Influence of silicon on the microstructure and mechanical properties of Zr-Si-N composite films

A series of Zr-Si-N composite films with different Si contents were synthesized in an Ar and N₂ mixture atmosphere by the bi-target reactive magnetron sputtering method. These films’ composition, microstructure and mechanical properties were characterized by energy dispersive spectroscopy, X-ray diffraction, scanning electron microscopy, atomic force microscopy and nanoindentation. Experimental results revealed that after the addition of silicon, Si₃N₄ interfacial phase formed on the surface of ZrN grains and prevented them from growing up. Zr-Si-N composite films were strengthened at low Si content with the hardness and elastic modulus reaching their maximum values of 29.8 and 352 GPa at 6.2 at% Si, respectively. With a further increase of Si content, the crystalline Zr-Si-N films gradually transformed into amorphous, accompanied with a remarkable fall of films’ mechanical properties. This limited enhancement of mechanical properties in the Zr-Si-N films may be due to the low wettability of Si₃N₄ on the surface of ZrN grains.     

Coupled Thermo-Hydro-Mechanical and Chemical Analysis of Expansive Clay Subjected to Heating and Hydration

A fully coupled formulation combining reactive transport and an existing thermo-hydro-mechanical (THM) code is presented. Special attention has been given to phenomena likely to be encountered in clay barriers used as part of containment systems of nuclear waste. The types of processes considered include hydrolysis, complex formation, oxidation/reduction reactions, acid/base reactions, precipitation/dissolution of minerals and cation exchange. Both kinetically-controlled and equilibrium-controlled reactions have been incorporated. The total analytical concentrations (including precipitated minerals) are adopted as basic transport variables and chemical equilibrium is achieved by minimizing Gibbs Free Energy. The formulation has been incorporated in a general purpose computer code capable of performing numerical analysis of engineering problems. A validation exercise concerning a laboratory experiment involving the heating and hydration of an expansive compacted clay is described.     

Structure and mechanical properties of Al/AlN multilayer with different AlN layer thickness

Nanometer scale Al/AlN multilayers have been prepared by dc magnetron sputtering technique with a columnar target. A set of Al/AlN multilayers with the Al layer thickness of 2.9 nm and the AlN layer thickness variation from 1.13 to 6.81 nm were determined. Low angle X-ray diffraction (LAXRD) was used to analyze the layered structure of multilayers. The phase structure of the coatings was investigated with grazing angle XRD (GAXRD). Mechanical properties of these multilayers were thoroughly studied using a nanoindentation and ball-on-disk micro-tribometer. It was found that the multilayer hardness and reduced modulus showed no strong dependence on the AlN layer thickness. Al2.9 nm/AlN1.13 nm multilayer had more excellent tribological properties than single layers and other proportion multilayers with a lowest friction coefficient of 0.15. And the tribological properties of all the multilayers are superior to the AlN single layer.     

p型未掺杂富锌ZnO薄膜的形成和性能研究

以高纯ZnO为靶材,氩气为溅射气体,利用射频磁控溅射技术在石英衬底上生长出纤锌矿结构的富锌ZnO薄膜.薄膜沿(002)择优取向生长,厚约为1.2μm,呈现电绝缘特性.将溅射的ZnO薄膜在10-3Pa,510~1 000 K的温度范围等温退火1 h,室温Hall测量结果表明ZnO薄膜的导电性能经历了由绝缘—n型—p型—n型半导体的变化.XPS测试表明ZnO薄膜的Zn/O离子比随退火温度的升高而降低,但一直是富锌ZnO,说明未掺杂的富锌ZnO也可以形成p型导电.p型未掺杂富锌ZnO薄膜的形成可归因于VZn受主浓度可以克服VO和Zni本征施主的补偿效应.     

磁控溅射ZnO薄膜的成核机制及表面形貌演化动力学研究

利用原子力显微镜分析了ZnO薄膜在具有本征氧化层的Si(100)和Si(111)基片上的表面形貌 随沉积时间的演化. 通过对薄膜生长形貌的动力学标度表征，研究了射频反应磁控溅射条件 下，ZnO薄膜的成核过程及生长动力学行为. 研究发现，ZnO在基片表面的成核过程可分为初 期成核阶段、低速率成核阶段和二次成核阶段. 对于Si(100)基片，三个成核阶段的生长指 数分别为β₁=1.04，β₂=0.25±0.01，β₃=0.74；对 于Si(11 关键词： ZnO薄膜 磁控溅射 生长动力学 成核机制     

基于LiCo0.8M0.2O2 (M=Ni,Zr)薄膜的全固态薄膜锂电池

用射频磁控溅射结合传统退火的方法制备LiCo0.8M0.2O2 (M=Ni,Zr)阴极薄膜．X射线衍射、拉曼光谱、扫描电子显微镜等手段表征了不同掺杂的LiCo0.8M0.2O2薄膜．结果显示,700℃退火的LiCo0.8M0．2O2薄膜具有类似α-NaFeO2的层状结构．通过对不同掺杂锂钴氧阴极的全固态薄膜锂电池Li／LiPON／LiCo0.8M0.2O2的电化学性能研究表明,电化学活性元素Ni的掺杂使全固态电池具有更大的放电容量(56μAh／cm2μm),而非电化学活性元素Zr的掺杂使全固态电池具有更好的循环稳定性．     

退火温度对低温生长MgxZn1－xO薄膜光学性质的影响

用射频磁控溅射法在80℃衬底温度下制备出Mg_xZn_1-xO(x=0.16)薄膜，用X射线衍射(XRD)、光致发光(PL)和透射谱研究了退火温度对Mg_xZn_1-xO薄膜结构和光学性质的影响.测量结果显示，Mg_xZn_1-xO薄膜为单相六角纤锌矿结构，并且具有沿c轴的择优取向；随着退火温度的升高，(002)XRD峰强度、平均晶粒尺寸和紫外PL峰强度增大，(002)XRD峰半高宽(F 关键词： xZn_1-xO薄膜')" href="#">Mg_xZn_1-xO薄膜 射频磁控溅射 退火     

Fabrication and characterization of sputtered titanium dioxide films

TiO₂ thin films were prepared under various conditions by using a reactive RF sputtering technique. The structural, optical and electrical characteristics of the films have been investigated. All as-deposited films were amorphous. After annealing at T > 673 K, the crystallinity of the observed tetragonal anatase phase appeared improved. The optical band gap, determined by using Tauc plot, has been found to amount to 3.38 ± 0.03 and 3.21 ± 0.03 eV for the direct and indirect transition, respectively. Also the complex optical constants for the wavelength range 300-2500 nm are reported. Using the two-point probe technique, the dark resistivity has been measured as a function of the film thickness, d. The resistivity, ρ, of the samples has been found to decrease markedly with increasing thickness, but only for d < 100 nm. The behaviour of ρd versus d was found to fit properly with the Fuchs and Sondheimer relation with parameters ρ_o = 4.95 × 10⁶ Ω cm and mean free path, l = 310 ± 2 nm. The log ρ versus 1/T curves show three distinct regions with values for the activation energy of 0.03 ± 0.01, 0.17 ± 0.01 and 0.50 ± 0.02 eV, respectively.     

Au/SiO2纳米多层薄膜的制备及其性质表征

利用多靶磁控溅射技术制备了Au/SiO₂纳米颗粒分散氧化物多层复合薄膜.研究了在保持Au单层颗粒膜沉积时间一定时薄膜厚度一定、变化SiO₂的沉积时间及SiO₂的沉积时间一定而改变薄膜厚度时，多层薄膜在薄膜厚度方向的微观结构对吸收光谱的影响.研究结果表明：具有纳米层状结构的Au/SiO₂多层薄膜在560 nm波长附近有明显的表面等离子共振吸收峰，吸收峰的强度随Au颗粒的浓度增加而增强，在Au颗粒浓度相同的情况下，复合薄膜 关键词： 2纳米复合薄膜')" href="#">Au/SiO₂纳米复合薄膜 多靶磁控溅射 吸收光谱 有效介质理论