Assessing the efficiency of galvanic cathodic protection inside domestic boilers by means of local probes

The efficiency of cathodic protection implemented through magnesium anodes has been investigated inside a 100 L domestic boiler, as a function of temperature (18-60 °C) and of water conductivity (50-500 μS/cm). Continuous monitoring of potentials and partial currents, corresponding to all metallic parts of the boiler and to six local probes, installed on the critical points of the tank, has been carried out. Cathodic protection is more efficient increasing water conductivity (500 μS/cm) and further low conductivities (50 μS/cm) tend to increase the probability of tank failure in a relatively short time, even in presence of magnesium anodes protection.