Microstructure,mechanical and tribological properties of TaCN composite films by reactive magnetron sputtering

In this paper, a series of TaCN composite films with different carbon content were deposited by the magnetron sputtering system and the microstructure, mechanical and tribological properties were investigated. The results showed that the deposited TaCN films exhibited a three-phase of face-centered cubic (fcc) Ta(C,N), hexagonal closed-packed (hcp) Ta(C,N) and amorphous CNx. With the increase of carbon content, the hardness of the TaCN films first increased and then decreased, after reaching a maximum of 33.1 GPa; the adhesion strength increased gradually; the coefficient of friction decreased monotonically and the wear property initially improved and then weakened at room temperature. The coefficient of friction of the TaCN film at 28.21 at.% carbon decreased first, then increased and then decreased again and its high-temperature wear rate first decreased slightly and then increased, as the temperature increased from room temperature (RT) to 600 °C. The TaCN film at 28.21 at.% carbon exhibited excellent an elevated-temperature tribological properties.     

Effects of nitrogen flow rate on the microstructure and mechanical and tribological properties of TiAlN films prepared via reactive magnetron sputtering

In this study, TiAlN ceramic films were fabricated via reactive magnetron sputtering on a Ti6Al4V titanium alloy substrate. The effects of N₂ flow rates on the microstructure and mechanical and tribological properties of the films were systematically studied. With increasing N₂ flow rate, the films underwent a morphological evolution from a fine columnar structure to a coarse structure with holes and microcracks. In addition, the preferred orientation of the films varied from TiAlN (220) to the (111) plane. However, a high N₂ flow rate (≥20sccm) resulted in target poisoning and reduced the deposition rate, which resulted in defects such as cavities and holes on the surface. Moreover, with increasing N₂ flow rate, the hardness and elastic modulus first increased and then reduced owing to grain refinement. The films deposited at a N₂ flow rate of 16 sccm exhibited the smallest wear width and the lowest wear rate. As the N₂ flow rate increased from 12 to 24 sccm, the wear mechanism of the films changed from abrasive and adhesion wear to abrasive wear caused by severe plastic deformation, which was directly related to the microstructural evolution and mechanical properties.     

Mechanical and tribological properties of boron,nitrogen-coincorporated diamond-like carbon films prepared by reactive radio-frequency magnetron sputtering

We have deposited boron- and/or nitrogen-incorporated DLC films by radio-frequency magnetron sputtering, and systematically investigated the structure and the mechanical and tribological properties. The N content in DLC films increased with increasing N₂ flow ratio [N₂/(Ar + N₂)], and it tended to be saturated at higher N₂ flow ratios. The N content further increased with an increase in the B content of the targets. The B/C ratios of the films were almost the same as those of the B-containing targets regardless of the N content. Scratch tests revealed that the adhesion strength of N-incorporated DLC films decreased with increasing N₂ flow ratio and the critical loads of B-incorporated films were lower than that of an unincorporated film. It was found that for B, N-coincorporated films there was an optimum N₂ flow ratio at which the critical load became a maximum value, which was higher than that of the unincorporated film. The optimum N₂ flow ratio increased with an increase in the B composition of the targets. The N-incorporated films peeled off during ball-on-plate friction tests. On the other hand, the B, N-coincorporated films showed good wear-resistant properties that the specific wear rates were lower than those of the unincorporated and B-incorporated films.     

Electrochemical properties of boron-carbon-nitride films formed by magnetron sputtering

The electrochemical behavior of B_1.0C_2.4N_1.0 thin film was investigated in acidic, neutral and alkaline solutions. The anodic polarization curve of the film in 1 M NaOH showed the anodic dissolution of the film. The curve of the film in 1 M HCl showed no anodic dissolution. The cathodic polarization curve in 1 M NaCl showed shift to a negative potential side, but the anodic polarization curve was the same as that of Pt. The anodic dissolution in 1 M NaOH depended on potentials, that is, no anodic dissolution was recognized in a potential range of −0.2 to 0.1 V but the dissolution rate increased with increasing potential in a range of 0.1-0.6 V. The anodic current density of the film is directly proportional to the dissolution rate at potentials higher than 0.1 V. The dissolution rate of the film was increased with increasing solution pH.     

Electrochemical properties of Si–Ge–Mo anode composite materials prepared by magnetron sputtering for lithium ion batteries

Si–Ge–Mo composites are prepared using an RF/DC magnetron sputtering method, and their potential use as anode materials for rechargeable lithium-ion batteries is investigated. The Si–Ge–Mo composite films present an amorphous structure. The reaction mechanism of the Si–Ge–Mo with Li is investigated by various analytical techniques. The fabricated Si_0.41Ge_0.34Mo_0.25 composite film shows excellent electrochemical properties, including a high energy density (1st charge: 1193 mAh g⁻¹), long cycleability (ca. 870 mAh g⁻¹ over 100 cycles), and good initial Coulombic efficiency (ca. 96%). Additionally, when coupled with a LiCoO₂ cathode, the Si_0.55Ge_0.22Mo_0.23 composite electrode used as an anode shows excellent cycleability with a high energy density. The excellent electrochemical properties demonstrated by the Si–Ge–Mo composite film electrode confirm its potential as an alternative anode material for lithium-ion batteries.     

Structural and mechanical properties of CNx thin films prepared by magnetron sputtering

In an attempt to define the role of nitrogen in CN chemical bonding and in the formation of CN_x thin films, several coatings with a variable concentration of N₂ were grown onto (100) Si substrates using magnetron sputtering in N₂/Ar discharge. The chemical composition of the as-deposited films was investigated by means of Rutherford backscattering spectroscopy (RBS) and showed an [N]/[C] ratio up to 0.7. Raman and Fourier transform infrared (FTIR) spectroscopy were carried out to measure the optical vibration properties for studying the bonding state of nitrogen.By means of grazing incidence X-ray diffraction (XRD) and transmission electron microscopy (TEM) electron diffraction the structure of the deposited films was proven to be mainly amorphous containing small crystallites of CN_x compounds. Scanning tunneling microscopy (STM) shows the clusterlike surface of the films where the cluster size is characterized by scaling behaviour. The mechanical properties of the CN_x thin films adhering their substrates were investigated using the nanoindentation technique. From the load–displacement curve the hardness H and the Young's modulus E of the films were calculated.The relationships between deposition parameters and properties of CN_x films are shown and discussed. In particular, the influence of the applied r.f. power and the role of the N₂ partial pressure are demonstrated.     

Luminescence properties of terbium-doped SiCN thin films by rf magnetron reactive sputtering

Terbium-doped SiCN (SiCN:Tb) thin films were deposited by rf magnetron reactive sputtering at 800 °C. The as-prepared samples were characterized by XRD, FTIR, and XPS. The results showed that SiCN:Tb films mainly contained both SiC and Si₃N₄ nano-compositions with complicated chemical bond networks. Photoluminescence measurements indicated that the undoped SiCN films exhibited a blue-green light emission, while SiCN:Tb films emitted a strong green one. The SiC nanocrystallites formed in the undoped SiCN films might be responsible for the blue-green light emission, while the formed quaternary Si-C-Tb-O compositions in the doped samples could account for the strong green PL behaviors.     

Structure, elemental composition, and mechanical properties of films prepared by radio-frequency magnetron sputtering of hydroxyapatite

The phase composition, substructure, and surface morphology of 0.1-to 5.0-μm-thick films grown on different substrates by radio-frequency magnetron sputtering of a hydroxyapatite ceramic target are investigated using transmission electron microscopy (TEM), high-energy electron diffraction, X-ray diffraction, IR spectroscopy, Auger electron spectroscopy, ultrasoft X-ray emission spectroscopy, Rutherford backscattering spectroscopy, scanning electron microscopy (SEM), and atomic-force microscopy (AFM). The hardness and adhesion strength of these films are studied using the nanoindentation and scratching methods. It is revealed that the structure of the films depends on the spatial inhomogeneity of the plasma discharge. Single-phase dense nanocrystalline hydroxyapatite films are formed when the substrate is located above the erosion zone. According to the X-ray diffraction, high-energy electron diffraction, and IR spectroscopic data, the structure of the films corresponds to the hydroxyapatite structure. As follows from the Auger electron, ultrasoft X-ray emission, and Rutherford backscattering spectroscopic data, the elemental composition of the films is similar to the stoichiometric composition of hydroxyapatite. The analysis of the X-ray diffraction and AFM data demonstrates that the films have a dense structure. The results of the mechanical tests show that the hardness of the coatings is higher than 10 GPa and that the maximum adhesion strength (L _C = 12.8 N) is observed for the hydroxyapatite coatings on the titanium substrate modified by the TiC-TaC-Ca₃(PO₄)₂ composite layer.     

直流溅射ITO薄膜光电性能研究

采用直流溅射法制备了高性能的ITO薄膜。结果表明,氧气分压比和衬底温度对薄膜的方阻、可见光透射率具有重要的影响。其最佳值分别为0.5/50和350℃;同时,随着膜厚的增加,薄膜的晶粒增大,导电率也相应降低。     

Study of the thermal stability of carbon nitride thin films prepared by reactive magnetron sputtering

CN_x amorphous films have been prepared by reactive magnetron sputtering in a pure N₂ discharge. The films grown on NaCl have been characterised by Fourier transform infrared spectroscopy (IR), transmission electron microscopy (TEM), and electron energy loss spectroscopy (EELS). C/N atomic ratios have been determined by EELS with values in the range 2.0–1.2 for samples grown under different conditions. The thermal stability of the films upon heating in vacuum was followed ‘in situ’ at the transmission electron microscope by EELS. This study has been completed by a thermogravimetric and mass spectrometer analysis of evolved gases upon heating in nitrogen flow and vacuum, respectively. Under these conditions the films are stable up to 1023 K. Above this temperature the films decompose by elimination of nitrogen remaining a carbonaceous residue. The thermal stability of the films upon annealing in air was studied by following the evolution of the X-ray photoelectron spectroscopy (XPS) peaks during heating in air of films grown on steel. Deconvolution analysis of the XPS spectra allows to determine the evolution of the different type of bonds. In particular pure carbon in the films appears more reactive to oxygen than CN and C–N bonds.     

Microstructural and optical properties of Ta-doped ZnO films prepared by radio frequency magnetron sputtering

Ta-doped ZnO films with different doping levels (0–5.02 at%) were prepared by radio frequency magnetron sputtering. The effects of the doping amount on the microstructure and the optical properties of the films were investigated. The grain size and surface roughness first significantly decrease and then slowly increase with the increase of Ta doping concentration. Both the grain size and the root mean square (RMS) roughness reach their minimum values at the doping content of 3.32 at%. X-ray Diffraction (XRD) patterns confirmed that the prepared Ta-doped ZnO films are polycrystalline with hexagonal wurtzite structure and a preferred orientation along the (002) plane. X-ray photoelectron spectroscopy (XPS) analysis reveals that Ta exists in the ZnO film in the Ta⁵⁺ and Ta⁴⁺ states. The average optical transmission values of the Ta-doped ZnO films are higher than those of the un-doped ZnO film in the visible region. The band gap energy extracted from the absorption edge of transmission spectra becomes large and the near band edge (NBE) emission energy obtained from PL spectra blueshifts to high energy when the Ta doping content grows from 0 at% to 5.02 at%, which can be explained by the Burstein–Moss shift.     

Yttrium-doped TiO2 films prepared by means of DC reactive magnetron sputtering

Y₂O₃-doped TiO₂ films were prepared on glass substrates by means of pulsed DC reactive magnetron sputtering method using titanium and yttrium mixed target. XPS results showed that the films were composed of fully oxidation states of the two elements, Y₂O₃–TiO₂ composite oxides. The existence of yttrium inhibited the crystal growth of TiO₂ in the films and Y₂O₃ mainly presented in its amorphous state in the films. UV–vis transmittance of the films decreased whereas their reflectance increased slightly. Yttrium doping had detrimental effect on photocatalytic activity of the TiO₂ films. Photocatalytic degradation efficiency of methyl orange solution declined along with increasing yttrium concentration.     

Effect of substrate temperature on the mechanical and tribological properties of W/WC produced by DC magnetron sputtering

W/WC bilayers were grown using the DC magnetron sputtering technique and varying substrate temperature. The mechanical and tribological behaviors were characterized using the nanoindentation and pin-on-disk techniques. The hardness and Young's modulus tended to increase, while the coefficient of friction tended to be stable with increasing substrate temperature. Moreover, better mechanical and tribological performances were observed for all of the coated systems compared with the uncoated steel. Furthermore, the inclusion of a W interlayer did not significantly influence the hardness; nevertheless, this interlayer dramatically improved the coating tribological behavior, thus producing less coating damage and decreasing the wear rate.     

Characterization of luminescent properties of ZnO:Er thin films prepared by rf magnetron sputtering

ZnO:Er thin films were deposited on c-plane sapphire substrates by rf magnetron sputtering and annealed at 700 °C under air and H₂ atmospheres for the luminescent improvement. The effects of sputtering parameters and the annealing conditions on visible and 1.54 μm IR emissions were investigated. Structural and luminescent properties strongly depended on the deposition conditions and annealing atmospheres. By tuning the excitation wavelength, ZnO:Er thin films exhibited a strong emission band at around 465 nm and a weak emission at 525 nm originated from the energy transition of ⁴I_15/2–⁴F_5/2 and ⁴I_15/2–²H_11/2, respectively, while 1.54 μm IR emissions due to ⁴I_15/2–⁴I_13/2 transition.     

Structure and properties of composite films prepared from cellulose and nanocrystalline titanium dioxide particles

Composite films were successfully prepared from cellulose and two kinds of nanocrystalline TiO₂ particles in a NaOH/urea aqueous solution (7.5 : 11 in wt %) by coagulation with H₂SO₄ solution. The structure, morphology, and properties of the films were characterized by transmission electron microscopy, scanning electron microscopy, X‐ray diffraction, TGA, tensile testing, UV–vis spectroscopy, and antibacterial test. The results indicated that TiO₂ particles in a cellulose matrix maintained the original nanocrystalline structure and properties. TiO₂(I) (anatase) and TiO₂(II) (the mixture of anatase and rutile) particles exhibited a certain miscibility with cellulose. The tensile strength of two kinds of composite films was higher than 70 and 75 MPa, when the content of TiO₂(I) and TiO₂(II) was 4 and 11 wt %, respectively. The cellulose composite films containing nanocrystalline TiO₂ particles displayed distinct antibacterial abilities and excellent UV absorption. This work provides a potential way for preparing functional composite materials from cellulose and inorganic nanoparticles in a NaOH/urea aqueous solution, without a destruction of the structure and properties of the particles. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3600–3608, 2006     

Effect of deposition parameters on properties of TiO2 films deposited by reactive magnetron sputtering

TiO₂ films were grown onto unheated 5083 aluminum alloy substrates by reactive magnetron sputtering from a pure Ti target in Ar-O₂ gas mixture in different power, bias voltage, Ar/O₂ ratio and deposition time at room temperature. The effects of different deposition parameters on the structure and properties of TiO₂ films were investigated systematically by field emission scanning electron microscope (FESEM), atomic force microscope (AFM), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), nanoindentation tests, electrochemical tests and antibacterial tests. The results show that power and bias voltage are two main factors to affect the structure and properties of TiO₂ films during the sputtering process. XRD results show that anatase phase is the main phase of the film, and the enhanced content of anatase phase with the increase of sputtering power and bias voltage. Nanoindentation tests exhibit that higher H/E (Hardness/Modulus) ratio can be achieved by depositing TiO₂ film. And the corrosion resistance and antifouling property are all improved after depositing TiO₂ film. 2# sample shows the optimal corrosion resistance, E_corr and I_corr are −0.27388 V and 3.7232 μA/cm², respectively. 1# sample exhibits excellent antibacterial property, the d ensity of bacteria is only 217 cell / mm², which is 484% higher than that of uncoated matrix.     

Comparative study of titanium carbide films deposited by plasma-enhanced and conventional magnetron sputtering at various methane flow rates

Titanium carbide (TiC_x) films were deposited by reactively sputtering Ti target with varied methane (CH₄) flow rates using an unbalanced magnetron sputtering equipment operating in conventional (CMS) and plasma-enhanced (PEMS) mode. The microstructure and properties of the TiC_x films were mainly scrutinized with X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, nano indentation, and ball-on-disk tribo-test. As the CH₄ flow rate is increased from 4 to 16 sccm, x in the TiC_x films deposited by PEMS and CMS is gradually increased from 0.28 to 0.96 and 0.28 to 0.73, respectively; and the concentration of TiC phase in the films rises. A densified microstructure with strong preferred growth is observed in the PEMS-deposited films, while a loose columnar microstructure with almost random growth exists in the CMS-deposited films. When the CH₄ flow rate is increased, the hardness of the films deposited by PEMS is firstly increased and then decreased, and reaches a maximum value of 29.6 GPa; but that of CMS-TiC_x film is fluctuated below 10.6 GPa. The friction coefficient of TiC_x-coated samples against pure aluminum is gradually increased with increasing CH₄ flow rate from 4 to 14 sccm, accompanied by a reduction of the aluminum adhesion. The wear rate of the TiC_x-coated samples as a function of the CH₄ flow rate is firstly decreased and then increased. The lowest wear rate of the PEMS-prepared samples is 7.2 × 10⁻¹⁶ m³/(N·m) obtained at a CH₄ flow rate of 14 sccm, while that of the CMS-prepared samples is 9.3 × 10⁻¹⁵ m³/(N·m) obtained at 12 sccm. Therefore, PEMS is a promising method to prepare TiC_x films with a good combination of the mechanical properties and wear-resistance against pure aluminum.     

Influence of postdeposition annealing on the properties of ZnO films prepared by RF magnetron sputtering

ZnO films were prepared on unheated silicon substrate by RF magnetron sputtering technique. Postdeposition annealing of ZnO films in vacuum were found to improve film structure and electrical characteristics, such as dense structure, smooth surface, stress relief and increasing resistivity. Suitable annealing temperature also reduced loss factor. The correlation between annealing conditions and the physical structure of the films (crystalline structure and microstructure) was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The preferred annealing condition has been found to improve ZnO film characteristics for piezoelectric applications. An over-mode acoustic resonator using the ZnO film after annealing at 400 °C in vacuum circumstance for 1 h showed a large return loss of 42 dB at the center frequency of 1.957 GHz.     

Structural and photoelectrochemical properties of SrTaO2N oxynitride thin films deposited by reactive magnetron sputtering

In this study, the influence of the degree of crystallization and thickness of films was correlated with the photoelectrochemical performance of SrTaO₂N semiconductor films for O₂ evolution reaction under visible light irradiation. Oxynitride films were deposited on various substrates using the sputtering in Ar + N₂ reactive atmosphere from a home-made SrTaO₂N target. Films with stoichiometric composition were obtained at a high temperature (T_S =800 °C) with reduced bandgap. The different substrates led to diverse degrees of film crystallization, from weakly crystallized to fully c-axis oriented. The photoelectrochemical performance was improved by improving the film crystallinity and the thickness. For further improvement of the photoelectrochemical performance, the following three limiting factors are identified: 1) low absorption coefficient, especially in the visible domain from 500 to 600 nm; 2) short lifetimes of excited charge carriers; and 3) permittivity with only moderate values lower than 10 in the visible-light domain.