Laser Cladding of Layered Ti/Nb/Cu Cathode with Homogeneous Arc Ablation Behaviors

Arc ablation threatens the cathode operating time and restricts the development of high‐power arc heaters. Surface modification is an effective strategy in improving cathode ablation resistance without reducing matrix conductivities. Herein, Nb layer and Ti layer are laser clad on Cu matrix to decrease the arc ablation of Cu cathode. The total thickness of laser‐clad Nb/Ti layer reaches 1850 μm. The Nb layer restrains Cu from diluting into surface cladding and no detrimental Ti–Cu intermetallic is formed. The surface Ti content is as high as 98.34 at%, guaranteeing the arc discharge homogeneity. The arc ablation behaviors of Ti/Nb/Cu cathodes are investigated in air atmosphere. The layered cathode discharges and ablates homogeneously. The arc discharge center is shallow with no appearance of deep pits or craters. The maximum ablation depth (72.1 μm) after 30 s discharging is ≈33.4% lower than that of Cu cathode. Besides, the cathode ablation rate, 1.61 μg C−1, is ≈27.5% lower than Cu cathode. The improved arc ablation resistance is interpreted in the protective effect of refractory TiO2 layer formed during air arc discharging. Nb layer and Ti layer are laser clad on Cu matrix to prepare Ti/Nb/Cu cathodes. The total thickness of Nb/Ti layer reaches 1850 μm. The surface Ti content is as high as 98.34 at%. The layered Ti/Nb/Cu cathode discharges and ablates homogeneously. The cathode ablation rate, 1.61 μg C−1, is ≈27.5% lower than that of Cu cathodes.