Korean Institute of Surface Engineering

pISSN : 1225-8024 | eISSN : 3399-8403


공학

한국표면공학회지 (52권3호 111-116)

High Temperature Corrosion of Cr(III) Coatings in N2/0.1%H2S Gas

High Temperature Corrosion of Cr(III) Coatings in N2/0.1%H2S Gas

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Lee, Dong Bok;Yuke, Shi;

School of Advanced Materials Science and Engineering, Sungkyunkwan University;
School of Advanced Materials Science and Engineering, Sungkyunkwan University;

DOI : 10.5695/JKISE.2019.52.3.111

Abstract

Chromium was coated on a steel substrate by the Cr(III) electroplating method, and corroded at $500-900^{circ}C$ for 5 h in $N_2/0.1%H_2S-mixed$ gas to study the high-temperature corrosion behavior of the Cr(III) coating in the highly corrosive $H_2S-environment$. The coating consisted of (C, O)-supersaturated, nodular chromium grains with microcracks. Corrosion was dominated by oxidation owing to thermodynamic stability of oxides compared to sulfides and nitrides. Corrosion initially led to formation of the thin $Cr_2O_3$ layer, below which (S, O)-dissolved, thin, porous region developed. As corrosion progressed, a $Fe_2Cr_2O_4$ layer formed below the $Cr_2O_3$ layer. The coating displayed relatively good corrosion resistance due to formation of the $Cr_2O_3$ scale and progressive sealing of microcracks.

Keywords

Chromium;carbon;electroplating;$H_2S$ corrosion;oxidation;