Comment on “Transpassive-repassivation process of Ni-base superalloys: The role of hidden subsurface alloy layer”

Hariharan K, Kosanam K, Schmuki P, Virtanen S (2026)

Publication Type: Journal article

Publication year: 2026

Journal

Corrosion Science Elsevier

Article Number: 114051

DOI: 10.1016/j.corsci.2026.114051

Abstract

We comment on recent reports proposing that transpassive dissolution in Ni–Cr–Mo alloys is driven primarily by the oxygen evolution reaction (OER) and that Mott–Schottky (MS) analysis demonstrates a stable p-type Cr-oxide passive film in the transpassive region. Using direct oxygen respirometry, electrolyte/surface observations, UV–vis spectra, and a reassessment of the MS methodology, we show that (i) OER is not measurably engaged under the stated conditions; (ii) acidification is fully explained by chromate formation; and (iii) the negative MS slope at high potential reflects chromate-induced surface charge distortions rather than intrinsic p-type semiconductivity.

Authors with CRIS profile

Karthikeyan Hariharan
Koushik Kosanam Professur für Werkstoffwissenschaften (Korrosion und Oberflächentechnik) Patrik Schmuki Lehrstuhl für Werkstoffwissenschaften (Korrosion und Oberflächentechnik) (LKO) Sannakaisa Virtanen Professur für Werkstoffwissenschaften (Korrosion und Oberflächentechnik)

Involved external institutions

Indian Institute of Technology Bombay IN India (IN)

How to cite

APA:

Hariharan, K., Kosanam, K., Schmuki, P., & Virtanen, S. (2026). Comment on “Transpassive-repassivation process of Ni-base superalloys: The role of hidden subsurface alloy layer”. Corrosion Science. https://doi.org/10.1016/j.corsci.2026.114051

MLA:

Hariharan, Karthikeyan, et al. "Comment on “Transpassive-repassivation process of Ni-base superalloys: The role of hidden subsurface alloy layer”." Corrosion Science (2026).

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