s sanjari - Department of Metallurgy and Materials Engineering, Semnan University, Semnan, Iran
a Habibolahzadeh - Department of Metallurgy and Materials Engineering, Semnan University, Semnan, Iran
m Heydarzadeh Sohi - School of Metallurgy and Materials, College of Engineering, University of Tehran, Tehran, Iran

In this study, surface of medium carbon steel (AISI 1045) was modified by titanizing followed by plasma nitriding. Titanizing was performed using pack cementation method, in a pack mixture of ferrotitanium, ammonium chloride and alumina, at 950 °C for 45 and 180 min. Plasma-nitriding wasconducted at two temperatures of 530 and 550 °C for 5 h, in a gas mixture of 75N2+25H2 (vol.%). Thesamples were characterized by scanning electron microscope (SEM), X-ray diffractometre (XRD),Vickers microhardness and pin-on-disk wear tests. The thickness of titanized layers was 8-10 μm, thethickness had no significant change after plasma nitriding. The duplex treated surface layers consisted of Fe4N, TiN and TiCN phases. Lower titanizing time and higher plasma nitriding temperatureprovided superior wear resistance and hardness. The highest wear resistance and the lowest frictioncoefficient were achieved in the sample which was titanized for 45 min and then plasma nitrided at 550 °C , with 2130 HV microhardness.

Medium Carbon Steel , Duplex Treatment , Plasma Nitriding , Titanizing , Microhardness , Wear