Abstract
Tribo-electrochemical behavior of a high chromium white cast iron (high-Cr WCI) used in, e.g., slurry pumps in mining and mineral processing applications, was investigated using a combination of electrochemical techniques, including zero resistance amperometry as well as potentiostatic and potentiodynamic polarisation. The effects of third body particles angularity on the localised tribocorrosion response of the cast alloy was studied during and post abrasion-corrosion by round ceramic beads and semi-angular silica sand particles. Advanced characterization methods such as electron backscatter diffraction and focused-ion beam cross-sectioning of affected areas were also employed to understand the wear and corrosion interactive actions. It was found that in chloride-free solutions, the behavior of high-Cr WCI resembled that of the austenitic 316 SS studied before. In contrast, in chloride-containing electrolytes, the semi-angular silica sand particles increased interfacial (carbide/matrix) localised corrosion susceptibility during and post-abrasion as indicated by the stark increase in anodic current and the morphology of the attack. Semi-angular silica sand abrasives had a greater adverse impact on post-abrasion interfacial corrosion vulnerability, compared to round ceramic beads. The complex behavior observed indicates that any material developed for tribocorrosive conditions must account for the particles angularity and their subsequent effects on localised corrosion.
Highlights
High chromium white cast irons are commonly used in applications where abrasion and corrosion concurrently occur; e.g. slurry pumps in mining and mineral processing applications.[1]
Chemical composition.—Table I provides the elemental analysis of 13Cr stainless steel and the matrix of the high-Cr WCI used in this study, measured by quantitative energy dispersive spectroscopy (EDS)
Based on the findings presented above the following conclusions were drawn:
Summary
High chromium white cast irons (high-Cr WCI) are commonly used in applications where abrasion and corrosion concurrently occur; e.g. slurry pumps in mining and mineral processing applications.[1]. In most cases for a single-phase passivating material (e.g., austenitic stainless steels), tribo-electrochemical methods such as open circuit potential (OCP) measurements,[14] potentiodynamic[15] and potentiostatic polarization,[16] and zero resistant amperometry (ZRA)[17] provide information on the interaction of abrasion and corrosion.[18] For example, revealing the effects of mechanical factors such as wear mechanisms, particles motion and angularity on disruption and repair of the passive film, and detecting possible localised corrosion post abrasion-corrosion process are a few benefits of these methods.[19]. In contrast to single-phase systems, for multiphase alloys such as high-Cr WCI, a combination of experimental methods is needed to account for the several tribocorrosion mechanisms that could be potentially occurring.[9,20] Interaction of the solid particles with the highCr WCIs multiphase microstructure and the non-uniformly distributed. Scanning electron microscopy (SEM) and focused ion beam (FIB) methods were, used to analyze the worn surfaces and to gain a better understanding of the subsurface deformation and localised dissolution
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
