Abnormal metastable-to-stable phase transformation in ion irradiated alumina

2017 Fiscal Year Final Research Report

• Project/Area Number: 16K14393
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Inorganic materials/Physical properties
• Research Institution: Kyushu Institute of Technology
• Principal Investigator: ISHIMARU Manabu 九州工業大学, 大学院工学研究院, 教授 (00264086)
• Project Period (FY): 2016-04-01 – 2018-03-31
• Keywords: 準安定相 / イオン照射 / 構造解析 / アルミナ / ジルコニア / 透過電子顕微鏡

Outline of Final Research Achievements

Thermally-induced structural changes of zirconium (Zr) ion irradiated α-Al2O3 (corundum type structure) was examined by transmission electron microscopy (TEM) and x-ray diffraction. A cubic spinel metastable phase was formed adjacent to the corundum stable phase at the topmost layer of the ion irradiated specimen. It was confirmed that the structure change from the stable phase to the metastable phase occurs at temperatures ranging from 1073 K to 1273 K. On the other hand, ordinary spinel-to-corundum phase transformation was induced at >1473 K, and Zr was precipitated as ZrO2. High resolution TEM observations and nanobeam electron diffraction experiments revealed that the ZrO2 has the same crystal structure as the high-pressure phase.

Free Research Field

回折結晶学