V-ZrSiO4 ceramic pigments synthesis from m-ZrO2 and different amorphous silica sources

In this study, vanadium-doped zircon (V-ZrSiO4) blue ceramic pigments were prepared by the conventional ceramic route from a mixture of monoclinic zirconia and amorphous silicas with NH4VO3 as colouring V source as well as NaF as mineralizer. Both rice husk ash-derived silica and precipitated silica were used as the silica source in order to assess suitability of the rice husk ash-derived silica in place of the precipitated silica. Effect of calcination temperatures on the crystalline phase formation was followed by X-ray diffraction, while morphologies of the synthesized pigments were characterized by scanning electron microscopy. Furthermore, colour properties of the prepared pigments were evaluated by using an UV-Vis spectrophotometer. While zircon phase formation started at temperatures as low as 750 degrees C, calcination temperature of around 950 degrees C was required to get strong blue colour formation for both the silica sources with similar colour intensities. Therefore, it is proposed that rice husk derived silicas can be used as a cheap alternative silica source to precipitated silicas.