Microstructural, structural and optical properties of nanoparticles of PbO-CrO₃ pigment synthesized by a soft route

Propriedades microestruturais, estruturais e ópticas de nanopartículas de pigmentos de PbO-CrO₃ sintetizadas por rota soft

PbCrO₄ and Pb₂CrO₅ particles were synthesized by the polymeric precursor method. Structural and microstructural properties of the particles were characterized by scanning electron microscopy with field emission gun, X-ray diffraction, and Raman spectroscopy techniques. The diffuse reflectance technique was employed to study the optical properties in the 400-700 nm range. The optical bandgap of the samples was obtained indirectly. Colorimetric coordinates L*, a*, b* were calculated for the pigment powders as a function of the heat treatment (400-700 ºC). The powders displayed colors ranging from green to red. X-ray diffraction patterns showed the presence of monoclinic PbCrO₄ phase in green samples, while red powders had a monoclinic Pb₂CrO₅ phase structure. The Raman spectra of the PbCrO₄ and Pb₂CrO₅ powders were in good agreement with those reported in the literature. The synthesized compounds can be used as green and red pigments with high thermal stability.

nanoparticles; PbCrO₄ ; structural properties; microstructural properties; optical properties