Projection par plasma de depots de dioxyde de titane: Contribution a l'etude de leurs microstructures et proprietes electriques.

摘要

The aim of this PhD work is, thanks to particle parameters (velocity and temperature) characterization, to try to understand the influence of plasma spray parameters on titania coating microstructures and the influence of the latter one on their electrical resistivity, for the same substrate conditions.;The experimental approach has consisted in using two plasma spraying processes (Arc plasma spraying and Inductive plasma spraying) which have permitted to obtain a broad range of particle velocities and temperatures leading to coatings with specific microstructures. Despite the stoichiometry of the starting powder, all coatings obtained were grey, the oxygen loss increasing with the particle temperature.;Isolating the stoichiometry influence has permitted to show that the decrease of the coatings electrical resistivity is especially due to the decrease of the number of bad interlamellar contacts.