Effect of calcination temperature on colorant behavior of cobalt-aluminate nano-particles synthesized by combustion technique

In this investigation, the normal nano-crystalline cobalt-aluminate spinel has been successfully synthesized by the combustion technique. In order to study the colorant behavior of powders after heat treatment, quantitative and qualitative experiments such as color spectroscopy, X-ray and Raman spectroscopy were applied. Transmission electron microscopy technique was used to estimate the particle size and observe the morphology of pigments. The green powder was identified as an inverse spinel structure whereas a normal spinel corresponding to blue color was produced at higher temperatures. For obtaining powder with the high colorant efficiency, it is better to carry out calcination at 1000 °C.