Environmental-friendly red-orange ceramic pigment based on Pr and Fe co-doped Y2Zr2O7

Abstract

A new environmental-friendly red-orange ceramic pigment based on the general formula Y2-xPrxZr2-yFeyO7-δ was prepared by polymeric sol-gel method at 1400 °C. The solid solution range with defect fluorite structure was determined by XRD and SEM/EDX. The oxidation states of the dopants were studied by UV/Vis absorption measurements, XPS and photoluminescence, and a possible redox mechanism was proposed. The colour of the pigment was determined by CIEL*a*b* chromatic coordinates in powder, glass, paint and polymer. All compositions presented a good stability in powder and in glass, the Y1.75Pr0.25Zr1.75Fe0.25O6.875 composition being the best red good colouration. This composition also showed an optimal NIR reflectance 80% in paint to be applied as “cool pigment” for roof isolation. The solid solutions were also tested in PMMA showing a good stability in the sunlight. Therefore, a red-orange environmental-friendly pigment was synthesised with potential applications in the field of the ceramic tiles, cool roofing materials and polymers.