Al2O3/Cr composite ceramic was ion‐nitrided in N2 under atmospheric pressure. The plasma was generated by two different systems: an ac high voltage corona discharge, and an ac high voltage concentric dielectric barrier discharge. An analysis of the plasma light emission revealed the presence of N 2+ ions (upto 50%) and confirmed the non‐isothermal state of the plasma. The treated surface of the high melting sinter was smoothened when its components were nitrided so that Cr is transformed into Cr2N and Al2O3 is transformed into AlN.

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Radially resolved emission measurements have been employed for a better understanding of plasma generated in a pulsed coaxial accelerator operating in a mixture of propane and butane under conditions which enable diamond-like layer deposition. The measurements were taken at two positions along the axis of symmetry of the discharge.Assuming the Boltzmann and Saha equilibrium, the emission from the plasma has been quantified. Abel-transformed radial profiles of the spectral lines of C I, C II and C III have been used to study radial changes in the concentration of excited neutral, singly and doubly ionized carbon, in the excitation temperature, in the ionization temperature and in the electron number density. Values of excitation and ionization temperatures and their radial profiles for a given axial position did not differ significantly. On the axis of symmetry of the discharge, the excitation temperature of C II and the electron density were found to reach values of about 29 000 K and 5 × 10 17 cm −3 , respectively.In addition, the relative densities of the C, C + and C 2+ species were evaluated, and hence the spatial inhomogeneous plasma structure with respect to the distribution of neutral and ionized fractions of carbon has been revealed and discussed in terms of deposition conditions.

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