Magnetic and bioactive properties of MnO2/Fe2O3 modified Na2O-CaO-P2O5-SiO2 glasses and nanocrystalline glass-ceramics

Glass and in-situ nanocrystalline glass-ceramics of compositions 45SiO2-25CaO-10Na2O-5P2O5-xFe2O3-(15-x) MnO2 are investigated for their magnetic and in-vitro bioactive properties. The ferrimagnetic character is observed in the high Fe2O3 containing in-situ nanocrystalline glass-ceramics. Saturation magnetization and coercivity increases with Fe2O3. After soaking in the simulated body fluid (SBF), the powdered as well as the bulk glasses and glass-ceramics are investigated using various characterization techniques. The presence of MnO2 increases the leaching of Na+ ions from the glasses and also attracts the Ca2+ cations from the SBF as compared to Fe2O3 containing nano-crystalline glass-ceramics. It also increases the tendency to form hydroxyl apatite (HAp) layer. Microwave Plasma Atomic Emission Spectroscopy (MP-AES), Fourier Transform Infrared (FTIR) spectra, X-ray diffraction and Scanning electron micrographs (SEM) after soaking in the SBF confirm the HAp formation on the surface of all the glasses and glass-ceramics. Urbach energy also indicates the structural modifications on the surfaces of the glass and glass-ceramics after soaking in the SBF.