Micro-hydrothermal reactions mediated grain growth during spark plasma sintering of a carbonate-containing hydroxyapatite nanopowder
Micro-hydrothermal reactions mediated grain growth during spark plasma sintering of a carbonate-containing hydroxyapatite nanopowder
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DOI：
10.1016/j.jeurceramsoc.2014.06.026
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发表时间：
2014-12
影响因子：
5.7
通讯作者：
Yi Liu;M. Eriksson;Z. Jin;M. Nygren;Z. Shen
中科院分区：
文献类型：
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作者：
Yi Liu;M. Eriksson;Z. Jin;M. Nygren;Z. Shen
在650 - 1100 °C的温度范围内通过放电等离子体烧结来固结含碳酸盐的羟基磷灰石纳米粉末。发现通过脱羟基化释放的水在900 °C以上被捕获在致密化HAp体中的纳米孔内。通过X射线衍射、傅里叶变换红外光谱和扫描电子显微镜分析，评价了水-纳米孔体系，并研究了其对晶粒生长的影响。结果表明，SPS烧结过程中，HAp陶瓷内部形成的局部微水热环境很可能是由于封闭的纳米孔中存在水的缘故。因此，在900 °C以上，局部微水热反应的激活促进了晶粒的生长。此外，当采用较高的温度或较高的加热速率时，也观察到异常的晶粒生长，这可能归因于局部高度活跃的水热反应。
A carbonate-containing hydroxyapatite nanopowder was consolidated by spark plasma sintering at the temperatures ranging from 650 to 1100 °C. It was found that the water released by dehydroxylation was trapped inside the nanopores in the densified HAp bodies over 900 °C. Based on the analysis by the X-ray diffraction, Fourier-transform infrared spectrometry and scanning electron microscope, the water-nanopore system was evaluated and its effect on the grain growth was also investigated. It was revealed that the water existed inside the closed nanopores most probably resulted in the formation of local micro-hydrothermal environments inside bulk HAp ceramics during SPS. Therefore, the grain growth was enhanced by the local micro-hydrothermal reactions activated above 900 °C. In addition, abnormal grain growth was also observed when a higher temperature or higher heating rate was employed, which may be attributed to the local highly active hydrothermal reactions.