Diagnóstico do plasma por espectrometria ótica e nitretação a plasma a alta temperatura de aço inoxidável ISO 5832-1

Abstract

Plasma nitriding is increasingly used as a surface treatment process in order to improve strength properties, wear and corrosion resistence. Some studies show that this treatment can be performed at low (<400°C) and high temperatures (> 1000°C). However, plasma nitriding above 1000°C presents difficulty in forming a nitrided layer. With this, the objective of this study was to perform a diagnosis of Optical Emission Spectroscopy (OES) in low and high temperatures and correlate these results with the nitriding of ISO-5832-1 steel. For both, analyzes were carried out at a temperature of 400, 600, 800 and 1000 ° C and pressure of 3, 4, 5, 10, 15, 20 and 30 torr, where the other parameters remained constant. The results show that the temperature increase has a direct influence on the formation of species present in the plasma, and the higher the temperature, the higher the formation of such species. The pressure exerted nonlinear effect, because in some cases has increased intensity of species and in others a decrease. After diagnosis the plasma in all the above-mentioned conditions, two nitriding at 1000 ° C, at 10 torr and 30 torr. Analysis by optical microscopy show that using a pressure of 30 torr was obtained a nitrided layer, while no layer was formed at 10 torr.