Synthesis And Investigation Of Perovskite Type Inorganic Pigments

In this dissertation yttrium aluminate pigment, vanadium doped calcium zirconate and bismuth ferrite based inorganic pigments are synthesized by the conventional solid state route. The crystalline structure and morphology are investigated with different sintering time, Sintering temperature and doping element. The structure and morphology of the powders were investigated employing powder X-ray diffractometer(XRD) and scanning electron microscope(SEM), respectively. Uv-vis-NIR Spectrophotometer was used to study the optical properties. The CIE 1976 L*a*b* system was used to describe the color properties.The results of X-ray diffraction patterns show that the powder samples contain mainly CaZr O3 phase. With the content of V5+ increasing, the near-infrared reflectance value attains 95.88%. The Eg value decreases from 3.88 eV to 3.84 eV. Meantime the brightness of the pigments increases from 90.71 to 93.66. The color of the pigments changes from rose pink to yellow and becomes deeper and brighter. The prepared CaZr0.9V0.1O3 pigment would be well served as ―cool colorant‖.The results of X-ray diffraction patterns show that the powder samples contain mainly YAl O3 perovskite and some Y3Al5O12 garnet phase. With the content of Bi3+ increasing, the color of the pigments changes from pink to yellowgreen. The Eg values range is from 3.78 to 3.95 eV. This phenomenon resulted from the Burstein Moss effect shift which causes by oxygen vacancy. The powdered pigments exhibit high near infrared(NIR) reflectance.According to the national standard JGT 235-2014, near infrared reflectance of bismuth ferrite based inorganic pigments: BiFeO3, BiFe0.9Mn0.1O3, Bi Fe0.9Al0.1O3 and BiFe0.9Cr0.1O3 are 53%, 55%, 61% and 65% respectively. The doping elements have different degrees of increase of BiFeO3 NIR reflectance. The NIR reflectance of BiFeO3, Bi Fe0.9Mn0.1O3, BiFe0.9Al0.1O3 and BiFe0.9Cr0.1O3 are higher than that of inorganic pigment reflectance standard reflection. So these pigments can be used as "cold" pigments. By the analysis of synthetic pigment color coordinates(L*, a*, and b*), the pigment color with Cr doped is deeper and more saturated.