Impact and Deposition of Single and Dual Metal Droplets on Solid Substrate

Abstract

Thermal spraying is a technique within the field of surface treatment processes. It involves the
ejection of molten or semi molten droplets onto a prepared substrate, where the droplets deposit
successively to produce splats. The accumulation of these splats subsequently forms the coating.
Achieving desired coating properties required comprehensive understanding of droplets impact and
deposition. Metal droplets deposition on solid surfaces is complex process that combines heat transfer,
fluid dynamics and solidification. In order to simulate the dynamics of spreading, deformation and
solidification of droplets during the formation of metallic lamella, we developed two-dimensional model
in Ansys code. The simulation is conducted by using the volume of fluid method to track the free surface
of the impinging droplets. The current study investigates both normal and oblique impact of single and
dual aluminum droplets with a diameter of 3.92 mm and an impact velocity of 3 m/s on stainless-steel
substrate. The model predicts the morphology of the resulting splat, it was found that the behavior of the
dual droplets shows a pattern similar to that of single droplet only with a higher rite of spreading. The
simulation results have shown an asymmetric spreading in the oblique impact. Furthermore, the
spreading rate of dual droplets is higher than of single droplet in both normal and oblique impact.