石墨烯强流电子发射阴极制备及其特性研究
发布时间：2019-06-17 16:31
【摘要】：石墨烯是一种半金属材料,具有热导率高,电导率高,比表面积大,发射边缘多,机械强度高等特点。石墨烯作为冷阴极材料具有较低的开启场和阈值场等优异的电子发射特性。本文将石墨烯应用于爆炸式强流电子发射阴极,以提高强流电子发射阴极的电子发射能力。分析研究了石墨烯强流电子发射阴极的制备方案、方法、其制备工艺,并制备了石墨烯强流电子发射阴极,测试了其在强流电子发射中的输出特性。采用改进Hummer法和热还原的方法制备氧化石墨烯和石墨烯;金属粉末为工业用的铜粉和锌粉;阴极的制备方法为压制混合均匀的石墨烯和铜粉与锌粉材料。在爆炸发射过程中表面材料脱落后,其内部更多的石墨烯尖端边缘裸露出来,替补表层脱落的部分,使发射面的物理形貌变动小,发射稳定,使用寿命长。通过其制备工艺的实验研究,选用石墨烯阴极中石墨烯的质量比为3%;材料混合的方法为球磨混合,球磨功率和时间为1.2kW,球磨120min;压制方法为单向压制,压力机为16t,压制阴极的压强为30MPa;在700℃环境下退火30min;然后根据测试系统结构的需要对阴极进行机械加工。在相对论磁控管中的测试结果中显示,石墨烯阴极发射的电流波形具有非常陡峭的上升沿和下降沿,很好的平顶性,脉宽约为74ns略小于加载阴极上的电压脉宽;最大发射电流约为56.67kA;阴极发射过程中产生的等离子体形成时间早,起振时间短,发射的电子束均匀;阈值电压小于650kV;延迟时间约为20ns,小于黄铜垫圈阴极的23ns和石墨阴极的25ns。相对于电泳,沉积和表面涂覆等方法制备的石墨烯阴极来说,明显提高了石墨烯强流电子发射阴极的使用寿命。
[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，
本文编号：2501119
[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，
本文编号：2501119
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