Corrosion Behavior of T91 Steel in Neutral Salt Spray with 5.0% NaCl Solution

The corrosion behavior of T91 steel in neutral salt spray with 5% (mass) NaCl solution was studied by mass loss analysis, macro and micro morphology observation and corrosion product analysis. The results show that in the first 75 h of salt spray corrosion, the corrosion rate of T91 steel was low, and the surface corrosion products grew slowly; after 75 h, the corrosion rate of T91 steel sharply increased, and the surface corrosion products rapidly increased in quantity and thickness. The corrosion products on the T91 steel surface were mainly composed of oxides of Fe and Cr. The T91 steel surface first generated localized corrosion, and then the localized corrosion developed into corrosion pits. Finally, new localized corrosion occurred at the bottom of the corrosion pits.