Plasma spray – physical vapor deposition (PS-PVD) is a low pressure plasma spray technology to deposit coatings out of the vapor phase. PS-PVD is part of the family of new hybrid processes recently developed by Sulzer Metco AG (Switzerland) on the basis of the well established low pressure plasma spraying (LPPS) technology. Included in this new process family are plasma spray - chemical vapor deposition (PS-CVD) and plasma spray - thin film (PS-TF) processes. In comparison to conventional vacuum plasma spraying (VPS) and low pressure plasma spraying (LPPS), these new processes use a high energy plasma gun operated at a work pressure below 2 mbar. This leads to unconventional plasma jet characteristics which can be used to obtain specific and unique coatings. An important new feature of PS-PVD is the possibility to deposit a coating not only by melting the feed stock material which builds up a layer from liquid splats but also by vaporizing the injected material. Therefore, the PS-PVD process fills the gap between the conventional physical vapor deposition (PVD) technologies and standard thermal spray processes. The possibility to vaporize feedstock material and to produce layers out of the vapor phase results in new and unique coating microstructures. The properties of such coatings are superior to those of thermal spray and EB-PVD coatings. In contrast to EB-PVD, PS-PVD incorporates the vaporized coating material into a supersonic plasma plume. Due to the forced gas stream of the plasma jet, complex shaped parts like multi-airfoil turbine vanes can be coated homogeneously with columnar thermal barrier coatings using PS-PVD. This paper reports on the progress made by Sulzer Metco to develop a thermal spray process to produce coatings out of the vapor phase.

Low-pressure plasma spray thin film (LPPS-TF) is a recently developed vacuum plasma spray technology that makes it possible to deposit coatings not only by melting feedstock material, but also by vaporizing injected particles. This capability fills a gap between conventional vapor deposition and thermal spray processes. The vaporizing of coating material and formation of layers out of the vapor phase result in unique coating microstructures with superior properties. This paper reports on the progress made in the development of functional coatings built up from the vapor phase of metal and oxide ceramics.

With the new development of the LPPS Thin-Film technology (LPPS-TF), which is a special modification of conventional LPPS using reduced chamber pressures below 10 mbar, a new window has been opened to deposit uniform and dense thin layers onto large areas in short coating times. This spray process will allow the access to new market areas and will be able to bridge the gap between conventional thin film (< 1 - 10 µm) deposition using PVD/CVD processes and thick (> 50 - 200 µm) thermally sprayed layers. This paper presents the status of the LPPS-Thin Film technology as a hybrid coating process between thermal spray and vapor deposition and gives an overview of potential applications for functional thin coatings and large area coverage.

A pilot plant equipment for continuous coating of technical textiles is implemented to establish thermal spraying as a new and promising coating technique in the textile industry. In order to apply thermal spraying to temperature sensitive and flexible fiber structures two main difficulties have to be taken into account. First, the flexible structure of a textile fabric has to be fixed and stretched to achieve a sufficient mechanical support. Second, the kinetic and thermal energy of the molten particles and the hot gas jet may damage the fibers and their woven structure both mechanically and chemically. Special winding equipment is designed to allow various fabrics to be fixed and stretched in a way that enables the coating of wound fabrics from “coil to coil”. With this equipment even temperature sensitive fabrics, like cotton or polyester, but also aramide, carbon and oxide ceramic fabrics are coated by atmospheric plasma spraying or electric arc wire spraying in the case that higher deposition rates are required. Fabric coils up to a web width of 1500 mm can be coated continuously with a well-defined pre-stress in one single procedure.