Shock Absorption Effect on Particle Fragmentation and Microstructural Features of Vacuum-Kinetic-Sprayed Al2O3 Film on Polycarbonate Substrate

Abstract

As the demand for flexible devices has increased, polymers have become very promising materials for these applications because they have excellent flexibility, lightweight, and low cost. Vacuum kinetic spraying can be a good alternative technology for film fabrication on polymers as dense ceramic films can be fabricated even at room temperature without thermal degradation of the polymer substrate. However, there is a lack of understanding of the deposition process of ceramic films on a polymer substrate. In this regard, the deposition behavior and microstructural features were investigated by comparing Al2O3 particle deposition on glass and polycarbonate (PC) substrates by using simulations and experimental methods. Simulations demonstrated that hard particles were prone to penetrate or be only embedded in the soft substrate without sufficient fragmentation. This is attributed to the shock absorption effect of the substrate. Particle kinetic energy was transferred mostly to the internal energy of the soft substrate but not to particle internal energy (plasticity and/or failure), which prevents particle fragmentation. Consequently, unusual interface microstructural feature was attributed to insufficient particle fragmentation by the shock absorption of the soft substrate.