Effect of Ni content on optical, colorimetric, surface and magnetic properties of Ni x Co1−x Al2O4 nanoparticles

Nano-sized aluminates of Ni x Co1−x Al2O4 (0 ≤ x ≤ 1) were synthesized by sol gel-combustion method using cetyltrimethyl ammonium bromide (surfactant) and polyethylene glycol as templates and glycine as a fuel. The samples were characterized for their structural, surface morphological, optical and magnetic properties by means of X-ray diffractions (XRD), infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), specific surface area analysis using BET technique, UV–visible spectroscopy and diffuse reflectance spectroscopy (DRS) as well as VSM techniques. The XRD analysis shows that the samples exhibit pure spinel phase with crystallite sizes in the range of 39–91 nm. Colorimetric data (CIE L*a*b* values) pointed out to a change in colors of Ni x Co1−x Al2O4 with an increase in the lightness, coordinate L*, with increasing the calcinations temperature. The results obtained reveal that nano Ni x Co1−x Al2O4 are promising materials that can be employed to obtain ceramic blue pigments. The prepared samples showed a mesoporous structure and a supermagnetic behavior.