REAL-TIME MONITORING OF LOCALIZED AND GENERAL CORROSION RATES IN DRINKING WATER SYSTEMS UTILIZING COUPLED MULTIELECTRODE ARRAY SENSORS

摘要

Real-time monitoring for localized and general corrosion rates of carbon steel, brass, and stainless steel materials was conducted in low-conductivity waters utilizing coupled multielectrode sensors at ambient temperature. It was demonstrated that the coupled multielectrode sensors are effective real-time tools for monitoring the localized and general corrosion rates in air-saturated waters. The steady-state maximum localized corrosion rates measured in the air-saturated natural spring water were found to be approximately 1 μm/yr (0.04 mil/yr) and 0.03 μm/yr (0.0012 mil/yr) for Type 260 brass and Type 316L stainless steel, respectively. The steady-state maximum pitting corrosion rate for the Type 1008 carbon steel was found to be approximately 1 mm/yr (40 mil/yr). Localized corrosion penetration depth factors, which are defined as the ratios of the cumulative maximum localized penetration depth to the cumulative general corrosion depth, were found to be approximately 11 for the brass, 4 for the carbon steel, and 2 for the stainless steel after two hours of immersion in the natural spring water. It was also demonstrated that the coupled multielectrode sensors were proficient tools for the measurement of the effectiveness of cathodic protection in the water system.