Application of Supersonic Free-Jet PVD applied to Nano-structure Coating

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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 through a specially designed supersonic nozzle at the supersonic flow of 4.2 Mach, number. With SFJ-PVD, We produce metal films and ceramic films that have smooth, compact and defect-free microstructure both in the film and at the interface between the substrate and the film and excellent adhesive strength to the substrate.