Adhesion and mechanical properties of Ti films deposited by DC magnetron sputtering

Titanium films were deposited on AISI 316L stainless steel substrates by D.C. unbalanced magnetron sputtering, the substrate temperature and deposition time were changed. In this study, the structural characterization was conducted by scanning electronic microscopy (SEM), spectroscopic ellipsometry (SE), X-ray diffraction (XRD) and atomic force microscopy (AFM). Furthermore, mechanical properties were obtained by nanoindentation. Adhesion and wear behavior were evaluated through progressive load scratch test (PEST) and pin-on-disk test, respectively. Titanium films thicknesses within a range of 2.5-4.2 gm were obtained, different XRD Ti peaks such as (002), (102) and (103) were identified. Values estimated for hardness were between 7.2 and 8.4 GPa, and for Young's modulus they were 126-162 GPa. Tensile cracks, compressive and gross spallation failure mechanisms were found with scratch tests. Preferred oriented sample only showed cracks, with a critical load of 2.6 N, and exhibited a better wear ratio (similar to 1.5 x 10(-4)), which is about two times better than substrate steel. This study provides evidence of how a preferred oriented Ti (002) film exhibits better hardness, adhesion and wear properties.