LIU Jiaxi ^{1, 2}, HE Gang ², LU Nan ^{1, 2}, LI Jiangtao ^{1, 2}
(1. University of Chinese Academy of Sciences, Beijing 100049, China; 2. Technical Institute of Physics and Chemistry, Chinese
Academy of Sciences, Beijing 100190, China)

Abstract: Commercial ferric oxide and aluminum powder were used as raw materials to prepare hercynite (FeAl₂O₄) by combustion synthesis. Phases and morphology of the prepared materials were characterized by XRD and SEM, respectively. The infrared emissivity of the samples were also been investigated by UV-Vis-NIR spectrophotometer and dual-band infrared emissometer (IR-2). The diffraction pattern of the XRD indicated that the hercynite single phase can be obtained from the sample with the quantity ratio of raw materials Fe₂O₃/Al=4:1.Compared with this component, ferrous oxide would be detected with the increasing of the ferric oxide in the reactants; and alumina would be found with aluminum excess in the reactants. The characterization of infrared emissivity shows that the infrared absorption (in the range of 0.75-2.5 μm) of the obtained hercynite is 0.9, and in the 1-22 μm, 8-14 μm and 3-5 μm can reach 0.905, 0.938 and 0.870, respectively, which demonstrate the high infrared emission property of hercynite. Additionally, ferrous oxide would promote the infrared absorption in visible/near infrared waveband, and the promotion can be enhanced by increasing the content of FeO. Conversely, the existence of alumina results in the decreasing of the infrared absorption.

Key words: hercynite; combustion synthesis; infrared emissivity; near-infrared absorption