Investigation on abrasion-corrosion properties of WC-based composite with fractal theory

Morphology analysis of a worn surface is one of the significant methods to study wear mechanism. To surmount the weakness of conventional surface characterization system and investigate the abrasion-corrosion properties of WC-based matrix, the fractal geometry combined with three-dimension cloud point has been adopted in this study. Tests were conducted in various saline slurry with a modified abrasion test rig capable of monitoring the in-situ electrochemical behavior. The microstructures and compositions of the worn surface were characterized by scanning electron microscopy (SEM) and Raman spectrometer respectively. Results indicate that the increased sodium chloride in the slurry can enhance the variation of the worn surface morphology, leading to a higher value of fractal dimension (FD). Specifically, a raise from 2.444 to 2.515 can be witnessed with the saline gradually increasing to saturation. Furthermore, the corrosion products on the worn surface were identified as a mixture of oxides and hydroxychloride, and the multi-oxide films were much more common. Interpretation for the change of FD combined with abrasion-corrosion mechanism has also been detailed in this paper.