Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : September 05, 2021 - September 08, 2021
The interest of polymer coating by cold spray process lies in the speed of the process, which requires less energy than the conventional manufacturing methods. However, the deposition efficiency and adhesion strength of polymer particles on a metallic substrate are usually very low. In our previous study, Ravi et al. (Ravi et al., Surface and Coatings Technology, 2019) cold sprayed Perfluoro alkoxy alkane (PFA) powder mixed with 5% of Fumed Nano-Alumina (FNA) on a metallic substrate. A super-hydrophobic fluoropolymer coating was manufactured with, however, low deposition efficiency. In this study, different methods were analyzed in an attempt to increase the deposition efficiency of the polymer feedstock on a metallic substrate. First, the substrate surface was laser-textured before spraying, increasing the deposition efficiency to 45%. Then, to further enhance the deposition efficiency, a metallic bond coat, consisting of Ti or Cu particles, was introduced as an intermediate layer between the substrate and the polymer coating. The deposition efficiency reached 81.4% while spraying the PFA-FNA feedstock on the Ti bond coat. Thus, the surface roughness plays a key role in the significant amelioration of the polymer particle deposition on a metallic substrate by promoting mechanical interlocking. Finally, by increasing the power output of the homogenizer used to mix PFA and FNA, 96% deposition efficiency was achieved. This new record shows that other factors, such as chemical interactions between PFA, FNA, and the metallic substrate, are also significant factors influencing the deposition of polymer powder.
