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Author(s): |
Xiao-hong Xu, School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, China, 430070
Shao-yang Qian, School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, China, 430070
Jian-feng Wu, School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, China, 430070
Bin-zheng Fang, School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, China, 430070
Guang-hui Leng, School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, China, 430070
Meng Liu, School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, China, 430070 |
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Abstract: |
Mullite bonded SiC ceramics were prepared from synthetic mullite and silicon carbide powder in this paper. The physical and chemical properties of mullite bonded SiC ceramic such as the apparent porosity, water absorption, bulk density, bending strength and thermal expansion were measured. The results showed that the sample with mulllite 20 % fired at 1 380 ℃ has the lowest porosity, water absorption, and the maximum bulk density which is 17 %, 10.88%, and 2.13 g?cm-3, respectively. The bending strength is up to 69.62 MPa and the coefficient of thermal expansion is 5.4 × 10-6 ℃-1. The samples did not crack through 30 times thermal cycling from room temperature to 1 000 ℃, The bending strength of the samples after 30 times thermal shock cycling tests is 114.49MPa, and increase rate of bending strength is 64.45%. The main crystalline phases determined by the X-ray diffraction analysis (XRD) were α-SiC, mullite (3Al2O3 ? 2SiO2), and a small amount of cristobalite. The microstructure was observed by scanning electron microscope (SEM) and the thermal shock resistance machanism was discussed. The solar absorbtance (α) of best sample obtained on UV-Vis-NIR spectrophotometer (Lamda 750, USA) was 0.80 which was a promising material as high temperature coating used on the non-vocuum solar receiver tube.
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