Property Relationship with In-Flight Particle Velocity and Temperature of Cermet Coatings

WC and Cr₃C₂ based coatings by HVOF spraying are widely used for wear and corrosion protection and regarded as one of the promising potential alternatives for the replacement of hard Cr plating. For the improvement of the properties of cermet coatings by HVOF, other advanced processes such as HVAF, cold spray, and warm spray have been studied. Primary purpose of these processes is reducing the flame temperature to avoid the detrimental effects of carbide decarburization. However, these processes would increase the process cost by decreasing the deposition efficiency of the coatings as well as by using special feedstock powders. In terms of feedstock powders, bimodal (nano and micro hybrid) carbides as well as nano carbides have been also investigated. In this presentation, corrosion and wear properties of various powders and spray processes, and the economic point of spray processes are compared with hard Cr plating for the replacement of Cr plating. It is also presented the results of flying particle velocity and temperature trying to correlate the coating properties and flying particle characteristics.