Hydrophobic properties and chemical state analysis of wear resistant coating prepared by electrical discharge process

Abstract

Electrical discharge coating (EDC) process has been used to prepare a corrosion and wear resistant super-hydrophobic coating on the steel substrate. The coating process has been carried out by using three types of green compact tool electrodes (WS2/Cu, MoS2/Cu, and hBN/Cu). In these tool electrodes, powder mixing ratios (40:60, 50:50, 60:40) are varied, and their effect on coating characteristics (surface morphology, wettability, corrosion, and wear behaviour) has been studied. In this investigation, the morphology and chemical state of coating has been observed by using a scanning electron microscopy (SEM) and X-ray photoemission spectroscopy (XPS). SEM images of the applied coating show a porous and hierarchical structure. This hierarchical structure helps in raising the contact angle (CA) to 165.6° (super-hydrophobic state). The XPS analysis reveals that the deposition of solid lubricants takes place with their negligible disintegration into non-lubricating compounds. In addition, the prepared coating exhibits excellent resistance to wear and corrosion.