过滤管道磁场在改进真空弧沉积系统中的作用

在90°磁过滤管道和MEVVA源阴极之间加30～60V的正偏压可使磁过滤管道起到阴极弧放电第二阳极的作用.在此情况下,就磁过滤管道磁场对MEVVA源阳极-阴极和磁过滤管道-阴极两个回路弧放电和磁过滤管道等离子体传输效率的影响进行了实验研究.研究结果表明随磁过滤磁场升高,磁过滤管道和阴极之间的弧放电规模降低,系统的等离子体传输效率升高,但对MEVVA源阳极和阴极之间的弧放电规模影响不大.     

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。     

中心螺线圈式大面积均匀金属等离子体形成方法

传统的磁过滤阴极真空弧系统的金属等离子体输出面积较小且出口处的密度呈高斯分布,阻碍了等离子体浸没离子注入与沉积(PⅢ&D)技术的工业化应用,使得大面积均匀金属等离子体的产生成为了业内研究的热点.本文提出了一种基于多阴极脉冲真空弧源对称配置的中心螺线圈式大面积均匀金属等离子体形成方法,可输出直径约为600mm的金属等离子体.沉积探针结果表明:载流螺线圈对沉积均匀性有较大的影响.单源X方向的沉积均匀性优于Y方向的沉积均匀性;四弧源的离子流密度约为单源的5.5倍,沉积均匀性最高可达83.8%.     

磁过滤真空弧沉积中过滤管道的第二阳极作用研究

利用一台磁过滤真空弧沉积装置,初步研究了磁过滤管道对系统弧放电的影响。实验证明,磁过滤管道在阴极真空弧沉积中不仅起到消除大颗粒的作用,还作为阴极真空弧放电的第二阳极对弧放电产生影响。给出了磁过滤阴极真空弧放电的等效电路,并用此电路对磁过滤阴极真空弧放电中的部分实验现象进行了解释。     

热等离子体

虽然已许多工业应用开发了热等离子体工艺，但是由于经济和竞争的原因，和／或再现性和可靠性方面的原因，它们未能作为一种制造技术得到广泛认可，本文着重评估现在对以下课题的了解：１）等离子体炬和吹弧（直流或交流）传热弧以及射频炬的性能；２）确认的工业应用，其重点是切割，焊接，喷涂，传热弧回收，再加热和纯化，再加热金属熔化，还原熔炼，化学运行以及废物破坏；３）最近对等离子体炬在电源，阴极（热的冷和热）阳极（     

一种用于煤粉点火等离子体发生器的电弧特性研究

介绍了一种用于煤粉点火等离子体发生器的实验装置，由一对并联的条形平行布置的阳极和同平面布置的圆柱形阴极构成，它们设置在煤粉输运通道中。采用高速CCD摄像和电弧电气参数测量等方法，研究了电弧形状、弧根的运动规律等。试验结果表明：（1）阳极弧根沿电极轴向无规则快速跳动及在两条电极间交替跳跃，这种弧根的快速跳跃有利于降低阳极损耗；（2）电弧在两条阳极之间的弧室内呈现不规则快速变化扭曲形状，使电弧弥漫于整个弧室，煤粉通过电弧放电通道高温区时与电弧混合而点火，使等离子体点火效率有了显著提高。     

采用磁过滤阴极弧沉积技术制备含Ti类金刚石薄膜的研究

采用磁过滤阴极弧沉积技术以金属Ti为阴极在真空室中加入C2H2气体来制备含Ti类金刚石薄膜，研究不同的过滤弯管电流和在有过滤磁场存在条件下不同的C2H2气压对含Ti类金刚石薄膜的成分和组织结构的影响规律。实验结果表明：薄膜是由TiC和类金刚石两种结构组成的复合薄膜。C2H2气压和过滤弯管电流都对含Ti类金刚石薄膜的成分和组织结构有显著的影响。增加C2H2气压和过滤弯管电流都使薄膜中雨元素的原子百分含量逐渐下降，C元素的原子百分含量逐渐增加，TiC峰强度逐渐降低，半高宽逐渐增加。     

用于材料表面强化处理的第三代多功能PⅢ装置

第三代多功能等离子体浸没离子注入（PⅢ）装置的强流脉冲阴极弧金属等离子体源既具有强的镀膜功能，同时也具有强的金属离子注入功能；它的脉冲高压电源能输出大的电流；并可获得高的注入剂量均匀性。该装置既能执行离子注入，又能把离子注入与溅射沉积，镀膜结合在一起，形成多种综合笥表面改性工艺。本文描述了它的主要设计原则、主要部件的特性以及近期的研究工作成果。     

磁驱动旋转电弧运动图像及弧电压脉动的实验研究

磁驱动旋转电弧产生扩散电弧等离子体过程中有许多有趣的物理现象。本文利用高速摄影技术研究了大气压条件下、非均匀磁场中、大尺度磁驱动旋转氩电弧的电弧结构；在一定的弧电流和外磁场条件下，电弧的平面形状表现为不断发展和增长的螺旋结构，电弧螺旋结构的破裂往往产生于阴极附近的等离子体射流。采用图像分析的方法计算了外部磁场作用下阳极斑点沿弧室内壁的移动频率，分析了磁驱动旋转电弧运动过程中的弧电压脉动现象。结合电弧图像分析和电弧电压脉动及其FFT分析得出：电弧电压的大幅波动与多层电弧螺旋结构破裂和重建相关，而电弧电压的小幅波动则是弧根小幅跳动引起电弧拉长和收缩的结果。     

述评：金属等离子体浸没离子植入和沉积

金属等离子体浸没离子植入和沉积（ＭｅＰＩＩＩＤ）是一项将阴极电弧沉积和等离子体浸没离子植入结合起来的混合工艺。本文评述了由真空电弧产生的金属等离子体的性能,并讨论了ＭｅＰＩＩＩＤ的结果。描述了各种类型的ＭｅＰＩＩＩＤ,并将它们与表面改性的传统方法如离子束辅助沉积（ＩＢＡＤ）作了比较。由于使用了各种离子粒种和能量,ＭｅＰＩＩＩＤ是一项非常通用的方法。在一种极端情况下,用能量范围为２０－５０ｅＶ的离子     

On Cooled Anodes in Contact with a Laminar Arc-Heated Flow

This paper is concerned with the physics and operating characteristics of cooled anodes In contact with an arc-heated laminar plasma flow in a constant area duct. Various modes of anode behavior are identified and described. Some Influences of gas type, flow rate, arc current, anode material and geometry are demonstrated. A theory is developed to explain the low-current mode of the anode characteristic. It is shown that the local current density on the anode surface is related approximately to the surface's local bias relative to its electrically floating voltage. Anode current distribution data is presented; the distribution is shown to be unstable above a transition bias volt,. age, with the current concentrating intensely on the edge of the anode toward the cathode. Neighboring points on the duct wall are shown to be electrically independent. This fact greatly simplifies an interpretation of anode phenomena. The information presented makes a fairly complete picture of the physical behavior of finite-length, cooled anodes in contact with fully-developed laminar plasma-arc flows.     

低能高束流氩离子源的结构及性能

离子源技术是等离子体研究中的一项重要内容,而低能大束流源则是离子源技术研究中的一个重要方向,因为这样的源在离子束刻蚀、离子束溅射镀膜以及荷能粒子与物质相互作用方面都有广泛的应用;本文采用空心阴极空心阳极结构,用热阴极电子发射弧放电驱动并用磁场约束产生等离子体,用曲面发射引出离子束,研制成了氩气放电溅射离子源;研究了灯丝加热电流、弧压对弧流的影响和弧流与工作气体压力对离子束引出的影响规律.离子源的引出电压在0-4.0 kV之间连续可调,最大引出束流为100 mA,束斑面积为φ6.0 cm,以Ti为溅射靶时的最大溅射沉积率为0.45 nm/s,离子源可连续工作160 h.     

Characteristics of Single Cathode Cascaded Bias Voltage Arc Plasma

A single cathode with a cascaded bias voltage arc plasma source has been developed with a new quartz cathode chamber,instead of the previous copper chambers,to provide better diagnostic observation and access to the plasma optical emission.The cathode chamber cooling scheme is also modified to be naturally cooled only by light emission without cooling water to improve the optical thin performance in the optical path.A single-parameter physical model has been developed to describe the power dissipated in the cascaded bias voltage arc discharge argon plasmas,which have been investigated by utilizing optical emission spectroscopy(OES) and Langmuir probe.In the experiments,discharge currents from 50 A to 100 A,argon flow rates from 800 sccm to 2000 sccm and magnetic fields of 0.1 T and 0.2 T were chosen.The results show:(a) the relationship between the averaged resistivity and the averaged current density exhibits an empirical scaling law as η∝ j~(-0.63369) and the power dissipated in the arc has a strong relation with the filling factor;(b) through the quartz,the argon ions optical emission lines have been easily observed and are dominating with wavelengths between 340 nm and 520 nm,which are the emissions of Ar~+-434.81 nm and Ar~+-442.60 nm line,and theintensities are increasing with the arc current and decreasing with the inlet argon flow rate;and(c) the electron density and temperature can reach 2.0 × 10~(19) m~(-3) and 0.48 eV,respectively,under the conditions of an arc current of 90 A and a magnetic field of 0.2 T.The half-width of the n_e radial profile is approximatively equal to a few Larmor radii of electrons and can be regarded as the diameter of the plasma jet in the experiments.     

Influence of heating on the discharge characteristics of a hollow cathode

Hollow cathodes are widely used as electron sources and neutralizers in ion and Hall electric propulsion. Special applications such as commercial aerospace and gravitational wave detection require hollow cathodes with a very wide discharge current range. In this paper, a heater is used to compensate for the temperature drop of the emitter at low current. The self-sustained current can be extended from 0.6 to 0.1 A with a small discharge oscillation and ion energy when the flow rate is constant. This is also beneficial for long-life operation. However, when the discharge current is high(1 A), heating can cause discharge oscillation, discharge voltage and ion energy to increase. Further, combined with a rapid decline of pressure inside the cathode and an increase in the temperature in the cathode orifice plate, electron emission in the orifice and outside the orifice increases and the plasma density in the orifice decreases. This leads to a change in the cathode discharge mode.     

真空弧离子源脉冲工作瞬间的放电行为

采用高速摄影和光谱诊断的方法研究了真空弧离子源脉冲工作瞬间的放电行为。拍摄了离子源放电瞬间吸氢电极上阴极斑的形成过程，分析了不同放电电流时阴极斑的发射光谱。实验结果表明，当脉冲工作电流为10^1—10^2A时，真空弧离子源放电区一般只有单个阴极斑，阴极斑的位置在同一次放电中的变化很小；较大的脉冲工作电流有利于提高阴极斑的温度，并最终导致氢离子浓度的增加，但也会使阴极材料的溅射更加严重，造成离子源等离子体品质下降。     

Parametric Study on Arc Behavior of Magnetically Diffused Arc

A model coupling the plasma with a cathode body is applied in the simulation of the diffuse state of a magnetically rotating arc.Four parametric studies are performed:on the external axial magnetic field (AMF),on the cathode shape,on the total current and on the inlet gas velocity.The numerical results show that:the cathode attachment focuses in the center of the cathode tip with zero AMF and gradually shifts off the axis with the increase of AMF;a larger cathode conical angle corresponds to a cathode arc attachment farther away off axis;the maximum values of plasma temperature increase with the total current;the plasma column in front of the cathode tip expands more severely in the axial direction,with a higher inlet speed;the cathode arc attachment shrinks towards the tip as the inlet speed increases.The various results are supposed to be explained by the joint effect of coupled cathode surface heating and plasma rotating flow.     

Investigation of cathode spot characteristics in vacuum under transverse magnetic field (TMF) contacts

With the continuous improvement of current levels in power systems,the demands on the breaking capacity requirements of vacuum circuit breakers are getting higher and higher.The breaking capacity of vacuum breakers is determined by cathode spots,which provide electrons and metal vapor to maintain the arc.In this paper,experiments were carried out on two kinds of transverse magnetic field (TMF) contacts in a demountable vacuum chamber,the behavior of the cathode spots was recorded by a high-speed charge-coupled device (CCD) video camera,and the characteristics of the cathode spots were analyzed through the image processing method.The phenomenon of cathode spot groups and the star-shaped pattern of the spots were both discovered in the experiment.The experimental results show that with the condition of TMF contacts the initial expansion speed of cathode spots is influenced by some parameters,such as the tested current,contact gap,the structure of the contact,the contact diameter,the number of slots,etc.In addition,the influence of the magnetic field on the formation of the cathode spot groups,the distribution,and the dynamic characteristics of the cathode spots were analyzed.It is concluded that the characteristics of the cathode spots are due to the effect of the magnetic field on the near-cathode plasma.The study of the characteristics of cathode spots in this paper would be helpful in the exploration of the physical process of vacuum arcs,and would be of guiding significance in optimizing the design of vacuum circuit breakers.     

Surface morphology influence on deuterium retention in beryllium films prepared by thermionic vacuum arc method

In a plasma-confinement device, material eroded from plasma facing components will be transported and re-deposited at other locations inside the reaction chamber. Since beryllium from the first wall of the ITER fusion reactor will be eroded, ionized in the scrape-off layer plasma and finally re-deposited on divertor surfaces flowing along the magnetic field, it is important to study the properties of divertor armour materials (C, W) coated with beryllium.By applying different bias voltages (−200 V to +700 V) to the substrates during deposition, the morphology of the obtained films was modified. The films’ morphology was characterized by means of AFM and SEM, and it was found that the coatings prepared using negative bias voltage at the substrate during deposition are more compact and have a smoother surface compared to the samples prepared with positive bias voltage. The thickness and composition of each film were measured using Rutherford backscattering spectrometry (RBS). A study of deuterium implantation and retention into the prepared films was performed at IPP Garching in the high current ion source.