Effect of processing parameters on the microstructure and properties of WC–10Co–4Cr coatings formed by a new multi-chamber gas-dynamic accelerator

Due to its superior sliding, erosive and abrasive wear properties WC–Co–Cr coatings are used in the coating industry. A series of WC–10Co–4Cr coatings (80–375 μm thick) have been prepared on a corrosion-resistant steel substrate with a new multi-chamber gas-dynamic accelerator (MCDS) with different powder feed rates (1200, 1500 and 2000, all in g/h). The influence of the powder feed rate on structural characteristics, hardness and wear resistance of the coatings was characterized. The microstructures and properties of the WC–10Co–4Cr coatings were examined with the use of optical microscopy, scanning electron microscopy, X-ray phase analysis, and a Vicker׳s hardness tester at a test load of 300 g. The wear behavior was carried out by the ball-on-disk tests. From the results, it was observed that the powder feed rate has influence on coating porosity, hardness and wear resistance. Porosity and wear resistance decreased with decreasing powder feed rate. It was found that a powder feed rate of 1200 g/h yielded minimum porosity of less than 0.2% and minimum specific wear rate of 1.234∙10–6 mm3(m N)−1. With an increase in the powder feed rate the hardness of the coatings increases. It was found that the coatings obtained at powder feed rate of 2000 g/h showed high hardness 967±230 HV0.3.