The synergism of electrochemical and mechanical factors in materials degradation
One of the big challenges that materials scientists and engineers have to face is to deal with materials degradation and the possible structure failures which cause serious concerns on safety and efficiency of industrial operations. For example, in heavy oil wells, carbon steel liner pipe often suffers from severe corrosion due to the corrosive environment with solid particles and bitumen.
This presentation provides an overview of our work on erosion corrosion behaviors of metals. A theoretical model that is able to quantitatively evaluate the synergism of electrochemical and mechanical factors in erosion-corrosion was developed based on non-equilibrium thermodynamics, electrochemistry and dislocation kinetics of erosion-corrosion of carbon steels in flowing slurry. The effects of hydrodynamics of flowing slurry on anodic dissolution rates of metals were theoretically and experimentally evaluated. The experimental results show that the material loss rate due to corrosion-enhanced erosion increases linearly with the logarithm of anodic current density, as predicted by the theoretical model. The in-situ nanoindentation shows that the presence of anodic current on surface results in the surface softening caused by an increase in the dislocation mobility in the surface layer. Both theoretical analysis and experimental evaluation show that corrosion-induced surface softening is a linear function of logarithm of current density, and the correlation of relative hardness degradation vs. anodic current density is almost independent of the polarization behavior of the materials. Finally, coatings resistant to corrosion and fouling will be introduced.
Dr. Jing-Li Luo is a professor in the Department of Chemical and Materials Engineering at the University of Alberta, Canada. Dr. Luo received her B. Eng. Degree from the Department of Physics and Chemistry of Metals, University of Science and Technology Beijing in 1982 and her Ph.D in Materials Science and Engineering at McMaster University, Canada in 1992 under the supervision of Professor Brian Ives. She joined the University of Alberta in 1995 after winning the Women’s Faculty Award funded by Natural Sciences & Engineering Research Council of Canada. Dr. Luo has conducted extensive research on corrosion control and the development of green energy systems and has published over 280 papers in refereed journals and holds five US patents. She co-edited three proceedings of the national and international symposiums and contributed one book chapter. Dr. Luo is elected as a Follow of Canadian Academy of Engineering in 2016 and is the recipient of a number of awards including Canadian Research Chair in Alternative Fuel Cells (2004-2015); Canadian Metal Chemistry Award in 2014; McCalla Professorship University of Alberta in 2003; and Morris Cohen Award in 2002. She has served as a member of International Corrosion Council since 2005.