Preparation and Characterization of Mullite-Silicon Carbide Heat Absorbing Ceramics for Solar Thermal Tower Plant  

作　　者：徐晓虹 RAO Zhenggang WU Jianfeng ZHOU Yang HE Dezhi LIU Yi 

机构地区：[1]School of Material Science and Engineering, Wuhan University of Technology

出　　处：《Journal of Wuhan University of Technology(Materials Science)》2015年第1期27-32,共6页武汉理工大学学报（材料科学英文版）

基　　金：Funded by the National Basic Research Program(973 Program)(No.2010CB227105)

摘　　要：The in-situ synthesized mullite bonded SiC ceramics for solar thermal tower plant were prepared from Silicon carbide （SIC）, manufactured aluminum hydroxide （Al（OH）3） and Suzhou kaolin via semi-dry pressing and pressureless firing. The results indicate that sample B3 （designed mullite content 15 wt%） fired at 1 400 ℃ exhibited optimal performance with a bending strength of 97.41 MPa. Sample B3 can withstand 30-cycles thermal shock without cracking （wind cooling from 1 100 ℃ to room temperature）, and the bending strength after thermal shock decreased by 17.92%. When the service temperature is 600℃, the thermal diffusivity, specific heat capacity, thermal conductivity and heat capacity are 6.48× 10-2 cm：.s-1, 0.69 kJ·kg-1. K-1, 9.62 W·m-1·K-1 and 977.76 kJ·kg-1, respectively. The XRD and SEM results show that SiC, mullite, or-quartz, and tridymite are connected closely, which gives the material a good bending strength. After 30-time thermal shock cycles, the structure of samples becomes loose. SiC grains are intersectingly arranged with rodshape mullite, exhibiting a favorable thermal shock resistance. The addition of Al（OH）3 and Suzhou kaolin can accelerate the synthesis of mullite, thus to reduce the firing temperature effectively. The volume effect of tfidymite is relatively small, improving the thermal shock resistance of materials. A higher designed muUite content yields a lower loss rate of bending strength. The mullite content should not be more than 15 wt% or else the bending strength would be diminished.The in-situ synthesized mullite bonded SiC ceramics for solar thermal tower plant were prepared from Silicon carbide （SIC）, manufactured aluminum hydroxide （Al（OH）3） and Suzhou kaolin via semi-dry pressing and pressureless firing. The results indicate that sample B3 （designed mullite content 15 wt%） fired at 1 400 ℃ exhibited optimal performance with a bending strength of 97.41 MPa. Sample B3 can withstand 30-cycles thermal shock without cracking （wind cooling from 1 100 ℃ to room temperature）, and the bending strength after thermal shock decreased by 17.92%. When the service temperature is 600℃, the thermal diffusivity, specific heat capacity, thermal conductivity and heat capacity are 6.48× 10-2 cm：.s-1, 0.69 kJ·kg-1. K-1, 9.62 W·m-1·K-1 and 977.76 kJ·kg-1, respectively. The XRD and SEM results show that SiC, mullite, or-quartz, and tridymite are connected closely, which gives the material a good bending strength. After 30-time thermal shock cycles, the structure of samples becomes loose. SiC grains are intersectingly arranged with rodshape mullite, exhibiting a favorable thermal shock resistance. The addition of Al（OH）3 and Suzhou kaolin can accelerate the synthesis of mullite, thus to reduce the firing temperature effectively. The volume effect of tfidymite is relatively small, improving the thermal shock resistance of materials. A higher designed muUite content yields a lower loss rate of bending strength. The mullite content should not be more than 15 wt% or else the bending strength would be diminished.

关 键 词：heat absorbing materials mullite-SiC composite ceramics thermal shock resistance thermal properties 

分 类 号：TQ174.1[化学工程—陶瓷工业]