Effect of pH in Systems on Crystallinity and Morphology of Synthesized Xonotlite Whiskers

The different pH values in CaO-SiO2-H2O systems were taken into account to prepare xonotlite whiskers without any surfactant, special instruments and synthesis conditions. Effect of pH values in system on the crystallinity and morphology of synthesized xonotlite whiskers was studied by using XRD and SEM techniques. The results indicated that the different pH values in system had little effect on the crystallinity of synthesized xonotlite, but posed significant impact on the morphology of xonotlite whiskers. The higher pH value is, the lager scale xonotlite whiskers appear. Little whiskers were synthesized in the system of pH 11.5, but in the system of pH 13.0, the formation of xonotlite whiskers was promoted and xonotlite whiskers with 20-40 μm in length and 400 nm in diameter were prepared at 225 °C for 15 h.