Polymer coating by cold spray presents interesting features such as the possibility of protecting metallic substrates or adding functionalities to a structure. However, it is characterized by a low deposition efficiency and a weak interface between the substrate and the coating. In this study, we performed fluoropolymer coatings by the cold-spray process. Analysis of the particle deposition during cold spray highlighted the importance of the particle size, substrate temperature and inlet gas temperature and pressure on the adhesion polymer/substrate. The addition of hydrophobized fumed nano-ceramics (FNC) to the polymer feedstock enhances the deposition efficiency and polymer adhesion on the substrate. The addition of fumed nano-alumina (FNA) to the polymer feedstock tends to give better results than fumed nano-silica in terms of deposition efficiency thanks to (1) the difference in surface charge leading to the attractive force between the polymer and the FNA during the powder preparation stage and (2) a homogeneous repartition of the FNA on the polymer particle surface. In addition, the hydrophobization of the FNC maintains and enhances the hydrophobicity and water repellency properties of the fluoropolymer coating.

中文翻译：

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冷喷涂含氟聚合物涂料的沉积机理分析及其润湿性评价

冷喷涂聚合物涂层具有有趣的特性，例如可以保护金属基材或为结构增加功能。然而，它的特点是沉积效率低，基材和涂层之间的界面较弱。在这项研究中，我们通过冷喷涂工艺进行了含氟聚合物涂层。冷喷涂过程中颗粒沉积的分析强调了颗粒尺寸、基材温度和入口气体温度以及粘附聚合物/基材上的压力的重要性。向聚合物原料中添加疏水化气相纳米陶瓷 (FNC) 可提高沉积效率和聚合物在基材上的附着力。由于 (1) 表面电荷的差异导致聚合物和 FNA 之间的吸引力，将气相纳米氧化铝 (FNA) 添加到聚合物原料中往往会在沉积效率方面提供比气相纳米二氧化硅更好的结果在粉末制备阶段和 (2) FNA 在聚合物颗粒表面上的均匀重新分配。此外，FNC 的疏水化保持并增强了含氟聚合物涂层的疏水性和防水性。