Preparation and properties of Al2O3/MoSi2 coating on Al2O3 base porous insulation materials
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摘要: 采用刷涂法在Al2O3基多孔隔热材料表面制备Al2O3/MoSi2涂层，涂层以硅溶胶作为粘结剂，纳米Al2O3与Al2O3纤维作为耐高温组分，MoSi2为高发射率组分。通过SEM、XRD对Al2O3/MoSi2涂层微观表面结构、物相组成进行分析。研究纳米Al2O3与Al2O3纤维的质量比和MoSi2含量对Al2O3/MoSi2涂层耐温性能的影响，并对Al2O3/MoSi2涂层的抗热震性能、发射率进行表征。结果表明，当纳米Al2O3与Al2O3纤维的质量比小于1∶1时，热考核后Al2O3/MoSi2涂层表面无裂纹产生；当纳米Al2O3与Al2O3纤维的质量比在1∶2~1∶4之间时，Al2O3/MoSi2涂层中的纤维网络较完整。MoSi2的含量为20%时，Al2O3/MoSi2涂层抗热震实验循环25次后表面保持完好，热考核后在2.5~25 μm波段的平均发射率在0.85左右，具有较高的发射率。
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关键词:
- Al2O3基多孔隔热材料 /
- 抗热震性能 /
- 高发射率 /
- 涂层 /
- 纳米纤维
Abstract: The Al2O3/MoSi2 coating on Al2O3 base porous insulation materials was prepared by brushing method. Silica sol served as binder and MoSi2 as high emissivity component while nano Al2O3 and Al2O3 fiber were used as high temperature component. The surface morphology and crystalline structure of the Al2O3/MoSi2 coating were analyzed by SEM and XRD. The effects of the mass ratio of nano Al2O3 to Al2O3 fiber and the content of MoSi2 on thermal endurance of the Al2O3/MoSi2 coating were studied. Thermal shock resistance and radiative property of the Al2O3/MoSi2 coating were investigated. The results indicate that there is no cracks on the Al2O3/MoSi2 coating surface when the mass ratio of nano Al2O3 to Al2O3 fiber is less than 1∶1. Fiber-network is relatively integrated on the Al2O3/MoSi2 coating at the mass ratio of nano Al2O3 to Al2O3 fiber of 1∶2–1∶4. The best content of MoSi2 in the Al2O3/MoSi2 coating is 20%. When the content of MoSi2 is 20%, the surface of Al2O3/MoSi2 coating remains unbroken after 25 thermal shock cycles. The Al2O3/MoSi2 coating has high emissivity which is around 0.85 at 2.5–25 μm after heat treatment. -
图 1 不同纳米Al2O3与Al2O3纤维质量比的Al2O3涂层热考核后的SEM图像
Figure 1. SEM images of Al2O3 coating with different mass ratios of nano Al2O3 to Al2O3 fiber after heat treatment
图 2 不同MoSi2含量的Al2O3/MoSi2涂层热考核后的SEM图像
Figure 2. SEM images of Al2O3/MoSi2 coating with different MoSi2 contents after heat treatment
图 3 不同MoSi2含量的Al2O3/MoSi2涂层热考核后的照片
Figure 3. Photographs of Al2O3/MoSi2 coating with different MoSi2 contents after heat treatment
图 4 不同MoSi2含量的Al2O3/MoSi2涂层热考核后的XRD图谱
Figure 4. XRD patterns of Al2O3/MoSi2 coatings with different MoSi2 contents after heat treatment
图 5 MoSi2含量为20%的Al2O3/MoSi2涂层1200℃抗热震循环实验前表面((a)、(b))、截面(c)及实验后表面((d)、(e))的SEM图像
Figure 5. SEM images of surface ((a), (b)) and cross section (c) before thermal shock cycles and surface after thermal shock cycles ((d), (e)) of Al2O3/MoSi2 coating with MoSi2 content of 20%
图 6 MoSi2含量为20%的Al2O3/MoSi2涂层抗热震循环前后的XRD图谱
Figure 6. XRD patterns of Al2O3/MoSi2 coating with MoSi2 content of 20% before and after thermal shock cycles
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