Size control of C@ZrSiO4 pigments via soft mechano-chemistry assisted non-aqueous sol-gel method and their application in ceramic glaze

The zircon-based encapsulation carbon black (C@ZrSiO4) inorganic pigments with controllable size were successfully prepared by non-aqueous sol-gel method with the assistance of soft mechano-chemistry (SMC) activation precursors. The XRD and FT-IR results showed that the SMC activation enhanced the reactivity of precursors and facilitated the formation of ZrSiO4 phase with the calcination temperature at 900-1050 degrees C, indicating the successfully synthesis of pure ZrSiO4 phase. The average size of C@ZrSiO4 inorganic pigments significantly declined from 45.20 to 4.50 mu m with the increase of SMC activation time of precursors, however, the L* values of pigments increased from 24.11 to 46.35. It was mainly because of the decreased amounts of protected carbon in ZrSiO4 matrix and the enhanced light reflectance, which lead to the slight color change from deep black to gray black tone. The colored glaze samples presented a black hue after applied in the ceramic glaze at 1200 degrees C. Moreover, the black hue intensity of glazed samples was higher than that of the corresponding C@ZrSiO4 inorganic pigments, indicating the prepared pigments have excellent tinctorial strength and hiding power. These results ensure that the obtained C@ZrSiO4 inorganic pigments possess the outstanding chromatic performance, excellent high-temperature stability, high chemical stability and suitable particle size, and exhibit great potential in the application of the industrial ceramic decoration.