Challenge for ultra-high toughning of functional oxide

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K14052
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Energy-related chemistry
• Research Institution: Tohoku University
• Principal Investigator: SATO Kazuhisa 東北大学, 工学研究科, 准教授 (50422077)
• Research Collaborator: KUMADA Keigo ; YOSHIDA Naoki
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: セラミックス / 酸素不定比性 / 酸化 / 還元 / 強度 / 靭性 / 欠陥 / 電子

Outline of Final Research Achievements

In this study, we searched for a method to give tenacity with a new concept for fragile ceramic materials. Specifically, the temperature and environment were systematically changed for ceria-based oxides, and changes in mechanical properties, oxygen defects, and ion-electron conduction were investigated. It has been found that the elastic modulus, which is an important factor of mechanical properties, decreases about 20% in the reducing environment as compared to the oxidizing environment. On the other hand, it was revealed that the fracture strength was improved by about 20% contrary to the elastic modulus. This fact is considered to be due to the fact that the electron conduction increases as the amount of oxygen defects increases under a reducing environment. Thus, a material that can contribute to the improvement of toughness can be developed by searching for an oxygen non-stoichiometric oxide.

Free Research Field

無機材料、材料力学

Academic Significance and Societal Importance of the Research Achievements

セラミックスというと脆くて弱いイメージがあり、構造材料にはほとんど用いられない。一方、耐熱性や耐薬品性などに優れているため、セラミックス単独で構造材を構築できれば応用範囲は格段に広がる。本研究は全く新たなコンセプトでセラミックスの強度を向上することに成功した。原子同士の結合力を弱め、欠陥近傍の滑りを起こすことで金属的な機能を付与することができたものと思われる。今後、き裂先端近傍の観察をより詳細に行うことで現在の金属材料を凌駕する新材料が開発できることが期待できる。