Ceramic pigments based on chromium doped alkaline earth titanates

In this paper M(Ti_1?xCr_x)O₃ with M=Mg, Ca, Sr, Ba and x=0.01, 0.03, 0.05, 0.1 compositions have been prepared by solid state reaction in order to analyze their reactivity, structure, limit of solid solution, stability and pigmenting properties in conventional ceramic glazes. Cr–MgTiO₃ crystallizes magnesium ilmenite MgTiO₃ (SG=R-3) with residual MgCr₂O₄ spinel that inhibits the Cr entrance in solid solution and do not show pigmenting properties. Cr–CaTiO₃ crystallizes orthorhombic perovskite (SG=Pbnm) pink solid solutions associated to Cr⁴⁺–Ti⁴⁺ substitutions which above x=0.03 unstabilizes in glazes and produce light green shades. Cr–SrTiO₃ crystallizes ideal cubic perovskite (SG=Pm3m) pink solid solutions that unstabilizes in glazes above x=0.01. Finally Cr–BaTiO₃ crystallizes tetragonal perovskite (SG=P4mn) with residual peaks of BaCrO₄ at x=0.1 showing pink solid solutions until x=0.05 that unstabilizes in glazes above x=0.03. All powders show aggregates (between 2–10 μm of size) of fine particles (between 200–1000 nm).