Synthesis and Thermal Stability of Si-Containing Calcium Phosphates

Si-containing calcium phosphates have been synthesized. The synthesized solid phases have been investigated by X-ray diffraction analysis, IR spectroscopy, and optical microscopy. SThe specific surface areas of the samples are determined by the Brunauer-Emmett-Teller (BET) method. It is shown that an increase in the concentration of silicate ions in the starting reaction solution decreases the content of phosphate ions in the composition of synthesized samples (which is indicative of possible isomorphic substitution by silicate ions). Dynamic dissolution is carried out, and the dissolution rates of solid phases with different contents of silicate ions before and after thermal treatment are compared. It is established that heat treatment of the samples leads to the formation of a mixture of Si-containing hydroxylapatite and beta-tricalcium phosphate.