Abstract
The surface-modified composite cathode is a promising candidate in alleviating arc ablation while retaining the matrix conductivity . In this work, mono-layered (ML) and bi-layered (BL) Zr/Cu claddings were prepared on the copper substrate through laser cladding. The arc ablation behaviors of BL Zr/Cu cathodes were investigated in the air atmosphere compared to ML Zr/Cu cathodes. The surface zirconium contents for the ML and BL Zr/Cu cathodes are 5.42 at.% and 65.91 at.%, respectively. The high-dilution Zr/Cu cladding serves as the intermediate buffer layer and promotes metallurgical bonding between the cladding and the matrix. The tight interlayer bonding is well maintained after long-term arc discharge . Cathode arc discharge homogeneity is improved as the surface zirconium content increases. The arc ablation rate of the BL Zr/Cu cathode (1.28 μg C −1 ) is 39.0% lower than that of the ML Zr/Cu cathode (2.10 μg C −1 ). The improved arc discharge behaviors are attributed to the surface ZrO 2 layer. The ZrO 2 layer homogenizes the arc discharge process with generating type 1 cathode spots while the copper matrix conducts the input energy flux. The layered structure realizes a combination of ablation-resistant surface and conductive matrix, which enhances the service life of the cathode. • Zr/Cu claddings were prepared on copper substrate through high-speed laser cladding. • Tight metallurgical bonding was well maintained among claddings after arc discharge. • High surface Zr content promoted sustainable and homogeneous arc discharge behaviors. • Bi-layered Zr/Cu cathode exhibited lowest ablation rate (38.5% reduction compared to Cu).
Published Version
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