具有碳化硅纳米线编织结构的氧化铝泡沫陶瓷的制备及性能研究

本文利用简单、高效的浆料直接发泡法制备气孔率高达96%的Al₂O₃/Si泡沫陶瓷,并选用简便、易行的焦炭埋烧工艺在Al₂O₃/Si泡沫陶瓷坯体中生长出大量SiC纳米线。通过控制烧结温度来观察分析SiC纳米线的生长形貌变化。采用扫描电子显微镜(SEM)、X射线衍射仪、BET比表面积测试仪、电子万能试验机等对泡沫陶瓷的微观结构、物相组成、比表面积、气孔率、抗压强度、热导率进行分析与表征。结果表明,1 450 ℃烧结时得到的SiC纳米线最多,纳米线在泡沫陶瓷孔壁交织缠绕。同时观察到SiC纳米线的存在改变了氧化铝泡沫陶瓷固有的脆性断裂模式,SiC纳米线可有效促进泡沫陶瓷在压缩过程中的裂纹偏转。本实验制备了一种新型的纳米线缠绕在孔壁上的三维网络结构的泡沫陶瓷,为在泡沫陶瓷内部原位生长SiC纳米线提供了新的方法,更好地拓展了泡沫陶瓷在环境过滤、催化剂载体等领域中的应用。

Synthesis and Properties of Alumina Foam Ceramics with SiC Nanowires Braided Structure

In this paper, Al₂O₃/Si foam ceramics with porosity up to 96% were prepared by simple and efficient slurry foaming method, and a large number of SiC nanowires were obtained in Al₂O₃/Si foam ceramics body by simple and convenient burying sintering process of coke. The growth morophology of SiC nanowires were observed and analyzed by controlling sintering temperature. The microstructure, phase composition, specific surface area, porosity, compressive strength and thermal conductivity of foam ceramics were analyzed and characterized by scanning electron microscope (SEM), X-ray diffractometer, BET specific surface area tester and electronic universal testing machine. The results show that the most SiC nanowires are obtained when sintered at 1 450 ℃. It is also observed that the presence of SiC nanowires change the inherent brittle fracture mode of alumina foam ceramics, and SiC nanowires can effectively promote its crack deflection during compression. In this study, a novel foam ceramics were prepared with three-dimensional network structure of nanowires wound on the hole wall, which provides a new method for in-situ growth of SiC nanowires inside the foam ceramics, and the application of foam ceramics in environmental filtration and catalyst carrier is expanded.