Structural, mechanical and tribological properties of Ti and TiN coatings on 316L stainless steel

316L stainless steel is commonly used in biomedical applications. However, its use is limited because of its insufficient tribological properties. In this study, a duplex surface modification process of laser melting and plasma nitriding is proposed and wear characteristics of coated 316L stainless steel were investigated. Titanium layers were produced on 316L steel samples at laser powers of 20 and 40 W by selective laser melting. The obtained films were plasma nitrided at 650 and 750 degrees C for 4 h under a gas mixture of 50% N-2-50% H-2. The structural, mechanical, morphological and tribological properties of untreated and processed samples were examined. It was observed that the hardness and wear resistance of coated and plasma nitrided samples were higher than the uncoated and Ti coated samples due to the formation of titanium nitride phases during nitridation. Also, the results indicated that wear resistance of Ti coated and plasma nitrided samples improved with increasing plasma nitriding temperature and laser power.