A Comparative Study on the Phase Structure, Optical and NIR Reflectivity of BaFe<sub>12</sub>O<sub>19</sub> Nano-Pigments by the Traditional and Modified Polyacrylamide Gel Method

Barium hexaferrite (BaFe 12 O 19 ) nano- pigment is a pigment with high near infrared reflection in the wavelength range of 1400-2500 nm. The BaFe 12 O 19 nano- pigments were synthesized by the traditional and modified polyacrylamide gel method and characterized by thermogravimetric and differential scanning calorimetry (TG-DSC) analyses, X-ray powder diffraction (XRD), fourier transform infrared (FTIR), transmission electron microscopy (TEM), and UV-Visible spectrophotometer. The physicochemical properties of BaFe 12 O 19 nanopigments are strongly dependent on the synthesis route. The introduction of carbon particles into the BaFe 12 O 19 precursor accelerates the formation of BaFe 12 O 19 phase, reduces its particle diameter and changes its color properties. The modified polyacrylamide gel method makes it possible to obtain a high efficient near infrared reflection BaFe 12 O 19 nano- pigments with a solar reflectance SR>90%. The high near infrared reflection makes BaFe 12 O 19 nano- pigments have potential applications in the field of heat shielding.