Development of Supersonic Free-Jet PVD with Fluidic Mixer

点击翻译按钮获取中文摘要

Recently, requirements for structural materials become increasingly severe. A coating process is one of the most promising methods to achieve the requirements. However, conventional coating processes generally have following major technical problems. We develop Supersonic Free-Jet PVD (SFJ-PVD) as a new coating process to solve the problems. The SFJ-PVD is a technique to deposit nanoparticles with supersonic gas flow and to form a thick coating film without a crack or a void. This method is composed of "gas evaporation" and "vacuum deposition". In a gas evaporation chamber, a source material is evaporated to form nanoparticles in an inert gas atmosphere. The nanoparticles are then carried to a substrate in a deposition chamber with an inert gas flow through a transfer pipe. The gas flow is generated by the pressure difference between the chambers and accelerated to supersonic velocity by a specially designed supersonic nozzle joined to the tip of the transfer pipe. In the vacuum deposition chamber, the nanoparticles are deposited onto the substrate. The velocity of the gas flow is one of the most important parameters in the SFJ-PVD. In order to increase gas velocity, we designed one-dimensional nozzles and a two-dimensional nozzle. We evaluate the effects of the nozzles on the properties of metal coating films with the SFJ-PVD.