Low temperature combustion synthesis of CoxMg1−xAl2O4 nano pigments using oxalyldihydrazide as a fuel

Nanosized blue refractory pigments MgAl2O4:xCo2+ (x = 0.00-0.10) were prepared by the low-temperature combustion synthesis (LCS) method using oxalyldihydrazine as a fuel. The synthesised and calcined powders were characterised by FTIR, electronic spectra, TGA, DTA, XRD and TEM. The colour measurements of the nano pigments were studied by diffuse reflectance spectroscopy (DRS) using the CIE-L*a*b* parameter method. The FTIR spectra showed frequency bands in the range 422-700 cm-1 corresponding to metal-oxygen bonds for the spinel structure. The average particle size of the prepared samples was 30 nm at 1100 C. The results also revealed the varying bulk density, particle size, shape and colour with different calcination times and temperatures.