Lilac ceramic pigments based on Ba0.5Sr0.5Zn2−xNixSi2O7 solid solutions

Lilac pigments were prepared within the solid solution series Ba0.5Sr0.5Zn2−xNixSi2O7 with 0.1≤x≤0.5 from the corresponding oxides and carbonates via solid-state reactions. Depending on the composition, the solid solutions exhibit the crystal structure of the low-temperature and the high-temperature phases of BaZn2Si2O7. This structural change leads to a change in the optical spectra, i.e. the coloration of the ceramic powders. The different colors are attributed to the variation of the coordination sites of Ni2+. In the case of samples with the structure of HT-BaZn2Si2O7, Ni2+-ions are incorporated into tetrahedrally coordinated sites. Spectra of samples with the crystal structure of LT-BaZn2Si2O7 are attributed to a mixture of Ni2+ in tetrahedral coordination but also to distorted sites with higher coordination numbers.