Microwave-assisted preparation of Ca6Si6O17(OH)2 and β-CaSiO3 nanobelts

Xonotlite (Ca6Si6O17(OH)2) nanobelts were synthesized by a microwave-assisted hydrothermal method at 180 °C for 90 min independent of the feeding molar ratio of Ca(NO3)2·4H2O to Na2SiO3·9H2O in the range of 0.8–3.0. Crystalline wollastonite (β-CaSiO3) nanobelts were obtained by microwave thermal transformation of Ca6Si6O17(OH)2 nanobelts at 800 °C for 2 h. Ca6Si6O17(OH)2 nanobelts were used as both the precursor and the template for the preparation of β-CaSiO3 nanobelts. The morphology and size of Ca6Si6O17(OH)2 nanobelts could be well preserved during the microwave thermal transformation process. The products were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and selected area electron diffraction (SAED).