The Influence of the Chemical Composition and of the Current Density on the F-Si Anodes Specific Consumption Cathodic Protection

摘要

Fourteen Fe-Si anodes containing 0,22 to 18,4wt/o silicon, having a ferrite structure with a minimum of 5% nodular and dot-shaped graphite, were tested as per "Short term test" - Det norske Veritas - standard. The effects of six-month anode exposure to 25g/L Na_2SO_4 electrolyte and 5, 20, 40, 60 and 80A/m~2 current density were analysed. The experimental results prove that at the usual current density of 20A/m~2, the minimum specifie anodie consumption is recorded for 14,44/18,4wt/o silicon content, being of 0,2/0,4kg/A.yr. But a little less silicon content gives a severe increase of the anodic consumption and at about 10wt/o silicon the determined specific consumption is of the same order of magnitude with that of the carbon steel in the experimental conditions. The specific consumption has a signifieant increase for 80A/m~2, getting double.