Development of Supersonic Free-Jet PVD with Fluidic Mixer

近年来，对结构材料的要求日益苛刻。涂层工艺是实现这一要求的最有前景的方法之一。然而，传统的涂覆工艺通常存在以下主要技术问题。为了解决这一问题，我们发展了超音速自由喷射PVD(SFJ-PVD)作为一种新的涂层工艺。SFJ-PVD是一种在超音速气流中沉积纳米颗粒，并在没有裂缝或空洞的情况下形成厚涂层的技术。该方法由“气体蒸发”和“真空沉积”两部分组成。在气体蒸发室中，源材料在惰性气体气氛中蒸发形成纳米颗粒。然后，纳米颗粒被带到沉淀室中的衬底上，惰性气体通过传送管流动。气体流动是由腔室之间的压差产生的，并通过连接到传输管末端的特殊设计的超音速喷嘴加速到超音速。在真空镀膜室中，纳米颗粒被沉积到衬底上。气流速度是SFJ-PVD中最重要的参数之一。为了提高气速，设计了一维喷嘴和二维喷嘴。我们用SFJ-PVD研究了喷嘴对金属涂层性能的影响。

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.