Dipartimento di Chimica, Materiali e Ingegneria Chimica OG. Natta,O Politecnico di Milano,20131 Milano, ItalyManganese-copper alloys were pulse plated from a sulfate solution with the addition of ammonium sulfate at pH 6.7. Anelectrochemical investigation of the MnÐCu electrodeposition system was conducted by potentiodynamic methods. The effect ofpulse-plating on cathodic efÞciency , m icrostructure, and crystallography of the deposits was analyzed and compared with theresults from continuous plating. Pulse plated coatings with short off-time w ere characterized by an uniform and homogeneousmorphology , suitable mechanical properties, and low copper content !! 5 w t % ".T he codeposition of copper prevented the phasetransformation of as-deposited ductile " -M n to the brittle and hard # -M n. All the coatings exhibited a good sacriÞcial protectionfor steel in sulfate and chloride media.© 2006 The Electrochemical Society . !DOI: 10.1 149/1.2216431 " All rights reserved.Manuscript submitted January 27, 2006; revised manuscript received April 28, 2006. A vailable electronically July 11, 2006.