Yang Xukun, Wan Yange, Li Jiancun, Liu Jiachen, Wang Mingchao, Tao Xin
Key Lab of Advanced Ceramics and Machining Technology of Ministry of Education, School of Materials Science and Engineering, Tianjin University, Tianjin 300072, China.
Beijing Institute of Astronautical Systems Engineering, Beijing 100076, China.
Materials (Basel). 2023 Dec 30;17(1):220. doi: 10.3390/ma17010220.
High emissivity coatings with sol as the binder have the advantages of room temperature curing, good thermal shock resistance, and high emissivity; however, only silica sol has been used in the current systems. In this study, aluminum sol was used as the binder for the first time, and MoSi and SiC were used as emittance agents to prepare a high emissivity MoSi-SiC-AlO coating on mullite insulation tiles. The evolution of structure and composition at 1000-1400 °C, the spectral emissivity from 200 nm to 25 μm, and the insulation performance were studied. Compared with the coating with silica sol as a binder, the MoSi-SiC-AlO coating has better structural uniformity and greater surface roughness and can generate mullite whiskers at lower temperatures. The total emissivity is 0.922 and 0.897, respectively, at the wavelength range of 200-2500 nm and 2.5-25 μm, and the superior emissivity at a low wavelength (<10 μm) is related to a higher surface roughness and reduced feature absorption. The emissivity reduction related to the oxidation of emittance agents at a high temperature (-10.2%) is smaller than that of the silica-sol-bonded coating (-18.6%). The cold surface temperature of the coated substrate is 215 °C lower than the bare substrate, suggesting excellent thermal insulation performance of the coating.
以溶胶为粘结剂的高发射率涂层具有室温固化、良好的抗热震性和高发射率等优点；然而，目前的体系中仅使用了硅溶胶。在本研究中，首次使用铝溶胶作为粘结剂，并使用MoSi和SiC作为发射剂，在莫来石隔热砖上制备了高发射率的MoSi-SiC-AlO涂层。研究了1000-1400℃下涂层的结构和成分演变、200nm至25μm的光谱发射率以及隔热性能。与以硅溶胶为粘结剂的涂层相比，MoSi-SiC-AlO涂层具有更好的结构均匀性和更大的表面粗糙度，并且能够在较低温度下生成莫来石晶须。在200-2500nm和2.5-25μm波长范围内，总发射率分别为0.922和0.897，低波长（<10μm）下的优异发射率与更高的表面粗糙度和减少的特征吸收有关。高温下发射剂氧化导致的发射率降低（-10.2%）小于硅溶胶粘结涂层（-18.6%）。涂覆基板的冷表面温度比裸基板低215℃，表明该涂层具有优异的隔热性能。
