Microstructures of TiN, TiAlN and TiAlVN coatings on AISI M2 steel deposited by magnetron reactive sputtering

In order to study the effect of the microstructure with Al and V added TiN coatings, TiN, TiAlN and TiAlVN coatings were deposited on AISI M2 high-speed steels by magnetron reactive sputtering. The microstructures of all the coatings were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicate that the addition of Al into TiN coatings reduces their lattice constant, but a further addition of V into TiAlN coatings increases their lattice constant. Moreover, the growth morphologies for TiN, TiAlN, and TiAlVN indicate that adding Al and V has a tendency to improve the columnar structure. The (111) and (200) orientations of TiN, TiAlN, and TiAlVN are identified. The ɛ(Fe3N-Fe2N) phase occurs because a small amount of Fe is present in the coatings. The interlayers of TiAlN and TiAlVN have the preferred orientation. The texture (columnar) structure of the (111) and (200) orientations is observed in the TiAlN and TiAlVN coatings. An orientation relationship of (01 0)α-Ti//(110)T.M occurs between the interlayer and tempered martensite (T.M) in TiAlVN.