Design of a separation device used in detonation gun spraying system and its effects on the performance of WC–Co coatings

During the detonation gun (D-gun) spraying process, the detonation products showed an undesirable dispersion when they were spurted out from the nozzle of the barrel at high velocity and pressure. To resolve this problem, a separation device was designed and constructed in the detonation gun spraying system. The WC–Co coatings were synthesized by the D-gun spraying system with and without using a separation device, respectively. The results showed that the use of the separation device resulted in better properties of the D-gun sprayed WC–Co coatings, e.g., lower the surface roughness, lower the porosity, higher the microhardness, higher the elastic modulus, and higher the interfacial adhesive strength. Also, the tribological performance of the WC–Co coatings was improved. The relationship of surface roughness, microhardness, elastic modulus, adhesive strength, and wear resistance of the WC–Co coatings with porosity was discussed. At the same time, there is an inevitable disadvantage for using the separation device, i.e., the relatively lower effective utility rate of the feedstock powder. Therefore, the separation device is suitable to be applied in occasions of high-performance requirements where increased costs are acceptable.