Effect of active gas mixtures on the efficiency of plasma surface hardening

Abstract

Investigations were carried out into the possibilities of obtaining special properties of the surface of a metal by a moving nitrogen-containing direct action plasma arc. Analysis of the calculated and experimental data indicates the effect of ‘freezing’ of nitrogen after implantation in the surface layer (up to 100 μm thick) as a result of a reduction of the rate of desorption from the surface and diffusion into the metal. At the same time, nitrogen dissolves to the concentration required for the formation of iron nitrides of different phase composition, and the metal with higher wear resistance of the surface layer can be produced. When carbon-containing gases are added to the mixture, the hardness and endurance limit of the surface of the metal increase.

Keywords:

• plasmotron
• surface modification
• nitriding
• diffusion
• desorption
• implantation
• plasma composition