离子发动机空心阴极寿命预测

为验证空心阴极的寿命,本文根据空心阴极LaB6发射体的损耗特点,采用数学建模方法对空心阴极的寿命进行了预测.预测结果表明兰州物理研究所研制的空心阴极工作在额定状态下(发射电流5.00 A),其寿命可达到40000 h以上.3500 h寿命试验后空心阴极解剖分析结果初步验证了预测模型的正确性.     

一种高熔点金属涂层的制备方法

研制了一种由多个空心阴极并列组合而成的，可直接作为溅射靶的多重空心阴极溅射靶，其溅射输出量可用电压，气压及空心阴极的高度和宽度比控制。人Ｗ，Ｍｏ合金制成的多重空心阴极溅射靶所做的合金涂镀试验表明，这种方法涂层沉积速度快，涂怪致密并与基体结合良好，适用于多种金属或其合金的溅射沉积，尤其是高熔点金属的溅射沉积。     

空心阴极放电稳定性试验研究

为研究空心阴极在起弧、稳态及熄弧等三个关键过程的放电特性从而改善地面测试试验中供电电源与空心阴极的匹配性,搭建了实验平台进行了试验研究,获得了这三个过程中阴极的典型伏安特性曲线。对阴极组件起弧及稳态工作过程进行监测,通过动态回路平衡方程确定了使用稳压稳流电源时系统的稳态工作点,并通过试验验证了空心阴极在不同流率点下放电特性的变化情况。最后对空心阴极熄弧过程的伏安特性进行了研究,通过拉偏测试试验确定了维持阴极自持放电的最小维持功率。结果表明:空心阴极与供电电源构成的系统具有两个工作点,阴极在起弧至稳态工作过程中将跨过首个工作点并最终稳定在在阻抗更小的工作点上。阴极的稳态工作伏安特性呈现为典型的负阻特性,适当增大气体流量和发射电流可以提升发射效率。维持LHC-5L型BLa_6阴极稳态放电所需最低输入功率为14 W,维持功率低于该值时空心阴极将熄弧。     

持续放电对空心阴极电性能及腐蚀特性的影响

为验证空心阴极持续工作对阴极关键零件的腐蚀情况,设计试验,使得六硼化镧空心阴极进行额定工况点下的持续放电工作并监测其电参数。试验结束后对阴极组件进行破坏性拆解,测量、拟合阴极关键零件腐蚀后的轮廓并与设计值进行对比,最终确定持续放电对阴极关键零件磨损情况的影响,最终为六硼化镧型阴极的设计改进提供依据。     

空心阴极在空间技术中的应用

空心阴极在空间技术中有广泛用途,本文介绍了空心阴极的工作特点,工作原理,并在此基础上综述了空心阴极在离子推力器、霍尔推力器、电动力学系绳、航天器电位控制、空心阴极微推力器的应用,最后就加快发展空心阴极技术提出意见.     

真空空心阴极电弧焊接研究和设备研制

介绍了国内研制的第一台真空空心阴极电弧焊接设备以及钛合金试板焊接工艺试验结果 .结果表明 :采用小孔膜片型空心阴极焊枪能够可靠地实现非接触引弧 ,焊接接头拉伸强度达到QJ1 666-95Ⅰ级接头要求 .     

离子发动机空心阴极失效形式分析

空心阴极是离子发动机关键部件,研究其失效形式,对提高离子发动机的可靠性有重要意义.介绍了离子发动机空心阴极的工作原理,分析离子发动机空心阴极的主要失效形式,并根据分析结果,提出了一系列提高离子发动机空心阴极可靠性的途径.     

离子推力器空心阴极点火可靠性评价研究

空心阴极作为离子推力器放电室等离子体电离源初电子和束流中和电子的电子源,其点火可靠性直接影响到推力器的工作可靠性。以20 cm离子推力器在轨工作剖面为例,对空心阴极预期寿命下的可靠度进行了评价。采用小样本的可靠性试验与可靠性评价理论结合的方法,得到了LHC-5空心阴极点火6 000次时在置信区间0.90和0.95的点火可靠性好于0.98。结果证明LHC-5空心阴极可靠性满足空间应用要求。研究成果对空心阴极可靠性增长设计和电推进产品可靠性评价方法研究具有积极意义。     

C12A7空心阴极研究进展

C12A7电子化合物因具有较低的逸出功和优良的化学稳定性备受电推进领域关注.介绍了这种新型发射体材料的特性,回顾了国内外C12A7空心阴极的试验结果和研究进展,分析了C12A7空心阴极存在的问题和关键技术,并对其应用前景和未来的发展方向进行了讨论.     

空心阴极等离子体与热耦合模型研究进展

空心阴极作为高效率的宇航级电子源,被广泛应用于空间电推进系统和航天器主动电位控制系统。研究空心阴极等离子特性与热特性的耦合过程,对于提高空心阴极效率和延长其寿命具有重要意义。通过分析空心阴极等离子体与热耦合模型和空心阴极参数测量方法的特点,建议先研究空心阴极零维等离子体与热耦合模型,初步满足空心阴极研制的仿真分析需求,再发展空心阴极二维等离子体与热耦合模型,逐步提高空心阴极仿真分析水平。     

Anwendung der Hohlkatodenplasmaquelle in der Vakuumtechnik

Various effective and simple constructed plasma sources can be developed by using the hollow cathode effect. The improve of the plasma efficiency is caused by the penetration of two or more glow regions of different parts of the cathode. The equatation p × d ∽ 1 mbar cm is a rule of thumb for the appearance of the hollow cathode effect. The hollow cathode arc discharge is caused by an additional thermal electron emission besides the effectes of the hollow cathode glow discharge. All this effects are the reason for the higher degree of ionization for a hollow cathode source in comparison with the most other plasma sources. Application of the hollow cathode glow discharge for surface finish are technics like plasmacleaning, electron beam ablation or gas flow sputtering. Latters are new technics which allow the development of new sources for the coating technology. The application of the hollow cathode are discharge is possible by using the thermal energy generated by the electron beam (electron beam heating, electron beam melting, and electron beam evaporation) and by using the different possibilities of coating technologies whith the hollow cathode arc source (plasma enhanced evaporation, plasma enhanced reactive PVD and plasma CVD).     

Measurement of total energy flux density at a substrate during TiOx thin film deposition by using a plasma jet system

The total energy flux density delivered to an electrically isolated substrate in a low-pressure pulsed DC hollow cathode plasma jet sputtering system during TiO₂ thin film deposition has been quantified. The plasma source was operated in constant average current mode and in a mixture of argon and oxygen or only in pure argon working gas. A titanium nozzle served as the hollow cathode. The total energy flux density measurements were made using a planar calorimeter probe. The main results from the calorimeter probe showed clearly that the total energy flux density at the electrically isolated substrate decreases significantly with duty cycle from 100% (DC mode) to 10% at a given pulsing frequency 2.5 kHz. A local maximum at duty cycle 60% for only pure argon operation has been observed. In addition, the voltage waveforms on the hollow cathode and before the ballast resistor have been saved for pulsed DC measurements for both pure argon and argon + oxygen mixture. A similar transient phenomenon on the cathode voltage and discharge current as observed recently in mid-frequency pulsed DC magnetron discharge has been discovered in the hollow cathode plasma jet sputtering system. We can conclude from these preliminary measurements that the main asset of the pulsed DC hollow cathode plasma jet discharge as distinct from the DC driving of the same plasma system lies in the possibility to reduce or to increase energy influx on the floating substrate within the change of duty cycle.     

Effect of aging the hollow cathode by sputtering on the analytical precision of the hollow cathode discharge emission source.

Sputtering changes the analytical performance of the hollow cathode as an emission source. Proper conditioning (aging) of the hollow with sputtering greatly improves precision. Conditioning decreases the blank emission signal and changes the shape of the hollow. Micrographs which show the evolution of the bottom of the hollow into a stable bulb shape are presented. The blank emission signal decreases with aging of the hollow and approaches a constant value when the hollow is properly conditioned. A short-term stability (n = 5) of approximately 1.8% RSD has been observed frequently. An average long-term stability over several days (n = 45) of 4.5% for Li and 3.5% for Na in the emission signal from microsamples (less than 50 nL) deposited in the hollow cathode discharge source is reported here. Instrumentation, operation, and sample preparation procedures are described.     

电推进系统空心阴极热特性研究进展

阐述了电推进系统空心阴极热特性研究的重要性以及目前国内外研究进展,并且进一步介绍了空心阴极热特性分析方法的发展前景和存在的主要技术难题,能够对未来空心阴极热场分析的发展提供借鉴和参考价值。     

Optimization and performance of atmospheric Fused Hollow Cathodes

Experimental results on the atmospheric hollow cathode plasma generation and performance, using a special configuration with tunable wall separations, are presented. The influence of the gas and type of the power used for generation on the optimum size of the cathode slit is investigated. The experimental results are in agreement with the hollow cathode model. The plasma source/plasma reactor design is of utmost importance for control of plasma-chemical kinetics. An example of the atmospheric hollow cathode plasma application for the NO_x conversion is given. The energy consumption and plasma characteristics are discussed.     

Evaluation of plume characteristics of arc-heaters with various oxygen injection systems

Arc-heater plumes generated by various oxygen injection systems were investigated by laser absorption spectroscopy. Firstly, oxygen was directly injected into a high-temperature cathode-jet region through a thoriated-tungsten hollow cathode. Although number density of atomic oxygen was increased, erosion of the cathode was too severe to maintain stable discharge. Then, zirconium was used as a cathode material to reduce cathode erosion by oxidation. As a result, stable discharge was maintained for 3 h with pre-mixed argon–oxygen injection and number density of atomic oxygen was successfully increased.     

Hollow cathode and hybrid plasma processing

Generation and features of the radio frequency (rf) hollow cathode discharge (HCD) and its transition into the hollow cathode arc (HCA) are described. Rf linear hollow cathodes for generation of plasma over large areas and suitable for further scale-up are presented. Examples of surface processing and coating by PVD, both by HCD and HCA, are given. The hybrid reactor, combining hollow cathode and microwave plasmas, integrates features of both and provides more options to control plasma characteristics and consequently properties of deposited films. The rf hollow cathodes can be operated in both, PVD and PE CVD regimes, depending on process parameters. These regimes can even be combined within one process. New concepts of fused hollow cathode (FHC), microwave antenna (MWA) and Hybrid hollow electrode activated discharge (H-HEAD) cold atmospheric plasma sources are introduced. The FHC with its modular concept can be used for gas conversion, cleaning and for surface treatment of temperature-sensitive materials at ambient atmosphere. The H-HEAD cold atmospheric plasma source, capable of generating plasma plumes more than 15 cm long, enables treatment of 3-d and complex geometry objects even at low gas flows.