Preparation and characterization of biphasic calcium phosphate ceramics of desired composition

• Published in: Journal of materials science. Materials in medicine Vol. 19; no. 8; pp. 2819 - 2825
• Main Authors: Zyman, Z. Z., Tkachenko, M. V., Polevodin, D. V.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.08.2008; Springer Nature B.V
• Subjects: Biomaterials; Biomedical Engineering and Bioengineering; Biomedical materials; Biomedical research; Calcium phosphates; Calcium Phosphates - chemical synthesis; Calcium Phosphates - chemistry; Ceramics; Chemistry and Materials Science; Composites; Glass; Hydroxyapatite; Materials Science; Microscopy, Electron, Scanning; Natural Materials; Polymer Sciences; Regenerative Medicine/Tissue Engineering; Spectrophotometry, Infrared; Surfaces and Interfaces; Thin Films; X-Ray Diffraction; Compressive Strength; Biphasic Calcium Phosphate; Acid Abundance; Porous Biphasic Calcium Phosphate; Phase Composition
• ISSN: 0957-4530; 1573-4838
• DOI: 10.1007/s10856-008-3402-9

A modified processing route for fabricating dense and porous biphasic calcium phosphate (BCP) ceramics of desired and reproducible phase composition (hydroxyapatite (HA)/β-tricalcium phosphate (β-TCP) ratio) has been developed. The principal idea of the route was combining a precipitation and a solid phase methods. First, a nonstoichiometric (slightly carbonated calcium-deficient) HA (CdHA) precipitate was synthesized by mixing a calcium carbonate (CaCO 3 ) water suspension with an orthophosphoric acid (H 3 PO 4 ) solution in abundance (related to the amount resulting in a stoichiometric HA) under definite conditions, and a powder of the precipitate was prepared and calcinated in air (860°C, 1.5 h). In the second stage, a BCP ceramics of the composition determined by the calcium-deficiency in a calcinated powder (the acid abundance in a mixture) was processed by sintering powder compacts with or without a porosizer under appropriate conditions (1,200°C, 2h). A calibrating dependence of the HA/β-TCP ratio in the ceramics on the acid abundance has been plotted which enabled a controlled preparation of BCP ceramics. A correlation based on unresolved bands in ν 4 -PO 4 3− domain in IR-spectra of nanostructured BCP materials was found. Using the correlation, the process of CdHA → β-TCP transformation could be easily monitored. The density and microhardness of the BCP ceramics neglectly depended on the composition, however, the compressive strength did: the lower the HA/β-TCP ratio, the higher the strength in the dense materials.