Suppression of abnormal grain growth in K0.5Na0.5NbO3: phase transitions and compatibility
Suppression of abnormal grain growth in K0.5Na0.5NbO3: phase transitions and compatibility
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DOI：
10.1038/s41598-019-56389-9
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发表时间：
2019-12-24
影响因子：
4.6
通讯作者：
Quandt, Eckhard
中科院分区：
文献类型：
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作者：
Pop-Ghe, Patricia;Stock, Norbert;Quandt, Eckhard
这项工作介绍了块状陶瓷 K0.5Na0.5NbO3 (KNN) 中异常晶粒生长的抑制。通过匹配研磨和煅烧持续时间来精确控制起始粉末形态，从而实现抑制。对所得样品形态、相变和相关电子材料性能的温度依赖性比较分析表明，异常晶粒生长确实是材料性能恶化的主要影响因素，正如其他工作在理论上所建议的那样。然而，研究表明，这种异常晶粒生长源于煅烧粉末而不是烧结，并且所有后续步骤都反映了初始粉末形态。具体而言，根据相容性理论和微观结构的预测讨论了结果。尽管材料具有多尺度异质性，但抑制异常晶粒生长可以显着改善功能特性，并且据报道，在微观结构完整性范围内的相容性理论正确预测了这种发展。可以证明，当通过粉末形态控制抑制异常晶粒生长时，功能疲劳被大大减少，同时热性能和电子性能得到改善。
This work presents the suppression of abnormal grain growth in bulk ceramic K0.5Na0.5NbO3 (KNN). The suppression is enabled by precise control of the starting powder morphology through match of milling and calcination duration. A comparative temperature-dependent analysis of the resulting sample morphology, phase transitions and related electronic material properties reveals that abnormal grain growth is indeed a major influence in material property deterioration, as has theoretically been suggested in other works. However, it is shown that this abnormal grain growth originates from the calcined powder and not from sintering and that all subsequent steps mirror the initial powder morphology. In specific, the results are discussed with respect to the predictions of the compatibility theory and microstructure. Despite the material's multi-scale heterogeneity, the suppression of abnormal grain growth allows for the achievement of significantly improved functional properties and it is reported that this development is correctly predicted by the compatibility theory within the borders of microstructural integrity. It could be demonstrated that functional fatigue is strongly minimised, while thermal and electronic properties are improved when abnormal grain growth is suppressed by powder morphology control.