磁控溅射法制备钨酸锆薄膜

在不同的气氛下,利用射频磁控溅射法在石英基片和硅片上制备了ZrW2O8薄膜.利用台阶仪和划痕仪测量了溅射薄膜的厚度和结合力,利用X射线衍射及原子力显微镜对薄膜的物相和表面形貌进行了分析和观察.初步研究了沉积条件对生长薄膜的厚度、附着力、相成分和表面形貌等的影响.结果表明:纯氩气下溅射的ZrW2O8薄膜最厚,膜基结合力随膜厚的增加而减小,溅射所得薄膜为非晶态,热处理后薄膜中出现了钨酸锆相,薄膜的表面形貌随气压的降低变得光滑.     

掺硅类金刚石薄膜的制备及其微观机械性能研究

采用射频感应耦合离子源（ICP）在硅基底上沉积了DLC薄膜,并利用离子束溅射固体单晶石墨的方法掺入Si元素。通过原子力显微镜（AFM）和拉曼光谱对DLC薄膜的表面形貌及结构进行了分析表征。并用UTM-2摩擦磨损试验仪对薄膜进行了刻划测试,通过临界载荷的对比,分析了掺硅和纯DLC薄膜与基底的结合能力。结果表明,掺硅DLC薄膜具有良好的膜-基结合能力。     

直流电弧等离子体喷射法高速制备高质量纳米金刚石膜研究

利用直流电弧等离子体喷射法沉积装置在底径Ф65mm高5mm的Mo球面衬底上成功制备出纳米金刚石薄膜,文章研究了在稳定电弧状态下碳氢比对金刚石膜形貌的影响.通过扫描电子显微镜、原子力显微镜及Raman光谱对样品的晶粒尺寸及质量进行了表征. 研究结果表明: 在稳定电弧状态下,通过提高碳氢比可以在Mo球面衬底上的表面高速沉积出高质量的纳米金刚石薄膜, 晶粒尺寸大约为4～80nm,平均粒径27.4nm.     

类金刚石薄膜改性橡胶表面摩擦学性能的研究进展

介绍了类金刚石薄膜的结构,概述了类金刚石薄膜改性橡胶的表面结构,以及膜基结合力、表面摩擦学性能的研究现状,并提出展望。     

硬质合金表面粗糙度对金刚石涂层附着力影响的研究

采用不同粒度的金刚石粉研磨硬质合金基体表面,然后采用酸碱两步法处理基体,清洗后利用热丝化学气相沉积法(HFCVD)沉积金刚石涂层.扫描电镜观察表面金刚石形貌,洛氏硬度压痕法评价涂层结合情况.实验结果表明适当的表面粗糙度可以有效地提高膜基结合水平.     

激光加热连接金刚石/铝基的工艺研究

在氩气保护条件下,用Ag-Cu-Ti钎料在4032、6061和7075三种铝合金基体上对金刚石进行激光钎焊,同时比较7075铝合金用三种不同方法去除表面氧化膜后的激光钎焊的实验。文章利用光纤激光器,用超景深显微镜对焊后金刚石形貌进行观察分析。研究表明:在化学法去除氧化膜后的7075铝合金基体上激光钎焊金刚石的效果最好,实现了Ag-Cu-Ti钎料与金刚石、铝合金基体的牢固焊接。     

液相法沉积DLC的表征及交流阻抗谱

分别以乙醇和甲醇为电解液,采用电化学沉积法,在Si(100)表面得到碳薄膜。通过拉曼光谱和傅立叶变换红外光谱分析,证实所制备的薄膜具有类金刚石(DLC)结构特征。利用扫描电子显微镜对不同工艺制备的薄膜进行了表面形貌分析,并研究了样品在0.5mol/LH2SO4溶液中的电化学交流阻抗谱。结果表明,与在乙醇体系中制得的DLC膜相比,在甲醇体系中制得的DLC膜具有更好的表面形貌和更好的抗腐蚀能力。     

HFCVD法制备金刚石薄膜影响因素的研究进展

金刚石薄膜由于其独特的性能成为研究热点。本文通过利用热丝气相沉积法(HFCVD)在基片上制备金刚石薄膜,研究对金刚石薄膜产生影响的各个因素,探讨各个影响因素的研究进展。基体表面预处理,可以提高基体的附着力,改善提高膜基结合力。通过改变甲烷和氢气浓度、沉积气压、温度等工艺参数,可影响是否能在基片上形成金刚石晶核,生成金刚石薄膜。通过对以上影响因素的研究进展,探讨制备过程各个最适宜的反应条件。     

甲烷浓度对金刚石薄膜(100)织构生长的影响

以H2和CH4的混合气体为气源,用微波等离子体辅助化学气相沉积法(MPECVD)在1 cm×1 cm S i(100)基体上沉积了金刚石薄膜。研究了不同的甲烷浓度对金刚石薄膜(100)织构生长趋势的影响。分别采用扫描电子显微镜(SEM),Ram an光谱对金刚石膜的表面形貌、质量进行了分析。结果表明,当基体温度为750℃,气压为4.8×103Pa,甲烷浓度为1.4%时,薄膜表面为(100)织构。     

利用甲烷/氢微波等离子体CVD工艺在纯钛基底上沉积纳米金刚石薄膜

与微米金刚石薄膜不同，纳米金刚石薄膜表面平滑。因此，在摩擦学应用领域中，纳米金刚石薄膜是最理想的。表研究利用CH4／H2微波等离子体CVD工艺在纯钛上沉积出纳米金刚石薄膜和微米金刚石薄膜。采用的沉积条件为：沉积温度约为1173K；沉积压力为8．0kPa；CH4浓度在0．5mol％和5mol％之间变化；沉积时间则从4h到12h不等。金刚石薄膜表面用扫描电镜（SEM）观察。在激光拉曼光谱中，微米金刚石薄膜在1332cm^-1处有sp^3键碳的锐峰。1140cm^-1附近的光谱带与纳米金刚石薄膜的特征有关。并用X射线衍射对金刚石薄膜进行了分析。X射线衍射花样证实，纳米金刚石薄膜存在（111）面和（220）面。金刚石薄膜的表面粗糙度随着CH4浓度的增加而减小。但是，甲烷浓度在2mol％与5mol％之间变化时，金刚石薄膜的表面粗糙度接近50nm。据证实，CH4浓度在2mol％和5mol％之间，利用CH4／H2微波等离子体CVD工艺可以沉积出纳米金刚石薄膜。     

A study of diamond film deposition on WC–Co inserts for graphite machining: Effectiveness of SiC interlayers prepared by HFCVD

Thin silicon carbide (SiC) films were deposited from tetramethylsilane/hydrogen gas mixture on Co-cemented tungsten carbide (WC–Co) inserts by using Hot-Filament Chemical Vapour Deposition (HFCVD) technique. Grazing incidence X-Ray Diffraction (XRD) confirmed that the films were composed of cubic silicon carbide (β-SiC) and that small amounts of dicobalt silicide (Co₂Si) were formed. These films were used as interlayers for subsequent CVD of diamond films. XRD and combined Scanning and Transmission Electron Microscopies showed that the binder phase reacted during CVD to form cobalt silicides. However, these intermetallic compounds did not have bad effects on diamond adhesion. Dry turning of graphite was chosen to check the multilayer (SiC + diamond) film performance. For the sake of comparison, machining tests were also carried out under identical conditions using commercial sintered diamond (PCD) inserts and WC–Co diamond coated inserts with no interlayer. The wear mechanism of the tools has been identified and correlated with the criterion used to evaluate the tool life. The results showed that multilayer (SiC + diamond) coatings exhibited the longest tool lives. Therefore, thin SiC interlayers proved to be a new viable alternative and a suitable option for adherent diamond coatings on cemented carbide components and cutting tools.     

Morphological study of thin films: Simulation and experimental insights using horizontal visibility graph

We studied the morphological nature of various thin films such as silicon carbide (SiC), diamond (C), germanium (Ge), and gallium nitride (GaN) on silicon substrate Si(100) using the pulsed laser deposition (PLD) method and Monte Carlo simulation. We, for the first time, systematically employed the visibility algorithm graph to meticulously study the morphological features of various PLD grown thin films. These thin-film morphologies are investigated using random distribution, Gaussian distribution, patterned heights, etc. The nature of the interfacial height of individual surfaces is examined by a horizontal visibility graph (HVG). It demonstrates that the continuous interfacial height of the silicon carbide, diamond, germanium, and gallium nitride films are attributed to random distribution and Gaussian distribution in thin films. However, discrete peaks are obtained in the brush and step-like morphology of germanium thin films. Further, we have experimentally verified the morphological nature of simulated silicon carbide, diamond, germanium, and gallium nitride thin films were grown on Si(100) substrate by pulsed laser deposition (PLD) at elevated temperature. Various characterization techniques have been used to study the morphological, and electrical properties which confirmed the different nature of the deposited films on the Silicon substrate. Decent hysteresis behavior has been confirmed by current-voltage (IV) measurement in all the four deposited films. The highest current has been measured for GaN at ～60 nA and the lowest current in SiC at ～30 nA level which is quite low comparing with the expected signal level (μA). The HVG technique is suitable to understand surface features of thin films which are substantially advantageous for the energy devices, detectors, optoelectronic devices operating at high temperatures.     

Micro- and nanomechanical properties of diamond film with various surface morphologies

The morphologies of chemical vapour deposited (CVD) diamond films can be changed over a wide range by controlling the process parameters of the deposition. The surface morphologies of the film in turn, govern the micro- and nanomechanical properties of the film. In view of these, diamond films having three different types of morphologies namely coarse ballas, fine ballas and faceted, have been deposited using microwave chemical vapour deposition (MWCVD) technique. The morphology, and nature of bonds of these films are characterised with the help of scanning electron microscopy (SEM) and Raman spectroscopy. Hardness of the films is evaluated using nanoindenter. Force spectroscopy, topographies and lateral force values of these films are estimated by means of atomic force microscopy (AFM). Results indicate that films having fine ballas morphology exhibit the minimum roughness whereas film with faceted morphology has highest relative hardness. The friction force was found to be minimum with the film having fine ballas morphology and the friction force was maximum with film having coarse ballas morphology.     

砷化镓上生长金刚石薄膜的研究

以CH4和H2为气源,用微波辅助等离子体装置,在10.0 mm×7.0 mm的砷化镓基底上沉积了CVD金刚石薄膜,用扫描电子显微镜观察沉积效果,拉曼光谱表征沉积质量,分析薄膜附着力与砷化镓材料性能的关系。结果表明,当基体温度为600℃,气压为5 kPa,甲烷浓度为2.0%时,在砷化镓片表面上沉积出了CVD金刚石薄膜,晶粒尺寸均匀,晶形完整、规则,晶界非常清晰。     

Planarizing CVD diamond films by using hydrogen plasma etching enhanced carbon diffusion process

Polycrystalline diamond films, deposited by microwave plasma chemical vapor deposition (MPCVD), were planarized in hydrogen plasma under the graphitization of iron film obtained by reduction of iron chloride under hydrogen plasma ambient. For this process, the free-standing diamond films were dipped in a saturated iron chloride solution and dried horizontally in atmospheric ambient. Then the diamond samples were heated by hydrogen plasma in the same MPCVD reactor. Under the effect of hydrogen reduction, iron thin film was formed on the surface of diamond films. Under ca. 800 °C, the carbon diffusion process was carried out under the graphitization effect of iron thin film. Since the iron film used in this process is very thin, the diffused carbon will diffuse from the diamond side to the hydrogen plasma side and then etched away by the plasma. Therefore, the etching rate of diamond film can be kept consistent. After etching the growth surface of a free-standing diamond film, we investigated the surface morphologies and the carbon phases on the etched surfaces of diamond films. Finally, compared with the result of mechanical lapping experiments, we suggest that the hydrogen plasma etching enhanced carbon diffusion process can serve as a new planarization method for rough diamond film surface. A mechanism for this enhanced etching effect is also presented and discussed.     

Hot filament chemical vapour deposition and wear resistance of diamond films on WC-Co substrates coated using PVD-arc deposition technique

Different Cr- and Ti-base films were deposited using PVD-arc deposition onto WC-Co substrates, and multilayered coatings were obtained from the superimposition of diamond coatings, deposited on the PVD interlayer using hot filament chemical vapour deposition (HFCVD). The behaviour of PVD-arc deposited CrN and CrC interlayers between diamond and WC-Co substrates was studied and compared to TiN, TiC, and Ti(C,N) interlayers. Tribological tests with alternative sliding motion were carried out to check the multilayer (PVD + diamond) film adhesion on WC-Co substrate. Multilayer films obtained using PVD arc, characterised by large surface droplets, demonstrated good wear resistance, while diamond deposited on smooth PVD TiN films was not adherent. Multilayered Ti(C,N) + diamond film samples generally showed poor wear resistance.Diamond adhesion on Cr-based PVD coatings deposited on WC-Co substrate was good. In particular, CrN interlayers improved diamond film properties and 6 μm-thick diamond films deposited on CrN showed excellent wear behaviour characterised by the absence of measurable wear volume after sling tests. Good diamond adhesion on Cr-based PVD films has been attributed to chromium carbide formation on PVD film surfaces during the CVD process.     

硬质合金上镀铬的研究

为提高硬质合金与金刚石膜层的结合力，在硬质合金上电沉积铬过渡层，介绍了硬质合金的镀前处理及镀铬工艺，利用扫描电镜观察了镀层表面及断面形貌，研究了H等离子处理对镀层表面、断面形貌及镀层与硬质合金结合强度的影响。结果表明，H等离子处理使得镀层与硬质合金基体相互扩散，从而明显提高了镀层与合金基体的结合强度。     

Tribological properties and cutting performance of boron and silicon doped diamond films on Co-cemented tungsten carbide inserts

Boron and silicon doped diamond films are deposited on the cobalt cemented tungsten carbide (WC-Co) substrate by using a bias-enhanced hot filament chemical vapor deposition (HFCVD) apparatus. Acetone, hydrogen gas, trimethyl borate (C₃H₉BO₃) and tetraethoxysilane (C₈H₂₀O₄Si) are used as source materials. The tribological properties of boron-doped (B-doped), silicon-doped (Si-doped) diamond films are examined by using a ball-on-plate type rotating tribometer with silicon nitride ceramic as the counterpart in ambient air. To evaluate the cutting performance, comparative cutting tests are conducted using as-received WC-Co, undoped and doped diamond coated inserts, with high silicon aluminum alloy materials as the workpiece. Friction tests suggest that the Si-doped diamond films present the lowest friction coefficient and wear rate among all tested diamond films because of its diamond grain refinement effect. The B-doped diamond films exhibit a larger grain size and a rougher surface but a lower friction coefficient than that of undoped ones. The average friction coefficient of Si-doped, B-doped and undoped diamond films in stable regime is 0.143, 0.193 and 0.233, respectively. The cutting results demonstrate that boron doping can improve the wear resistance of diamond films and the adhesive strength of diamond films to the substrates. Si-doped diamond coated inserts show relatively poor cutting performance than undoped ones due to its thinner film thickness. B-doped and Si-doped diamond films may have tremendous potential for mechanical application.     

Adhesion properties of functionally gradient diamond composite films on medical and tool alloys

We have investigated the adhesion properties of microcrystalline diamond thin films on Ti-Al-V alloy, Co-Cr-Mo alloy and steel. Microcrystalline diamond possesses high hardness, a low coefficient of friction, extreme chemical inertness and biocompatibility; these properties can enhance the performance of metal alloys used in medical implants and in machine tools. We have adopted three methods for improving the adhesion of microcrystalline diamond to commonly used metal alloys: (1) by alloying the substrate surface to minimize graphitization; (2) by employing appropriate buffer layers between the diamond film and the substrate; and (3) by creating functionally gradient diamond-(titanium carbide, tungsten carbide, titanium nitride and aluminum nitride) composites. We have demonstrated that functionally gradient discontinuous buffer layers of titanium carbide, titanium nitride, aluminum nitride and tungsten carbide are able to control stress and graphitization in microcrystalline diamond thin films. This work on buffer layers and functionally gradient coatings should allow the development of more adherent crystalline diamond films for medical and tribological applications.