Ceramics-Silikáty

Hydroxyapatite (HA) is a bioceramic of considerable interest in orthopaedic and dental applications due to its compositional similarity to natural bone and teeth. However, achieving the precise control over its crystallinity and surface area remains a challenge for enhancing the bioactivity and clinical performance. In this study, HA was synthesised via controlled precipitation by titrating (NH₄)₂HPO₄ into Ca(NO₃)₂ with syringe-assisted feeding, followed by calcination at 600 °C for 5 h. The influence of the polyethylene glycol (PEG), pH adjustment, phosphate feed rate, and syringe needle size was systematically examined. Among these parameters, the phosphate feed rate was identified as the most critical factor affecting both the crystallite size and specific surface area. A feed rate of 1 mL/min produced the highest surface area (45.55 m²/g), compared to 37.85 m²/g at 3 mL/min, while also maintaining favourable alkaline conditions for HA nucleation and growth. These findings demonstrate that the careful regulation of feed parameters enables the reproducible tailoring of HA structural features without complex synthesis routes. The approach provides a simple and scalable pathway for producing high-surface-area HA, offering new opportunities for the development of advanced biomaterials for medical and dental applications.