本文選題：多孔鎢基體　切入點(diǎn)：活性發(fā)射物質(zhì)　出處：《電子科技大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：作為大功率微波源—回旋管的核心部件,陰極提供高質(zhì)量的電子注參與注波互作用,直接影響回旋管的整管性能。受限于工藝條件和陰極理論尚未成熟,影響陰極發(fā)射性能和工作穩(wěn)定性的因素往往很復(fù)雜。本文從多孔鎢基體、活性發(fā)射物質(zhì)、陰極組件結(jié)構(gòu)、電泳沉積工藝等方面入手,研究了各關(guān)鍵工藝機(jī)理及其對(duì)陰極性能的影響。主要研究?jī)?nèi)容如下:1、確定了制備多孔鎢基體的最佳工藝參數(shù),成功地采用模壓方法制備出滿足要求的多孔鎢基體,設(shè)計(jì)的錐度CrWMn鋼模具解決了鎢餅脫模過程存在的崩角、斷層等問題,將脫模造成的鎢餅損壞降為零。2、采用化學(xué)沉積方法取代傳統(tǒng)機(jī)械混合方法制備活性發(fā)射物質(zhì)原料,直流發(fā)射性能測(cè)試結(jié)果表明,陰極在1000℃時(shí)偏離點(diǎn)電流密度為為3.26A/cm2,優(yōu)于普通B型陰極2 A/cm2的發(fā)射能力。3、確定了陰極組件模型的接觸條件:發(fā)射帶與支撐筒理想接觸、填充物與熱子及填充物與支撐筒接觸面熱導(dǎo)系數(shù)為0.001 W/(mm2貹)。在此基礎(chǔ)上模擬熱子圈數(shù)、熱子絲徑和填充高度對(duì)熱場(chǎng)分布影響,并設(shè)計(jì)新的組件結(jié)構(gòu)。仿真結(jié)果顯示,新結(jié)構(gòu)的熱子工作溫度下降200多度,組件溫度分布更加均勻,這對(duì)提高熱子的工作壽命和陰極的工作穩(wěn)定性具有重要意義。4、利用靜電場(chǎng)邊界條件建立電泳沉積模型,推導(dǎo)出沉積量與電壓和沉積時(shí)間的二次關(guān)系式。根據(jù)關(guān)系式,在不同的電泳條件下得到相同厚度的氧化鋁絕緣層。熱處理后測(cè)得40V電壓下沉積6s得到的氧化鋁熱子絕緣層電阻率最高。老煉結(jié)果顯示,熱子可以在1100℃下連續(xù)工作超過3000h。5、采用排氣臺(tái)二極管測(cè)試系統(tǒng)和回旋管整管測(cè)試系統(tǒng)對(duì)陰極發(fā)射性能進(jìn)行驗(yàn)證。結(jié)果表明:陰極在溫度為1100℃時(shí),偏離點(diǎn)電流大于5.05 A/cm2。在40kV工作電壓下,加載功率43.5W時(shí),脈沖電流發(fā)射密度達(dá)到13.1 A/cm2,陰極性能滿足回旋管要求。
[Abstract]:As the core component of the high power microwave source-gyrotron, the cathode provides high quality electron beam to participate in the beam-wave interaction, which directly affects the whole performance of the gyrotron. The factors that affect the emission performance and working stability of the cathode are often very complicated. In this paper, the porous tungsten matrix, the active emitter, the structure of the cathode module, the electrophoretic deposition process, etc. The main contents of this paper are as follows: 1. The optimum process parameters for the preparation of porous tungsten matrix have been determined and the porous tungsten matrix has been successfully prepared by moulding method. The design of taper CrWMn steel die solves the problems such as collapse angle and fault in the demoulding process of tungsten cake, and reduces the damage of tungsten cake caused by demoulding to zero. 2. The chemical deposition method is used instead of the traditional mechanical mixing method to prepare the active emitter material. The DC emission performance test results show that the current density of the cathode at 1000 鈩，

本文編號(hào)：1567530