Abstract
The purpose of this study is to investigate the effects of texture and the Zr interlayer on the structure and properties of nanocrystalline ZrN thin film. Nanocrystalline ZrN thin films were successfully deposited both on (100) p-type Si and AISI 304 stainless steel at a constant temperature 400℃ with introducing three different N2 flow rate, 1,3, and 4.2 sccm, to control the ZrN film textures as (111), random, and (200) by unbalanced magnetron sputtering system(UBMS). In addition, to understand the effects of Zr interlayer, Zr thin films with thickness of 130 nm were pre-deposited on SS304 substrate and then covered with ZrN thin films which were deposited under the three deposition conditions mentioned above respectively. The N/Zr ratios ranged from 0.8 to 0.9 by Rutherford Backscattering Spectroscopy (RBS) measurements. The effects of texture were remarkable on residual stress and corrosion resistance. ZrN thin films with random texture deposited both on Si and SS304 substrates showed the higher residual stress than those with (111) and (200) textures. The intrinsic corrosion potentials were obtained by ZrN/Si specimens from potentiodynamic polarization scanning in 1N H2SO4 solution. Intrinsic corrosion potentials exhibit positive values ranging from 19 to 149 mVSCE. ZrN films with (200) texture deposited on SS304 substrate displays the best protection of metal substrate. Different textures showed no distinct effect on hardness for ZrN/Si specimens. ZrN thin films deposited under random orientation condition showed (200) preferred orientation by introducing a highly (0002) preferred Zr interlayer with thickness of 130 nm. Only with a Zr interlayer which was more (0002) preferred with thickness up to 240 nm, ZrN thin film deposited under (200) preferred orientation condition displayed random preferred orientation. The Zr interlayer improved the crystallinity of the upper ZrN films, which resulted in higher hardness values of ZrN films. In addition, Zr interlayer can promoted the corrosion resistance of upper ZrN films with (111) and random textures due to bi-layer effect which can effectively prevent solution to attack the metal substrate by interrupting the connection of pinholes from film surface to metal substrate. However, Zr interlayer can not help the upper ZrN films to relieve residual stress on the contrary it decreases the adhesion of ZrN films.