Plasma spray apparatus for applying a coating utilizing particle kinetics

摘要

A plasma spray apparatus for applying a coating to an article, wherein the apparatus includes a cup shaped plasma nozzle and a main gas nozzle coaxially surrounding the exterior of the plasma nozzle forming a passage between the main gas nozzle and the plasma nozzle through which the main gas containing powder particles is caused to coaxially flow, and a converging/diverging nozzle positioned at the exit of the plasma nozzle and main gas nozzle, having an entry chamber into which the plasma gas and the main gas with powder particles entrained therein flow and combine to establish a gas mixture, the gas mixture accelerating through the extended bore of the converging/diverging nozzle to a sonic or supersonic velocity so that upon impact onto the surface of the article a cohesively bonded coating will form and build-up.