Cathodic protection has been studied as a method for protecting iron objects during cleaning in
acid solutions. The effect of the type of acid, potential and distance between the anode and cathode
were investigated. Iron sheets, polished and corroded, were immersed in 0.5 M citric, sulphuric, or
ortho-phosphoric acid baths while cathodic protection was used. Applying a potential of -650 mV and
-850 mV Ag/AgCl to the immersed samples successfully protected them. Some of the samples were
only slightly etched and this was related to surface size of the anode. Both the geometry and distance
between anode and cathode have a large influence on the cleaning and etching of the original surface.
Unprotected iron sheets were strongly etched by the acids after an immersion of three hours. Cathodic
protection thus appears to be a good technique for protecting iron objects during acid cleaning. 0.5 M
ortho-phosphoric acid baths was considered to be the best electrolyte for practical considerations.
However, further research is needed before this treatment can be safely carried out on objects.