EFFECT OF ALLOY COMPOSITION ON THE ENVIRONMENTAL CRACKING OF NICKEL ALLOYS IN BICARBONATE AND CHLORIDE SOLUTIONS

NATALIA S. ZADOROZNE; RICARDO M. CARRANZA; MABEL C. GIORDANO; ALICIA E. ARES; RAUL B. REBAK

San Antonio, Texas, USA

Simposio; MATERIALS SCIENCE OF NUCLEAR WASTE MANAGEMENT SYMPOSIUM; 2013

THE MINERALS, METALS AND MATERIALS SOCIETY

Slow strain rate tests (SSRT) of Ni-22Cr-13Mo-3W-3Fe (N06022) showed that it is susceptible to environmental cracking in presence of bicarbonate plus chloride ions at temperatures higher than 60°C and at high anodic applied potentials. Cracking does not happen in hot solutions at the corrosion potential or at high anodic potentials at ambient temperature. The window of cracking susceptibility may be associated to the instability of a protective film that form on the surface. It was important to demonstrate which alloying element in N06022 maybe responsible for the cracking. The following six Ni alloys are being characterized in order to clarify the effect of alloying elements: N06022, N06600 (Ni-16Cr-9Fe), N08800 (Fe-32Ni-21Cr), N02200 (99Ni), Ni-20Cr and N10675 (Ni-29Mo). Results from anodic polarization as well as slow strain rate tests will be presented.