Synthesis and characterization of a suspension of CoAl2O4 as a blue pigment

A suspension of nano CoAl2O4 pigment commonly used for coloring ceramic products was synthesized by polyol method. Two different precursors were used to prepare nano CoAl2O4 pigments and the results were compared. The microstructure and crystal structure of nano pigments were characterized by SEM and XRD. Particle size distribution and zeta potential of the suspended nano pigments were measured by dynamic light scattering (DLS). The suspensions are stable for several weeks. The colorimetric data (CIE-L*a*b*) show blue color for the heated nano pigments and UV-Vis transmission spectra of the suspensions confirm the samples are blue.