Aluminosilicate bioglass-ceramics: investigation of the crystallization trend through kinetic calculation and experimental study

The presence of both mullite and apatite phases in the chemical composition of aluminosilicate bioglass-ceramics made them a favorable biomaterial for bone regeneration. One of the efficient parameters in controlling the physical and chemical properties of the bioglass-ceramics is an accurate monitoring of the crystallization trend. In the present work, aluminosilicate bioglass-ceramics (2CaF₂-3CaO-1.5P₂O₅-3Al₂O₃-4.5SiO₂) were prepared using the melt-quenching method heat-treated at 700, 900, and 1100 °C. Additionally, the presence of the BaO and TiO₂ additives, separately and simultaneously, has been investigated on the mechanism of the crystallization. This is the first time that the crystallization behavior of aluminosilicate bioglasses was investigated via experimental and theoretical studies using Ozawa, Marotta, Augis-Bennett, and LSM methods. Experimentally, increasing the heat treatment temperature led to more facile crystallization of the fluorapatite and mullite phases. The differential thermal analysis (DTA) results indicated that TiO₂ oxide enhanced crystallization temperature while BaO oxide decreased the mentioned temperature. Field emission scanning electron microscopy (FESEM) images also showed the nucleated phases in an amorphous matrix. Theoretically, the activation energy of the non-containing additive sample was 310±10 KJ/mol and reached 410±10 and 265±5 (KJ/mol) for TiO₂ and BaO-containing samples, respectively. Utilizing the kinetic models indicated that the nucleation and growth mechanisms of the crystalline phases were in needle-like morphology as confirmed by FESEM. In conclusion, both experimental and theoretical results are in good agreement together. Furthermore, the aluminosilicate bioglass-ceramics with controllable crystallization behavior would be great choice for bone tissue engineering applications.