RKKP bioactive glass-ceramic material through an aqueous sol-gel process

In this work, the synthesis of RKKP bioactive glass composition by an aqueous sol-gel method is reported. A complete and systematic characterisation of the produced material was carried out. Characteristic functional groups were detected by Fourier transform infrared (FT-IR) spectroscopy, the thermal behaviour was investigated by simultaneous thermogravimetric and differential thermal analysis (TG-DTA), crystallisation kinetics and phase evolution were followed by X-ray diffraction (XRD) analyses. The microstructure of RKKP pellets thermally treated at properly selected temperatures was investigated by means of Scanning Electron Microscopy (SEM) equipped with Energy Dispersive X-Ray Spectrometry (EDS). Thermal dilatometry (peak temperature of 1100 °C) was performed on bars pressed at 400 MPa; final densities and microstructures were also evaluated. The expected glass-in-glass phase separation and carbonation induced by shelf-aging of the powders in common atmosphere were experimentally demonstrated. After thermal treatment at high temperature, the RKKP pellets experienced a drastic microstructure evolution, developing a highly porous matrix, in agreement with the de-densification phenomenon detected by dilatometry.