In situ synthesis of SiC-bonded cordierite-mullite ceramics for solar thermal energy storage
In situ synthesis of SiC-bonded cordierite-mullite ceramics for solar thermal energy storage
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DOI：
10.1016/j.ceramint.2016.08.059
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发表时间：
2016-11
影响因子：
5.2
通讯作者：
Xiaohong Xu;Yinfeng Zhang;Jianfeng Wu;Cheng Hu;Chenglong Lu;Dongbin Wang
中科院分区：
文献类型：
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作者：
Xiaohong Xu;Yinfeng Zhang;Jianfeng Wu;Cheng Hu;Chenglong Lu;Dongbin Wang
堇青石-莫来石陶瓷是下一代太阳能热发电系统中最有前途的蓄热基质材料之一。它被期望具有高的导热性和良好的机械强度，以获得良好的运行。本研究采用原位反应结合技术，采用不同的碳源（石墨、酚醛树脂）和硅源（Si、SiO2）合成SiC，制备SiC结合堇青石-莫来石复合材料。研究了SiC含量对复相陶瓷性能和结构的影响。结果表明，SiC与堇青石-莫来石的最有效结合是硅与石墨的原位反应。相应地，当SiC含量为40wt%时，复合材料的力学强度和热导率均得到了明显的提高，分别为109.67 MPa和5.8782（25 °C）W/（m K）。结果表明，所合成的SiC颗粒直径均匀，表面光滑，具有完全缠结的结构，形成了SiC-SiC的导热通道，具有增强机械强度的增韧效果。为了了解复合陶瓷中SiCw结合的合成机理，我们发现硅源起着关键作用，并提出SiC的生长机制是液-固（L-S）机制。
Cordierite-mullite ceramic has been engaged as one of the most promising substrate materials for thermal storage in the next-generation solar thermal power generation systems. It's expected to possess high thermal conductivity and excellent mechanical strength for a good running. In this study, an in situ reaction bonding technique was developed to prepare SiC-bonded cordierite-mullite composites, using different carbon sources (graphite, phenolic resin) and silicon sources (Si, SiO2) for the synthesis of SiC. The effects of SiC content on performance and structure of the composite ceramics were studied. Results showed that the most effective bonding for SiC with cordierite-mullite was an in situ reaction between silicon (Si) and graphite. Correspondingly, the optimum sample with 40 wt% SiC showed an obvious improvement of both mechanical strength and thermal conductivity, which was 109.67 MPa and 5.8782 (25 °C) W/(m K) respectively. The characterization of the as-synthesized SiC showed a relatively uniform diameter, a much smooth surface and a completely intertwined structure, which formed thermally conductive channels of SiC-SiC and presented mechanical strength enhancement of reinforcing-toughening effect. To understand the synthesis mechanism of SiCwbonded in the composite ceramics, we found that the silicon source played a key role and suggested that the growth mechanism of SiC was a liquid-solid (L-S) mechanism.