【摘要】：石墨烯是一種半金屬材料,具有熱導(dǎo)率高,電導(dǎo)率高,比表面積大,發(fā)射邊緣多,機(jī)械強(qiáng)度高等特點(diǎn)。石墨烯作為冷陰極材料具有較低的開啟場(chǎng)和閾值場(chǎng)等優(yōu)異的電子發(fā)射特性。本文將石墨烯應(yīng)用于爆炸式強(qiáng)流電子發(fā)射陰極,以提高強(qiáng)流電子發(fā)射陰極的電子發(fā)射能力。分析研究了石墨烯強(qiáng)流電子發(fā)射陰極的制備方案、方法、其制備工藝,并制備了石墨烯強(qiáng)流電子發(fā)射陰極,測(cè)試了其在強(qiáng)流電子發(fā)射中的輸出特性。采用改進(jìn)Hummer法和熱還原的方法制備氧化石墨烯和石墨烯;金屬粉末為工業(yè)用的銅粉和鋅粉;陰極的制備方法為壓制混合均勻的石墨烯和銅粉與鋅粉材料。在爆炸發(fā)射過程中表面材料脫落后,其內(nèi)部更多的石墨烯尖端邊緣裸露出來,替補(bǔ)表層脫落的部分,使發(fā)射面的物理形貌變動(dòng)小,發(fā)射穩(wěn)定,使用壽命長(zhǎng)。通過其制備工藝的實(shí)驗(yàn)研究,選用石墨烯陰極中石墨烯的質(zhì)量比為3%;材料混合的方法為球磨混合,球磨功率和時(shí)間為1.2kW,球磨120min;壓制方法為單向壓制,壓力機(jī)為16t,壓制陰極的壓強(qiáng)為30MPa;在700℃環(huán)境下退火30min;然后根據(jù)測(cè)試系統(tǒng)結(jié)構(gòu)的需要對(duì)陰極進(jìn)行機(jī)械加工。在相對(duì)論磁控管中的測(cè)試結(jié)果中顯示,石墨烯陰極發(fā)射的電流波形具有非常陡峭的上升沿和下降沿,很好的平頂性,脈寬約為74ns略小于加載陰極上的電壓脈寬;最大發(fā)射電流約為56.67kA;陰極發(fā)射過程中產(chǎn)生的等離子體形成時(shí)間早,起振時(shí)間短,發(fā)射的電子束均勻;閾值電壓小于650kV;延遲時(shí)間約為20ns,小于黃銅墊圈陰極的23ns和石墨陰極的25ns。相對(duì)于電泳,沉積和表面涂覆等方法制備的石墨烯陰極來說,明顯提高了石墨烯強(qiáng)流電子發(fā)射陰極的使用壽命。
[Abstract]:Graphene is a kind of semi-metal material, which has the characteristics of high thermal conductivity, high conductivity, large specific surface area, many emission edges, high mechanical strength and so on. Graphene, as a cold cathode material, has excellent electron emission characteristics, such as low opening field and threshold field. In this paper, graphene is applied to explosive high current electron emission cathode to improve the electron emission ability of high current electron emission cathode. The preparation scheme, method and preparation technology of graphene strong current electron emission cathode were analyzed and studied, and the graphene strong current electron emission cathode was prepared. The output characteristics of graphene strong current electron emission cathode in high current electron emission were tested. Graphene oxide and graphene were prepared by improved Hummer method and thermal reduction method; metal powder was used as copper powder and zinc powder for industrial use; cathode was prepared by pressing uniformly mixed graphene and copper powder and zinc powder material. After the surface material falls off in the process of explosion, more graphene tip edges are exposed in the interior, and the falling part of the surface layer is replaced, so that the physical morphology of the emission surface changes little, the emission is stable and the service life is long. Through the experimental study of its preparation technology, the mass ratio of graphene in graphene cathode is 3%, the material mixing method is ball milling mixing, ball milling power and time is 1.2 kW, ball milling is 120 min, pressing method is unidirectional pressing, press is 16 t, pressing cathode pressure is 30 MPA, annealed at 700 鈩，

本文編號(hào)：2501119