An ozone condensation system is evaluated from the viewpoint of an ozone supplier for oxide thin film growth. Ozone is condensed by the adsorption method and its concentration is analyzed using the thermal decomposition method. The concentration of ozone exceeds 90 mol% and ozone is supplied for a sufficiently long time to grow oxide thin films. Investigation of the ozone decomposition rate demonstrates that ozone can be transferred into the film growth chamber without marked decomposition. The ozone concentration is also evaluated using a quadrupole mass analyzer and the accuracy of this method is compared with the results of the thermal decomposition method.

A heat transfer analysis has been undertaken to predict the influence of process parameters on the decomposition of in-flight particles and deposited layers during thermal spraying of polymer coatings. The theoretical analysis shows that polymers are unique in developing large temperature gradients, which accelerates the degradation of the surface of the particles and the coating layers. However, the analysis indicates that the degradation can be limited by the control of the plasma gas composition, the spraying distance and the torch traverse speed. The theoretical analysis has been confirmed by weight loss measurements, wear tests and microstructural observations of plasma sprayed PMMA coatings. The work shows the existence of a critical traverse speed below which satisfactory coatings cannot be produced.

Thermal spraying of silicon nitride has been considered impossible because the high temperatures involved lead inevitably to decomposition/oxidation of the material. To address these issues, improved silicon nitride-based powders were developed, two of which have been tested as reported in this paper. The powders were applied using low pressure plasma spraying (LPPS) and the resulting coatings characterized based on microhardness, adhesion, and cohesion strength. Phase transformations of the powders during spraying were also investigated and preliminary optimization strategies by statistical variation of plasma spray parameters were tested.