Plasma Characteristics of Supersonic Nitrogen/Hydrogen-Mixture and Ammonia Plasma Jets and Nitrided Material Properties

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Spectroscopic and electrostatic probe measurements were made to examine plasma characteristics under nitriding for a 10-kW-class direct-current arc plasma jet generator with a supersonic expansion nozzle in a low pressure environment. Heat fluxes into the plate from the plasma were also evaluated. Ammonia and mixtures of nitrogen and hydrogen were used as the working gas. The H-atom electronic excitation temperature and the N2 molecule-rotational excitation temperature intensively decreased downstream in the nozzle although the NH molecule-rotational excitation temperature did not show an axial decrease. As approaching the titanium plate, the thermodynamical nonequilibrium plasma came to be a temperature-equilibrium one. Both the electron number density near the plate and the heat flux increased with H2 mole fraction for mixtures gases. In cases with mixtures of N2 and H2, a radical of NH with a radially wide distribution is considered to contribute to the better nitriding as a chemically active and non heating process.

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Periodical:

Materials Science Forum (Volumes 449-452)

Edited by:

S.-G. Kang and T. Kobayashi

Pages:

373-376

Citation:

H. Tahara et al., "Plasma Characteristics of Supersonic Nitrogen/Hydrogen-Mixture and Ammonia Plasma Jets and Nitrided Material Properties", Materials Science Forum, Vols. 449-452, pp. 373-376, 2004

Online since:

March 2004

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$38.00

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