Super Hard WC Cermet Coating by Low Pressure Cold Spray Based on Optimization of Powder Properties

摘要

From the appearance of HVOF thermal spray system in 1980s, WC cermet coatings have been used as an anti-wear coating in many industrial manufacturing. Recently, WC cermet spray materials have been applied using new thermal spray methods such as Warm Spray and Cold Spray for improvements of coating property, spray efficiency and so on. Low pressure Cold Spray is expected to be one of efficient spray processes. In this work, WC cermet coating was sprayed by low pressure cold spray to investigate the influence of powder compressive strength and metal binder on coating properties. Powder compressive strength was measured by a micro-compression tester that can test single particle. Cobalt and ferroalloy were used as metal binders for WC cermet powders. It was found that the compressive strength affected deposition efficiency and coating hardness. In addition, about 200MPa was optimum compressive strength value for low pressure cold spraying; the coating microstructure was dense and coating hardness was over 1500Hv.