Development Carbonated Hydroxyapatite Powders from Oyster Shells (Crassostrea gigas) by Sintering Time Controlling

Carbonated-hydroxyapatite (CHAp) is a hydroxyapatite substituted with carbonate ions and is known to resemble the hard bone structure of humans. CHAp was synthesized from biogenic material. Oyster shells (Crassostrea gigas) was biogenic materials that used as a calcium source. In addition, sodium bicarbonate and ammonium hydrogen phosphate were also used as sources of carbonate and phosphate. In this research, the oyster shells used were milled, calcined, and characterized to determine the phase changes from CaCO<inf>3</inf> to CaO by decomposition process. CHAp powders which were synthesized by precipitation method, were sintered at 650 °C for 0.25, 0.5, 1, 2 and 4 hours. To find the quality of CHAp powders with different sintering time, characterization process using Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffractometer (XRD), and Scanning Electron Microscope-Energy Dispersive X-Ray (SEM-EDX) has been successfully done. FTIR, XRD, and SEM-EDX was used to determine functional groups, to confirm the presence of carbonate groups, to analyse the crystallography, and to calculate the Ca/P molar ratio and carbonate content of CHAp powders. Based on the results of characterization process showed that the oyster shells weres successfully synthesized into CHAp and the length of sintering time effects of the crystallite size and crystallinities. CHAp powders sintered for 4 h have 41.385 and 31.499 nm degree of crystallinity and crystallite size, respectively.