corrosion. The presence of hexavalent chromium can easily be prevented by ensuring the presence of nitrogen peroxide thereby decreasing the corrosion rate, and improving the deviation of results in the boiling nitric acid test. A suggested mechanism for the formation of hexavalent chromium is put forward, and the effect on the electrode potential of the specimen in the acid is demonstrated. (auth)

• Research Organization: Gt. Brit. Culcheth Labs., Culcheth, Lancs (United Kingdom)
• NSA Number: NSA-13-011186
• OSTI ID: 4278069
• Report Number(s): RISLEY-8012
• Country of Publication: United Kingdom
• Language: English

Related Subjects

AUSTENITE
BOILING
CHROMIUM
CHROMIUM STEELS
CORROSION
EFFICIENCY
ELECTRIC POTENTIAL
ELECTRODES
ELECTRONS
METALLURGY AND CERAMICS
NICKEL ALLOYS
NITRIC ACID
NITROGEN OXIDES
QUANTITY RATIO
SOLUTIONS
SURFACES
VALENCE
VARIATIONS
VOLUME