Transcripción del resumen del autor. Stress corrosion cracking (SCC) of Alloy 625 (UNS N06625) has been investigated in pH 2 aqueous solution at high temperatures (300°C to 426°C) and high pressure (24.1 MPa) to understand the corrosion behavior in supercritical water oxidation (SCWO) systems, which can destroy aqueous organic wastes with high efficiency with no harmful byproducts. Alloy 625 was exposed to 11 operational (chemical, thermal, pressure) cycles. SCC at subcritical temperature comes from the chemical stability of the elements, which produces a dealloyed oxide layer where Ni is selectively dissolved and Cr forms stable oxides. Its growth is accelerated along the grain boundaries, where SCC develops during the operational cycles. As a result of the defective dealloyed oxide layer structure, the diffusivity of Ni is fast, intermediate between the surface and grain boundary diffusivities. SCC at supercritical temperature comes from the direct chemical attack of associated hydrochloric acid (HCl) molecules.

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