Characterization of Ba2+-added alumina/cobalt nanoceramic pigment prepared by polyacrylamide gel method

Nanocrystalline Ba2+ added alumina/cobalt blue nanoceramic pigment was prepared using a polyacrylamide gel method. The samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and UV-vis spectroscopy. The XRD patterns indicated the characteristic peaks of the spinel structures related to the CoAl2O4 and BaAl2O4 phases with a good crystallinity. The crystallite sizes of spinels increased with the increase of barium content. The partial substitution of Co2+ by bigger ions like Ba2+ can cause a distortion in the unit cell compared to pure CoAl2O4 sample. UV-vis analysis showed that at a wavelength of 450 nm the absorbance of the sample was changed with the increase of Ba content and yielded a blue pigment with an improved color point.