Thursday, March 20, 2008 - 8:55 AM Convention Center, Second Level, R04 (Ernest N. Morial Convention Center) 08668
Effects of Slurry pH on the Surface Mechanical Properties and Erosion Corrosion Resistance
Baotong Lu, Univ of Alberta; Ke Wang and Jingli Luo, University of Alberta; Xuemei Wan, Department of Chemical and Materials Engineering
Effects of anodic dissolution in corrosive slurries with different chemical compositions and pHs on the in-situ surface mechanical properties and slurry erosion resistance of carbon steel were investigated. The experimental measurements indicate the existence of corrosion-enhanced erosion because the erosion is accelerated by the anodic current and it depends heavily on the slurry pH and chemistry. The in-situ nanoindentation shows that the presence of anodic current on surface reduced the surface hardness. When the anodic current density was held unchanged, both the corrosion-enhanced erosion in acidic slurries and the corrosion-induced surface hardness degradation in the acidic solutions were much more pronounced than those in neutral and alkaline slurries/solutions. In the neutral and alkaline media, the corrosion-enhanced erosion and the in-situ surface hardness degradation were hardly affected by the chemical composition of aqueous media but a remarkable impact of chemical composition was observed when corrosive media are acidic. The agreement in the high-to-low order of erosion rates in corrosive slurries and the corrosion-induced surface hardness degradation suggests that the corrosion-induced surface mechanical property degradation is an important mechanism of corrosion-enhanced erosion.