Improving the flowability of fine WC-12Co powder using atmospheric pressure nitrogen microwave plasma torch treatment

WC-Co powders are mainly used in thermal spray coatings, which improve corrosion and wear resistance as well as the regeneration capacity of damaged components. The use of fine powders in the thermal spray coating process is essential to form a dense coating layer. However, fine powders possess poor flowability due to their morphology and van der Waals forces between particles. These characteristics limit their application in thermal spray coatings. In this study, a nitrogen microwave plasma torch was applied to WC-12Co powder (D50 = 20 mu m) to improve the flowability of the powder. The rough surface of the particle was melted and changed to a smooth, spherical surface. As a result, the flowability of the plasma-treated powder improved significantly from 0 to 4.02 g/s. Thus, a microwave plasma torch improves the flowability of fine WC-12Co powders and is suitable for continuous treatment and mass production of plasma spray powders.