Accession Number:

ADA272271

Title:

The Effects of Dissolved Ozone on the Corrosion Behavior of 304 Stainless Steel, Monel 400 and Naval Brass in Artificial Sea Water

Descriptive Note:

Final rept. Jan 1990-Oct 1993

Corporate Author:

RENSSELAER POLYTECHNIC INST TROY NY DEPT OF MATERIALS ENGINEERING

Personal Author(s):

Report Date:

1993-11-01

Pagination or Media Count:

75.0

Abstract:

The effects of 0.02, 1.2 and 2.3 mgL ozone on the corrosion behavior of 304 stainless steel, Monel 400, and naval brass were studied at room temperature in artificial sea water at pH 7.5, and the results were compared with those obtained for aerated solutions. Corrosion potentials and cyclic polarization curves were measured after 1 and 17 hour exposure times. Instantaneous corrosion rates were measured using linear polarization resistance LPR techniques. Long term 30 day crevice corrosion experiments were also performed on stainless steel and naval brass in aerated and 0.8 mgL ozonated solutions. Increasingly noble corrosion potentials were observed in the cases of stainless steel and Monel with increasing ozone concentration due to the noble redox potential of ozone. Naval brass, on the other hand, maintained a fairly constant corrosion potential, independent of ozone concentration, due to the formation of a bulk corrosion product on the metal surface. LPR measurements on naval brass reflected the corrosion rates of both zinc and copper due to dezincification occurring on the metal surface. These corrosion rates were found to Corrosion, Stainless steel, Copper nickel alloy, Dissolved ozone, Chloride solutions be independent of ozone concentration and exposure time, although it appears that exposure to 0.02 mgL ozone after 17 hours resulted in complete dezincification at the surface. The corrosion rate of Monel was found to increase at elevated ozone concentrations, independent of exposure time. Stainless steel, however, showed a decreasing corrosion rate with increasing ozone concentration after one hour due to ozone quickly stabilizing the passive film.

Subject Categories:

  • Physical Chemistry
  • Properties of Metals and Alloys
  • Marine Engineering

Distribution Statement:

APPROVED FOR PUBLIC RELEASE