Influence of Surface Condition and Preheating Treatments on the Deposition Characteristics of Cold-Sprayed IN718 Alloy

This study examines the influence of surface condition and preheating treatment on the deposition thickness and uniformity of cold-sprayed Inconel 718 alloy. Three distinct surface finishes were applied to the Inconel 718 substrates: grinding with 60 and 600 SiC grit emery paper, and polishing. Subsequently, some of the substrates were subjected to preheating at 1040 °C for 2 hours to promote improved interfacial bonding between the substrate and the initial layer of deposited particles. The results revealed that the preheated Inconel 718 substrate ground with 600 SiC emery paper exhibited a uniform deposition, attaining a maximum thickness of approximately 70 μm. Conversely, interface delamination and crack formation were found in all surface conditions of the non-preheated substrates. However, powder particle detachment was observed in both preheated and non-preheated substrates, which was consistent with the surface morphologies. To enhance interparticle bonding and promote increased deposition thickness, the Inconel 718 powder was preheated at 200 °C for 24 hours. This treatment resulted in a deposition thickness of approximately 160 μm, which can be ascribed to the improved deformability of the powder particles induced by thermal softening mechanism.