Synthesis and characterization of Fe3+ doped YIn1-yMnyO3 black pigment with high near-infrared reflectance

Near infrared reflective inorganic pigment YIn 1-x-y Mn y Fe x O 3 (x/y = 0.1–0.5) was prepared by solid state reaction. The X-ray diffraction analysis and CIE1976 L*a*b* colorimetric analysis reveal that the main phase of the sample is changed from YInO 3 phase to YFeO 3 phase and the color of the sample is changed from blue to black (x ≥ 0.4) with the increase of iron content. The brightness value of black pigment ranges from 23.27 to 32.12. When In 3+ is replaced by Fe 3+ and Mn 3+ , the band gap of the black sample is decreased from 1.73eV to 1.39eV. The near-infrared reflectance (R) and near-infrared solar reflectance (R*) of the sample reach the maximum when x = 0.4 and y = 0.1, which are 77.82% and 53.44%, respectively. YIn 1-x-y Mn y Fe x O 3 (x = 0.4–0.5, y = 0.1–0.5) black samples have higher near infrared reflectivity than common commercial black pigments. In the thermal insulation study, under the condition of infrared irradiation for 90 min, the internal air temperature difference between the iron car model coated with YIn 0.5 Mn 0.1 Fe 0.4 O 3 pigment and the iron car model coated with commercial iron black pigment can reach 7 °C. YIn 0.5 Mn 0.1 Fe 0.4 O 3 black pigment was soaked in 5% acid-alkali solution for 24 h, the chromaticity was almost unchanged before and after immersion, indicating that the sample has good chemical stability. The above properties show the potential of synthetic black pigments in the field of energy conservation.