Synthesis and Characterization of Magnetic Al/NiO Composite Pigments with Low Infrared Emissivity

Abstract

Generally, traditional low infrared coatings based on metallic pigments cannot have low lightness, low infrared emissivity and low radar reflectivity simultaneously. Herein, we used a simple and efficient method to synthesize magnetic Al/NiO composite pigments which possessed all these attributes to a degree. The results indicated that the covering area of NiO on the aluminum flake could be tuned by the addition amount of NiCO3 and the reaction temperature of hot-flowing, both of which played a key role on the VIS/IR spectral reflectance and magnetic properties. The magnetic Al/NiO composite pigments with low lightness and low infrared emissivity could be obtained at 130 °C for 24 h in hot flowing liquid. The lightness L* could be decreased to 75.94, however the infrared emissivity (8-14 μm) was also low to 0.421. Compared with the single aluminum flakes, the Al/NiO magnetic composite pigments presented stronger magnetic properties. Therefore, the Al/NiO magnetic composite pigments offered a new choice for the pigments of multispectral stealth coating.