Adhesion improvement of TiN film on tool steel by a hybrid process of unbalanced magnetron sputtering and plasma-based ion implantation

Abstract

An interfacial mixing layer and a titanium (Ti) layer between the titanium-nitride (TiN) film and the substrate material was produced to improve the adhesion of TiN film on tool substrates by a hybrid process of unbalanced magnetron sputtering (UBM) and plasma-based ion implantation (PBII). Before TiN deposition by UBM, the negative high-voltage pulse and DC-bias were applied to the substrate immersed in the Ti plasma, resulting in implantation as well as deposition of Ti ions to the substrate. As a result, a Ti layer and a graded mixing layer of Ti and substrate materials was produced to work as a buffer interface between substrate and TiN film. The adhesion strength of TiN film with the interfacial treatment on tool steel substrates was evaluated by scratch and indentation tests, showing the considerable improvement of adhesion by the formation of the Ti and the interfacial mixing layers. The suitable ion implantation energy for the improvement of adhesion strength was found.