Deposition Behavior of α-Al2O3 upon Impact: Large Scale Atomistic Study of Aerosol Deposition

Aerosol Deposition (AD) is a coating method which allows to produce dense ceramic films on a wide range of metallic and ceramic substrates. In this process, ceramic particles are accelerated towards the substrate using a relatively low-temperature supersonic gas flow, which maintaining them below the melting point prior to their impact. Therefore, the AD process is unique due to its ability to deposit brittle ceramic particles in the solid-state. In situ investigation of this process is challenging. Hence, numerical methods have been used as the best alternative to investigate this process and enhance the understanding of the process physics.

In this study, Molecular Dynamics (MD) method were performed to predict and provide detailed understanding of the deformation and deposition behavior of solid α-Al₂O₃ particles accelerated against an α-Al₂O₃ substrate. Single-crystal particles with 0.2 µm diameter were modeled. The results showed that the deformation behavior of particles is strongly dependent on their initial microstructure. The role of impact velocity and crystal orientation on the particle’s deposition was demonstrated. Moreover, despite the fact that dislocation movements are very limited in α-Al₂O₃, MD allowed us to capture the significant role of plastic deformation in the fracture and/or deposition of this material in AD.