Some properties of (Ti,Mg)N thin films deposited by reactive dc magnetron sputtering

(Ti,Mg)N coatings were deposited onto high speed steel (HSS) and glass substrates using reactive dc magnetron sputtering. Because of the addition of Mg to TiN the colour changed from golden to violet and metallic blue as measured by spectrophotometry. The chemical composition, morphology and structure of the coatings was investigated by energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The addition of Mg to TiN leads to a shift of the TiN peaks in the XRD patterns. Probably, this is due to the substitution of titanium atoms by the bigger magnesium atoms. The indentation hardness and the open-circuit-potential (in NaCl solution) of the (Ti,Mg)N coatings is decreasing with increasing Mg contents. The oxidation resistance of (Ti,Mg)N coatings could be drastically improved with increasing Mg content.