Corrosion of carbon steel and alloys in concentrated ammonium chloride solutions

K. Toba*, M. Ueyama, K. Kawano, J. Sakai


    研究成果: Article査読

    27 被引用数 (Scopus)


    Corrosion resistance and the behavior of carbon steel and alloys in high concentration ammonium chloride (NH 4Cl) solutions were investigated. This study was conducted to better understand material performance in severe NH 4Cl corrosive environments in refineries. Immersion tests were performed under boiling 20 wt% and 40 wt% NH 4Cl solutions. Sixteen materials commonly used in refineries and two new alloys were examined, including carbon steel; aluminized carbon steel; aluminum brass; Types 405, 410, 304L, 316L, and 321 stainless steels (UNS S40500, S41000, S30403, S31603, and S32100); 300-series stainless steel with 6% Mo; two types of super duplex stainless steels; Alloys 800, 625, and C-276 (UNS N08800, N06625, and N10276); Grade 2 and Grade 19 titanium (UNS R50400 and R53530); Alloy A (equivalent to a modified Type 317L [UNS S31703] stainless steel); and a modified Alloy 825 (UNS N06845). Significant corrosion was observed in carbon steel in both solutions. The corrosion rates of carbon steel were as high as 25.4 mm/y and 60.4 mm/y in 20 wt% and 40 wt% NH 4Cl solutions, respectively. However, neither general corrosion nor pitting was observed on titanium alloys and alloys with a pitting resistant equivalent number (PREN) of 40 and higher. The maximum pit depth had a close relationship with the PREN. In addition, an electrochemical study was used to investigate the corrosion behavior of carbon steel. The effects of the temperature and NH 4Cl concentration were determined from polarization curves and the corrosion potential.

    出版ステータスPublished - 2012 11月

    ASJC Scopus subject areas

    • 材料科学(全般)
    • 化学工学(全般)
    • 化学 (全般)


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