Blown Arc Plasma Source for the Elaboration of Finely Structured Coatings

New emerging technologies using blown arc plasma sources allow elaborating finely structured coatings which find many applications fields. Among them, Suspension Plasma Spraying consists in injecting within a dc plasma jet a liquid jet containing submicron solid particles which are plasma-sprayed to form coatings. This new technology has renewed the interest devoted to the understanding and the development of blown arc plasma sources. This paper focuses on a non-exhaustive description of standard (subsonic) dc plasma torches involving blown arcs related to the Suspension Plasma Spraying (SPS). The emphasis is put on important features for SPS, i.e. on the influence of operating parameters on plasma properties, the understanding of the origin of electric arc instabilities and their influence on suspension injection, and at last, the coating characteristics.