The oxidation of alloy 690 in simulated pressurized water reactor primary water.

The oxide film formed on alloy 690 in simulated pressurized water reactor primary water is decorated with NiFe 2 O 4 particles which remain epitaxial with matrix. The penetrative inner oxides on both surface and crack wall are composed of Cr-rich (Fe,Cr,Ni) 3 O 4 and Cr 2 O 3 which were formed by solid state reactions of substrate with inwards diffusing oxygen and have orientation relationships with the substrate. Cr 2 O 3 forms first along the widely spaced planes of substrate. Compact Cr 2 O 3 layer cannot develop as there is no long-range outward diffusion of Cr in substrate with low defect density at low temperature. [ABSTRACT FROM AUTHOR]