Development of ethylene glycol-based gelcasting for the preparation of highly porous SiC ceramics
Development of ethylene glycol-based gelcasting for the preparation of highly porous SiC ceramics
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DOI：
10.1016/j.ceramint.2019.12.009
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发表时间：
2020-04-15
影响因子：
5.2
通讯作者：
Zhang, Zhiguo
中科院分区：
文献类型：
--
作者：
Jin, Yicheng;Zhang, Biao;Zhang, Zhiguo
由于水的高表面张力导致坯体的干燥收缩较大，因此水溶液凝胶注模成型不适合制备高孔陶瓷。为了解决这一问题，人们开发了使用表面张力低得多的有机溶剂的非水凝胶注模成型。然而，对于大多数有机溶剂，凝胶的沉淀聚合导致生坯强度较低，不利于大尺寸零件的制造。在本工作中，开发了一种新型的乙二醇基凝胶注模成型来制备高孔率的碳化硅陶瓷。乙二醇有效地促进了凝胶的溶液聚合，提高了生坯的强度。此外，乙二醇基凝胶的高柔韧性可以释放干燥过程中的内应力。采用优化的凝胶注模成型工艺成功制备了大尺寸高孔碳化硅陶瓷。
Aqueous gelcasting is inappropriate for the preparation of highly porous ceramics, due to the large drying shrinkage of green bodies caused by the high surface tension of water. To solve this problem, non-aqueous gelcasting using organic solvents with much lower surface tension was developed. However, for most organic solvents, the precipitation polymerization of gels led to the low strength of green bodies, which was inconvenient for the fabrication of large size workpieces. In this work, a novel ethylene glycol-based gelcasting was developed to prepare highly porous SiC ceramics. Ethylene glycol induced the solution polymerization of gels and increased the strength of green bodies effectively. In addition, the high flexibility of the ethylene glycol-based gels could release the inner stress in the drying process. Highly porous SiC ceramics with large size were successfully prepared by the optimized gelcasting method.