碳化硅网眼多孔陶瓷的制备

本工作采用有机泡沫浸渍工艺制备了具有相互贯通气孔的碳化硅网眼多孔陶瓷．通过选择合适的流变剂获得了对海绵具有良好涂覆性能的浆料．探讨了粘结剂对网眼多孔陶瓷性能的影响，结果表明：硅溶胶是一种比较理想的粘结剂．ＸＲＤ、ＳＥＭ研究了烧结制品的晶相组成及显微结构，同时还对烧结制品的孔筋密度、气孔率、力学性能等进行了表征．本工作在１４５０℃下保温１ｈ获得了气孔率为７５％～８５％、抗弯强度达２．５ＭＰａ以上的碳化硅网眼多孔陶瓷，其主要晶相由α－ＳｉＣ、α－Ａｌ_２Ｏ_３、方石英和莫来石组成．

Preparation of Silicon Carbide Reticulated Ceramics

The open cell silicon carbide reticulated ceramics were prepared by impregnating a polyurethane sponge with aqueous ceramic slurry. TG-DTA analysis of the polyurethane sponge was used to determine the global thermal cycle for the consolidation of the porous ceramic bodies.A thixotropical slurry by adding effective rheological agents was optimized to uniformly coat the polyurethane sponge. The effect of processing conditions on properties of the sintered was studied.The effect of binders on processing was discussed in detail and it was found that colloidal silica is an effective binder. The structure of the sintered bodies were characterized by SEM and the phases of the sintered bodies were determined by XRD. Some properties including bulk density,strut density, porosity and strength of the sintered bodies, were characterized. The SiC reticulated ceramics, having 75%～85% porosity and bending strength as high as 2.5MPa, can be obtained under firing temperature 1450℃ for lh. The phases of the fired bodies are composed of α-SiC,α-Al2O3, cristobalite and mullite.