Microstructure and Defects of MgO/ZrO₂ Nanocrystals Investigated by Positron Annihilation Spectroscopy

Abstract:

Pure MgO, ZrO₂ and mixture MgO/ZrO₂ nanocrystals were annealed in air from 100 to 1200°C. Variation of the microstructure and defects was investigated by positron lifetime spectroscopy and X-ray diffraction. The experiment results showed that the average positron lifetime of mixture MgO/ZrO₂ was more larger than that of single phase MgO and ZrO₂, and decreased with the increasing annealing temperature. Thermal annealing below 600°C, the movement of grain boundaries mainly led a reduce of the number of microvoids, and vacancy defects began to recover due to the growth of MgO nanoparticles after annealing between 600 to 900°C. Furthermore, ZrO₂ nanoparticles began to grow above 900°C, meanwhile the recovery of vacancy and vacancy clusters in MgO/ZrO₂ nanoparticles are restrained because of synergic effect between MgO and ZrO₂ nanoparticles.

• Periodical: Defect and Diffusion Forum (Volume 373)
• Pages: 249-253
• DOI: https://doi.org/10.4028/www.scientific.net/DDF.373.249
• Online since: March 2017
• Authors: Jia Heng Wang, Jian Jian Shi, Wei Yang, Zhe Jie Zhu, Yi Chu Wu*
• Keywords: Defect, Microstructure, Nanocrystal, Positron Annihilation

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