Silica Effect on Porous Calcium Phosphate Ceramics from the Freeze Gelation Route

Calcium phosphate ceramics have a high potential for biomedical applications. In this work Si‐modified calcium phosphate ceramics were prepared from the silica‐containing hydroxylapatite (HAp) suspensions using the freeze gelation technique, an environment‐friendly low‐cost method for the near‐net‐shape fabrication of ceramic components. Sintering behavior, phase composition, and microstructural characteristics of HAp with varying silica content were studied using dilatometry, thermogravimetry, XRD, REM, and Hg‐intrusion. It was shown that the addition of silica has an essential effect on the sintering behavior and the phase composition of the samples and allows the in situ control over the HAp/Si–HAp to tricalcium phosphate (TCP)/Si–TCP ratio.