强脉冲电子束在聚酯薄膜表面产生的化学气相沉积

一、引言 高功率密度脉冲电子束(>10~9W/cm~2)轰击金属,将引起金属剧烈蒸发,产生高温等离子体。等离子体中的金属离子获得一定能量后将与本底气体分子相互作用而形成化合物。本文介绍在低压氮气环境中,利用强脉冲电子束轰击铜靶,产生了氮铜化合物沉积在聚酯薄膜表面的实验结果。并用ESCA分析束处理过的聚酯薄膜表面的化学组成的变化。     

强流脉冲电子束辐照对铝薄膜的结构和性能影响

用多弧离子镀方法在DZA镍基合金基体上沉积3μm厚Al膜,用强流脉冲电子束辐照处理,加速电压为27 kV,束流密度为1.5 J/cm2,脉冲数为1次、5次和10次.SEM表面分析显示,脉冲处理后薄膜表面平整度随脉冲次数增加,但10次脉冲处理后有明显的微裂纹.电子束处理后有熔坑和喷发现象,5次脉冲处理后喷发现象最明显.截面的EPMA分析显示,电子束处理使Al膜与基体问混合.掠入射XRD分析表明,随着脉冲次数增加,Al含量减少,基体Ni含量增加,1次脉冲处理有非晶成份出现,多次脉冲处理后有NiAI新相出现,有利于薄膜耐腐蚀性能的提高.电子束辐照Al膜的耐腐蚀性能明显提高,自腐蚀电位提高约70%.     

激光驱动飞秒电子束消色差传输束线设计

激光等离子体加速输出的电子束具有fs量级脉冲长度的优异品质。由于强激光场的存在，直接应用存在一定困难，更多应用场景需要把电子束传输到应用端。能散导致电子束在传输中产生能量啁啾，需要通过束流光学设计抑制脉冲长度的增长。通过对电子束在消色差束线中传输的研究，探索了消色差和非消色差传输中脉冲长度压缩的差异，以及消色差束线中偏转角度、偏转半径对不同能量电子束脉冲长度压缩的影响。针对消色差传输中仅有某个能量电子束得到最优压缩的局限，利用四极透镜磁场梯度的调节使电子束的传输适度偏离消色差，改变对能量啁啾的影响，实现在固定尺寸束线中不同能量电子束的压缩。     

离子束增强沉积技术

采用离子束增强沉积(IBED)铜过渡层和电子束蒸镀铜膜结合制备的单质膜结构,比采用电子束蒸镀钛-铜多层膜结构工艺简单,且不增加光刻腐蚀工艺难度,铜膜沉积于低表面粗糙度(Ry≤0.1 μm)的氧化铝陶瓷基片表面获得了良好的膜-基附着力.实验证明:IBED铜过渡层和电子束蒸镀铜膜结合的制膜方法是目前几种制造器件的工艺方法中最佳制膜工艺方法.     

离子束增强沉积技术

采用离子束增强沉积（IBED）铜过渡层和电子束蒸镀铜膜结合制备的单质膜结构，比采用电子束蒸镀钛－铜多层膜结构工艺简单，且不增加光刻腐蚀工艺难度，铜膜沉积于低表面粗糙度（Ry≤0．1μm）的氧化铝陶瓷基片表面获得了良好的膜－基附着力。实验证明：IBED铜过渡层和电子束蒸镀铜膜结合的制膜方法是目前几种制造器件的工艺方法中最佳制膜工艺方法。     

利用2TW激光器产生具有超小归一化发散角的准单能电子束团的实验和模拟研究

利用2TW、80fs激光脉冲和等离子体相互作用,产生了能量为(23.0±0.8)MeV、电量为6pC的准单能电子束。该电子束的归一化发散角只有92mrad,较之前激光等离子体加速领域所获得的实验结果至少小了5倍以上。二维数值模拟结果显示,此结果的产生归功于加速机制上从自调制激光尾场加速向激光尾场加速的平稳过渡。     

强流脉冲电子束加速器的安全防护评价

一、前言强流脉冲电子束加速器的主要特点是短脉冲、高电压、强束流。这类加速器在模拟核爆、惯性约束聚变、等离子体物理、爆轰物理和激光等许多领域中得到了广泛的应用和发展。这类加速器的安全问题,主要包括强脉冲x射线和中子的防护,高电压的安全和有毒气     

HCPEB处理ZK60镁合金的表面微观组织和耐磨性

采用强流脉冲电子束对ZK60镁合金进行表面改性,研究电子束处理后镁合金微观组织结构和耐磨性的变化.微观组织结果表明,电子束处理使ZK60镁合金表面熔化,晶界变得不明显,元素偏析得到改善,合金表面化学成分均匀化分布,且在镁合金表面生成一层厚为5-11 μm的高致密度的重熔层,晶粒得到细化.耐磨性测试结果表明,电子束处理后镁合金的耐磨性明显提高,且15次脉冲处理的样品的耐磨性最好,其耐磨性是原样品的2.5倍.     

电子束表面改性对变形镁合金AZ31结构和性能的影响

本文用强流脉冲电子束对变形镁合金AZ31进行表面处理。用光学显微镜、扫描电镜和X射线衍射分析表面处理层形貌和组织结构,并测试显微硬度和摩擦磨损性能。结果表明,处理样品表面完全重熔,残存有数百MPa压应力,且随脉冲次数增加,改性层加深,距表面数百μm范围内显微硬度均呈增加,15次脉冲处理后样品相对抗磨性提高5.6倍。     

激光与陡峭密度梯度等离子体相互作用电子加热机制研究

本文利用二维PIC模拟了超短超强激光与陡峭密度梯度等离子体相互作用过程中电子的加热机制。结果表明,在10²³ W/cm²的超短超强激光场与陡峭密度分布的μm级等离子体层相互作用的过程中有质动力加速、大幅度等离子体尾场及共振吸收共同决定了电子束的加速与加热。     

Modification of DLC films by Ni ions implantation

Enhanced diamond-like carbon (DLC) multilayer films were produced by a method of alternating the magnetic filtered vacuum cathode arc deposition and the metal vapor vacuum arc (MEVVA) implantation of Ni⁺ ions. The microstructure and mechanical properties of these multilayer films were studied by XPS, Raman, SEM, AFM, XRD, nano-intender and internal stress measurement. The results reveal that with the increasing dose of implanted Ni⁺ ions, the sp³ contents are declining and reduction of the nanohardness and release of the internal stress are observed.     

磁过滤等离子体沉积和注入技术

利用阴极真空弧放电技术能够产生高密度的金属等离子体。经过90度的磁过滤器，可以除去金属等离子体中的大颗粒微粒，从而为制备高质量的、致密的各种薄膜提供了一种全新的技术。利用该技术制备薄膜具有非常广泛的应用。本文介绍了阴极真空弧放电技术的应用，以及磁过滤等离子体沉积和注入装置及其应用。     

CrAlN/TiAlN纳米多层膜界面结构的中子与X射线反射研究

采用反应磁控溅射技术在单晶硅基片上制备了CrN纳米单层膜和CrAlN/TiAlN纳米周期膜,利用非极化中子和X射线反射对膜层厚度、膜层界面粗糙度、界面扩散等表面、界面结构和性质进行了系统研究。中子反射测得的CrN纳米单层膜和CrAlN/TiAlN纳米周期膜的厚度与设计厚度的差别为3.8%～4.2%。散射长度密度（SLD）分析结果表明,膜层间和膜层与基底间界面较为清晰,扩散较少。X射线反射测得的膜层厚度较中子反射测得的膜层厚度偏高,对于较小调制周期的多层膜,界面弥散会对X射线反射结果产生较大误差。     

磁控溅射法制备金/钆柱腔工艺研究

采用直流磁控溅射方法制备金/钆(Au/Gd)多层膜,并研究不同制备参数对多层膜结构与性能的影响。溅射压强高于1Pa时,Au膜与Gd膜的沉积速率均随溅射压强的增大而下降;在较低溅射气压下,随着溅射气压的降低,金膜与钆膜的均方根粗糙度有所减小;随着溅射功率的减小,金/钆多层膜的周期性结构变好,界面更为清晰。本工作制备了不同原子比的金/钆膜柱腔,探讨了有关柱腔成型的解决方法。     

Numerical Approach of Interactions of Proton Beams and Dense Plasmas with Quantum-Hydrodynamic/Particle-in-Cell Model

A one dimensional quantum-hydrodynamic/particle-in-cell(QHD/PIC) model is used to study the interaction process of an intense proton beam(injection density of 1017cm~(-3))with a dense plasma(initial density of ~ 1021cm~(-3)), with the PIC method for simulating the beam particle dynamics and the QHD model for considering the quantum effects including the quantum statistical and quantum diffraction effects. By means of the QHD theory, the wake electron density and wakefields are calculated, while the proton beam density is calculated by the PIC method and compared to hydrodynamic results to justify that the PIC method is a more suitable way to simulate the beam particle dynamics. The calculation results show that the incident continuous proton beam when propagating in the plasma generates electron perturbations as well as wakefields oscillations with negative valleys and positive peaks where the proton beams are repelled by the positive wakefields and accelerated by the negative wakefields. Moreover, the quantum correction obviously hinders the electron perturbations as well as the wakefields. Therefore, it is necessary to consider the quantum effects in the interaction of a proton beam with cold dense plasmas, such as in the metal films.     

Characterization of Fe-based alloy coating deposited by supersonic plasma spraying

The objective of the present study is to characterize the Fe-based alloy coating deposited by the supersonic plasma spraying process. The condition of the melting particles was in situ monitored. The microstructure of the coating was examined by scanning electron microscope and high resolution transmission electron microscope. The phase composition was examined by X-ray diffraction. The microhardness and porosity were also measured, respectively. Results show the prepared coatings have excellent properties, such as few oxides, high microhardness and a low porosity amount. At the same time, a mass of amorphous/nanocrystalline phases was found in the coating. The mechanism of the formation of amorphous/nanocrystalline phases was investigated. The appropriate material composition of spraying material and flash set process of plasma spraying are the key factors. Moreover, the mechanism for oxidation resistance is also investigated, where the separation between melting metal and oxygen by the formation of SiO₂ films is the key factor.     

Initial damage processes for diamond film exposure to hydrogen plasma

Diamond is considered to be a possible alternative to other carbon based materials as a plasma facing material in nuclear fusion devices due to its high thermal conductivity and resistance to chemical erosion. In this work CVD diamond films were exposed to hydrogen plasma in the MAGnetized Plasma Interaction Experiment (MAGPIE): a linear plasma device at the Australian National University which simulates plasma conditions relevant to nuclear fusion. Various negative sample stage biases of magnitude less than 500 V were applied to control the energies of impinging ions. Characterisation results from SEM, Raman spectroscopy and ERDA are presented. No measureable quantity of hydrogen retention was observed, this is either due to no incorporation of hydrogen into the diamond structure or due to initial incorporation as a hydrocarbon followed by subsequent etching back into the plasma. A model is presented for the initial stages of diamond erosion in fusion relevant hydrogen plasma that involves chemical erosion of non-diamond material from the surface by hydrogen radicals and damage to the subsurface region from energetic hydrogen ions. These results show that the initial damage processes in this plasma regime are comparable to previous studies of the fundamental processes as reported for less extreme plasma such as in the development of diamond films.     

Effect of Electron Irradiation on Polypropylene Films

Effect of both electron beam irradiation on the properties of polypropylene (PP) films the irradiation on the different layers of a multilayer PP film are studied. A Fourier transform infrared spectroscope was used to investigate the chemical structure of the films. The results showed that the chemical properties of the first layer were improved, that is, more functional groups responsible for dye ability and hydrophilicity of the film were produced on its surface, while noticeable improvement was not detected on the surface of other layers. This was also confirmed by testing the dye ability of the layers. However, the results obtained by atomic force microscopy showed that the electron irradiation caused some topographical changes, not only on the surface of the first layer but also on the others.     

Metal/amorphous silicon multilayer radiation detectors

A multilayer structure is described for use in a number of radiation detectors. The structure consists of alternating layers of metal and amorphous silicon (a-Si). The absorption of radiation mainly occurs in the metal layers, while electron-hole pairs are generated in the a-Si layers by the emitted secondary particles from the metal layers. The fundamental applicability of this novel detector for X-ray detection was confirmed by Monte Carlo computer simulations as well as by results for an experimental five-layer Ta(0.5 μm)/a-Si(3 μm)/Mo(0.5 μm) X-ray sensor fabricated on a 1.5-cm×4-cm glass plate. The authors have confirmed that the detector has rectifying characteristics, with the Mo and Ta layers forming Schottky barrier and ohmic contacts respectively     

Mechanism of high growth rate for diamond-like carbon films synthesized by helicon wave plasma chemical vapor deposition

A high growth rate fabrication of diamond-like carbon(DLC)films at room temperature was achieved by helicon wave plasma chemical vapor deposition(HWP-CVD)using Ar/CH_4gas mixtures.The microstructure and morphology of the films were characterized by Raman spectroscopy and scanning electron microscopy.The diagnosis of plasma excited by a helicon wave was measured by optical emission spectroscopy and a Langmuir probe.The mechanism of high growth rate fabrication for DLC films by HWP-CVD has been discussed.The growth rate of the DLC films reaches a maximum value of 54μm h~(-1)at the CH_4flow rate of 85 sccm,which is attributed to the higher plasma density during the helicon wave plasma discharge.The CH and H_αradicals play an important role in the growth of DLC films.The results show that the H_αradicals are beneficial to the formation and stabilization of C=C bond from sp~2to sp~3.