Exploration on the Stress‐induced Internal Corrosion of NaCl-deposited GH4169 under humid intermediate temperature environments

Abstract

The internal corrosion penetration of GH4169 with NaCl-deposited in humid environments was analyzed by graded times, stress levels and temperatures. Dynamic principles are proposed that the depth increases with time by the parabolic law and develops with the stress level exponentially in limited exposure time. Accelerated inward diffusion of oxygen aggravates the penetration due to the reduced growth activation energy, as the stress gradient promoted the diffusion of oxygen vacancies along penetrations. Oversaturated vacancies and voids caused by active corrosion release the stress of oxides’ volume change, affecting the stress gradient, and causing the corrosion penetration to grow negatively.