The rapid advancement of vacuum electronic devices has necessitated enhanced performance requirements for cathode electron sources,including high current density,superior emission uniformity,minimal evapotranspiration rates,and prolonged lifespan. This paper investigates the impact of varying cathode surface morphologies on cathode performance through the application of different surface treatment processes,which yield distinct microstructures on the M-type cathode emission surfaces. All pre-treatments and tests were conducted under controlled conditions. Microstructural analysis reveals that,compared to mechanical treatments,sandblasting produces a uniform and finely textured concave-convex surface on the tungsten-based cathode,significantly expanding the effective electron emission area and enhancing the uniform distribution of the emission-active material,barium (Ba). Consequently,the surface roughness of sandblasted cathodes doubles,which is advantageous for improving the adhesion strength between the tungsten base and metal film layers,thereby extending the cathode's lifespan. Emission and evaporation characteristics analysis indicates that sandblasted cathodes exhibit superior pulse emission capabilities and uniformity compared to their mechanically treated counterparts. Although the evaporation rate of the sandblasted cathodes is greater than that of the mechanically treated ones,both cathode types exhibit a decline in evaporation rates after a period of aging.
维普
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