Development of a glass–ceramic composite reinforced with β-wollastonite synthesized via a hydrothermal method Scientific paper

Abstract

β-wollastonite (β-CaSiO₃) microfibres were successfully synthesized using a one-step, template-free hydrothermal reaction involving calcium nitrate and sodium metasilicate in an alkaline medium. The synthesis of microfibres was completed at 220 °C within only 240 min under an autogenous pressure of 19 bar (1.9 MPa). This method avoids the formation of xonotlite as an intermediate phase, elimin­ating the need for subsequent calcination to achieve wollastonite. X-ray diffraction (XRD) confirmed the β-wollastonite phase, while post-cal­cination analyses indicated enhanced crystallinity and structural characteristics. Scanning electron microscopy (SEM) revealed a needle-like morphology and N₂ adsorption-desor­ption analysis demonstrated a developed surface area of 26 m2 g^-1 with notable mesoporosity. These advantageous features facilitated the integ­ration of β-wollas­tonite into the synthesis of a glass–ceramic composite, which was characterized for its morphological, structural, textural, and in vitro bioact­ivity properties. The composite was prepared by mixing β-wollastonite and bio­active glass powders in a 1:4 mass ratio, followed by compaction through uni­axial pressing and sintering at 1000 °C for various time intervals. For com­parison, compacted pure bioactive glass samples were also sintered under iden­tical conditions. Structural, morphological, textural and in vitro bioactivity char­acterizations demonstrated that the incorporation of β-wollastonite led to a more uniform and narrower pore size distribution and promoted neck formation between particles, indicating its potential for bone regeneration applications.