XPS study of the a-C:H/Ti and a-C:H/a-Si interfaces

In this study ultrathin hydrogenated amorphous carbon (a-C:H) films have been grown onto the titanium and amorphous silicon (a-Si) overlayers by direct ion beam deposition using acetylene gas as a hydrocarbon source. X-ray photoelectron spectroscopy (XPS) was used for study of the DLC-Ti and DLC-Si interfaces. It was revealed that a-Si is a good interlayer for improvement of adhesion in the case of diamond-like carbon film deposition onto the steel substrate at room temperature. a-C:H film growth without substantial intermixing occurred on the a-Si. On the other hand, adhesion between the Ti interlayer and the diamond like carbon film was very sensitive to the deposition conditions (presence of the pump oil) as well as structure and stress level of the Ti film. It was explained by strong intermixing between the growing carbon film and Ti. Bad adhesion between the growing DLC film and Ti interlayer was observed despite formation of the TiC. At the same time, formation of the TiO_x was not an obstacle for good adhesion. It is shown that composition of the used hydrocarbon gas, structure of the Ti thin film and mechanical stress in it had greater influence on adhesion with a-C:H film than elemental composition of the Ti interlayer surface.     

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.     

Study of diamond-like carbon films on LiNbO3

Diamond-like carbon (DLC) films have been successfully deposited on Y-cut LiNbO₃ substrates using the plasma enhanced CVD technique. A thin interlayer of SiC between the DLC films and the LiNbO₃ is necessary to ensure a good adhesion of the DLC films to the LiNbO₃ substrate. The physical properties and structural network of the DLC films have been investigated in detail. It is observed that the film hardness is increased with increasing the film thickness, as is the adhesion of the DLC films to the LiNbO₃ substrates. The effect of accelerating surface acoustic wave by the DLC films has been confirmed.     

H13钢离子渗氮(PN)与类金刚石(DLC)复合处理的摩擦磨损性能研究

采用阳极层流离子源与非平衡磁控溅射结合的沉积方法在H13钢基体表面沉积出类金刚石膜(DLC),并对H13钢经不同表面预处理对后沉积的DLC膜的摩擦学性能进行了对比研究.结果表明:DLC膜结构致密,且DLC膜与梯度过渡层及基体三者之间结合牢固;H13钢经离子氮化后,梯度过渡层与氮化层间结合紧密,提高了膜与基体的承载能力;在保持相同摩擦速率的条件下,摩擦系数随着载荷的增加先增大后减小;H13钢离子渗氮处理后沉积的DLC膜其摩擦系数远小于未采用离子渗氮处理沉积的DLC薄膜.     

TiNi合金表面沉积类金刚石薄膜的性能评价

类金刚石膜作为新型的生物材料得到了广泛的关注。本实验制备的薄膜为典型的类金刚石膜,膜层比较致密、均匀和光滑。膜层硬度随离子束能量变化,在束电源为750V附近出现峰值,硬度达到了15GPa,该膜的摩擦系数为0.124。在Troyde’s模拟体液中的电化学分析表明,类金刚石膜显著提高了TiNi合金表面抗点蚀能力。     

Fabrication and characterization of solid oxide fuel cell electrolyte films by electron beam vapor deposition

Thin films of SDC for SOFC electrolyte were prepared using electron beam deposition technique. The influence of annealing temperature, substrate temperature and e-beam gun power on the structure and surface morphology of the thin films was examined. It was found that the SDC thin films annealed at 800 degrees C consisted of a single cubic phase and the main crystal structure of the thin films represented those of evaporated electrolyte powders. The crystal orientation of the SDC films increased with substrate temperature and decreased with e-beam gun power. The higher XRD peak intensity was observed for the SDC films deposited on NiO-YSZ substrate compared with those on SiO2 substrate due to the polycrystalline structure of the NiO-YSZ substrate. A good adhesion to the substrate and a columnar structure were observed by the fractured cross-sectional view of the SDC films on NiO-YSZ anode substrate. Electrical conductivity of SDC film with 5 microm thickness was observed to be 2.31 x 10(-3) Sm(-1) at 800 degrees C.     

Dynamic interaction of floating substrates with an ion beam from a three grid microtech system operated without neutralizer

A 3 grid commercial ion gun was operated at efficient microtech condition but without a neutralizer, and the substrate was allowed to float to high voltages. The space charge effects of the ion beam, which was blocked by the substrate, were traced also by a movable floating probe. The substrate voltage and the deposition energy could be partly controlled by affecting the secondary electron generation at the decelerating grid of the ion gun. The technique was used to deposit diamond-like carbon (DLC) films at energies below 30 eV, which were harder than usual.     

Ion beam energy effects on structure and properties of diamond like carbon films deposited by closed drift ion source

In the present study DLC films deposited from acetylene gas by a closed drift ion source were investigated. Ion beam energy effects on structure as well as optical and electrical properties of the synthesized films were studied. Non-monotonic dependence of structure of the DLC films on ion beam energy was observed. The highest sp³/sp² ratio as well as highest optical transparency was observed in the case of the films synthesized by 500 eV energy ion beam. However, the bandgap of the DLC films synthesized by 500 eV energy ion beam was the lowest between all investigated samples, while resistivity non-monotonically decreased with increase of the ion beam energy. These results were explained by changes of the sp³/sp² ratio, structure of sp² bonded clusters as well as hydrogen content in the film due to the competition between the increased (decreased) ion beam energy and decreased (increased) ion/neutral ratio.     

铜合金垫片表面类金刚石薄膜的制备及其摩擦学性能研究

采用物理气相沉积工艺在黄铜H62垫片上制备了DLC薄膜,对DLC薄膜进行了拉曼光谱分析和截面形貌观察,测试了薄膜厚度、纳米硬度和结合力,进行了磨擦磨损试验,分析了薄膜的减摩耐磨性能。结果表明,在H62铜合金垫片制备碳膜为DLC薄膜,薄膜总厚约2.31μm,底层厚约0.49μm。薄膜纳米硬度22.1 GPa,薄膜与基体结合良好,结合性能HF1级,结合力41.1 N。H62铜合金垫片制备DLC薄膜后,摩擦系数由0.55降至0.25,磨损率由1.3×10^-4 mm³/Nm降至1.1×10^-5 mm³/Nm,具有优异的减磨性能和耐磨损性能。装拆10次后,垫片表面DLC薄膜完整,基本无损伤,满足使用要求。     

类金刚石薄膜在不锈钢表面结合强度及耐腐蚀性研究

类金刚石(DLC)薄膜与不锈钢的结合强度是DLC薄膜应用于血管支架表面改性的关键技术问题.利用磁过滤阴极真空弧源沉积方法在316L不锈钢表面沉积DLC薄膜,研究沉积时基体偏压、薄膜厚度以及钛过渡层对DLC薄膜与基体结合强度的影响.研究结果表明,316L表面制备相同厚度的DLC薄膜,采用-1000V脉冲偏压制备的薄膜结合强度明显优于-80V直流偏压下制备的DLC薄膜;随着DLC薄膜厚度的增大,DLC薄膜与316L基体的结合力下降;316L不锈钢表面制备一层100nm的钛过渡层之后可以改善DLC薄膜的结合状况,并且经过20%的拉伸变形后,DLC薄膜完整,耐蚀性优于未表面处理的316L不锈钢.以上研究结果表明,磁过滤阴极真空弧源方法制备DLC薄膜与316L结合强度高,可以有效的提高316L的耐腐蚀性,是一种具有应用前景的血管支架表面改性方法.     

A compact ion source using a hollow cathode discharge and its application to thin film formation

A compact and simple ion beam source was developed and its application to ion beam sputter deposition of thin films was studied. The ion source consisted of a hollow cathode, an anode and an extraction electrode. Two acceleration electrodes were mounted at the edge of the cathode. Since the gas pressure in the cathode should be kept at a relatively high value (more than 0.05 Torr) to maintain the discharge, the ion source employed a differential pumping system. The fundamental discharge characteristics of the ion source were studied using argon or helium as the working gas.The ion source was applied to the ion beam sputter deposition of copper and ruthenium oxide films. The crystallinity of the copper films increased with an increase in the acceleration voltage, while all the ruthenium oxide films appeared to be amorphous or of very small grain size, regardless of the acceleration voltage. The effect of the acceleration voltage on the film resistivity was also studied.     

DLC膜厚度对镁基表面DLC/MAO复合膜层性能的影响

采用线性离子束沉积技术于AZ80镁合金微弧氧化(MAO)陶瓷层表面沉积不同厚度的类金刚石碳(DLC)膜,形成DLC/MAO复合膜层。对比研究4种膜基系统的表面结构特征、力学性能以及摩擦学性能差异。结果表明:随DLC膜厚度增加,复合膜层表面微孔数量减少,孔径减小,但凹凸不平趋势增加,且DLC膜表面颗粒特征更加明显,表现为DLC-80min/MAO/AZ80膜基系统具有最小的表面粗糙度,最大的硬度H、弹性模量E及H/E值;不同厚度DLC/MAO/AZ80膜基系统平均摩擦因数较MAO/AZ80显著降低;DLC膜厚度增加导致3种复合膜基系统的表面微观结构改变,使得摩擦因数与磨痕形貌存在差异;各膜基系统表面磨痕处均形成了Fe的转移层,由于表层DLC膜"裸露"的大量C对磨损界面具有很好的润滑作用,而使得镁合金基体获得有效保护。     

The study of adhesion and nanomechanical properties of DLC films deposited on tool steels

In this study, thin diamond-like carbon (DLC) films were deposited onto a steel substrate. By using the plasma immersion ion implantation (PIII) technique, a nitrogen layer was formed on the steel surface before depositing the DLC films. This PIII formed nitrogen layer, which acts as the buffer layer, has apparently increased the adhesion between the DLC film and the steel substrate. The microstructures, the nanomechanical properties, and the adhesion of the DLC were investigated by the techniques of X-ray diffraction (XRD), transmission electron microscopy (TEM), nanoindentation, and nanoscratch. Results show that the hardness and Young's modulus were significantly improved, up to 2 to 9 times; while the implantation depth and the microstructure of the nitrogen layers vary with nitrogen/hydrogen ratio (N:H = 1:0, 1:1, 1:3). Raman analyses indicate that the I(D)/I(G) ratio increases with the thickness of DLC film. By using the PIII technique in the steel substrate, the adhesion of the DLC film onto the substrate is greatly enhanced, and wear resistance is elevated if the DLC film is sufficiently thick.     

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.     

Study of adhesion of carbon nitride thin films on medical alloy substrates

The adhesion improvement of biocompatible thin films on medical metal alloy substrates commonly used for joint replacement implants is studied. Diamond-like carbon (DLC) and carbon nitride (CN) thin films are, because of their unique properties such as high hardness, wear resistance and low friction coefficient, candidates for coating of medical implants. However, poor adhesion on substrates with high thermal expansion coefficient limits their application. We deposited CN films by pulsed DC discharge vacuum sputtering of graphite target on CoCrMo and Ti6Al4V substrates. Surface nitridation of the substrate, changing the deposition parameters and use of interlayer led to improved adhesion properties of the films. Argon and nitrogen gas flow, thickness of the film and frequency of the deposition pulses had significant influence on the adhesion to the substrate. Properties of deposited films were analyzed using Scanning Electron Microscopy, Raman spectroscopy and tribology tests.     

用PBⅡ方法在硼膜中注入氮形成BN的结构

用电子束蒸发纯硼,在硅片上沉积不同厚度的硼膜,然后用等离子体基离子注入（ＰＢⅡ）技术在硼膜上主入氮以形成氮化硼（ＢＮ）,用ＸＰＳ分析膜的成分深度分布及化学价态;用傅里叶变换红外（ＦＴＩＲ）透射谱分析膜的结构。氮在膜中呈类似高斯分布,随着注入电压增大,膜的Ｎ／Ｂ比增大且影响氮在膜中的分布,在较高的注入电压时,膜基间产生界面混合,对ＸＰＳＢｌｓ谱进行Ｇａｕｓｓ－ｏｒｅｎｔｚ拟合表明,硼在膜中以ＢＮ及游     

Microstructure of interface for high-adhesion DLC film on metal substrates by plasma-based ion implantation

The diamond-like carbon (DLC) film was prepared on various metal substrates with a plasma-based ion implantation and deposition using superimposed RF and negative high-voltage pulses. The adhesion strength of DLC film was enhanced above the epoxy resin strength by implantation of carbon ions or mixed ions of carbon and silicon to the substrate surface before DLC deposition. In order to clarify the mechanism for improvement in adhesive strength, the microstructure of an interface between DLC film and substrate was examined in detail by transmission electron microscopy (TEM) observations in combination with EDS analysis. As a result, the enhancement in adhesion strength of DLC film by C ion implantation resulted from the formation of amorphous-like phase in the ion-implanted region of substrate, the production of carbon-component graded interface, the destruction of the oxide layer on the top surface of substrate, and the reduction of residual stress in DLC film by ion implantation during the deposition. The production of stress-free DLC film allowed us to demonstrate a supra-thick DLC film of more than 400 μm in thickness.     

霍尔离子源制备类金刚石薄膜研究

采用霍尔离子源沉积类金刚石薄膜是近年来新出现的一种方法 ,本文研究了自行研制的霍尔离子源的性能以及采用此离子源制备类金刚石薄膜及工艺参数的影响。结果表明 ,霍尔离子源在较低的电压即可起辉 ,可提供稳定的能量较低的离子束流。采用霍尔离子源沉积类金刚石薄膜的沉积速率约为 0 5nm/s。随着霍尔离子源灯丝电流的升高 ,离子源放电电压下降 ,制备的类金刚石薄膜的硬度下降。放电电流的变化对类金刚石薄膜的硬度影响不大。     

Growth and properties of the ion beam deposited SiOx containing DLC films

In the present study SiO_x containing diamond-like carbon (DLC) films were synthesized by the closed drift ion source from hexamethyldisiloxane vapor. Kinetics of the growth of DLC films was investigated using optical emission spectroscopy (OES). Structure, chemical composition, electrical and optical properties of the synthesized films were studied. The effects of ion beam energy were investigated. The main atomic hydrogen Balmer series lines and the intense broad CH group related peak were detected in the OES spectra registered in-situ during SiO_x containing diamond-like carbon film synthesis. The intensity ratio of H-β/CH peaks increased with the increase of applied ion beam energy. It was explained by activation of the dissociation of the hexamethyldisiloxane molecules. Changes of the structure of the diamond-like carbon films were observed for the films deposited under intense dissociation conditions.     

金属等离子体浸没离子注入与沉积技术合成类金刚石薄膜研究

采用金属等离子体浸没离子注入与沉积技术在9Cr18轴承钢基体表面合成了类金刚石薄膜.研究了注入脉宽和工作气压对合成薄膜性能及化学组成的影响;通过激光Raman光谱、维氏硬度、针盘试验和电化学腐蚀等测试手段分别表征了合成薄膜后试样表面的化学组成和微观结构、显微硬度、摩擦磨损性能和抗腐蚀性能.结果表明:合成薄膜后,试样的显微硬度增大了88.7%,摩擦磨损和抗腐蚀性能也明显改善.