INVESTIGATION OF CARBON SOURCE AND ATMOSPHERE DURING REDUCTION–CARBONIZATION PROCESS OF SYNTHESIZING WC–Co COMPOSITE POWDERS VIA SPRAY CONVERSION METHOD

Abstract

Ultrafine WC–Co composite powders are synthesized via spray conversion method. The effect of carbon source (organic carbon and carbon black) and atmosphere (H₂ and N₂) on the composite powders is investigated in terms of phase composition, particle size distribution, morphology, and carbon content, including the total carbon and free carbon using X-ray diffraction, particle size analyzer, scanning electron microscope, and infrared carbon and sulfur analyzer. The results show that using organic carbon or carbon black and H₂ or N₂ has its own advantages and disadvantages. Therefore, carbon source and the atmosphere can be chosen according to the application of the composite powders, i.e. cemented carbides and thermal spraying.