Concurrent photocatalytic degradation of organic contaminants and photocathodic protection of steel Ag–TiO2 composites

The final publication is available at Elsevier via https://dx.doi.org/10.1016/j.mtla.2018.08.033 © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/In this study, coupled titanium dioxide-silver composite and steel electrode pairs were investigated for their use in cathodic protection under illuminated and dark conditions to prevent corrosion and enhance contaminant degradation under photocatalysis. A series of photoelectrochemical tests were used to determine the properties of the photoanode and identify the cathodic protection behaviour in the presence and absence of organic/inorganic contaminants. Additionally, corrosion-prone steel was used to test the principle of photocathodic protection in reducing oxide formation and mass loss under base metal and welded materials.Natural Sciences and Engineering Research Council of Canada [STPG-494554-2016]Schwartz-Reisman Foundation through the Waterloo Institute of Nanotechnology − Technion University gran

On the Measurability and Predictability of HAZ Softening in GMAW of Automotive DP980 Steel

Dual Phase (DP) steel, composed of a ferrite matrix with dispersed islands of martensite, has become popular in auto-body car construction due to its outstanding mechanical properties (i.e., high strength and good ductility). DP steel softens at the sub-critical heat-affected zone (SC-HAZ) when subjected to welding thermal cycles, owing to the tempering of the martensite phase. In this work, DP980 steel was subjected to varied thermal cycles: (a) furnace-tempering treatment, (b) gas metal arc welding (GMAW), and (c) resistance spot welding (RSW), in order to characterize the tempering of martensite below the Ac1 critical temperature and at the sub-critical heat-affected zone (SC-HAZ) in the case of the welded specimens. The coarsening stage of cementite phase was characterized through microstructure observations and hardness measurements. As expected, the comparative results indicated an advanced stage of the martensite tempering in the furnace heat-treated specimens, followed by the GMAW and the RSW specimens. Further, developed softening kinetic models have been suitably employed and adjusted in order to predict the extent of softening along the SC-HAZ of the GMAW specimen. Finally, as the advanced stage of cementite coarsening is due to the influence of the arc welded thermal cycle, a reasonable estimation of the hardness profile was obtained, particularly for tempering temperatures above 400 °C