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Corrosion-Electrochemical Behavior of 13% Chromium (Cr) Martensitic Stainless Steel in Hydrochloric Acid (HCl) Solutions1 N. Chermat-Aourassea and R. Kesrib
a Research and Development Center of Sonatrach, Avenue du 1ér novembre 35 000 Boumerdés-Algeria b Laboratory of Electrochemical Corrosion, Structural Metallurgical and Mineral Chemistry; Chemical Institute-University
of Science and Technology Houari Boumedienne (USTHB)—Algiers e-mail:
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Received February 3, 2006 Abstract — Corrosion-Electrochemical behavior of a commercial API5CT grade L80 type 13Cr tubing enriched with microalloying elements is studied in 6, 7.5, 9, 12 and 15% HCl solutions by electrochemical methods. The objective is to contribute to the comprehension of corrosion phenomena caused by HCl of similar concentrations, generally used in acidizing job. The corrosion morphology is examined by scanning electron microscopy (SEM) coupled with EDAX. The soluble corrosion products are analyzed by atomic absorption spectroscopy and colorimetric methods. General, as well as localized, corrosion is present. The severest general corrosion with a maximum rate of 26 mm/year is obtained at 15% HCl. The localized corrosion which morphologically differs as function of HCl concentrations is revealed by SEM investigation. In all the above HCl solutions, the commercial 13% Cr martensitic stainless steel tubing shows no passive state. Above 6% HCl, the microalloying elements promote forming a discontinuous film of the corrosion products. The corrosion rate slightly decreases in 15% HCl compared to the published data on a conventional 13% Cr martensitic stainless steel tubing. This is due to both the chemical composition (silicon, manganese and vanadium) and microstructural properties. Copper seems to additionally accelerate the corrosion of the alloy. Key: words: 13% Cr, martensitic stainless steel, polarization, hydrochloric acid, corrosion resistance, pitting. PACS numbers: 82.45.Bb DOI: 10.1134/S0033173207040054
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