Effect of dissolved precursors on corrosion characteristics of Ni-based alloy Inconel 625, stainless steel 316L and titanium alloy TA2 in acidic and neutral supercritical water: A comparative study

• Published in: The Journal of supercritical fluids Vol. 209; p. 106249
• Main Authors: Jiang, Guanyu, Liu, Lu, Xu, Donghai, Liu, Huanteng, Wang, Mingjun, Yang, Jianqiao
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2024
• Subjects: Corrosion resistance; Intergranular corrosion; Metal oxides; Supercritical water; Metal oxides; Corrosion resistance; Supercritical water; Intergranular corrosion
• ISSN: 0896-8446; 1872-8162
• DOI: 10.1016/j.supflu.2024.106249

This work investigated the corrosion characteristics of nickel-based alloy Inconel 625, stainless steel 316L (SS 316L), and commercial grade 2 titanium alloy (TA2) in ZrO(NO3)2-containing and ZrO(NO3)2/KOH-containing supercritical water (SCW) at 400 °C and 25 MPa. During ZrO(NO3)2-containing SCW exposure, Inconel 625 undergoes pitting and intergranular corrosion, while SS 316L and TA2 suffer uniform corrosion. Based on corrosion rate and metal oxide stability, the corrosion resistance follows an order of TA2 > Inconel 625 > SS 316L. The addition of KOH reduces the intergranular corrosion sensitivity of Inconel 625, and leads to different oxide distribution of SS 316L. The thick TiO2 oxide layer mixed with ZrO2 formed in ZrO(NO3)2/KOH-containing SCW enables TA2 to exhibit superior corrosion resistance than Inconel 625 and SS 316L. [Display omitted] •Inconel 625 undergoes pitting and intergranular corrosion in ZrO(NO3)2-containing SCW.•Acidic dissolution of anatase TiO2 leads to higher corrosion rate in the presence of ZrO(NO3)2.•Coexistence of ZrO(NO3)2 and KOH facilitates the formation of ZrO2.•TiO2 oxide layer mixed with ZrO2 enables TA2 to display superior corrosion resistance.