Preparation of mica-based glass-ceramics with needle-like fluorapatite

Objectives The aim of this study was to prepare mica-based glass-ceramics containing needle-like fluorapatites, and to understand the relationship between the composition, the microstructure and mechanical properties. Methods The specimens were prepared by casting and subsequent heat treatment. The crystalline phases in the specimens were determined by X-ray diffraction (XRD). The microstructures of the fractured surface were examined by using a scanning electron microscope with an energy dispersive spectrometer (SEM/EDS). The Vickers hardness and fracture toughness were determined by the indentation method. Statistical analysis of the results was performed by one-way analysis of variance (ANOVA) and Tukeyʹs test. The bioactivity of the glass-ceramics was evaluated by soaking the polished specimens in the simulated body fluid (SBF). Results Needle-like fluorapatite crystals were successfully obtained in mica-based glass-ceramics by controlling the heat treatment process. The formation of needle-like fluorapatite crystals, instead of particle-like crystals reported in previous studies, can be attributed to the one-dimensional rapid growth of fluorapatite along the c-axis. The mechanical properties of the glass-ceramics are related to the fluorapatite content. The higher the fluorapatite content, the higher the Vickers hardness and the fracture toughness (p < 0.01). The bioactivity test showed that the needle-like fluorapatite-containing glass-ceramics possess very good bioactivity. Significance As the needle-like fluorapatite crystal has the same morphology as human bones, it endows the mica-based glass-ceramics with good bioactivity. Moreover, the needle-like fluorapatite crystal toughens the base glass-ceramics. Therefore, the mica-based glass-ceramics with needle-like fluorapatite have the potential for the restoration of bone defects and implants.