Characteristics and mechanical properties of titanium-containing diamond like carbon films deposited by cathodic arc evaporation

Depositions of titanium-containing diamond-like carbon (Ti-DLC) films were conducted by mixing C+ and Ti+ plasma streams originated from cathodic arc plasma sources in argon (Ar). The deposition was processed at Ti target current ranging from 20 Amp to 70 Amp. Film characteristics were investigated using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS). Film microstructures were evaluated using field emission scanning electron microscopy (FEGSEM), an atomic force microscope (AFM), X-ray diffractometry (XRD) and high-resolution transmission electron microscopy (HRTEM). Mechanical properties were investigated by using a nanoindentation tester and ball on disc wear test. Results shows that surface roughness (Ra) of the films ranged between 2.4 and 7.2 nm and roughness increased relative to the increase in Ti target current. The FESEM studies showed that the surface micrographs of Ti-DLC films revealed a cauliflower-like microstructure and the cross-sectional micrograph revealed a snake-skin like structure. HRTEM studies showed that the Ti-DLC films consisted of nano scale TiC particles which were comparable with low angle XRD and XPS results. XPS analysis established that the Ti2p spectrum is present when the Ti target current reaches 30 Amp or higher. Ti concentration increased as the Ti target current was increased. An extremely thin TiO2 layer exists on the top of the Ti-DLC films which was comparable with the AES results. The film thickness which could be deposited for Ti-DLC is much higher than that of conventional DLC films. Nanoindentation tests show that the nanohardness of the films ranging 15-22 GPa, with Er values ranging from 145 to 175 GPa. The wear test demonstrates the friction coefficient of the 420SS substrate, DLC and Ti-DLC films were about 0.8, 0.3 and 0.2, respectively. Obviously, the friction coefficients of the Ti-DLC films were lower than that of the DLC films.     

沉积气压对电弧离子镀制备MgO薄膜的结构及性能的影响

采用阴极真空电弧离子沉积技术在玻璃及Si衬底上成功地制备了具有择优结晶取向的透明MgO薄膜。利用X射线衍射仪（XRD）、扫描电子显微镜（SEM）及紫外-可见吸收光谱仪分别对MgO薄膜微观结构、表面形貌及可见光透过率进行了测试与分析。XRD结果表明,所制备的MgO薄膜具有NaCl型立方结构的（100）、（110）和（111）3种结晶取向,在沉积气压为0.7～3.0Pa的范围内,薄膜的择优结晶取向随沉积气压的升高先由（100）转变为（110）,最后变为（111）。SEM图表明随着沉积气压的升高,MgO薄膜的晶粒逐渐变小,薄膜结晶质量变差。在380～900nm范围内,沉积气压为0.7Pa下制备的MgO薄膜其可见光透过率高于90%,随着沉积气压的升高,薄膜的可见光透过率有所下降。     

沉积气压对电弧离子镀制备ZnO薄膜的结构和性能影响

采用阴极真空电弧离子镀技术在玻璃衬底上制备出了具有择优取向的透明ZnO薄膜. 利用X射线衍射仪、扫描电子显微镜及紫外-可见吸收光谱仪分别对ZnO薄膜的结构、表面形貌及可见光透过率进行了分析.XRD结果表明,所制备的ZnO薄膜具有六角纤锌矿结构的(002)和(101)两种取向,在沉积气压＞1.0Pa时所制备的ZnO薄膜具有(002)择优取向,并且非常稳定.SEM图表明,ZnO晶粒大小较为均匀,晶粒尺寸随着气压升高而变小.在400～1000nm范围内,ZnO薄膜的可见光透过率超过80%,吸收边在370nm附近,所对应的光学带隙约为3.33～3.40eV,并随着沉积气压上升而变大.     

Phase separated AlSi thin films prepared by filtered cathodic arc deposition

Phase separated AlSi films composed of Al cylinders embedded in an amorphous Si matrix were prepared on conducting Si substrates by filtered cathodic arc deposition. The compositional dependence of AlSi films on a negative substrate bias showed a different trend depending on the cathode composition because of the self-sputtering process during the deposition. The porous structure was obtained from the phase separated AlSi film after removal of Al cylinders by wet etching in an ammonia solution. Scanning electron microscope images of the etched AlSi films showed that the average diameter of pores was increased from 3 nm to 7 nm by applying a negative substrate bias voltage during the deposition. The honeycomb ordered arrangement of pores was observed at 0 V and − 25 V substrate bias. The substrate temperature during the depositions had almost the same effect on the film morphologies as the negative substrate bias.     

Transparent conducting ZnO thin films deposited by vacuum arc plasma evaporation

A high rate deposition of co-doped ZnO:Ga,F and ZnO-In₂O₃ multicomponent oxide thin films on large area substrates has been attained by a vacuum arc plasma evaporation method using oxide fragments as a low-cost source material. Highly transparent and conductive ZnO:Ga,F and ZnO-In₂O₃ thin films were prepared on low temperature substrates at a deposition rate of approximately 375 nm/min with a cathode plasma power of 10 kW. A resistivity of 4.5×10⁻⁴ Ω cm was obtained in ZnO:Ga,F films deposited at 100 °C using ZnO fragments co-doped with 1 wt.% ZnF₂ and 1 wt.% Ga₂O₃ as the source material. In addition, the stability in acid solution of ZnO films was improved by co-doping. It was found that the Zn/(In+Zn) atomic ratio in the deposited ZnO-In₂O₃ thin films was approximately the same as that in the fragments used. The ZnO-In₂O₃ thin films with a Zn/(In+Zn) atomic ratio of approximately 10-30 at.% deposited on substrates at 100 °C exhibited an amorphous and smooth surface as well as a low resistivity of 3-4×10⁻⁴ Ω cm.     

Effect of bias voltage on microstructure, mechanical and wear properties of Al-Si-N coatings deposited by cathodic arc evaporation

Al-Si-N coatings were deposited on tungsten carbide (WC-Co) and silicon wafer substrates using Cr and AlSi (12 at.% Si) alloy targets using a dual cathode source with short straight-duct filter in the cathode arc evaporation system. Al-Si-N coatings were synthesized under a constant flow of nitrogen, using various substrate bias voltages at a fixed AlSi cathode power. To enhance adhesive strength, the Cr/(Cr_xAl_ySi_z)N graduated layer between the top coating and the substrate was deposited as a buffer interlayer. The effects of bias voltage on the microstructure, mechanical and wear properties of the Al-Si-N films were investigated. Experimental results reveal that the Al-Si-N coatings exhibited a nanocomposite structure of nano-crystalline h-AlN, amorphous Si₃N₄ and a small amount of free Si and oxides. It was also observed that the deposition rate of as-deposited films gradually decreased from about 25.1 to 18.8 nm/min when the substrate bias was changed from − 30 to − 150 V. The XRD results revealed that h-AlN preferred orientation changed from (002) to (100) as the bias voltage increased. The maximum hardness of approximately 35 GPa was obtained at the bias voltage of −90 V. Moreover, the grain size was inversely proportional to the hardness of the film. Wear test results reveal that the Al-Si-N film had a lower coefficient of friction, between 0.5 and 0.7, than that 0.7 of the AlN film.     

Optical and photoconductivity properties of ZnO thin films grown by pulsed filtered cathodic vacuum arc deposition

High quality transparent conductive ZnO thin films with various thicknesses were prepared by pulsed filtered cathodic vacuum arc deposition (PFCVAD) system on glass substrates at room temperature.The high quality of the ZnO thin films was verified by X-ray diffraction and optical measurements. XRD analysis revealed that all films had a strong ZnO (200) peak, indicating c-axis orientation. The ZnO thin films are very transparent (92%) in the near vis regions. For the ZnO thin films deposited at a pressure of 0.086 Pa (6.5 × 10⁻⁴ Torr) optical energy band gap decreased from 3.21 eV to 3.19 eV with increasing the thickness. Urbach tail energy also decreased as the film thickness increased.Spectral dependence of the photoconductivity was obtained from measurements of the samples deposited at various thicknesses. Photoconductivities were observed at energies lower than energy gap which indicates the existence of energy states in the forbidden gap. Photoconductivities of ZnO thin films increase with energy of the light and reach its maximum value at around 2.32 eV. Above this value surface recombination becomes dominant process and reduces the photocurrent. The photoconductivity increases with decreasing the film thickness.     

Hemocompatibility of ZnO thin films prepared by filtered cathodic vacuum arc deposition

Zinc Oxide (ZnO) thin films were prepared by cathodic vacuum arc deposition (CVAD) and filtered cathodic vacuum arc deposition (FCVAD) technology with a mixture of O₂, Ar and N₂. XRD patterns indicated that ZnO thin films prepared by CVAD had a combined orientation of ZnO (002) and ZnO (101). The preferential orientation ZnO (002) could be obtained at an optimum deposition pressure. On the other hand, a perfectly oriented ZnO (002) thin film prepared by FCVAD was obtained in lower pressure, which was beneficial to enhance the crystallization. The wetting behavior showed that all the ZnO thin films prepared by FCVAD were hydrophobic with low surface energy, but the reference samples of the polyurethane (PU) and glass are hydrophilic. Platelet adhesion test indicated that fewer platelets adhered and aggregated on the ZnO thin films prepared by FCVAD. The mechanism of hemocompatibility of ZnO thin films has also been investigated. It is suggested that hydrophobic surface with lower polar component and adhesive work are the two factors responsible for the excellent hemocompatibility.     

Evaluation of microstructures and mechanical properties of diamond like carbon films deposited by filtered cathodic arc plasma

Diamond-like carbon (DLC) films were deposited by a cathodic arc plasma evaporation (CAPD) process, using a mechanical shield filter combined with a magnetic filter with enhanced arc structure at substrate-bias voltage ranging from − 50 to − 300 V. The film characteristics were investigated using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and high-resolution transmission electron microscopy (HRTEM). The mechanical properties were investigated by using a nanoindentation tester, scratch test and ball on disc wear test. The Raman spectra of the films showed that the wavenumber ranging from 900 to 1800 cm^− 1 could be deconvoluted into 1140 cm^− 1, D band and G band. The bias caused a significant effect on the sp³ content which was increased with the decreasing of I_D/I_G ratio. The XPS spectra data of the films which were etched by H⁺ plasma indicated the sp³ content are higher than those of the as-deposited DLC films. This implied that there is a sp²-rich layer present on the surface of the as-deposited DLC films. The nanoindentation hardness increased as the maximum load increased. A 380 nm thick and well adhered DLC film was successfully deposited on WC-Co substrate above a Ti interlayer. The adhesion critical load of the DLC films was about 33 N. The results of the wear tests demonstrated that the friction coefficient of the DLC films was between 0.12 and 0.2.     

Influence of Ge addition on the morphology and properties of TiN thin films deposited by magnetron sputtering

Thin films of TM-X-N (TM stands for early transition metal and X = Si, Al, etc.) are used as protective coatings. The most investigated among the ternary composite systems is Ti-Si-N. The system Ti-Ge-N has been chosen to extend the knowledge about the formation of nanocomposite films. Ti-Ge-N thin films were deposited by reactive magnetron sputtering on Si and WC-Co substrates at T_s = 240 °C, from confocal Ti and Ge targets in mixed Ar/N₂ atmosphere. The nitrogen partial pressure and the power on the Ti target were kept constant, while the power on the Ge target was varied in order to obtain various Ge concentrations in the films. No presence of Ge-N bonds was detected, while X-ray photoelectron spectroscopy measurements revealed the presence of Ti-Ge bonds. Transmission Electron Microscopy investigations have shown important changes induced by Ge addition in the morphology and structure of Ti-Ge-N films. Electron Energy-Loss Spectrometry study revealed a significant increase of Ge content at the grain boundaries. The segregation of Ge atoms to the TiN crystallite surface appears to be responsible for limitation of crystal growth and formation of a TiGe_y amorphous phase.     

Oxygen partial pressure dependence of the structural properties of CdO thin films deposited by a modified reactive vacuum evaporation process

Thin films of cadmium oxide were thermally deposited on glass substrates at partial pressures of oxygen, pO₂ in the range 1.33×10⁻² to 0.133 Pa at a substrate temperature of 160 °C. Energy dispersive analysis of X-ray fluorescence (EDAX) revealed that the CdO films deposited at pO₂ value of 4.00×10⁻² Pa were nearly stoichiometric. X-ray diffractometry (XRD) confirmed the polycrystalline nature of the film structure. All the films showed an fcc structure of the NaCl-type, as the dominant phase. The films exhibited preferred orientation along the (1 1 1) diffraction plane. The texture coefficients calculated for the various planes at different oxygen partial pressures (pO₂) indicated that the maximum preferred orientation of the films occurred along the (1 1 1) plane at an oxygen partial pressure of 4.00×10⁻² Pa. This was interpreted in terms of oxygen chemisorption and desorption processes. The lattice parameters determined from the diffraction peaks were in the range 4.655–4.686 Å. The average lattice parameter a₀ found by extrapolation using the Nelson–Riley function was 4.696 Å. Both the lattice parameter and the crystallite size were found to increase with increased partial pressure of oxygen. On the other hand, the strain and dislocation density were found to decrease as the partial pressure of oxygen was raised. A maximum (80%) in the optical transmittance at λ=600 nm and minimum in the electrical resistivity (9.1×10⁻⁴ Ω cm) of the films occurred at an optimum partial pressure of oxygen of 4.00×10⁻² Pa. The results are discussed.     

Analysis on microstructure and characteristics of TiAlN/CrN nano-multilayer films deposited by cathodic arc deposition

In this study, TiAlN/CrN multilayer thin films were deposited on SUS 403 stainless steel by cathodic arc deposition. The effects of substrate orientation (substrate surface parallel/perpendicular to target surface) and rotation speed were investigated in detail. Microstructure of the coatings was analyzed by X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy. Meanwhile, tribological and corrosion tests were performed. The experimental results showed that the as-deposited films exhibit a nano-scale multilayer structure consisting of TiAlN and CrN phases. The TiAlN/CrN multilayer films prepared by a parallel orientation and a rotation speed of 4 rpm not only possesses the best coating hardness and hardness/elastic modulus ratio, but also reveals superior abrasion resistance and corrosion resistance.     

Physical properties of very thin SnS films deposited by thermal evaporation

SnS films with thicknesses of 20-65 nm have been deposited on glass substrates by thermal evaporation. The physical properties of the films were investigated using X-ray diffraction (XRD), scanning electron microscopy, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and ultraviolet-visible-near infrared spectroscopy at room temperature. The results from XRD, XPS and Raman spectroscopy analyses indicate that the deposited films mainly exhibit SnS phase, but they may contain a tiny amount of Sn₂S₃. The deposited SnS films are pinhole free, smooth and strongly adherent to the surfaces of the substrates. The color of the SnS films changes from pale yellow to brown with the increase of the film thickness from 20 nm to 65 nm. The very smooth surfaces of the thin films result in their high reflectance. The direct bandgap of the films is between 2.15 eV and 2.28 eV which is much larger than 1.3 eV of bulk SnS, this is deserving to be investigated further.     

CrAlN coatings deposited by cathodic arc evaporation at different substrate bias

CrAlN is a good candidate as an alternative to conventional CrN coatings especially for high temperature oxidation-resistance applications. Different CrAlN coatings were deposited on hardened steel substrates by cathodic arc evaporation (CAE) from chromium-aluminum targets in a reactive nitrogen atmosphere at negative substrate bias between − 50 and − 400 V. The negative substrate bias has important effects on the deposition growth rate and crystalline structure. All our coatings presented hardness higher than conventional CrN coatings. The friction coefficient against alumina and tungsten carbide balls was around 0.6. The sliding wear coefficient of the CrAlN coatings was very low while an important wear was observed in the balls before a measurable wear were produced in the coatings. This effect was more pronounced as the negative substrate bias was increased.     

Microstructure evolution and age hardening in (Ti,Si)(C,N) thin films deposited by cathodic arc evaporation

Ti_1 − xSi_xC_yN_1 − y films have been deposited by reactive cathodic arc evaporation onto cemented carbide substrates. The films were characterized by X-ray diffraction, elastic recoil detection analysis, transmission electron microscopy, energy-dispersive X-ray spectroscopy, electron-energy loss spectroscopy and nanoindentation. Reactive arc evaporation in a mixed CH₄ and N₂ gas gave films with 0 ≤ x ≤ 0.13 and 0 ≤ y ≤ 0.27. All films had the NaCl-structure with a dense columnar microstructure, containing a featherlike pattern of nanocrystalline grains for high Si and C contents. The film hardness was 32-40 GPa. Films with x > 0 and y > 0 exhibited age-hardening up to 35-44 GPa when isothermally annealed up to 900 °C. The temperature threshold for over-ageing was decreased to 700 °C with increasing C and Si content, due to migration of Co, W and Cr from the substrate to the film, and loss of Si. The diffusion pathway was tied to grain boundaries provided by the featherlike substructure.     

Deposition and characterization of TiBCN films by cathodic arc plasma evaporation

TiBCN thin films were deposited on Si(100) substrate by reactive cathodic arc evaporation from a graphite/boron-containing composite target and Ti target in an N₂ atmosphere. Characteristics and microstructures of the films were investigated, deposited under different target currents. Raman spectroscopy and high resolution X-ray photoelectron spectroscopy (HRXPS) were employed to investigate the spectrum and bonding states of films. The film microstructures were evaluated by using an atomic force microscope (AFM), a field emission scanning electron microscopy (FEGSEM), a glancing angle X-ray diffractometry (GAXRD) and a high-resolution transmission electron microscopy (HRTEM). Results demonstrated that the TiBCN films were synthesized successfully and adhered well to the silicon substrate. The Raman spectra showed that wavenumbers ranging from 900 to 1800 cm^− 1 consisted of D and G bands, similar to that of cathodic arc plasma deposited DLC. Raman spectra proved that the intensity of D and G bands decreased by increasing Ti target currents. HRTEM results established that TiBCN films revealed an amorphous structure while the Ti target current was low. As the Ti target current increased, the TiBCN films revealed a nanocomposite structure, an amorphous matrix consisting of nano scale Ti(C,N) and TiB crystalline, which were comparable to GAXRD, Raman and HRXPS results. The HRXPS spectra of B1s, C1s, N1s and Ti2p in the TiBCN films reveal much broader peaks; this indicated that there is more than one category of bonding state surrounding each of Ti, B, C and N atoms. Morphology, characteristics and film concentration as a function of deposition parameters were also investigated in this study.     

Synthesis and properties of CeN thin films deposited by arc ion plating

Cerium nitride films were deposited by ion plating in an electron-beam sustained Ce arc discharge in a nitrogen atmosphere. The crystal structure was strongly affected by the arc discharge current and the substrate temperature. The lattice spacing of CeN film is 0.5020 nm with a density of 7.82 g cm^–3. This film showed a paramagnetic property at 10 K in a magnetic field of 20 kOe. The Knoop hardness for CeN film is over 1600. The electrical resistivity was 4.6 × 10^–4 cm with p-type conductivity. The carrier concentration of the CeN film increased after exposure to the air, which suggested that the valence of Ce in CeN is probably 4+.     

Deposition of zirconium oxynitride films by reactive cathodic arc evaporation and investigation of physical properties

The area of metal oxynitrides is poorly explored, and understanding of the fundamental mechanism that explains structural, mechanical, electrical, and optical properties is still insufficient. Therefore, the purpose of the present investigation is to analyze structural, electrical, and optical properties of ZrN_xO_y films deposited by reactive cathodic arc evaporation.Depending on the oxygen flow, cubic ZrN:O, monoclinic ZrO₂:N, and tetragonal ZrO₂:N phases films were prepared. The sheet resistance and the optical transmittance very much depend on the oxygen flow. Optical transparent ZrN_xO_y films with transmittance of 86% at 650 nm, the sheet resistance 1.1 · 10³ Ω/sq, and the figure of merit 2 · 10^− 4 Ω^− 1 are deposited with the 60 sccm oxygen flow.     

Effect of precursor ratio on the structural properties of ZnO thin films deposited by low pressure MOCVD

The effect of precursor ratio (H2O/DEZ) on the texture orientation, surface morphology, optical transparency and electrical resistivity of ZnO thin films deposited by MOCVD was investigated. Deposition temperature and pressure were fixed at 120 degrees C and 0.67 torr, respectively. The precursor ratio was varied between 0.1 and 4. It was found that the texture orientation changed from (0002) to (1120) with increase of the precursor ratio. (1120) textured film shows well facetted tetrapod like rough surface morphology, which scatters the incident light very effectively. The electrical resistivity was in the range of about 0.1 omega cm in the undoped state, which was found to decrease with increase of the film thickness and decrease of the precursor ratio.