Characterization of Mg1−xNixAl2O4 solid solutions prepared by combustion synthesis

Mg1−xNixAl2O4 (x = 0, 0.25, 0.5, 0.75 and 1) solid solutions have been prepared by combustion synthesis. After annealing the combustion synthesized powders at 1000 °C for 3 h single-phase Mg1−xNixAl2O4 was obtained over the entire range of compositions. The lattice parameter of Mg1−xNixAl2O4 gradually increased from 8.049 Å (NiAl2O4) to 8.085 Å (MgAl2O4), which certified the formation of the spinel solid solutions. All samples prepared by combustion synthesis had blue color shades, denoting the inclusion of Ni2+ in the spinel structure in octahedral and tetrahedral configuration. The crystallite size of Mg1−xNixAl2O4 was in the range of 35–39 nm and the specific surface area varied between 5.8 and 7.0 m2/g.