Cost effective plasma spraying for large-scale applications

Abstract for ITSC 2018

Poster

Cost effective plasma spraying for large-scale applications

Plasma spraying of large-scale components (e.g. paper mill rolls, rocket exit nozzles) and powder spheroidisation are just two examples of industrial applications where the processing time is critical. To ensure productivity and cost-effectivity of the process, it is necessary to use plasma torches which can handle high powder throughputs in tens of kilograms per hour. Such torches must have sufficiently high enthalpy and plasma temperature, to ensure homogeneous particle treatment. Hybrid water stabilised plasma (WSP-H) system with its enthalpy of more than 140 MJ/kg and plasma temperature of 25 000 K is able to process up to 40 kg of powders per hour. Since the WSP-H torch consumes only 15 slm of Ar at full power of 180 kW, it is a very powerful and also economical tool that meets all the prerequisites for large-scale plasma spraying applications. Spraying of several ceramics: alumina, zircon and yttria-stabilised-zirconia is presented in this study, revealing the influence of high powder throughputs on particle velocity, temperature and coating quality. Deposition efficiency of the processes is discussed and the coatings are analysed by SEM and XRD.