Utilizing the autocatalysis of Co to prepare low‐cost WC‐Co powder for high‐performance atmospheric plasma spraying

Abstract

A novel method of incorporating fluidized bed chemical vapor deposition (FBCVD) with electroless plating was developed to effectively prepare the core-shell structured WC-Co composite powders. The Co nanoparticles decorated on the surface of WC particles by FBCVD acted as active catalysts for the subsequent electroless plating process. The particle size and quantity of the decorated Co particles determined the electroless plating rate but the particle size played more important role. For the conditions tested, the maximum electroless plating rate of 2.34 mg/g/min was obtained by using an optimal FBCVD pretreatment at 750°C for 3 minutes. WC-12Co composite powders with a commercial composition widely used for atmospheric plasma spraying (APS) were efficiently prepared. The composite powders exhibited excellent suitability for APS by forming a homogenous CoW -C ternary liquid stream. The APS coating is not only well-bonded with the substrate but also consisted of hard nonequilibrium Co 3 W 3 C and W 2 C phases with a uniform distribution. Both remarkably improved the hardness and tribological properties of the APS coating.

Microscopic Characteristics and Properties of Fe-Based Amorphous Alloy Compound Reinforced WC-Co-Based Coating via Plasma Spray Welding

“…The WC coating compounded with Co element has a high hardness value in a certain temperature range. At the same time, its impact resistance and toughness are very good, and the porosity of the coating is low, and it is combined with the substrate's high strength [3,30,31]. The influence and mechanism of the added Fe-based amorphous powder amount on the microstructure and properties of the spray welding layer are discussed.…”