Laboratory measurement of currenft density and calcareous deposit during sacrificial protection of steel in tropical sea water

Abstract

Cathodic protection of steel in tropical sea water was studied under laboratory condition. In order to measure in the laboratory the effects each of four factors (anode type, carbon content of steel, temperature, and agitation) and all the interactions among these four factors for a two level (Zn/Al for anode type, 0.06%/0.43% for carbon content of steel, 20° C/32° C for temperature, and no/yes for agitation) factorial experiment, the Taguchi L16 (24) array was used. The two responses measured were current density (mA/m2) and weight of calcareous deposit (mg/dm2). Current density is significantly influenced by (in decreasing order) anode type, sea water temperature and steel type (carbon content). Weight of calcareous deposit is significantly influenced by (in decreasing order) anode type, sea water temperature, steel type and agitation. The relationship between current density and weight of calcareous deposit is found to be: Current Density (mA/m2) = 64.9 + 0.326 × Weight of calcareous deposit (mg/dm2).