**2.3. Glow discharge optical emission spectroscopy**

The process of defining the distribution of nitrogen and carbon in the nitrided and carbonitrided samples has been realised by means of the GDOES device GDA – 750, vom Spectruma-Analytik GmbH. The parameters of the glow discharge plasma are as follows: current - 20 mA, voltage - 800 V, plasma density - 1010-1011 cm-3, electron temperature 0.1 - 0.5 eV and plasma volume 15 cm3. The turbomolecular pump (56 ℓ⋅s-1) works constantly. The basic pressure is 10-6 Ра. The surfaces are polished beforehand in order to achieve congestion in the plasma sector of the GDOES device. The standardizing of the device has been carried out with a sample containing 7 weight per cents of nitrogen and 1 weight per cent of carbon.
