瓶体内表面制备类金刚石膜流场结构的格子波尔兹曼模拟

类金刚石膜(Diamond-like Carbon,DLC)具有优异的气体阻隔性能.在PET瓶体内表面制备DLC阻隔涂层时,阻隔涂层的均匀性会受到瓶体内流场结构(气压分布、速度分布等)的显著影响.本文应用格子波耳兹曼方法(Lattice Boltzmann Method/Model,LBM)对PET瓶体内制备DLC阻隔涂层时的流场结构进行模拟,研究了送气速度、气体运动粘度系数和装置结构变化时瓶体内部流场结构的变化.研究结果表明,降低进气速度和提高气体运动粘度系数有利于减弱回流而获得层流结构;装置结构的调整能够改变瓶体内的流场结构,采用恰当的异型装置可以获得较理想的流场结构,对实验工作具有一定的指导意义.     

Effect of annealing on diamond-like carbon characteristics by electron spin resonance spectral analysis

We have examined the effect of annealing on physicochemical properties of the diamond-like carbon (DLC) films to produce higher quality films by the electron spin resonance spectral analyses of the immobilized dangling-bond sites (DBS), since amount of DBS reflects the characteristics of DLC films. On heat treatment of DLC deposited from ethylene monomer under anaerobic condition, the DBS decay was clearly shown, as the temperature raised. The decay described by second-order kinetics indicated that the recombination reaction of DBS progressed on heat treatment, suggesting that annealing treatment would accelerate the carbon-carbon covalent bonding network to produce harder films. In fact, the resulted DLC film derived from ethylene monomer showed non-existence of any type of oxygen atom based on X-ray photoelectron spectrum measurement, and water contact angle measurement showed higher hydrophobic surface of the DLC films.     

辅助气体组成对类金刚石薄膜结构和性能的影响

分别以氩气-甲烷、氩气-乙炔为辅助气体,高纯石墨为靶材,利用中频脉冲非平衡磁控溅射技术制备了类金刚石薄膜.采用Raman光谱、X射线光电子能谱、纳米压痕测试仪、原子力显微镜对所制备类金刚石薄膜的键结构、机械性能、表面形貌进行了分析.Raman光谱和X射线光电子能谱测试结果表明,以氩气-甲烷为辅助气体制备的类金刚石薄膜中sp3杂化键的含量比以氩气-乙炔为辅助气体制备的类金刚石薄膜的高.纳米压痕测试结果表明,以氩气-甲烷为辅助气体制备的类金刚石薄膜的纳米硬度比以氩气-乙炔为辅助气体的高.原子力显微镜测试结果表明,以氩气-甲烷为辅助气体制备的类金刚石薄膜的RMS表面粗糙度比以氩气-乙炔为辅助气体的低.以上结果说明辅助气体组成对类金刚石薄膜的键结构、机械性能、表面形貌有较大的影响.     

大气等离子体枪制备类金刚石薄膜

大气下,采用DBD等离子体枪为等离子体聚合装置,以甲烷为单体,氩气为工作气体,在载玻片和单晶硅片上沉积类金刚石薄膜(DLC).考察了基片预处理、内电极形状、进气方式、以及等离子体炬喷口和基材的距离对DLC薄膜沉积的影响.通过傅立叶变换红外光谱(FTIR)分析聚合膜结构并探索可能的沉积机理;表面轮廓仪测定了成膜速率;并对薄膜进行了机械性能测量.     

等离子体源离子注入法制备类金刚石薄膜

用等离子体源注入(PSII)在Si(100)上制备类金刚石膜，放电气体采用CH4，用微波电子回旋共振(ECR)产生等离子体。将-20～-30kV的高压加在衬底上，来提高离子的能量。通过Raman光谱和FT-IR光谱检测了类金刚石膜的化学组成及状态，并对其机械性能和表面形貌进行了检测。结果显示，硅片硬度和摩擦因数得到了改善，用PSII能够制备出性能优良的膜，可以将其应用到微电子器件(MEMS)上去。     

Precursor gas effect on the mechanical and optical properties of ion beam deposited diamond-like carbon films

The effect of precursor gases on the diamond-like carbon (DLC) film deposition was investigated by the direct ion beam deposition method. DLC films were deposited using methane and benzene as the precursor gases. Ion energies for the deposition range from 100 to 700 eV were achieved by adjusting the beam voltage. The residual stresses, refractive indices and optical band gaps were compared at the same ion energy. We observed significant differences in residual stress and optical properties between these films. As in r.f. plasma-assisted CVD, the residual stresses of the films deposited from benzene show a characteristic behaviour of lower ion energy deposition than those deposited from methane. The present observations are discussed in terms of the difference in ion energy per carbon atom at the growth surface. We also observed that the Ar addition effect on the residual stress is strongly dependent on the precursor gases.     

Fabrication of diamond-like carbon film on rubber by T-shape filtered-arc-deposition under the influence of various ambient gases

Diamond-like carbon (DLC) films were prepared on rubber substrates using T-shape filtered-arc-deposition (T-FAD), which effectively removes the macrodroplets emitted from the graphite cathode spot from the processing plasma. In the present study, the influence of ambient gas (no gas, Ar, H₂, C₂H₂, C₂H₄, CH₄) was investigated. The DLC films adhered well to the rubber substrate. When the substrate was stretched, the small DLC islands were separated and clefs were opened. The deposition rate on rubber was approximately twice higher than that on a Si substrate. When hydrocarbon gas was introduced as an ambient gas, the deposition rate became higher than that for no gas and H₂ gas. In the cases of C₂H₄ and CH₄ gases, the DLC film was considered to contain a considerable amount of hydrogen. When C₂H₂ gas was used, the highest deposition rate with less surface roughness was achieved.     

An examination of trace surface on diamond-like carbon film after ball-on disk measurement

Hydrogenated diamond-like carbon (DLC) films were prepared by the radio frequency plasma-enhanced chemical vapor deposition method on silicon substrates using methane (CH₄) and hydrogen (H₂) gas. The wear track on DLC films was examined after the ball-on disk (BOD) measurement with a Raman mapping method. The BOD measurement of DLC films was performed for 1 to 3 h with a 1-hour step time. The sliding traces on the hydrogenated DLC film after the BOD measurement were also observed using an optical microscope. The films synthesized in this work had a very low friction coefficient (about 0.06) and were adhered very well without peeling off during the BOD measurement even with very thin thickness. Energy dispersive X-ray spectra show the decrease of C atomic % and the increase of O atomic % according to the sliding time. The novel Raman mapping method effectively showed the graphitization of DLC films according to the sliding time.     

Metal-doped diamond-like carbon films synthesized by filter-arc deposition

Diamond-like carbon (DLC) thin films are extensively utilized in the semiconductor, electric and cutting machine industries owing to their high hardness, high elastic modulus, low friction coefficients and high chemical stability. DLC films are prepared by ion beam-assisted deposition (BAD), sputter deposition, plasma-enhanced chemical vapor deposition (PECVD), cathodic arc evaporation (CAE), and filter arc deposition (FAD). The major drawbacks of these methods are the degraded hardness associated with the low sp³/sp² bonding ratio, the rough surface and poor adhesion caused by the presence of particles. In this study, a self-developed filter arc deposition (FAD) system was employed to prepare metal-containing DLC films with a low particle density. The relationships between the DLC film properties, such as film structure, surface morphology and mechanical behavior, with variation of substrate bias and target current, are examined. Experimental results demonstrate that FAD-DLC films have a lower ratio, suggesting that FAD-DLC films have a greater sp³ bonding than the CAE-DLC films. FAD-DLC films also exhibit a low friction coefficient of 0.14 and half of the number of surface particles as in the CAE-DLC films. Introducing a CrN interfacial layer between the substrate and the DLC films enables the magnetic field strength of the filter to be controlled to improve the adhesion and effectively eliminate the contaminating particles. Accordingly, the FAD system improves the tribological properties of the DLC films.     

微波ECR等离子体源离子注入法制备DLC薄膜

用微波ECR等离子体源离子注入 (PSII)法 ,在硅片 ( 10 0 )上制备了类金刚石 (DLC)薄膜 ,工作气体采用CH4气体 ,研究了不同的气体流量对薄膜的影响。对制备的DLC薄膜 ,用拉曼光谱、FT IR光谱、AFM以及纳米压痕等手段对化学成分、化学键结构、表面形貌以及硬度等进行了表征     

Synthesis of functional diamond-like carbon nanocomposite films containing titanium dioxide nanoparticles

Synthesis of diamond-like carbon (DLC) films with UV-induced-hydrophilicity function was studied by inductively-coupled plasma (ICP) chemical vapor deposition. Titanium tetraisopropoxide (TTIP) and oxygen gases were employed as the precursors to deposit diamond-like nanocomposite films containing titanium dioxide (TiO₂) nanoparticles. X-ray diffraction and high-resolution transmission electron microscopy revealed that TiO₂ nanocrystallites were formed in the DLC films when oxygen concentration was higher than TTIP concentration during deposition. The DLC nanocomposite film was hydrophobic without ultraviolet (UV) irradiation, and became highly hydrophilic under UV irradiation, exhibiting the self-cleaning effect. A very broad peak centered at 1580 cm^− 1 was observed in the Raman spectra confirming the formation of DLC films. The hardness of the film was about 8 GPa with a stress of 3 GPa. ICP was essential in forming the photocatalytic TiO₂ nanoparticles in the DLC matrix.     

Fabrication of high frequency ZnO thin film SAW devices on silicon substrate with a diamond-like carbon buffer layer using RF magnetron sputtering

Diamond-like carbon (DLC) film is a promising candidate for surface acoustic wave (SAW) device applications because of its higher acoustic velocity. A zinc oxide (ZnO) thin film has been deposited on DLC film/Si substrate by RF magnetron sputtering; the optimized parameters for the ZnO sputtering are RF power density of 0.55 W/cm², substrate temperature of 380 °C, gas flow ratio (Ar/O₂) of 5/1 and total sputter pressure of 1.33 Pa. The results showed that when the thickness of the ZnO thin films was decreased, the phase velocity of the SAW devices increased significantly.     

Adhesion property of SiOx-doped Diamond-like Carbon Films Deposited on Polycarbonate by Inductively Coupled Plasma Chemical Vapor Deposition

SiO_x-DLC (diamond-like coating) films as candidates for protection coating of polymers were prepared by using a pulse-biased inductively coupled plasma chemical vapor deposition system with acetylene, tetramethylsilane and oxygen gasses. Effects of the gas composition and O₂ plasma pre-treatment on adhesion of the SiO_x-DLC films were investigated. Adhesion strength of Si-DLC films (with 0% oxygen) was almost the same to that of undoped DLC films. By employing O₂-plasma pre-treatment, adhesion strength of the Si-DLC films was considerably improved, while that of the undoped DLC films was not. The SiO_x-DLC films with the carbon to oxygen (O/C) ratio of 0.15 showed adhesion strength as high as that of the Si-DLC films on the O₂-plasma pre-treated substrate. However, further improvement of adhesion strength of the SiO_x-DLC was not realized by employing the O₂-plasma pre-treatment. On the other hand, the SiO_x-DLC films showed favorable feature of high deposition rate and large optical band gap although higher O/C ratio (> 0.15) brought about poor adhesion strength of the films.     

Tribological properties of multilayer DLC/W-DLC films on Si

Multilayer films of diamond-like carbon (DLC) and tungsten-containing diamond-like carbon (W-DLC) films were deposited onto silicon wafers using radio frequency chemical vapor deposition (RFCVD) and a magnetron sputtering method. The W-DLC layer was deposited on the silicon wafer with less than 60 W magnetron output. The DLC layer was then deposited on the W-DLC layer.Surface morphology was investigated by atomic force microscopy and the film structure by transmission electron microscopy. Friction tests for multilayered films were performed in a nitrogen atmosphere at room temperature using a ball-on-disk tribometer. A conventional stainless steel ball was used for the test.The surface profiles seen by atomic force microscopy showed that round-shaped clusters of around 100 nm were observed in just the single W-DLC layer. These clusters were considered to be tungsten or tungsten-carbon composites. In the case of the DLC/W-DLC multilayered structure, the top DLC layer covered the W-DLC single layer and smoothed the surface of the W-DLC film.Friction tests demonstrated that the friction coefficient of the W-DLC single layer was above 0.6 and increased gradually as the number of cycle increased. The W-DLC films partially broke down during our measurements. However the DLC/W-DLC multilayer films showed stable friction properties and were observed for up to 100,000 cycles. Their friction coefficient was typically less than 0.1 at 10 cm/s rotating speed. The DLC/W-DLC multilayer films exhibited stable low friction properties in a long term test under a nitrogen atmosphere.     

Deposition of diamond-like carbon films on the inner surface of narrow stainless steel tubes

Diamond-like carbon (DLC) films were deposited on the inner surface of 304-type stainless steel tube with an inner diameter of 10 mm by DC glow discharge plasma. The influence of the deposition time, pressure and the ratios of CH₄ in CH₄/Ar gas mixture on the DLC film deposition were investigated. The images of Scanning Electron Microscopy (SEM) show that the DLC films are featureless and free of porosity. Fibre-like structure was recognized on the film surface by Atomic Force Microscopy (AFM). The film deposition rate decreases with increasing the deposition time. Relative higher deposition rate (40 nm/min) can be obtained at 20-30 Pa, higher and lower pressure will significantly decrease the deposition rate. Raman spectrum analysis shows that the films deposited in 30 min at 20-30 Pa have more sp³ content. The corrosion resistance of the films was measured by potentiodynamic polarization test. The DLC films deposited on the inner surface of the 304-type stainless steel tube significantly improve its corrosion resistance.     

Influence of hydrogen on the mechanical properties and microstructure of DLC films synthesized by r.f.-PECVD

This paper aims to investigate the influence of hydrogen on the variation of mechanical properties and microstructure of diamond-like carbon (DLC) films synthesized by radio frequency plasma chemical vapor deposition (r.f.-PECVD). The DLC films were deposited on a silicon substrate (p-type). The reactant gases employed in this paper are a mixture of acetylene and hydrogen. The ratio of hydrogen in the gas mixture was successively varied to clarify its influence on the roughness, thickness, microstructure, hardness, modulus, residual stress and wear depth for the DLC films. The results reveal that increasing the concentration of hydrogen decreases thickness and roughness. Meanwhile, increasing the hydrogen concentration causes the decrease of sp³ ratio, hardness as well as modulus. Finally, wear behavior is correlated to the surface morphology and hydrogen concentration for deposition with hydrogen-containing reactant gas.     

非平衡磁控溅射技术制备用于红外减反射的无氢碳膜

红外减反射保护膜具有特定的厚度要求,如能进一步减小无氢类金刚石膜(DLC)的光学吸收,就能使其在较大厚度时不过分损失光通量而得以广泛应用.从这点来讲,无氢类金刚石膜是一种极具开发潜力的材料.本文采用非平衡磁控溅射技术(UBMS)制备了无氢类金刚石膜,并研究了其厚度均匀性.研究结果表明:该非平衡磁控溅射装置有能力获得大于φ150 mm的均匀性范围.对DLC膜红外透射谱的分析表明,分别在Si和Ge基底表面单面制备的DLC薄膜,其峰值透射率在波数2983/cm时分别为68.83%和63.05%,这一结果接近无吸收碳材料理论上所能达到的值.同时,在5000到800/cm范围内,未发现明显的吸收峰.这些优良的光学特性表明,采用非平衡磁控溅射技术制备的无氢DLC膜可以作为窗口的红外增透保护膜使用.     

Adhesion studies of diamond-like carbon films deposited on Ti6Al4V substrate with a silicon interlayer

Diamond-like carbon (DLC) films have proven quite advantageous in many tribological applications due to their low friction coefficient, their extreme hardness, and more recently their high adherence on different substrate materials. However, for many applications, DLC films as thick as 2 μm are required, which cause high residual stress. In order to overcome this problem, this study observed the behavior of different thicknesses of silicon interlayer between DLC films and Ti6Al4V substrates. The study also analyzed the relation of growth parameters to the mechanical properties of DLC films. Silicon and DLC films were grown by using a rf-PECVD at 13.56 MHz with silane and methane atmospheres, respectively. The contribution of an interlayer thickness to the adhesion between the DLC films and Ti6Al4V substrate was evaluated by using a micro-scratch technique. The hardness and friction coefficient were evaluated by using microindentation and lateral force microscopy (LFM), respectively. Raman scattering spectroscopy was used to characterize the film quality. A correlation was found between the intrinsic stress and adhesion of DLC film and the parameters of the silicon interlayer growth. The addition of a silicon interlayer successfully reduced intrinsic stress of the films, even as measured by using a perfilometry technique.     

Characterization and tribological application of diamond-like carbon (DLC) films prepared by radio-frequency plasma-enhanced chemical vapor deposition (RF-PECVD) technique

Diamond-like carbon (DLC) films were successfully prepared on glass substrates and surfaces of selenium drums via radio frequency plasma enhanced chemical vapor deposition method. The microstructure, surface morphology, hardness, film adhesion, and tribological properties of the films were characterized and evaluated by X-ray photoelectron spectroscopy, atomic force microscopy, and micro-sclerometer and friction-wear spectrometer. The results showed that DLC films have smooth surfaces, homogeneous particle sizes, and excellent tribological properties, which can be used to improve the surface quality of the selenium drums and prolong their service life.     

Microstructure and property evolution of Cr-DLC films with different Cr content deposited by a hybrid beam technique

Cr-containing diamond-like carbon (Cr-DLC) films was deposited on silicon wafers by a hybrid beams system, which consists of a DC magnetron sputtering and a linear ion source. The chromium content in the films was adjusted by varying the fraction of Ar in the Ar and CH₄ gas mixture. The composition, microstructure, surface morphology, mechanical properties and tribological behavior of the films were investigated by XPS, TEM, AFM, SEM, nano-indentation and tribological tester as a function of Cr content. It is shown that, as the Cr content increased from 1.49 to 40.11 at.%, the Cr-DLC films transfer from amorphous DLC with dispersed metallic-like Cr to composite DLC with carbide phases embedding in the DLC matrix, and the film surface morphology also evolve from flat surface into rough surface with larger hillocks. The amorphous Cr-DLC films exhibit a low friction coefficient and wear rate as pure DLC, while the composite Cr-DLC films show a higher friction coefficient and wear rate, although they possess a relatively high hardness.