Regularities of the selective dissolution of components of some corrosion resistant alloys

Component partial dissolution rate kinetics in Cr28 and Cr20Ni20 steels and Ni70Mo28 alloy in homogenized condition has been studied in a wide potential ranae with the help of gamma-spectrometer methods using specimens previously irradiated in a nuclear reactor by thermal neutron flux. The Ni70Mo28 alloy is shown to have the selectivity coefficient Zsub(Mo) changed from values < 1 towards values > 1 with positive potential bias due to the transition from molybdenum passivity potentials to molybdenum repassivation potentials. The above information permits a prediction of dissolution selectivity to be made and suitability of alloying with a given element assessed with due regard to estimated alloy service conditions. Layers enriched with relatively stronger components under given conditions are normally formed on the alloy surface contact with a liquid reactive medium