电弧烧蚀制约了铜阴极的服役寿命,表面强化型阴极兼具表层耐电弧烧蚀和基体高导电、导热性能的优势,能够有效延长阴极服役寿命.通过调控铜基锆覆层阴极的中间层,采用逐层激光熔覆制备了Zr#2/Zr#1/Cu、Zr/Cr/Cu和Zr/Nb/Cu三种阴极结构,表征了覆层阴极的微观组织和物相结构,根据成形质量和裂纹缺陷成因分析,明确了多层阴极的中间层选取原则.进一步地,对Zr/Nb/Cu层状阴极的空气电弧放电行为和电弧烧蚀机理进行了研究.结果表明:Zr/Nb/Cu 层状阴极具备优异的耐电弧烧蚀性能,其电弧烧蚀速率为 1.40 μg/C,相比纯 Cu 阴极降低了41.2%.这与其表面难熔氧化层关系密切.Zr/Nb/Cu层状阴极具备作为加热器阴极使用的潜能.
Study on Laser Cladding Preparation and Arc Ablation Behaviors of Crack-free Zr/Cu Cathodes Based on Optimization of Inter-layer
Arc ablation restricts the service life of the copper cathode.The surface strengthened cathode has the advantages of surface arc ablation resistance and high electrical conductivity and thermal conductivity of the substrate,which can effectively extend the service life of the cathode.By adjusting the inter-layer of the copper-based zirconium cladding layer cathode,three types of Cu-based cathodes,Zr#2/Zr#1/Cu,Zr/Cr/Cu,and Zr/Nb/Cu,were prepared by layer-by-layer laser cladding.The microstructure and phase structure of the layered cathodes were investigated.According to the forming quality and the cause of crack defects,the selection principle of multilayer cathode was defined.Furthermore,the air arc discharge and cathode ablation behaviors of the Zr/Nb/Cu cathode were investigated.The results show that the Zr/Nb/Cu cathode exhibits an improved arc ablation resistance,the cathode ablation rate of Zr/Nb/Cu cathode is 1.40 μg/C,41.2%lower than that of the Cu cathode.It is ascribed to the refractory oxide layer on the surface.Zr/Nb/Cu cathode exhibits potential as cathode in arc heaters.
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