EFFECT OF CHROMIUM ION FROM AUTOCLAVE MATERIAL ON CORRSION BEHAVIOR OF N NI BASE ALLOYS IN SUPERCRITICAL WATER

摘要

Seven kinds of corrosion tests were carried out on thirteen kinds of Ni-base alloys in sub-critical and supercritical water containing 0.01mol/kg-H2SO4 and 800ppm-^sO2 using Ni-44Cr-1Mo autoclave. The obtained corrosion rates were significantly lower than the previous experiments done in the same conditions using a Ti autoclave. A compact oxide scale was found on the specimens tested in the Ni-44Cr-1Mo autoclave. The Cr-rich oxide layer would originate from the autoclave material and provide protective function against corrosion. The corrosion retardation phenomenon has been explained by dependencies of　^sCr2O3 solubility on phase state of water and temperature.