Topic: Improved corrosion resistance performance of aluminium alloys using trivalent chromium conversion coating with a post-treatment

Speaker: Prof. Philippe  Marcus

         Alexandre Romaine, Anca-Iulia Stoica, Francesco Di Franco, Sandrine Zanna,

         Antoine Seyeux, Jolanta  swiatowska

         CNRS - Chimie ParisTech - PSL University

         Institut de Recherche de Chimie Paris/ Physical Chemistry of Surfaces

         11 rue Pierre et Marie Curie, 75005 Paris, France

Time: 9:00-10:00, (Thu.) Nov.1, 2018

Venue: Room 403, Shi Changxu Building, IMR CAS

Welcome to attend !

Abstract:

This presentation will focus on the effect of a post-treatment containing lanthanum salt and hydrogen peroxide applied on TCP coatings deposited on aluminium alloy 2024. The coatings without and with post-treatment were studied by electrochemical and surface analytical techniques. The coating performance was evaluated by Electrochemical Impedance Spectroscopy (EIS) and Linear Sweep Voltammetry (LSV), showing the improved corrosion resistance of the post- treated TCP layers in chloride solution. The influence of post-treatment time on the cathodic inhibition of oxygen reduction was studied. Surface analysis by ToF-SIMS revealed the presence of Lanthanum mostly in the outer part of the TCP coating. The appearance of chromium (VI) at the extreme surface of the coating layer and at a very low concentration was evidenced by XPS.3D ToF-SIMS images allowed us to observe a homogeneous deposition of lanthanum on the surface of the TCP layer even if the formation of TCP (deposition of Cr and Zr compounds) appears to be modified over copper-rich intermetallic particles with reference to Al matrix. Reduced susceptibility to cracking of the TCP conversion layer after post-treatment was observed, and assigned to lanthanum sealing of pores and defects.

Short Curriculum Vitae

Pr. Philippe Marcus is Director of Research at CNRS (Centre National de la Recherche Scientifique) and Head of the Research Group of Physical Chemistry of Surfaces of Institut de Recherche de Chimie Paris, Ecole Nationale Supérieure de Chimie de Paris, Chimie ParisTech, France. Dr Marcus received his Ph. D. (1979) in Physical Sciences from University Pierre and Marie Curie, Paris, France.

Pr. Marcus has published over 450 papers in scientific journals, books and conference proceedings in the areas of surface chemistry and electrochemistry, surface analysis, corrosion science, and materials science, plus three books “Corrosion Mechanisms in Theory and Practice”, “Analytical Methods in Corrosion Science and Engineering”, and “Molecular Modeling of Corrosion Processes”. His h-index is 67, and number of citations15405 (source: Google Scholar, September 2018). He has given over 120 invited lectures at International Conferences. He serves or served on the editorial board of five major journals in Electrochemistry and Corrosion: Electrochimica Acta, Corrosion Science, Materials and Corrosion, Corrosion Engineering, Science, and Technology, and Corrosion Reviews. Pr. Marcus has received a number of awards and honors, including the 2005 Uhlig Award from the Electrochemical Society, the 2008 Whitney Award from NACE International, the Cavallaro Medal of the European Federation of Corrosion in 2008, the U.R. Evans Award of the UK Institute of Corrosion in 2010, the Lee Hsun Award of the Institute of Metals Research of the Chinese Academy of Sciences in 2012.

Pr. Marcus was President of the European Federation of Corrosion from 2008 to 2012. He was Chair of the Electrochemical Materials Science Division of the International Society of Electrochemistry. He is currently Chair of the EFC Working Party on Surface Science and Mechanisms of Corrosion and Protection, Chair of the International Steering Committee for the European Conferences on Applications of Surface and Interface Analysis, Head of the Paris Office of the European Federation of Corrosion, and President of the French Corrosion Society (CEFRACOR).