Papers by Keyword: Reactive Magnetron Sputtering

Abstract: In the present work, reactive DC magnetron sputtering method is used to deposit TiO₂ thin films on glass substrates. The structural, surface morphology and optical studies of TiO₂ thin films were discussed by varying the oxygen flow rates from 1 to 4 sccm. X-ray diffraction patterns of TiO₂ thin films show amorphous nature. The surface morphological and elemental composition of TiO₂ thin films were examined by field emission scanning electron microscopy and energy dispersive X-ray spectroscopy. From the optical absorption spectra, the shifting of absorption edge towards the longer wavelength leads to the decrement of optical bandgap from 3.48 to 3.19 eV with an increase of oxygen flow rate from 1 to 4 sccm.

Abstract: TiCrN thin films have been prepared using a reactive DC magnetron sputtering system from a mosaic target. The effects of sputtering current, in the range of 300 to 700 mA, on the structure of the thin films were investigated. The crystal structure, microstructure, thickness, and composition were characterized by GI-XRD, FE-SEM and EDS technique, respectively. The results revealed that all the as-deposited films were formed as a (Ti,Cr)N solid solution. The as-deposited TiCrN films showed a nanostructure with a crystallite size less than 70 nm. The crystal sizes of all planes were in the range of 22.2 to 69.9 nm. The lattice constants were in the range of 4.149 Å to 4.175 Å. The thickness increases from 1630 nm to 4910 nm with increasing the sputtering current. The elemental composition (Ti Cr and N contents) of the as-deposited films were varied with the sputtering current. Lastly, the all of the thin films in this work showed compact columnar and dense morphology as a resulted of increasing the sputtering current.

Abstract: An increase of the service life of tribological systems subjected to dynamic-mechanical loads is important for numerous mechanical applications. The present study deals with the impact of several micro-structured surface topographies of graded Cr/CrN_x/(Cr,W)C_y/a-C:H:W/a-C:H PVD hard coatings on their friction and wear behavior. The coatings were applied by reactive magnetron sputtering on a hardened 1.2379 steel substrates and subsequently micro-structured by laser ablation using a picosecond laser. Pin-on-disc tests were carried out against aluminum under both oil lubrication and dry conditions. The diameters of the micro-dimples were varied between 50 μm, 100 μm and 150 μm at a constant degree of coating coverage of about 60 %. The coefficients of friction and wear were determined after 20,000 cycles by confocal laser-scanning microscope (CLSM), scanning electron microscopy (SEM) and by energy-dispersive X-ray spectroscopy (EDX) to analyze possible transfer layer formations.

Abstract: In this research, CO₂ gas was used as carbon and oxygen source to prepare carbon-doped TiO₂ (C-TiO₂) films on stainless steel by reactive magnetron sputtering. In order to grasp the relationship between sputtering process, microstructure and mechanical and photocatalysis properties of C-TiO₂ thin film, a orthogonal experiment design validated by following mechanical analysis and photo-degradation experiments was employed to determine the optimal reactive sputtering parameters, including substrate temperature, sputtering power and CO₂ gas flow rate. nanoindentation and nanoscratch tests were employed to analyze the hardness, modules and adhesion strength of as-deposited C-TiO₂ films, respectively. Taking the hardness, modules and adhesion between the film and the substrate as a reference of integrated mechanical properties, range analysis of as-prepared C:Ti-O films were done to search the optimal combination of sputtering parameters. The photocatalytic activities of as-prepared C-TiO₂ films using methyl orange (MO) as colored dye indicator were also evaluated by measuring absorbance and calculating the MO’s decolorization rate under different UV light irradiation time. The results of photocatalysis experiment compared with a blank group proved that C-TiO₂ films sputtered at the optimized reactive sputtering parameters can achieve both superior photocatalysis and mechanical properties.

Abstract: In this study, CrN_x thin films were prepared on 304 stainless steel substrate by DC reactive magnetron sputtering technique. Different N₂ gas partial pressure from 10 to 30% was employed in the sputtering process while sputtering power, sputtering pressure and total film thickness were kept constant. In order to improve structural, morphological, and mechanical properties, vacuum annealing process was adopted on the CrN_x thin films at the temperature of 400 oC. The standard characterization techniques such as X-ray diffraction, scanning electron microscope, atomic force microscope and hardness (load force of HV0.1) were used to reveal the properties of as-deposited and annealing films. The as-deposited films show two-phase crystal structure of Cr₂N and CrN depending on N₂ gas partial pressure. After the annealing process, the films effectively enhance the crystal structure and found the phases change from Cr₂N to CrN for the film deposited at low N₂ partial pressure. The surface roughness of the films was between 5 - 20 nm, and as expected the annealing films shows smoother surface than the as-deposited films. Hardness of the CrN_x films is in the range of 7 to 10 GPa. The mechanism of improvement in structural and mechanical properties of annealing films is introduced based on strain relaxation.

Abstract: The CrN thin films were deposited using reactive magnetron sputtering by varying base pressure to investigate the crystal structure, microstructure and composition of thin film. In this work, the films properties were characterized by XRD, FE-SEM and EDX techniques. The crystal structures were obtained the cubic of CrN with the crystal size between 23.23 – 28.25 nm and lattice parameters a = b = c = 4.142 - 4.160 Å. The XRD results indicated that the growth of preferred orientation was changed from (200) to (111) plane with increased the base pressure. The surface morphology of CrN thin films did not affected from base pressure. The thickness of CrN thin films which obtained from cross section analysis was decreased from 1788 to 1745 nm by varying the base pressure. The columnar pattern acccompany with the dense structure were investigated from the cross-section analysis. The Cr composition was substantly decreased whereas theN₂ composition were increased which observed from EDX technique.

Abstract: The CrN thin films were deposited on silicon (100) substrate using reactive magnetron sputtering technique. The films were characterized by XRD, FE-SEM, EDS and nanoindentation techniques to examine the effect of deposition time on crystal structure, compositions, microstructure and hardness. The crystal structure, microstructure, element composition and hardness. The higher crystallinity through longer deposition time were investigated. The grain aggregration with columnar structure were obtained from FE-SEM. The Cr and N contents were not direct relationship with deposition time. The CrN coated sample performed hardness varied between 9 - 16 GPa.

Abstract: In this work, titaniumoxynitride (TiO_xN_y) thin films were deposited on glass slide substrates by using reactive dc magnetron sputtering technique. The reactive gas ratios between O₂ and N₂ were studied in the range of 15-30% with a constant of Ar gas at 110 sccm and a time of 120 minutes. Microstructure, optical, and electrical properties of TiO_xN_y thin films were analysis by using SEM, AFM, GIXRD, UV-VIS spectrophotometer, and 4-point probe measurements. We found that the thickness of the films decreases from 1.0 to 0.8 μm by increasing of O₂ gas ratios. The TiO_xN_y thin films have smooth surface related to small nanograin size. The roughness of the films slightly decreases when O₂ gas ratios increase. From optical transmission spectra, we observed that the transparent of the films increases with different O₂ gas ratio and shifts the band gap from 2.67 to 3.32 eV. The resistivity of the films obviously increases from 3.04 x 10^-3Ω-cm to 5.45 Ω-cm depending on O₂ gas ratio. These results indicate the phase changes of the TiO_xN_y films from metallic to oxide phases. The XRD spectra show poor crystalline TiN (220) and TiO₂ (021) at 15% of O₂ ratio and then the films become amorphous structure by increasing the O₂ gases. The O₂:N₂ gas ratios also affects to the different concentration of oxygen and nitrogen into the TiO_xN_y thin films that lead to the various structural, optical and electrical properties.

Abstract: Ni-doped copper nitride films have been prepared by co-sputtering of Ni and Cu targets. The addition of Ni to Cu₃N films reduced the intensity of the (111) diffraction peak, and lead a little angular shifts of the peaks. The films showed a large difference in reflectance in the infrared and visible before and after thermal decomposition, which is applicable to optical recording media. The films change from a semiconductor to a conductor with the increased ratio of Ni in Cu₃N films.

Abstract: Zirconium aluminum nitride coatings have been deposited onto Ti-6Al-4V substrates by reactive magnetron sputtering in order to investigate the influence of Al-content on the microstructure and mechanical properties. The morphology and microstructure of the coatings were investigated by field emission scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). Nanoindentation and Vicker’s indentation methods were employed to measure the hardness and toughness of the coatings, respectively. The results show that a structure of single cubic phase with twinning is formed at Al content of x ≤ 0.23, and a two-phase structure of hexagonal and cubic phase is formed at Al content of x ≥ 0.47. Hardness and toughness of the Zr_1-xAl_xN coatings show similar tendency with the increasing of Al-content. Both of them reach the maximum values at x=0.23 and drop to the minimum values at x=0.47, after that, they slightly increase with the increasing Al-content. The enhanced hardness and toughness achieved at x=0.23 is ascribed not only to single cubic phase structure but also to twinning structure.