An Initial Investigation of Calcareous Deposits Upon Cathodic Steel Surfaces in Sea Water

The influence of potential and nominal sea water velocity upon the nature of calcareous deposits formed upon a cathodic steel surface has been investigated. Specific attention was focused upon change with exposure time of the current density to maintain a prescribed cathodic potential and upon thickness of the calcareous film. Equations have been developed whereby pH of the electrolyte adjacent to both a filmed and film-free surface can be rationalized in terms of cathodic current density and character of the electrolyte flow. Structure of calcareous deposits was investigated by scanning electron microscopy. Results are discussed within the frame of current understanding of marine cathodic protection and cathodic protection practices.