Less is more: Measure of chloride removal rate from wrought iron artifactsduring electrolysis

Electrolysis performs three useful functions for the conservator: it mechan ically cleans artifact surfaces, removes salt, and (theoretically reduces c orrosion products. Because each of these functions is fundamentally differe nt, they must be separated for study. Mechanical cleaning and the reduction of corrosion products during electrolysis are recognized as relatively min or effects; therefore, from the perspective of the archaeological conservat or, the most important function is chloride removal. The authors implemente d a study to discover what current density most efficiently promotes this f unction with respect to wrought-iron artifacts recovered from marine enviro nments. Complete data are presented for three experiments performed on arch aeological specimens in which current was controlled an the quantity of chl oride removed was measured. Over the course of four experiments, the lower current density of 50 muA.cm(-2) removed an average of 4.9 times more chlor ide (expressed in mg A(-1)) than a higher current density of 200A.cm(-2.)