Synthesis, characterization and color performance of novel Co2+-doped alumina/titania nanoceramic pigments

Blue–green nanoceramic pigments from Co2+-doped alumina–titania (xCo2+–Al2O3/TiO2) have been synthesized by alkoxide sol–gel route from a mixture of titania and boehmite sols that derived from titanium isopropoxide and aluminum nitrate precursors. The composition of the alumina/titania (AT) matrix is 3:1 M ratio. A series of xCo2+:3TiO2:1Al2O3 mixed oxides with different Co2+-dopant ion concentration has been prepared. The molar ratio of the Co2+-dopant ion in the Al2O3/TiO2 matrix is from x = 0 to 0.5 M ratio relative to the titania composition. Characterizations of Co2+-doped alumina/titania nanocomposites are carried out using reflectance spectroscopy, transmission electron microscope (TEM), scanning electron microscopy (SEM-EDS), thermo-gravimetric analysis (TGA) and X-ray diffractometer (XRD). The experimental results demonstrated that the prepared Co2+-doped alumina–titania nanocomposites fulfill the current technological requirements for ceramic pigment applications that exhibit a high physico-chemical and thermal stabilities at high firing temperatures.

Graphical abstractBlue–Green Co2+-doped alumina–titania nanoceramic pigments calcined at different temperatures.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Blue–green x%Co–Al2O3/TiO2 nanoceramic pigments were prepared by sol–gel methods. ► High thermal stability up to 1200 °C. ► Color intensity increased as the amount of Co increased at calcination temperatures.