Study Of The Preparation Of Graphene Flow Field Emission Cathode And Its Characteristics

Graphene is a kind of semi-metallic,with high thermal conductivity,high electrical conductivity,high aspect ratio,large quantities of edges for field emission,high mechanical strength,etc.As cold cathode material,graphene has extraordinary properties of low open field and threshold field for field emission.The application of graphene in the strong explosion flow field emission cathode is proposed in this paper,in order to increase the ability of the electron emission.We do some exploration of the preparation of electron emission cathode solution and method and the preparation process,and the cathode electron emission characteristic of test research.we get the cathode made of graphene and its output characteristic of electron emission in strong flow.The graphene used in the experiment is made in the method of oxidation-reduction,and the oxidized graphene is made by the method of improved Hummer.The powder of copper and zinc that used are both industrial metal powder.In order to increase its service life,in this paper,the scheme of strong flow field emission cathode is prepared by suppressing the mixed power of graphene and materials powder of copper and zinc,which can reduce the change of physical morphology of emission surface after explosion.The internal edges of graphene are bared after the surface layer falling off,which can prolong the service life of cathode.After a great many of repeated experiments and researches,the mass ratio of graphene in cathode is 3%,the power of ball mill that used to mill cathode power is 1.2 kW,the last time of the process of mixture is 120 minutes,and the intensity of pressure in pressing cathode is 30 Mpa with the 32 tons presser.The test results of graphene strong flow field emission cathode in the relativistic magnetron showed that the emission pulse current waveform is approximate rectangle with a very steep rising edge and low-going edge,and the fluctuation of the top of pulse current waveform is less than 3%.The biggest emission current of graphene strong flow field emission cathode is about 56.67 kA,which is slightly lower than the current curve peak of graphite cathode,but in the emission process,the plasma movement of graphene cathode is relatively uniform,and the emission pulse current waveform rectangular is complete.It The output pulse current width is about 46 ns pulse,which is slightly smaller than the width of loading on the cathode voltage pulse.The threshold voltage of graphene cathode is less than 200 kV,with the time delay is about 20 ns to the voltage pulse,which is less than the brass washer cathode and graphite cathode,which are respectively about 23 ns and 25 ns.Relative to the preparation scheme of electrophoretic deposition and coating graphene to the surface of shape cathode,the cathode of graphene made by suppressing the mixed power of graphene and materials powder survives a longer service life in the process of strong flow electron emission.