Process development and coating characteristics of plasma spray-PVD

Plasma spray physical vapor deposition (PS-PVD) was developed with the aim of depositing uniform and relatively thin coatings with large area coverage. At high power input (similar to 150 kW) and very low pressure (similar to 100 Pa) the plasma jet properties change considerably compared to conventional plasma spraying and it is even possible to evaporate the powder feedstock material enabling advanced microstructures of the deposits. This relatively new technique bridges the gap between conventional plasma spraying and physical vapor deposition (PVD). Moreover, the resulting microstructures are unique and can hardly be obtained by other processes. In this paper, plasma characteristics of different gas mixtures are investigated. The measurements and calculations provide indications of the growth modes and help to explain the resulting microstructures and coating chemistries. Coatings sprayed from different ceramic powders are discussed. (C) 2012 Elsevier B.V. All rights reserved.