The critical role of liquid surface tension in determining cavitation erosion and dry wear performance of WC-17Co coatings produced by cold spray technology

Hard coatings, especially WC-Co, have been used for wear-resistant applications, and parts or components exposed to cavitation, dry erosion, and abrasion have been coated by thermally sprayed WC-Co coatings. High-velocity oxy-fuel (HVOF) and atmospheric plasma spraying (APS) are the most mature deposition techniques; however, this work evaluates cold spray (CS) to deposit a nanosized WC-17Co powder. Due to its principles, CS prevents degradation of the WC grains when exposed to high temperatures during the deposition by HVOF or APS, producing a hard and dense coating with unaltered WC grains. This study evaluates the performance of CS WC-17Co coatings under erosion by solid particles and abrasion by third body testing, as well as sliding wear behavior. For water-flow exposed surfaces, e.g., piping or hydro turbines, measuring the cavitation and water jet erosion is essential, and minimizing the cavitation phenomena has been a challenge for scholars and design teams. This work presents the effect of different water characteristics (surface tension) on the CS WC-17Co coatings performance. It is noted that reducing this liquid property improves the coating life. Comprehensive characterization of the coatings included scanning electron microscopy, light microscopy, microhardness, porosity, phase structure analysis via X-ray diffraction, and energy dispersive spectroscopy. • Surface tension variations influence cavitation erosion of Cold Spray WC-17Co coatings. • Cold Spray WC-17Co coatings show excellent wear performance in dry conditions. • Ethanol solutions reduce surface tension, improving cavitation erosion resistance of WC-17Co coatings.