Juan Fernando Montoya Carvajal

Effect of the Fuels Glycine, Urea and Citric Acid on Synthesis of the Ceramic Pigment ZnCr2O4 by Solution Combustion

In this study, ceramic nanopigment ZnCr2O4was prepared by solution combustion using glycine, urea and citric acid as fuels. The objective is to study the influence of fuel on the morphology and the diffuse reflectance spectrum. The nanoparticles were characterized by field emission scanning electron microscopy (FESEM), the phase was investigated by X-ray diffraction (XRD), the thermal behavior was studied by thermogravimetry analysis (TGA) and differential scanning microscopy (DSC), the color was determined by diffuse reflectance spectroscopy and CIE L*a*b* colorimetric analysis. The average crystallite sizes obtained were 18.40 nm, 42.05 nm, and 18.69 nm when are used glycine, urea, and citric acid, respectively. Finally, the effect of fuel in the diffuse reflectance showed that the scattering of the light by the particles depend of the morphology. Also, the nanopigment was obtained by solution combustion at lower temperature than solid state reaction and it could be used in digital decoration.

Properties of Ceramic Pigment Zn 0.5 Cu 0.5 Cr 2 O 4 Synthesized by Solution Combustion Method

The present study reports the effect of the fuels: glycine, urea, and citric acid on the optical properties of ceramic pigment Zn0.5Cu0.5Cr2O4, synthesized by solution combustion. The powders were characterized by X-ray diffraction, which showed the formation of the expected phases. Scanning electron microscopy (SEM) was also used, and the images showed the formation of agglomerates and porous samples. Finally, VIS-spectroscopy, and CIEL*a*b* color-measurements showed the powders are black. The results demonstrated that the synthesis by the combustion reaction was very fast and safe, and that the heat released in the combustion reaction is a function of fuel, releasing more heat with glycine, and less with citric acid. It was observed that the powder is more black with urea and citric acid that with glycine. The optical properties showed that the powders could be used as ceramic pigments.

Properties of Ceramic Pigment Zn0.5Cu0.5Cr2O4 Synthesized by Solution Combustion Method

The present study reports the effect of the fuels: glycine, urea, and citric acid on the optical properties of ceramic pigment Zn0.5Cu0.5Cr2O4, synthesized by solution combustion. The powders were characterized by X-ray diffraction, which showed the formation of the expected phases. Scanning electron microscopy (SEM) was also used, and the images showed the formation of agglomerates and porous samples. Finally, VIS-spectroscopy, and CIEL*a*b* color-measurements showed the powders are black. The results demonstrated that the synthesis by the combustion reaction was very fast and safe, and that the heat released in the combustion reaction is a function of fuel, releasing more heat with glycine, and less with citric acid. It was observed that the powder is more black with urea and citric acid that with glycine. The optical properties showed that the powders could be used as ceramic pigments.

Método de evaluación de blancura para el blanqueamiento visual de talcos por adición de pigmento cerámico

El color de las materias primas incide en la aceptacion o rechazo por parte del consumidor. Este trabajo estudia como se modifica la apariencia amarillenta del talco por adicion de pigmentos, brindando una apariencia visual mas blanca. Los resultados presentan un metodo para la evaluacion colorimetrica de agregados en polvo, asi como para determinar la dispersion de la luz incidente como una aplicacion espectrofotometrica en la determinacion de parametros de la medida del color tales como: Las coordenadas colorimetricas CIELAB, ΔE y la blancura, mediante las curvas de reflectancia para el talco con y sin pigmento