He Lihua, Zhao Yan, Xing Liying, Liu Pinggui, Zhang Youwei, Wang Zhiyong
School of Materials Science and Engineering, Beihang University, Beijing 100191, China.
Beijing Institute of Aeronautical Materials, Beijing 100095, China.
Materials (Basel). 2018 Aug 22;11(9):1502. doi: 10.3390/ma11091502.
A low infrared emissivity coating was prepared using graphene surface-modified flaky aluminum complex powders (rGO-FAl) as fillers. The flaky aluminum powders were coated with graphene through chemical bonding. Compared with pure flaky aluminum, the Vis-NIR diffuse reflectance of rGO-FAl complex powders was significantly decreased, which was beneficial to the low glossiness of the coating. After the modification, the glossiness at 60° of the coating with 40% (mass fraction) pigments decreased from 12.8 to 6.7, while the coating maintained low infrared emissivity (0.238~0.247) at a spectral range of 8⁻14 μm. In the electrochemical impedance spectroscopy (EIS) measurement, at the lowest frequency, the impedance of the Al-rGO test plate was at least two orders of magnitude greater than that of the control Al test plate, and the graphene layer significantly increased the bandwidth of the maximum phase angle, which indicates a good protective effect of the ultra-thin graphene layer on metal in a corrosive environment. The coating with 40% rGO-FAl complex powders can maintain its appearance after 500 h of salt spray corrosion testing. In contrast, the color of the coating with the original aluminum powders changed after only 300 h.
以石墨烯表面改性片状铝复合粉末（rGO-FAl）为填料制备了一种低红外发射率涂层。片状铝粉通过化学键合包覆石墨烯。与纯片状铝相比，rGO-FAl复合粉末的可见-近红外漫反射率显著降低，这有利于涂层的低光泽度。改性后，含40%（质量分数）颜料的涂层在60°时的光泽度从12.8降至6.7，同时涂层在814μm光谱范围内保持低红外发射率（0.2380.247）。在电化学阻抗谱（EIS）测量中，在最低频率下，Al-rGO测试板的阻抗比对照Al测试板至少大两个数量级，并且石墨烯层显著增加了最大相角的带宽，这表明超薄石墨烯层在腐蚀环境中对金属具有良好的保护作用。含40% rGO-FAl复合粉末的涂层在经过500 h盐雾腐蚀试验后仍能保持其外观。相比之下，含原始铝粉的涂层仅在300 h后颜色就发生了变化。
