Abstract
The water heated and pressurized above the critical point (648K, 22.1MPa) is called supercritical water (SCW) and allows high solubility of organic substance in the water. As a result, the condition of SCW in this phase requires high corrosive-resistance for the reactor vessel materials, so that the practical application of this technology has been delayed. Fe based alloy is tried to applied for corrosion-resistance materials and the alloy indicates various corrosion-resistances due to a change of heat, pressure and chemical composition. In this study, the effects of Cr, Ni, and Mo addition on the corrosion-resistivity and corrosion-behavior of Fe based alloy was investigated.
Cr addition of above 10.0 mass% on the alloy, Fe2O3 and FeCr2O4 produced a protective boundary. Moreover, Cr addition of above 15.0 mass% on the alloy produced a single Cr2O3 layer of the protective boundary and while remarkably decreasing the corrosion-rate under the condition of 10～ permittivity. Cr addition of above 25.0 mass% on the alloy produced a single Cr2O3 layer of the protective boundary over the condition of 10～ permittivity. The effect of Ni addition on the corrosion-rate of the alloy, which transformed the matrix from ferrite to austenite, was low value. By addition of Mo to the alloy, the production of pitting-corrosion was decreased. Moreover, Mo addition of 25.0 mass% or less on Fe-25%Cr alloy decreased the corrosion-rate.
