CVD制备Ir/Re复合材料的显微组织和再结晶研究

采用CVD方法制备了Ir/Re复合材料。研究了Ir层中Ir晶粒的形貌和生长特点,计算得到Ir晶粒生长动力学方程:(x2-x02)/t=4.31×103exp(-2.65eV/kT)(μm2·s-1)。研究了CVD过程中Re层表面晶粒生长和V,W型浸蚀纹的关系。对靠近Ir层的细晶粒区和Re层中部的柱状晶粒区中Re晶粒的再结晶长大进行了研究,计算得到柱状晶区中Re晶粒的生长动力学方程:(x2-x02)/t=2.55×103exp(-1.52eV/kT)(μm2·s-1),研究了Ir/Re扩散、Re扩散对细晶区中Re晶粒生长动力学的影响。     

A comparative study of the mechanical strength of chemical vapor-deposited diamond and physical vapor-deposited hard coatings

Four mechanical parameters of physical vapor-deposited (PVD) hard coatings were obtained, which were the residual strain, Young's modulus, film toughness, and interface toughness, concerning titanium aluminum nitride (TiAlN) and titanium nitride (TiN) coatings deposited on WC-Co substrates. The results were quantitatively compared with the author's previous trials for the case of chemical vapor-deposited (CVD) diamond coatings. Due to the significant difference in the mechanical properties between PVD hard coatings and CVD diamond coatings, it was necessary to develop new experimental techniques, which could properly evaluate those parameters for the case of PVD hard coatings. As a conclusion, film toughness of PVD hard coatings was surprisingly brittle. It was an order of magnitude smaller than that of CVD diamond coatings. In contrast, no significant difference was found in interface toughness between these different kinds of coatings. Concerning the residual strain, TiN had far larger level than the other two. These differences in mechanical properties were further discussed in relation to the difference in their wear behavior.     

CVD法制备的碳包覆(Fe,Co)纳米粒子的结构及电磁特性

以溶胶—凝胶超临界干燥技术合成的含Fe、Co双金属的SiO2纳米气凝胶为催化剂，采用CVD法高温气相催化裂解甲烷的方法合成了碳包覆铁钴的C—(Fe，Co)／SiO2纳米复合材料。用透射电子显微镜(TEM)，X射线衍射仪(XRD)等对材料的形貌、相结构进行了检测，并采用微波矢量网络分析仪测量了微波频率下材料的复介电常数～↑ε和复磁导率～↑μ。实验表明，C-(Fe，Co)/SiO2纳米复合材料中含有大量碳包覆(Fe，Co)粒子及少量纳米碳管，其中碳包覆（Fe,Co)纳米粒子主要呈球形和椭球形，包覆层为约20层的石墨层；另还有少量的纳米碳管，其端部包覆有不同粒径酌纳米粒子，所制备的复合材料中铁和钴的比例对材料的电磁参数影响较大。     

低温化学气相沉积SiC涂层沉积机理及微观结构

由MTS-H2体系在1000～1300℃沉积了SiC涂层,研究了SiC涂层沉积速率和温度之间的关系,MTS-H2体系沉积反应的平均活化能为114kJ/mol,用理论模型证明了低温化学气相沉积SiC为动力学控制过程.SiC涂层表面的显微结构随沉积温度变化而呈现规律的变化:沉积温度T<1150℃时,CVD SiC涂层表面致密、光滑;T≥1150℃时,CVD SiC涂层表面变得疏松、粗糙.随着沉积温度的升高,CVD SiC涂层的结晶由不完整趋向于完整;当沉积温度T≥1150℃,CVD SiC涂层的XRD谱图中除了β-SiC占主体外还出现了少量α-SiC.     

硬质合金刀具涂层技术的研究进展

随着涂层技术的进步，使得硬质合金刀具涂层方法在不断地进步，日趋复杂化和多样化；硬质合金刀具涂层种类也在不断地更新，从单一的化合物涂层朝着多元复杂化合物涂层发展，涂层层数也从几层到十几层发展。本文简要地综述了目前国内外涂层硬质合金刀具的特点，高温化学气相沉积涂层(HTCVD或简称CVD)、物理气相沉积涂层(PVD)、等离子化学气相沉积涂层(PCVD)、中温化学气相沉积涂层(MTCVD)和离子辅助物理气相沉积涂层(IBVD)这5种硬质合金刀具涂层方法的机理、特点和缺点，以及单渗层涂层硬质合金、多渗层涂层硬质合金和新渗层涂层硬质合金这3种硬质合金刀具涂层的特点和应用。     

Improvement of Heater Surface Flatness and Uniformity of TiN Film Deposition

The deposition rate and the thickness uniformity of chemical vapor deposition (CVD) titanium nitride films depend on wafer temperatures. The heater surface conditions, such as flatness, roughness, and surface imperfections, can greatly affect heat transfer efficiency from the heater surface to the wafer, and the process performance. Because heater surface imperfections or “hot spots” that caused poor uniformity had to be eliminated, the origin of “hot spots” was identified by a detailed study of heater surface profiles. A better visualization of “hot spots” could be obtained by comparing wafer-chucking patterns with deposition patterns. Thus, the time needed to locate “hot spots” could be shortened. The manufacturing process was revised to prevent “hot spots” and improve heater performance.     

CVD growth and characterization of 3C-SiC thin films

Cubic silicon carbide (3C-SiC) thin films were grown on (100) and (111) Si substrates by CVD technique using hexamethyldisilane (HMDS) as the source material in a resistance heated furnace. HMDS was used as the single source for both Si and C though propane was available for the preliminary carbonization. For selective epitaxial growth, patterned Si (100) substrates were used. The effect of different growth parameters such as substrate orientation, growth temperature, precursor concentration, etc on growth was examined to improve the film quality. The surface morphology, microstructure and crystallinity of grown films were studied using optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis and X-ray photoelectron spectroscopy (XPS).     

Electron-beam-induced fabrication of metal-containing nanostructures

An experimental system based on a transmission electron microscope JEM-100CX has been developed for electron beam-induced chemical vapor deposition. Direct electron beam-induced growth of nanometer-wide self-supporting rods has been performed inside the microscope operating in scanning mode by decomposition of carbonyls of chromium Cr(CO)₆, tungsten W(CO)₆, and rhenium Re₂(CO)₁₀. In situ phase and structure transformations under annealing inside the microscope column were studied. Nanoscale rods and strips grown from rhenium carbonyl are of special interest because, after annealing, they consist of a single pure rhenium phase. The described method of metallic nanoelements fabrication enables us to produce highly conductive nanowires and tips for application in nanoelectronics, emission electronics, and scanning tunneling microscopy.     

掺硼金刚石膜的电火花加工研究

由于金刚石膜的加工极其困难，提出了一种通过在制备过程中掺杂使金刚石膜导电的金刚石膜精加工新工艺，利用电火花对掺杂金刚石膜进行电加工。研究了电参数对金刚石膜加工性能的影响，用SEM和Raman分析了金刚石膜电火花加工表面的形貌和成分。研究了掺硼金刚石膜电火花加工的加工机理，建立了电火花加工模型。试验结果表明，电参数对金刚石膜的加工速度、表面粗糙度有较大影响，掺杂金刚石膜的电火花加工是汽化、熔化、氧化、石墨化等多种效应的综合作用结果，通过掺杂可以显著改善金刚石膜的可加工性。     

The Atmospheric Scanning Electron Microscope with open sample space observes dynamic phenomena in liquid or gas

Although conventional electron microscopy (EM) requires samples to be in vacuum, most chemical and physical reactions occur in liquid or gas. The Atmospheric Scanning Electron Microscope (ASEM) can observe dynamic phenomena in liquid or gas under atmospheric pressure in real time. An electron-permeable window made of pressure-resistant 100 nm-thick silicon nitride (SiN) film, set into the bottom of the open ASEM sample dish, allows an electron beam to be projected from underneath the sample. A detector positioned below captures backscattered electrons. Using the ASEM, we observed the radiation-induced self-organization process of particles, as well as phenomena accompanying volume change, including evaporation-induced crystallization. Using the electrochemical ASEM dish, we observed tree-like electrochemical depositions on the cathode. In silver nitrate solution, we observed silver depositions near the cathode forming incidental internal voids. The heated ASEM dish allowed observation of patterns of contrast in melting and solidifying solder. Finally, to demonstrate its applicability for monitoring and control of industrial processes, silver paste and solder paste were examined at high throughput. High resolution, imaging speed, flexibility, adaptability, and ease of use facilitate the observation of previously difficult-to-image phenomena, and make the ASEM applicable to various fields.