Influence of bilayers period on mechanical properties of TaNx/TaCx multilayers obtained by direct current magnetron sputtering

摘要

In this paper, the mechanical properties of TaNx/TaCx bilayers obtained by direct current magnetron sputtering are studied. The materials were manufactured by stacking bilayers formed by the periodic alternation TaN and TaC. Initially, samples of 40 bilayers were produced varying the deposition temperature (200, 300, 400 and 500 degrees C), finding the best mechanical properties for the sample grown at 500 degrees C; after that, the number of bilayers was varied, taking values of 10, 20, 40, 80 and 160. Transmission electron microscopy images show the layers formation and thicknesses between 1.2 and 1.6 mu m. In addition, X-ray diffraction patterns were acquired to observe the crystalline structure of samples produced varying the number of bilayers. Hardness was related to the preferential orientation and the competition between surface free energy and strain energy. The sample exhibiting the greatest hardness was obtained with 40 bilayers, in which, there is an equilibrium between both energies.