Properties of TiAlN coatings synthesized by closed-field unbalanced magnetron sputtering

Abstract

The characteristics, such as deposition rate, microstructure, surface morphology and mechanical properties, of titanium aluminum nitride films synthesized by unbalanced magnetron sputtering (UBMS) and closed-field unbalanced magnetron sputtering (CFUBMS) were compared in this article. TiAlN films were deposited from an alloyed TiAl (50/50 at.%) target at various N 2 partial pressures by two types of magnetron sputtering: (i) the single UBMS and (ii) CFUBMS with four magnetron sources. The deposition rate of TiAlN films produced by CFUBMS with four magnetron sources was increased up to approximately 1.35 times in comparison with that obtained in the single UBMS. The results of AES and XRD analyses revealed that TiAlN films deposited by two types of magnetron sputtering have similar chemical composition and crystal structure as a function of the N 2 partial pressure. However, TEM analysis showed that TiAlN film synthesized by CFUBMS with four magnetron sources has a denser columnar structure and its column width and grain size were increased up to approximately two times compared with film by the single UBMS. In addition, the nanoindentation tests showed that the hardness and elastic modulus of films by CFUBMS have higher values than those of films by the single UBMS. This enhancement in the CFUBMS with four magnetron sources system on the mechanical properties could be attributed to the formation of dense and well-crystallized film by the high-level ion bombardment of growing film.