MATERIAL COATING USING ELECTROMAGNETICALLY ACCELERATED PLASMA JET

摘要

In magneto-plasma-dynamic (MPD) arcjet generators, plasma is accelerated by electromagnetic body forces. Two types of MPD arcjet generator were developed for applications to mullite, zirconia, titanium-nitride and silicon-nitride sprayings. The MPD spray process could successfully form dense, uniform and hard ceramic coatings. In titanium nitride reactive spraying, plasma diagnostic measurement and flowfield calculation were also carried out A large amount of N and N~+ was expected to be exhausted with a high velocity from the MPD generator. Both the electron temperature and the electron number density were kept high at a substrate position compared with those for conventional low-pressure thermal sprayings. A chemically active plasma with excited particles of N~+, Ti, Ti~+ and Ti~(2+) was considered to contribute to better titanium nitride coatings. The coating characteristics showed that the MPD arcjet generator had high potentials for material spraying.