Study of Cr-SnO2 ceramic pigment and of Ti/Sn ratio on formation and coloration of these materials

In this study, CrxSn1−xO2 (0 ≤ x ≤ 0.06) and Cr0.03Sn0.97−yTiyO2 (0 < y ≤ 0.97) compositions were synthesized by the ceramic method and characterized by X-ray diffraction, UV–vis spectroscopy and CIE L*a*b* (Commission Internationale de l’Eclairage L*a*b*) parameters measurements. From CrxSn1−xO2 samples fired at 1600 °C/1 h, x = 0.03 was established as the composition limit of formation of solid solutions. When x ≤ 0.01, better coloration of glazed tiles were obtained from short thermal treatment (1400 °C/1 h or 1600 °C/1 h) than from long thermal treatment (1400 °C/24 h). When 0.01 < x < 0.06 small variations of color in glazed tiles were obtained from samples fired at 1400 °C/24 h and 1600 °C/1 h. From Cr0.03Sn0.97−yTiyO2 compositions, a better purple color was obtained when y = 0.02 (Ti/Sn ∼ 2.1 × 10−2) than when y = 0.