机械研磨法制备晶体密度钼膜技术研究

 具有晶体理论密度的高质量金属薄膜对于材料的高温高压状态方程研究十分重要。通过机械研磨抛光技术制备出厚度大于20 μm，均方根粗糙度小于100 nm，厚度一致性好于99％的钼膜。研究了工艺条件对薄膜表面形貌、厚度一致性与表面粗糙度等的影响。机械研磨抛光时，采用较小粒径的磨料和材质较软的研具，可以获得较高的表面质量。在研磨过程中，工件的边缘受到的磨料切削作用最强，采用工件在工装表面均匀分布的形式，薄膜的厚度一致性有较大改善。探讨了目前制备极薄的薄膜工艺存在的问题及可能的解决办法。     

用金刚石车削技术制备EOS实验用铝薄膜和铜薄膜

 具有材料理论密度的金属薄膜对于材料高压状态方程(EOS)研究而言具有重要的意义。本文提出采用金刚石车削技术，利用超精密金刚石车床、金刚石圆弧刀具及真空吸附夹持技术，对纯铝和无氧铜进行端面车削，完成了EOS实验用铝薄膜和铜薄膜的车削加工，实现了薄膜密度接近材料理论密度。精加工工艺参数为：进给量0.001 mm/r，主轴转速3000 r/min，切削深度1 μm。采用Form Talysurf series 2型触针式轮廓仪进行测量，结果表明：铝薄膜、铜薄膜厚度可以达到小于10 μm水平，表面均方根粗糙度小于5 nm，原始最大轮廓峰-谷高度小于50 nm，厚度一致性好于99%。     

热蒸镀法制备Z箍缩用铝镁合金箔材及其性能

厚度低于5 m的AlMg合金箔材可作为带材切割的原材料应用于Z箍缩物理实验。利用热蒸镀方法,通过控制沉积速率在超光滑的NaCl基片上获得了AlMg薄膜,最终在脱膜后获得了厚度低于5 m的无支撑AlMg箔材。实验对该箔材的厚度均匀性、表面粗糙度、衍射峰位、晶粒尺寸及距表面不同距离下的成份进行了分析表征。实验发现,此热蒸镀法制备的AlMg合金箔材的厚度均匀性优于8%,两面的表面粗糙度均小于180 nm,晶粒尺寸约20 nm;不同厚度样品的衍射峰位未明显偏移,箔材内应力很小;不同深度下Mg含量稳定分布,而在箔材表面杂质含量较高,在距表面6 nm以下合金含量达到预期值并趋于稳定。热蒸镀法制得的无支撑AlMg合金箔材具有厚度可控且均匀、成分稳定、内应力小的特点,适用于制备Z箍缩带阵负载。     

掺溴聚苯乙烯平面调制箔靶的制备及测量

 平面调制靶是ICF分解实验中的重要用靶。介绍了在过去工作的基础上掺溴聚苯乙烯平面调制箔靶的制备工艺,研究旋转涂覆和流延工艺对靶的表面起伏图形转移的影响,采用SEM观察薄膜表面起伏图形的形貌,对掺杂溴的含量进行测量和控制,以台阶仪测量靶的表面粗糙度。     

白光LED用铝/氧化铝复合陶瓷基板铝表面层形貌及光学特性

利用钎焊工艺实现氧化铝敷铜陶瓷基板与铝箔的连接,成功制备出了具备良好导热性能的新型铝/氧化铝复合陶瓷基板。采用机械抛光、化学抛光和电解抛光等方式对铝表面层进行抛光处理。研究结果表明机械抛光、化学抛光和电解抛光等抛光方式均可有效提高铝层表面的光洁度和平整度。而复合抛光即先化学抛光再电解抛光的样品表面粗糙度最低、平整度最好,样品表面反光率在4种抛光方式中最高。     

退火工艺对ICF靶用冷轧镍膜的影响

 为了满足惯性约束聚变（ICF）和状态方程（EOS）实验以及靶装配工艺的需要，在薄膜轧制过程中间以及轧制工艺完成以后需要对镍膜进行热处理来改善其组织结构和力学性能。对多辊轧机冷轧的方法制备的厚11 mm镍膜中间退火工艺进行了研究，根据确定的合适的退火工艺退火后继续轧制得到成品镍膜厚7 mm，表面粗糙度小于50 nm，基本满足目前状态方程实验对箔膜的要求。金相显微照片表明镍膜晶粒经500 ℃保温1 h退火由轧制前的条带状变为等轴晶；镍膜硬度经500 ℃退火后由4 GPa降低到了2.3 GPa左右；XRD衍射测试表明镍膜经500 ℃以上温度退火后，高角度的衍射峰开始出现，织构得到一定程度的改善。由此可以确定镍膜合适的中间退火温度为520 ℃保温1 h。     

状态方程实验用铜多台阶靶制备工艺

 采用单点金刚石切削技术,通过合理的刀具设计、夹具设计及工艺过程设计,确定了加工工艺参数,完成了厚度几μm至几十μm的无氧铜多台阶靶的制备。通过触针式轮廓仪,台阶仪,白光干涉仪对表面轮廓及粗糙度进行了测量。结果表明：通过单点金刚石切削技术加工成形的铜多台阶靶,各台阶表面均方根粗糙度小于50 nm,工件表面轮廓平直,台阶垂直度较好。采用阿基米德原理对材料密度进行测量,加工成形后密度为(8.945±0.074) g/cm3,接近材料理论密度。     

基底材料对磁控共溅射Al-Cu-Fe薄膜特性的影响

 采用磁控共溅射工艺来制备Al-Cu-Fe薄膜,选用抛光状态的纯Al、纯Cu和不同粗糙度的不锈钢基作为基底材料。通过原子力显微镜分析薄膜的表面形貌,利用扫描电镜能谱仪分析薄膜的元素含量;通过MTS纳米力学综合测试系统分析薄膜的结合强度和摩擦因数。分析结果表明：不锈钢作为基底材料的薄膜与基体的结合强度最大,其次为纯铝和纯铜。纯铜基底薄膜的摩擦因数最大,达到0.17,其余两种薄膜的摩擦因数均不大于0.03。而薄膜表面形貌与基底材料的原始形貌有直接的联系,基底原始粗糙度越小,薄膜的表面组织也越细;基底原始粗糙度越大,薄膜表面形成的晶粒的团聚越明显。     

电化学在ICF靶制备中的新应用

报道了近年来在电解加工技术制备理论密度金属薄膜和电沉积技术制备金属纳米丝阵列材料等领域取得的进展。采用硫酸+甲醇电解液体系获得了表面粗糙度小于30nm的钛膜。采用阳极氧化铝模板电沉积技术制备出长度约10μm、直径约300nm的金纳米丝阵列。主要讨论了电解液配方及电解加工参数的选择,金属纳米丝直径与长度的控制等问题。     

状态方程靶制备技术研究

随着状态方程物理实验的深入，对靶的制备精度和要求不断提高，采用原有的工艺制备的EOS靶已经不能满足物理实验的要求。考虑现有设备情况，采用轧机轧制法制备金属薄膜，精密切削加工楔形靶，真空扩散连接法制备Al-Cu阻抗匹配靶。     

Operating characteristics of a segmented hollow cathode over a widepressure range

A segmented hollow cathode has been designed, constructed and operated over a wide pressure range from 1 mbar to 200 mbar to determine optimum operating characteristics for a series of unique applications. The device is designed for use as a plasma source for molecular gas lasers operating in the UV and visible spectra. The cathode consists of 1 mm thick nickel disks and 0.1 mm tungsten foil disk segments stacked alternately, forming a cylindrical geometry on its outer surface and a near-spherical geometry inside. The tungsten foil disk inner diameters vary along the longitudinal axis of the cathode. With this special geometric arrangement one hollow cathode structure is embedded within another. The spacing between the segments (tungsten foil disks) creates one hollow cathode geometry, and the spherical geometry formed by the inner diameter of the segments is a second hollow cavity. This design permits one to operate the device at an expanded pressure range. The device's voltage and current characteristics are studied at different operating pressures and the optimum operating parameters such as pressure, voltage, current, and foil thickness are investigated. Helium, argon or a helium-argon mixture is used as the fill gas throughout the series of experiments     

Backscattering of Relativistic Electrons Incident on a Planar Foil at a Small Angle to Its Surface

Photographs of cross sections of an electron beam backscattered from a thin tungsten target have been obtained on a dosimetric film. The procession of images makes it possible to obtain the spatial distribution of backscattered particles. The angles of back reflection θ_br of electron beams from foils have been measured. A 7.4-MeV microtron has been used as a source of electrons. The experiments have been performed with a tungsten foil 386 mg/cm² (200 μm) thick and a tantalum foil 1328 mg/cm² (800 μm) thick. Particles have been injected at an angle of α = 10° to the foil surface. The Monte Carlo simulation of the scattering of relativistic electrons incident on a planar target at small angles to its surface has been performed. The spatial and energy distributions of backscattered particle fluxes both transmitted through the target and reflected from it have been calculated. The dependences of fluxes on the direction of injection of particles and on the material and thickness of the target have been considered.     

Experimental investigation of heat transfer in a rivulet on the inclined foil

Heat transfer at rivulet water flow over the constantan foil with the length of 80 mm, width of 35 mm, and thickness of 25 mm was studied experimentally. The foil surface temperature was measured by an IR-scanner. Distributions of heat flux density on the surface of the foil, where the liquid flowed, were obtained. To determine the heat flux density from the foil to liquid near the contact line, the Cauchy problem was solved for the stationary heat equation using the thermographic data. Calculation results showed that the maximal heat flux occurs in the area of the contact line and exceeds the average heat flux from the entire foil surface by several times. This is explained by the influx of heat from the periphery of foil to the rivulet due to the relatively high value of heat conductivity coefficient of the foil material and high evaporation rate in the region of the contact line.     

Effect of copper surface morphology on grain size uniformity of graphene grown by chemical vapor deposition

The graphene grain boundaries (GGBs) of polycrystalline graphene grown by chemical vapor deposition (CVD) typically constitute a major reason of deterioration of the electrical properties of graphene-based devices. To reduce the density of GGB by increasing the grain size, CVD growth conditions with a reduced CH₄ flow rate have been widely applied and, recently, electropolishing of copper (Cu) foil substrates to flatten the surface has been undertaken prior to graphene growth. In this study, we show that polycrystalline graphene layer grown on typical Cu foil features two heterogeneous regions with different average grain sizes: small-grain regions (SGRs) and large-grain regions (LGRs). Statistical analysis of the grains of the graphene layers grown under different process conditions showed that SGRs (which form on Cu striations) limit the average grain size, the ability to control the grain size through adjustment of growth conditions, and global grain-size uniformity. Analysis showed that the surface-flattening process significantly improves grain-size uniformity, and monolayer coverage, as well as the average grain size. These results suggest that a process for flattening the surfaces of Cu substrates is critical to controlling the quality and uniformity of CVD-grown graphene layers for practical device applications.     

低能宽幅电子束引出特性研究

研究了能量在100到300 keV区间的低能宽幅电子束从真空引出到空气中的特性。利用EGS5程序模拟了电子束穿过不同厚度钛箔后,在空气中距离钛箔5~10 cm距离处的能量损失、束流损失和束流分布均匀性等。模拟结果显示,对于低能电子,钛箔厚度应该在10 μm左右为宜,其透射率与能量直接相关,在距离钛箔5 cm的位置,电子束的分布不均匀度低于±2%,优于工业应用±10%的标准（特殊情况下要求为5%）,完全满足工业辐照要求。In order to investigate the characteristics of extracting low-energy electron beam from vacuum into air, EGS5 is used to simulate the energy loss, beam loss and spatial distribution uniformity at the irradiation position, which is 5~10 cm to titanium foil with different thickness. The simulation results show that the transmittance is directly related to the incent energy of low-energy electron. When the titanium foil thickness is 10 μm, the inhomogeneity about the energy beam spatial distribution is below 5% on the treatment plane 5 cm away from the titanium foil. And totally meet the industrial needs.     

Silicon diffusion through thin tungsten films on silicon,studied with Auger spectroscopy

Silicon out-diffusion through ? 3000 Å tungsten films deposited on silicon by r.f. sputtering was studied using Auger spectroscopy. Silicon first diffuses to the tungsten film surface by grain boundary diffusion and surface migration. The out-diffusion kinetics were most strongly dependent on the thickness of the silicon dioxide layer between tungsten and silicon, and this (native) oxide thickness varied with substrate doping. The out-diffusion rate was independent of tungsten film thickness at 540 Å and 2400 Å. For substrates from which the native oxide was removed by backsputtering just prior to tungsten deposition, no Si out-diffusion to the W film surface was observed until almost the entire film had converted to WSi².     

Structural changes on the surface of tungsten foils under uniaxial tension

A change in the surface morphology of recrystallized tungsten foil under the effect of uniaxial tension in ultrahigh vacuum is studied by low-energy electron diffraction and atomic force microscopy. It is found by using low-energy electron diffraction that on the foil surface consisting of separate blocks with dominant face (112), there is a turn in orientation of the structural blocks. The analysis of the topograms of different areas of the side surface of a broken sample, obtained by atomic force microscopy, enabled the association of changes in the atomic structure of the surface layers of foil with a change in its relief by mechanical action.     

Dynamics of the Surface Morphology of a Tungsten Foil under Load

Physics of the Solid State - The dynamics of changes in the surface morphology of recrystallized tungsten foil under the action of uniaxial tension was studied in situ by the methods of low-energy...     

Electron emission characteristics of the porous polycrystalline silicon diode

It is estimated that a porous polysilicon (PPS) diode with a structure of Au/PPS/n-type Si operates as an efficient stable surface emitting cold cathode. 2.0 μm of an non-doped polysilicon layer is formed on an heavily doped n-type silicon wafer and anodized in a solution of HF (50%):ethanol=1:1 under illumination by a 500 W tungsten lamp from a distance of 20 cm. The electron emission properties of the PPS diode were investigated as a function of anodizing condition such as anodizing current density. The electron emission trajectory was investigated, and it was also demonstrated their good uniformity in the emitting area.