Relation Between Coating Parameters and Structural and Mechanical Properties of Magnetron Sputtered TiAlN Coatings

Abstract

In this paper, it is aimed to investigate the structural and mechanical properties of TiAlN coatings deposited by the magnetron sputtering method on silicon substrates using a compound Ti0.5Al0.5 target at different nitrogen partial pressures of 0.3, 0.6 and 1.2 mtorr, substrate bias voltages of 0, −100 and −200 V and target to substrate distances of 6, 11, 16 and 21 cm. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, atomic force microscopy, the CSEM nano-hardness tester and CSEM-Calotest were used to characterize the coatings. The results showed that the hardness and mechanical properties of the coatings increased at low nitrogen pressures and high bias voltages, and that target to substrate distance showed a significant effect on the structural and mechanical properties of the coatings. With a shorter target to substrate distance, densified TiAlN coatings of substantially higher hardness and Ti content were produced with enhanced deposition rate. Furthermore, 11 cm target to substrate distance was found as the critical distance for the hardness and Al content of the coatings, especially at low bias voltage and low nitrogen pressure, respectively. In addition, X-ray diffraction analysis in this study showed that short target to substrate distances and high bias voltages indicated significant effect on a (2 0 0) preferred orientation of the NaCl structure.