摘要
以SiC和Si3N4为主要原料,采用陶瓷制备工艺无压烧结制备了Si3N4-SiC吸热陶瓷材料。采用现代测试技术,测试和分析了烧结样品的烧结收缩率、抗折强度、吸水率、气孔率、体积密度、耐火度、氧化增重率、物相组成以及显微结构。结果表明,最佳配方是1 360℃烧结的D2样品,其Si3N4添加量为20%,抗折强度为79.60 MPa、气孔率为22.23%、吸水率为10.32%、体积密度为2.15g/cm3、耐火度为1 650℃、1 300℃氧化5h后的样品氧化增重率为1.333mg/cm2。XRD和SEM分析表明烧结样品由α-SiC、Si3N4、莫来石和石英组成,Si3N4在样品中呈短棱柱体分布,添加纳米SiC对Si3N4可以起到钉扎作用,阻止Si3N4晶粒长大,从而提高样品的抗折强度和抗热震性能。Si3N4-SiC吸热陶瓷具有高的强度以及良好的微观组织结构,是一种适合塔式太阳能热发电吸热器用吸热材料。
Si3N4-SiC heat absorbing ceramics was fabricated by pressureless sintering from SiC, Si3N4 and other raw material. The bending strength, water absorption, porosity, bulk density, refractoriness, growth rate of oxidation weight, phase composition and microstructure of the sample were tested and analysised by adding modern test methods. The results indicate that the best formula is D2 which sintered at 1 360 ℃ with 20% SiaN4, bending strength is 79. 60 MPa, porosity is 22. 32%, water absorption is 10. 32%,bulk density is 2. 15 g/cma, refractoriness is 1 650 ℃, growth rate of oxidation weight is 1. 333 mg/cm2 after oxidation at 1 300 ℃ for 5 h. XRD and SEM studies show that the phase composition of the sintered specimens are a-SiC, Si3N4, mullite and cristobalite. Si3N4 phase distributes like short prismatic in the specimens. Adding of nanometer SiC work as nails in the matrix and prevent the abnormal grain growth of Si3N4, thereby improving the bending strength and thermal shock resistance of the specimen. Si3N4-SiC heat absorbing ceramic have a high bending strength and good microstructure which suit to use as absorbing ceramic in tower type solar thermal power generation.
出处
《武汉理工大学学报》
CAS
CSCD
北大核心
2013年第3期1-6,共6页
Journal of Wuhan University of Technology
基金
国家重点基础研究发展计划(973)项目(2010CB227100)
关键词
太阳能热发电
吸热陶瓷材料
SI3N4-SIC
无压烧结
微观结构与性能
solar thermal power generation
heat absorbing ceramic materials
Si3N4-SiC
pressureless sinte- ring
microstructure and properties
