Growth of nitrided layer after cathode sputtering

Abstract

The authors present results of the investigations on the growth of nitrided layer formed during gas nitriding after the surface activation. Cathode sputtering was used as an activation treatment which increases the number of activated centres. The surface of the samples was bombarded by nitrogen or argon ions.The experiments were carried out on the samples made of α-Fe. The parameters of the sputtering were as follows: voltage—700–1350V, current density—1–4mA/cm2, time—10–60min. The nitriding atmosphere was composed of ammonia and dissociated ammonia.For every sample the following investigations were made: metallography of cross-section of nitrided layers and layer thickness measurements (the compound layers), surface observation by SEM and XRD analysis.It was observed that cathode sputtering improves the kinetic of gas nitriding and this effect was observed for both sputtering gases. The mathematical relationship between the thickness of nitride layer and voltage and current density of sputtering was also established.