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Title
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Comparison of anti-corrosive properties between hot alkaline nitrate blackening and hydrothermal blackening routes
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Type
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JournalPaper
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Keywords
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Carbon steel Hydrothermal treatment Hot alkaline nitrate treatment Corrosion EIS SEM
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Abstract
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In this study, the oxide films were formed on carbon steel by using hot alkaline nitrate and hydrothermal treatments. A dense and protective oxide film was obtained by hydrothermal method due to application of high pressure and by increasing solution temperature from boiling temperature (155 C) to 250 C. Oxide films were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and electrochemical tests including potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). These analyses showed that the magnetite film which was formed on carbon steel surface by hydrothermal treatment offers the best resistance in 3.5 wt.% NaCl solution. Although thicker oxide film could be obtained via hot alkaline nitrate black oxidizing, corrosion resistance was lower as a result of being highly porous and the presence of hematite.
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Researchers
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(Second Researcher), Arash Fattah-alhosseini (First Researcher), Akbar Heydarpour (Third Researcher)
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