Corrosion Behavior and Mechanism of Heat-Resistant Steel T91 in High-Temperature Carbon Dioxide Environment

Abstract

Corrosion behavior of martensitic heat resisting steel T91 in high-temperature carbon dioxide environment at 500-700 °C was investigated. X-ray diffraction, scanning electron microscopy and glow-discharge optical emission spectrometry were employed to characterize the corrosion products. The results showed that the corrosion kinetics of T91 followed a parabolic law with experimental time. The oxide scale thickness of T91 followed an exponential growth law from 500 °C to 700 °C. Internal carburization was detected underneath the corrosion scale. What’s more, the carburization depth was larger than the corrosion scale. The variations of Cr and C elements distribution were discussed.