| High-temperature Corrosion of CrAlSiN Thin Films in N2/0.1%H2S Gas |
| Muhammad Ali Abro1, Junhee Hahn2, Dong Bok Lee3 |
1Department of Mechanical Engineering, MUET, SZAB Campus, Khairpur Mir’s 66020, Pakistan
2Center for Energy Materials Metrology, Korea Research Institute of Standards and Science, Daejon 34113, Republic of Korea
3School of Advanced Materials Science & Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea |
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Received: 21 November 2017; Accepted: 29 January 2018. Published online: 5 April 2018. |
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| ABSTRACT |
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Cr25.2Al19.5Si4.7N50.5 thin films were deposited on steel substrates by cathodic arc plasma deposition. They consisted of alternating fcc-Cr(Al)N/hcp-Al(Cr,Si)N nanolayers. They were corroded at 900 and 1000 oC for 5-100 h in N2/0.1%H2S gas atmosphere. Their corrosion mechanism, the structure of the formed scales, and the role of film-constituting elements during corrosion were studied. Despite the presence of hydrogen and sulfur in the corrosion gas, the films displayed good corrosion resistance because Cr, Al, Fe preferentially reacted with impurity oxygen in the corrosion gas to form Cr2O3, Fe3O4, and amorphous Al2O3 owing to the thermodynamic stability of these oxides. The films were corroded by the outward diffusion of Cr, Al, Fe and nitrogen as well as the inward transport of sulfur and then oxygen. Silicon in the film was primarily oxidized by the inwardly transported oxygen. This study aimed to investigate the high-temperature corrosion behavior of nano-multilayered Cr25.2Al19.5Si4.7N50.5 thin films in a serious H2S-containing environment. |
| Keywords:
CrAlSiN thin film, H2S corrosion, oxidation, sulfidation |
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