Surface hardening by ion-nitriding of non-ferrous metal and its alloys and determination of physical properties of hardened material

V ABSTRACT Titanium and its alloys are widely used in biomedical applications because of their corrosion resistance and biocompatibility. Nevertheless, the use of these materials for implants creates sometimes problem because of their poor surface hardness and wear resistance. To improve the poor surface hardness and wear resistance of titanium alloys used for surgical implants undergoing wear has been plasma nitrided. In this investigation, the surface hardening of Tİ6A14V titanium alloy by plasma nitriding technique has been aimed with various temperatures ( from 600 to 850 °C), times (from 2 to 20 h) and the volumetric ratio of N2 in the plasma atmosphere of H2+N2 gaseous mixture as process parameters. The study presents the results of the examinations of microstructures, hardnesses, thicknesses, wear behaviours of surface layers formed on the Tİ6A14V titanium alloy by plasma nitriding. By microhardness measurements investigations, the maximum surface hardness has been obtained in the plasma nitrided sample over a period of 7h 850 °C in a nitriding atmosphere containing %80 N2+%20H2 gaseous mixture. The case depth were found to increase with increasing process temprature and time. By optical microscope investigations, the deepest diffusion layer has been obtained in the plasma nitrided sample over a period of lOh 850 °C in a nitriding atmosphere containing %80 N2+%20H2 gaseous mixture. Wear rates were observed to decrease with increasing compound layer (TİN + Tİ2N) thickness. Keywords: 1) Plasma Nitriding 2) Titanium Nitriding 3) Surface Treatments