Physical, structural and mechanical characterization of Ti1−xSixNy films

Abstract

Abstract Within the frame of this work, Ti 1− x Si x N y hard coatings with 0≤ x ≤0.37 and thicknesses ranging from 1.2 to 3.5 μm, were prepared by r.f. reactive magnetron sputtering in an Ar/N 2 gas mixture. X-ray diffraction and Fourier analysis of X-ray profiles were used to investigate the structure and grain size, and its correlation with hardness behaviour, as a function of the Si content, bias voltage and working gas (argon) flow rate. In this respect, the results show that a double cubic phase of NaCl type was developed with lattice parameters of 4.18 and 4.30 A, revealing the (111) orientation for low Si content ( x =0.05), (220) for intermediate Si contents (0.13≤ x ≤0.22) and (200) for the highest Si contents (0.30≤ x ≤0.37). Regarding the results of ultramicrohardness tests, and although all samples with 0.05≤ x ≤0.30 present a hardness value higher than 30 GPa, the Ti 0.85 Si 0.15 N 1.03 revealed the highest hardness value, around 47 GPa, which is more than twice as high as that of common TiN. Furthermore, the study of hardness as a function of the applied bias voltage revealed that best results are achieved between −50 and 0 V. The variation in hardness as a function of the argon flow showed that best results in hardness are obtained when working with flow rates around 110 cm 3 /min.