氧化结合法制备多孔碳化硅陶瓷及其特性

Preparation and Characterization of Porous SiC Ceramics by Oxidation Bonding Method

以不同粒径碳化硅为骨料,羧甲基纤维素钠(CMC)为粘结剂,在大气中利用碳化硅颗粒表面氧化成的SiO2粘接在一起低温合成多孔碳化硅陶瓷。分析了粒径大小、烧结温度、成型压力对氧化结合多孔碳化硅陶瓷特性的影响。用TG-DSC、XRD、SEM研究了碳化硅陶瓷的氧化性能,物相组成,微观形貌。结果表明:原始粒径越小,碳化硅陶瓷的活性越高,相应的氧化程度越高,在1μm时氧化率最高达到49.58%,但其在1000℃保温100 h质量增重也最高达7.53%;随着烧结温度升高,碳化硅氧化率增加,气孔率相应地降低;成型压力也对碳化硅陶瓷的氧化率,气孔率产生一定影响。

Porous silicon carbide （SiC） ceramics were prepared by an oxidation bonding process from SiC, CMC in air at low temperature, The surface of SiC was oxidized to SiO2, SiC particles were bonded by oxidation-derived SiO2 to prepare porous SiC ceramics. The effects of particle size and sintering temperature and molding pressure of oxidation bonding porous SiC ceramics were studied. The oxidation behavior, composition and microstructure of the samples were investigated by TG-DSC, XRD, SEM. The results show that, the finer the SiC particles, the higher their activity and their oxidizability, and The oxidation degree up to a maximum of 49.58% with the particle size 1 μm,but the specimen＇s mass-gain in air at 1000 ℃ for 100 h was 7.53%. The oxidation degree of SiC increases quickly under the high temperature. Accordingly, the porosity is decreasing; the molding pressure also play a role in porosity and the oxidation degree of SiC ceramics.