Studies on Preparation and Characterizations of CaO-Na2O-SiO2-PaO5 Bioglass Ceramics Substituted with Al2O3, TiO2 and ZrO2

摘要

Glasses having weight percent composition (45-X) SiO2-24.5Na2O-24.5CaO-6P2O5 (where X = 0 to 2% Al2O3, TiO2 ZrO2 or their mixture) were prepared by conventional melting process in an electric globar furnace at 1400±10°C with air as furnace atmosphere. The Controlled crystallization were carried out to convert the bioglasses to their corresponding bioglass ceramics. Nucleation and crystallization regimes were determined by DTA. The density and compressive strength were measured and found to increase with increasing Al2O3, TiO2 and ZrO2 substituted for SiO2 in the glass composition. The X-ray diffraction patterns of glass ceramic samples have shown the crystalline phases of sodium calcium silicate (Na2Ca2Si3O9), sodium calcium phospho-silicate (Na2Ca4(PO4)2SiO4), sodium titanium phospho-silicate (Na5Ti2Si2(PO_(12))), sodium zirconium phospho-silicate (Na3Zr2Si2PO_(12)) and sodium calcium aluminum phospho-silicate (Na2AI2Ca3(SiO4))2 phase. The investigation of bioactivity of the prepared glass and glass ceramic samples was done by infrared absorption and reflection spectrometry after immersion in the simulated body fluid for different periods at 37.8 °C. The scanning electron microscopic (SEM) analysis was also carried out and it was found that the micrographs of bioglass ceramic samples had shown the formation of hydroxy carbonate apatite layer after 7 days immersion in SBF solution. The Chemical durability of these materials were determined by pH measurement methods after immersing the samples in SBF for different intervals of times and it was observed that the pH of the solution increased from 1 to 7 days and further decreased after 7 to 30 days under physiological condition at 37.8 °C.