Identification of the Inclusion Efficiency of the Zircon-cristobalite-Hematite Nanocomposite Pigment

The inclusion or encapsulation of a reactive, colored or toxic crystal into a highly stable crystalline matrix gives a protection effect to the guest crystal by the host crystal. The guest crystal becomes inactive within the host [1-2].Among synthetic inorganic ceramic pigments, to be used in the ceramic industry, there is a restricted choice for red/pink and orange colors. These are generally easily etched by glasses, can be sensitive to the atmosphere and firing temperatures and a number of them contain toxic and pollutant elements. Therefore in recent years, there has been a developing interest toward new nontoxic inorganic red pigment [1-2].Inclusion pigments present the following characteristics: 1) these contain two or more different crystalline phases insoluble that are not a solid solution of a colored pigment in another no colored one; 2) their behavior in the presence of glazes is like a chromatic unit from a pigmentation point of view and the crystals responsible for the color are small colored crystals occluded during the sintering process of the matrix [3-5].Amorphous silica may be considered to have a relatively low price giving it a potential to be used in occluded pigments as a matrix, due to its properties and, in particular, to the sufficient thermal and chemical stability towards glassy phases. The high thermal stability of the silicon lattices and their properties such as the sinter-ability at relatively low temperatures are well known [4].Based on these considerations, the aim of the present work was to study the optimization of synthesizing red inorganic pigments for ceramic applications