| As a high-efficiency,clean high-density energy source,high current pulsed electron beam has been widely studied in the field of material surface modification.As an important component of the electron beam source,the performance of the graphite cathode affects the uniformity and energy of the electron beam and the stability of the material modification.This paper hopes to improve the performance of electron beam by exploring new graphite fiber cathode preparation process.T700 short cut carbon fiber was used as raw material to prepare graphite fiber cathode by carbonization sintering,and the effects of different processes on the uniformity and discharge properties of the graphite fiber were investigated.In the preparation process,hydroxyhexyl cellulose with a concentration of 0.5%with mechanical agitation can achieve the best dispersion effect for chopped carbon fibers.5g short cut carbon fiber can be dispersed in 600ml solution.The formability of the cathode made by starch binder is poor and is not suitable for the discharge test;the phenolic resin binder has good preparation effect and the graphite fiber cathode can be machined and the cathode surface is homogenized when the mass fraction is 50%.The carbonization process of graphite fiber cathode rises to 1000~oC at 5~oC/min heating rate,and then drops to room temperature at 5~oC/min rate after holding 30min.In the electron beam emission performance of the cathode,the electron beam can be emittedafter a certain number of triggering.The stability of cathode is enhanced with the increase of the number of discharge.The addition of carbon fiber powder(350 mesh)will gather more phenolic resin in the forming process,which has a certain effect on the vacuuming process.When the content of carbon fiber powder is between 3 and 6g,the duration and uniformity of the emission electron beam emission are all improved.The discharge result of the cathode made by 8g 2mm carbon fiber mixed with 3g carbon fiber powder is the best,and its resistance is about 1.45Ω;the electron emission duration is 1.5μs;the emission success rate is above 90%;the electron beam diameter is about 50mm;the emission energy is high and the beam spot is uniform. |
