Grain Growth Behavior of (K0.5Na0.5)NbO3 Ceramics Doped with Alkaline Earth Metal Ions

서지정보

ㆍ발행기관 : 한국재료학회 ㆍ수록지정보 : 한국재료학회지 / 33권 / 4호
ㆍ저자명 : Il-Ryeol Yoo, Seong-Hui Choi, Kyung-Hoon Cho

목차

Abstract
1. Introduction
2. Experimental Procedure
3. Results and Discussion
4. Conclusion
Acknowledgement
References

영어 초록

The volatilization of alkali ions in (K,Na)NbO3 (KNN) ceramics was inhibited by doping them with alkaline earth metal ions. In addition, the grain growth behavior changed significantly as the sintering duration (ts) increased. At 1,100 °C, the volatilization of alkali ions in KNN ceramics was more suppressed when doped with alkaline earth metal ions with smaller ionic size. A Ca2+-doped KNN specimen with the least alkali ion volatilization exhibited a microstructure in which grain growth was completely suppressed, even under long-term sintering for ts = 30 h. The grain growth in Sr2+-doped and Ba2+-doped KNN specimens was suppressed until ts = 10 h. However, at ts = 30 h, a heterogeneous microstructure with abnormal grains and small-sized matrix grains was observed. The size and number of abnormal grains and size distribution of matrix grains were considerably different between the Sr2+-doped and Ba2+-doped specimens. This microstructural diversity in KNN ceramics could be explained in terms of the crystal growth driving force required for two-dimensional nucleation, which was directly related to the number of vacancies in the material.

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