Spinel Cobalt Blue Pigment Preparation And Performance

In this paper, nano-cobalt blue pigments were prepared by precipitation and citrate gels auto-combustion methods. On the basis of precipitation, composite cobalt blue pigments was prepared by doping Zn²⁺, Mg²⁺, Ni²⁺, Y³⁺ metal ions. Additionally, nano-cobalt blue pigment and composite cobalt blue pigments were charactered by using XRD, thermal analysis technology, FT-IR and electron microscopy analysis.For the cobalt blue pigments prepared by precipitation method, the effect of reaction temperature, metal ions concentration, precipitator, dispersant and calcination temperature on the crystal morphology, particle size and distribution were discussed. Furthermore, the preparation conditions of citric acid dosage, reaction temperature, reactant concentration, pH, glycol dosage, heat-treatment method and calcination temperature were studied by the citrate gels auto-combustion.For this two methods, the coloring, thermal stability and infrared absorption properties of cobalt blue pigments were discussed. The results show that the spinel cobalt blue pigments with bright color, uniform distribution and the average size of 0.11μm were obtained by precipitation method. And the dispersion of cobalt blue pigments can be improved by adding dispersant PEG-600. Although the calcination temperature of cobalt blue pigments prepared by citrate gels auto-combustion method was lower than the precipitation, the cobalt blue pigment with light blue color and poor dispersion can only be obtained. Dispersion of cobalt blue pigment was improved by adding glycol. Compared to direct calcinations, the cobalt blue pigments prepared by the self-combustion has better dispersion. This two methods have better thermal stability and no obvious change of infrared absorption.Cobalt blue pigments was modified by doping Zn²⁺, Mg²⁺, Ni²⁺, and Y³⁺. The effect of different ions and ions with different concentrations on the crystal structure, thermal stability, color performance and infrared absorption of cobalt blue pigment was investigated. The researches show that composite cobalt blue pigments have a spinel crystal structure and better thermal stability. And the cobalt blue pigments with different hue were prepared by doping different metal ions. The pigment color can be changed from dark green to navy blue. Moreover, with the doping dosage increasing, the color performance decreases under the condition of doping same metal ion.