Influence of substrate hardness on deposition behavior of single porous WC 12Co particle in cold spraying
Abstract Deposition of a dense coating with solid particles by cold spraying requires sufficient deformation of impacting particles and previously deposited underlying particles. The cermet particles and subsequent coating with a high hardness are difficult to deform upon impact. To increase the ability of deformation, the cermet spray particles with a porous structure are used to fulfill the requirements of deformation on impact. To understand the deposition mechanism, the deposition behaviors of single WC Co spray particles impacting on the substrates with different hardness during cold spraying were examined using WC 12Co powders with different porosities. The substrates with different hardness including stainless steel, nickel based self fluxing alloy coatings were employed to examine the effect of substrate deformation on the cermet particle deposition. It was found that the WC Co cermet particles with the porosities of 30% and 44% could be deposited on the substrate of different hardness from 200 to 800 kgf/mm 2 The deposition of the particles is mainly attributed to the deformation of powders themselves. The properly designed porous cermet powder with certain hardness is necessary to deposit hard WC Co cermet coating.