磁控电弧离子镀阴极斑点特性的高速摄影研究

利用高速摄影技术，对磁控电弧离子镀中阴极斑点大小、寿命及运动轨迹进行了观测，得到了极斑点电流密度、运动速度随磁场、电弧电流及背景气体压力改变而变化的关系曲线。     

真空阴极弧离子镀阴极斑点的移动研究

建立了真空阴极弧离子镀圆形平面靶侧面引弧时 ,阴极斑点的受力模型 ,分析了影响电弧运动的因素 ,改进了圆形平面靶侧面形状 ,大大提高了石墨靶阴极斑点从侧面到靶平面的过渡速度     

真空开关电弧形态的实验研究

真空电弧形态的研究对真空开关能否有效控制和保护电路有着重要的影响.本文设计了真空开关电弧实验系统,建立了基于高速摄像设备CMOS的真空开关电弧采集系统.通过该采集系统可以每秒200,000帧采集速度得到了真空开关电弧图像.实验结果表明,真空开关电弧起始处于扩散形态,随着电流的增大,电弧月逐渐集聚,并产生阳极斑点,峰值电流过后再次转变成扩散形态,最终在阴极表面形成很多阴极斑点,做高速运动并数量不断减少至电弧完全熄灭.     

真空阴极弧离子镀阴极斑点的移动研究

建立了真空阴极弧离子镀圆形平面靶侧面引弧时,阴极斑点的受力模型,分析了影响电弧运动的因素,改进了圆形平面靶侧面形状,大大提高了石墨靶阴极斑点从侧面到靶平面的过渡速度。     

粗晶/细晶CuCr50触头材料的电弧运动行为及其烧蚀特性

将高能球磨和等离子烧结(SPS)技术相结合制备出粗晶和细晶CuCr50电触头材料，对其成分、密度、显微硬度和电导率、放电过程中触头表面阴极斑点的分布、移动速度和触头表面侵蚀的形貌进行表征，研究了粗晶和细晶CuCr材料的电弧侵蚀特性。结果表明，细晶CuCr50触头的硬度(160.29HV)比粗晶CuCr50触头的硬度(104.15HV)高，在50 Hz工频条件下细晶触头阴极斑点的运动速度为16.9 m/s，比粗晶触头的17.78 m/s低4.9%。这表明，粗晶触头表面的阴极斑点运动到触头边缘的速度略比细晶触头的高。与粗晶触头相比，在燃弧过程中细晶触头表面产生的阴极斑点尺寸小、数量多、亮度低且更均匀；在电流幅值相同的条件下，细晶CuCr触头的电弧电压降比粗晶触头的低。电弧烧蚀后细晶CuCr触头的整体形貌平整，没有明显的大烧蚀坑和液滴喷溅。综合研究结果表明，细化第二相Cr相能显著提高CuCr50触头的整体电接触性能，细晶CuCr50触头的抗电弧烧蚀特性比粗晶触头的高。     

多弧沉积技术综述

自从八十年代初多弧镀设备成功地在刀具、模具上镀氮化钛镀层以来,多弧镀受到广泛的关注。国内刀具行业纷纷引进设备,许多研究所和设备制造厂也相继研制,“多弧”热的浪潮一度掀起。如何客观地评价这一技术呢?如何合理地利用它的长处呢?本文想在目前所了解的资料的基础上作一综述。 一、多弧镀的概述 1.什么是多弧镀 多弧镀是一种利用真空电弧放电的沉积技术。但它不是空芯阴极放电的那种热电子电弧,而是一种非热电子电弧。它的电弧形式是在冷阴极表面上形成一个或多个阴极电弧斑点。过些斑点具有高的电流密度,从而使阴极材料汽化,形成金属…     

插接式真空灭弧室电弧形态的试验研究

为了解决传统对接式真空负荷开关在大容量发电机出口负荷开关开发过程中存在无法满足大负荷电流的瓶颈问题,基于插接式触头结构的真空灭弧室具有承载大负荷电流的优势,使其成为发电机出口端真空负荷开关设计的一种优选方案.同时,通过引入横向磁场对插接式触头结构进行了改进,改进后的真空灭弧室经过试验验证也具有了开断大负荷电流的能力.在小电流情况下(I＜2 kA),插接式电极结构真空电弧特性的试验研究发现阴极斑点或者仅在单一触指上分布,或者在各个触指之间跨越同时并联存在.当阴极斑点在单一触指上分布时,一部分阴极斑点在触指开槽处成群聚集静止不动,另一部分阴极斑点沿着S型轨迹在该触指表面边缘运动;当阴极斑点从一个触指向相邻触指跨越过程中,原来触指上的阴极斑点并不熄灭而是同时并联存在.     

用于真空电弧离子镀膜的受控电弧蒸发源

本文在研究了阴极弧斑运动规律的基础上，发展了多功能受控电弧蒸发源，它可在自由电弧状态下运行，而在２００～２５０Ａ高参数运行时，可使阴极弧斑覆盖几乎整个阴极表面且多轨迹旋转，使阴极烧蚀均匀，提高了镀膜沉积速率，薄膜质量也相应提高。研制的另一种环形阴极旋转电弧蒸发源，可基本消除液滴，使阴极利用率更高。     

真空电弧放电稳定性

本文研究了真空阴极电弧放电过程中阴极电弧源工作稳定及其影响因素,研究了真空电弧斑的产生及运动规律。     

添加Al2O3对CuW70合金阴极斑点运动特性的影响

采用熔渗法制备了不同Al2O3添加量的CuW70合金,研究了Al2O3对CuW70合金组织和真空击穿性能的影响,利用高速摄影观察了CuW70合金表面阴极斑点运动规律.结果表明:未添加Al2O3的CuW70合金烧蚀主要集中在Cu聚集区;在放电过程中,阴极斑点运动表现为原地重复的燃烧,合金表面烧蚀严重.添加Al2O3后,CuW70首击穿相发生转移,集中在Al2O3颗粒上,阴极斑点更为分散,合金主烧蚀区面积明显减少;Al2O3的添加延长了电弧寿命,降低了截流值.     

The effect of axisymmetric two-dimensional magnetic field on the configuration of vacuum-arc plasma

An experimental investigation is made of the effect of axisymmetric two-dimensional magnetic field on the forming of plasma and on the configuration of cathode spots in a vacuum-arc discharge. It is demonstrated that a magnetic field with a transverse (relative to the discharge axis) component has a significant effect on the shape of plasma column and on the rate of expansion of the cathode spot region. In a magnetic field, arc plasma has the form of truncated cone expanding toward the anode. The cathode spots take up a part of the cathode area which decreases with increasing magnetic field. Arguments are given in support of the assumption that the arrangement of cathode spots and the form of arc plasma are defined by the minimum principle similar to the Steinbeck principle. In so doing, the displacement of spots is caused by their emergence in a new region corresponding to a lower arc voltage. Also discussed is the mechanism associated with retrograde motion of cathode spot in view of the effect of azimuthal magnetic field on the axial component of current and of the effect of axial magnetic field on the azimuthal component of current.     

Dynamics studies of cathode spots in a vacuum-arc discharge with ring electrodes

The effect of an external pulse magnetic field with axial and radial components on electric characteristics of the discharge and the configuration of cathode spots of a vacuum arc discharge with ring electrodes is studied experimentally. For arc currents within the range of 0.05–2 kA, shots of the cathode spots at different instants of time are obtained. The dependences of the number of the spots on the discharge current and the mean current per spot are determined. It was found that the expansion rate of the cathode spots area depends significantly on the instant value of the discharge current. It is shown that, when the pulse magnetic field is applied, the discharge voltage increases and the discharge current and number of the cathode spots decreases. It was found that the current interruption is a probability process. The probabilities of the current interruption depending on the maximal value of the external pulse magnetic field induction are determined.     

Retrograde motion of cathode spots of the first type in a tangential magnetic field

We consider the dynamics of dense plasma of an explosive-electron-emission center—a cell of cathode spot of a vacuum arc in an applied magnetic field. It is established that the explosive expansion of plasma in a transverse magnetic field induces an electric field and an associated current. It is shown that this current initiates the cells of cathode spots of the first type in the direction opposite to the Ampere force action. In this case, the ignition time of a new spot does not exceed a few nanoseconds at a magnetic field of a few kilogauss.     

Effect of tangential magnetic field on ecton processes in cathode spot of vacuum arc

Emission and erosion processes involved in the final stage of the cathode spot cell operation in vacuum arc in the presence of an external magnetic field have been numerically simulated. It is established that the application of a magnetic field leads to asymmetry in the distributions of current density and heat flux, so that their maxima shift in the “anti-Ampere” direction. For more detailed analysis of the phenomenon of retrograde motion of the cathode spot in a magnetic field, it is necessary to study the behavior of a liquid metal phase in the spot.     

Control of cathodic arc spot motion under external magnetic field

A closed circular transverse magnetic field is designed to control the spot motion of a cathodic arc on a large rectangular target. Stable and controllable spot motion is observed from both graphite and copper. The arc stability, spot velocity, and etched pattern on the cathode surface are studied systematically. Circular tracks are etched on the target surface by the repetitive spot movement and the surface morphology and resistivity of the cathode materials influence the spot velocity.     

Magnetic‐Field Effect on Heat Transfer within a Cathode Arc Spot

The authors present results of an experimental study of the heat flux within the arc spot of the copper cathode of an electric‐arc heater with magnetic‐field‐induced displacement of the arc in an air medium — one of the most important parameters determining the erosion and service life of such a cathode. The investigations were carried out at a current strength of 110–?450 A, a magnetic induction of 0.009–0.38 T, and atmospheric pressure.     

Structure of the Welding Arc Cathode Spot with a Nonconsumable Electrode

The cathode spot autographs on a glass surface are investigated through an electron microscope, with a magnification up to 100000. We discover that the welding arc cathode spot consists of separate cells with the substructure, current channels, 10–60 nm in diameter. We acquire color photographs of the welding arc cathode spot with the cathode torch. Photograph processing through different filters reveals the shape of the cathode spot and the cathode torch. We perform the estimate calculations of the current density in the welding arc cathode spot substructure.     

Measuring the robson angle in vacuum arcs of various length

It is established that the Robson angle, which determines the direction of motion of a cathode spot of vacuum arc in a homogeneous electric field sloped relative to the cathode, depends mostly on the inter-electrode gap width. The dependence of the Robson angle on the field slope at various gap widths has been measured for molybdenum and tungsten cathodes. The knowledge of this angle is necessary for correct choice of the optimum magnetic field configuration controlling the cathode spot dynamics in setups for vacuum-arc deposition of various coatings and in vacuum commutation devices.     

Study of the direct current breakage process in an external nonuniform magnetic field

We study experimentally the influence of an external nonuniform magnetic field with transverse and longitudinal components on the electric characteristics, plasma configuration, and cathode spot arrangement of vaccum-arc discharge. It is revealed that for a cylindrical cathode, cathode spots are nonuniformly distributed on the cathode surface, the spot configuration has no axial symmetry, and the arrangement of spots changes in time depending on the induction value of the external pulsed magnetic field. With an increase in induction, spots (on average) are arranged closer to the cathode, i.e., displaced to the region of weaker transverse field. For two cathode geometries, the probabilities of direct current breakage depending on the induction of the external nonuniform magnetic field are experimentally determined. To determine the conditions of current breakage, a three-dimensional mathematical model of ion motion is suggested and the current breakage criterion is formulated. The trajectories of fast cathode ions in an electrode system with a ring cathode have been calculated using the model. Calculations were performed in a nonuniform magnetic field, the radial and axial components of which have been measured experimentally. It is shown that conditions of current breakage determined with this criterion agree with the results of experiment.     

Velocity of the electric arc in a plasmatron discharge chamber

An experimental investigation of the velocity of a high-current arc with air injection in the discharge chamber of a coaxial sectioned plasmatron is described. The experiments showed that the velocity of the cathode spot on the electrode surface depends on the arc current and on the external magnetic field strength. The air flow rate in the plasmatron chamber was 7.1 g/sec.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 17, No. 3, pp. 570–574, September, 1969.