Preparation of Porous HA/Beta-TCP Biphasic Bioceramic Using a Molten Salt Process
Bioceramics based on calcium phosphate is convinced to be well biocompatible after abundant researches. In this study, a biphasic bioceramic block (10 mm by 5 mm) (BBB) composed of hydroxyapatite and beta-tricalcium phosphate (40/60 in wt%) was prepared using a molten salt approach. At 800oC, the molten sodium chloride well helped the sintering of the precursor powders. A second calcination at 1000oC was then used to evaporate the salt so that a pure biphasic bioceramic block was obtained. This approach can provide porous BBB with 60% porosity, and powder x-ray diffraction patterns ensured the phasic compositions. However, the electrom probe microanalysis showed that around 2 at% of sodium was retained in the BBB. Scanning electron microscope revealed well-dispersed connective micro-pores of 3 micron and random macro-pores of >100 micron in the BBB. Because the salt was evaporated during the preparation of the BBB, the spatial voids were created, and, as a result. The compressive strength of the BBB can only reach a value of 3 MPa. Subcutaneous implantation of the BBB in mice showed that both acute and chronic imflammation were mild. In summary, the molten salt approach is feasible to fabricate biphasic calcium phosphate ceramics having controlled porosity.
Takashi Nakamura, Kimihiro Yamashita and Masashi Neo
R. J. Chung et al., "Preparation of Porous HA/Beta-TCP Biphasic Bioceramic Using a Molten Salt Process ", Key Engineering Materials, Vols. 309-311, pp. 1075-1078, 2006