Corrosion Rate Monitoring of Cu Alloy Tubing in Flowing NaCl Solution by Linear Polarisation Resistance (LPR) Technique

Abstract

Corrosion rate (CR) measurements with commercial instrumentation working on the 3-electrode linear polarisation (LPR) method, were made on copper alloys for condenser tubes (Al-Brass, Al-Bronze, Cu–Ni 90–10) in aerated NaCl solution at 50°c, flowing at 2 ms⁻¹. Good agreement was obtained between CR obtained by the LPR technique and by weight loss measured on the same replaceable electrodes. The validity of the calibration adopted is thus established provided that the corrosion reaction of Cu in the alloys is assumed to involve the transfer of 1 electron (Cu → Cu⁺ + e⁻) in Al-Brass and 2 electrons (Cu → Cu²⁺ + 2e⁻) in the nobler Al-Bronze and Cu–Ni 90–10 alloys.