Directional solidification, nanoindentation and thermionic properties of LaB6(100)-ZrB2 eutectic composite

Authors：Yang, Xinyu^*; Deng, Chenhui; Gu, Zengjie; Shang, Jihua; Wang, Yan; Zhang, Jiuxing; Su, Haijun

Source：Journal of the European Ceramic Society, 2022, 42(6): 2726-2734.

DOI：10.1016/j.jeurceramsoc.2022.01.048

• LaB6(100)-ZrB2
• Eutectic composite
• Nanoindentation
• Thermionic emission
• Practical work function distribution (PWFD)

LaB6 (100)-ZrB2 eutectic composite was directionally solidified by optical floating melting zone at solidification rate V = 100 mm/h. It was shown that the stable eutectic growth can be achieved by periodic diverging and convergent growth, indicating that eutectic spacing was not unique value, but existed a limited range under a given rate. The atoms of the LaB6 (100)/ZrB2 interface were directly bonded. The mechanical property of the individual eutectic phase was evaluated by the nanoindentation. Both average Berkovich hardness and elastic modulus of LaB6/ZrB2 phases was higher than that of LaB6 phase. Thermionic emission of DS LaB6(100)-ZrB2 eutectic obeyed the Longo theory, indicating only the metal ceramic of LaB6 matrix in the composite emitted the electron. The practical work function distribution of DS LaB6(100)-ZrB2 eutectic composite ranged from 2.51 to 3.18 eV, and the lowest work function was located around the LaB6/ZrB2 interface, where had the highest current density

• Institution
  西北工业大学