Different interfacial reaction modes between ZrO 2 and active metals: Insights from interfacial reaction experiments and molecular dynamic simulation

FG Qi and ZW Yang and Y Wang and HM Ding and Q Liu, CERAMICS INTERNATIONAL, 50, 14326-14339 (2024).

DOI: 10.1016/j.ceramint.2024.01.344

Unveiling the mechanisms and process of the interfacial reaction between transition metal oxides and metals have far-reaching implications for their superior application. Herein, the interfacial reaction between ZrO 2 and metals was comparatively studied, and the interfacial reactions between three types of ZrO 2 and Zr were systematically investigated by MD simulations. Comparative experiments show that the c -ZrO 2 reacts more vigorously with the active metal than the m -ZrO 2 under the same conditions, and modified c -ZrO 2 nanoparticles have core-shell structures due to the resulting oxygen concentration gradient. The MD simulations reveal that the crystal structure of ZrO 2 has a great influence on its oxygen loss rate (5.14 % - 6.46 %) and oxygen distribution induced by the ZrO 2 /metal interface reaction. Meanwhile, the differences in ZrO 2 properties lead to two modes of ZrO 2 /metal interfacial reactions, which are distinguished by the characteristics of the oxygen distribution in the modified ZrO 2 . One is that there is no obvious oxygen concentration gradient inside the ZrO 2 during the interfacial reaction, and the crystal defects in the modified ZrO 2 are uniformly distributed, such as c -ZrO 2 and tZrO 2 . Another reaction mode is that only the region immediately adjacent to the interface in ZrO 2 undergoes diffusion of oxygen ions to the metal, and the interfacial reaction process proceeds layer by layer, such as m -ZrO 2 . In addition, when the oxygen density and V O density of ZrO 2 are both low while the oxygen conductivity is high, the ZrO 2 /metal interfacial reaction tends to proceed according to mode A, resulting in modified ZrO 2 with uniformly distributed defects.

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