Effect of Cs content on K1-xCsxAlSi2O6 ceramic solidification forms

K_1-xCs_x-geopolymers with chemical compositions of about K_1-xCs_xAlSi₂O₆·nH₂O were used as precursors to prepare K_1-xCs_xAlSi₂O₆ ceramic solidification forms through the thermal treatment method. The structures of K_1-xCs_xAlSi₂O₆ ceramic solidification forms obtained at different sintering temperatures have been characterized by X-ray diffraction, scanning electron microscopy and fourier transform infrared spectroscopy. It has been observed that the crystallization temperature and phase of K_1-xCs_xAlSi₂O₆ ceramic were significantly influenced by the Cs content. An increase in the Cs content resulted in a decrease in the crystallization temperature of the K_1-xCs_xAlSi₂O₆ cubic phase. K_1-xCs_xAlSi₂O₆ ceramic obtained at 850 °C was lecucite cubic or pollucite cubic phase when x ≥ 0.2, and the lattice parameters of cubic phase increased with increasing of Cs content. However, leucite tetragonal phase formed at elevated heating temperature (1100 °C and 1300 °C) except for the case x = 0.3, 0.4, 0.5 and 1. The c/a ratio of leucite tetragonal phase obtained at 1100 °C and 1300 °C was much more closed to 1 with Cs content increased, which made it hard to be indexed between cubic and tetragonal phase. In this case, leucite tetragonal phase could also be considered as pseudo-cubic phase. Additionally, the product consistency test leaching results showed that K_1-xCs_xAlSi₂O₆ ceramics possessed superior chemical durability.