Characterization of MgxM2 − xP2O7 (M = Cu and Ni) solid solutions

In this study, MgxM2 − xP2O7 (M = Cu, Ni; 0 ≤ x ≤ 2) and Mg3 − yNiy(PO4)2 (0 ≤ y ≤ 3) compositions were synthesized by the chemical coprecipitation method and characterized by X-ray diffraction, UV–vis–NIR spectroscopy and CIE L* a* b* (Commission Internationale de l’Eclairage L* a* b*) parameters measurements. Solid solutions with α-Cu2P2O7 and α-Ni2P2O7 structures and solid solutions with Ni3(PO4)2 structure were obtained from diphosphate and orthophosphate compositions respectively. Isostructurality of α-Ni2P2O7 and α-Mg2P2O7 structures enlarges the compositional range of solid solution formation respect to the MgxCu2 − xP2O7 solid solutions one. The CIE L* a* b* parameters in MgxNi2 − xP2O7 samples were obtained comparable with these parameters in others yellow materials suitable for ceramic pigments. Mg0.5Ni1.5P2O7 composition fired at 800 °C or 1000 °C is the optimal composition to obtain yellow materials with α-diphosphate structure in conditions of this study