Marcel Pourbaix (16 September 1904 – 28 September 1998) was a Belgian chemist and pianist. He performed his most well known research at the University of Brussels, studying corrosion. His biggest achievement is the derivation of potential-pH, better known as “Pourbaix Diagrams”. Pourbaix Diagrams are thermodynamic charts constructed using the Nernst equation and visualize the relationship between possible phases of a system, bounded by lines representing the reactions that transport between them. They can be read much like a phase diagram. In 1963, Pourbaix produced "Atlas of Electrochemical Equilibria", which contains potential-pH diagrams for all elements known at the time. Pourbaix and his collaborators began preparing the work in the early 1950s. Early life He was born in Myshega (Aleksin District, Tula Governorate, Russian Empire), where his father was a consultant on an engineering project. He studied in Brussels and graduated from the Faculty of Applied Sciences of the Université Libre de Bruxelles in 1927. By 1938, he had devised the potential-pH diagrams. In 1939, just before the outbreak of World War II, he presented to the Faculty his doctoral dissertation, accompanied by a thesis entitled "Thermodynamics of Dilute Aqueous Solutions. Graphical Representation of the Role of pH and Potential." The war and some confusion among the jury on the sign of electrode potential impeded the completion of his graduation process. However, the thesis was presented to the Technical University Delft. Career During the fifties and early sixties, Marcel Pourbaix and his collaborators produced potential-pH diagrams for all the elements and published the "Atlas of Electrochemical Equilibria" in French in 1963 and in English in 1966. As early as in 1962, he introduced the concept of a protection potential against the propagation of localized corrosion, which he developed in 1963, in relation with the peculiar electrochemical conditions in occluded electrochemical cells. Pourbaix' doctoral thesis had a major influence on corrosion science. Ulick R. Evans found this work important and arranged for an English translation, published by Arnold (London) in 1949. In 1949, he was one of the founders of CITCE (Comite International de Thermodynamique et Cinetique Electrochimiques) together with 13 other electrochemists: C.Boute, J.Gillis, A. Julliard (Belgium), P. Delahay, P.Van Rysselberghe (USA), J.O'M.Bockris, T.P.Hoar (UK), G.Charlot, G.Valensi (France), R.Piontelli (Italy), G.Burgers (The Netherlands) and J.Heyrovsky (Czechoslovakia). CITCE was a success. In 1971 the name was changed to International Society of Electrochemistry (ISE). The current membership is over 1100 with members