6. Conclusions and outlook

Over the last two decades, a great deal of work has gone into the industrial development of ceramic and non-ceramic functional coatings for both thin-film and thick-film deposition processes. In both cases, the development of new measurement techniques, and their extension for use on industrial installations, have enabled us to significantly improve the reproducibility and reliability of these deposits, and hence their industrial use. For example, for thermal spray deposits, in-flight measurements (temperature distributions, speeds, trajectories, diameters) of sprayed particles, coupled with electronic process control devices, have been available since the 2000s. In plasma spraying, for example, they enable us to compensate for electrode wear by keeping the average temperatures and speeds of the particles in flight constant, by acting on the arc current. We can therefore safely assume that...