Consideration of the criteria for successful deposition in cermet kinetic spraying using WC-17Co powder

Abstract

There have been several studies related to the cermet kinetic spraying, despite its difficulty of proper deposition. However, there is no specific deposition criteria for kinetic spraying of cermet due to the unclearness of deposition mechanism in cermet kinetic spraying. Thus, in this study, the criteria of the successful cermet kinetic spraying was considered using commercial WC-17Co powder by correlating the numerical and experimental results on the basis of the reported phenomena in other previous studies. Especially, in terms of numerical analysis, newly established impact model was applied to deduce thermomechanical response of the supersonic impacted WC-17Co particle. Firstly, alteration in the deposition behavior of WC-17Co powder according to the change of impact velocity was investigated and classified from the results of single particle impact tests. Afterward, by correlating the numerical and experimental results, the deposition criteria of cermet kinetic spraying was considered. As a result, two criteria were derived: high particle impact velocity i) enough to cause a plastic deformation of metallic matrix of WC-17Co particles to such an extent that temperature rise to melting point occurred around the interface region, ii) but not enough to make elastic recovery energy overly dominant than plastic deformation energy. When the practical kinetic spraying of WC-17Co powder was conducted after the choice of process condition compatible to such criteria, it was confirmed that the two deposition criteria mentioned above was fairly effective, although expected conditions were not the most optimized.