太阳能吸热器用莫来石--碳化硅陶瓷的原位合成(英文)  

In-Situ Synthesized Mullite Bonded Silicon Carbide Ceramics Used in Solar Heat Receiver

作　　者：徐晓虹[1] 饶郑刚[1] 吴建锋[1] 张亚祥[1] 劳新斌 徐笑阳[1] 李坤[1] 

机构地区：[1]武汉理工大学、硅酸盐建筑材料国家重点实验室,武汉430070

出　　处：《硅酸盐学报》2014年第7期869-877,共9页Journal of The Chinese Ceramic Society

基　　金：国家“973”计划(2010CB227105)资助项目

摘　　要：采用半干压成型和无压烧成技术,原位合成了用于太阳能热发电吸热器的莫来石结合碳化硅（SiC）吸热陶瓷。研究结果表明：经1 520℃烧成的样品B2（粒径≤61μm SiC 72%,粒径≤20μm SiC 18%,工业氧化铝4.64%,苏州高岭土5.36%）的综合性能最佳,其显气孔率、吸水率、体积密度和抗折强度分别为28.40%、13.35%、2.13g/cm^3和44.20MPa;热震试验30次（1 100℃~室温,风冷）,样品无裂纹,强度增加率达52.30%;在1 300℃氧化100h后,样品的氧化增重为25.43mg/cm^2,氧化动力学常数为1.80×10^-7kg^2/（m4·s）。物相分析表明,样品的相组成为碳化硅、莫来石、石英和刚玉。显微结构分析表明,原位合成的莫来石结合于碳化硅颗粒间,赋予样品较好的抗折强度。热震试验30次后,可在样品中观察到更加致密的结构,碳化硅晶粒被树枝状微晶紧密联接,改善了样品的抗热震性。莫来石--碳化硅复相陶瓷可作为塔式太阳能热发电吸热器的潜在应用材料。An in-situ synthesized mullite bonded silicon carbide （SIC） as a heat absorbing material was prepared via semi-dry pressing and subsequent pressureless firing. The results indicate that the specimen 132 with 72% SiC in the size of 61 gin, 18% SiC in the size of 20 μm, 4. 64% alumina, 5.36% Suzhou kaolin clay sintered at 1 520 ℃ has the optimal performance. The ap- parent porosity is 28. 40%, the water absorption is 13.35%, the bulk density is 2.13 g/cm3 , the bending strength is 44.02 MPa, the specific weight gain is 25.43 rag/era2 （oxidized at 1 300 ℃ for 100 h）, and the kinetic constant of oxidation is 1.80× 10-7 kg2/（m4 .s）. The specimen 132 can withstand S0-time thermal shock cycles （by wind cooling from 1 100 ℃ to 25 ℃ ） with- out cracking. The bending strength after the thermal shock tests is increased by 52.30%. The phase compositions of the speci mens are SiC, mullite, quartz and corundum. The microstructure analysis shows that the irrsitu synthesized mullite is bonded with SiC grains, giving the optimum bending strength of the material. After 30-time thermal shock cycles, the more compact microstructure appears. SiC particles are connected with branch shape crystallites, exhibiting the superior thermal shock resist- ance. Mullite-SiC composite is a promising material for solar heat receiver.

关 键 词：太阳能吸热材料 莫来石--碳化硅复相陶瓷 原位合成 抗热震性能 

分 类 号：TQ175[化学工程—硅酸盐工业]