Functionally graded tricalcium phosphate/fluoroapatite composites

This study was conducted to prepare fluorine-substituted apatite (FA)/beta-tricalcium phosphate (β-TCP) composites to combine the biostability of FA with the bioresorbability of β-TCP. The FA was prepared for the first time by mixing hydroxyapatite (HA) with aluminium fluoride (coded as AF). On the other hand, the β-TCP was prepared from a mixture of HA and CaHPO4 (calcium hydrogen phosphate). The dissolution behaviour of the composites was tested using a 10-wt.% citric acid solution. Scanning electron microscopy (SEM) indicated that β-TCP dissolved in the citric acid much faster than FA, resulting in macropores among the FA matrix. In addition to bulk FA/β-TCP composites, novel functionally gradient FA/β-TCP composites were also prepared by varying the particle size and the volume content of the β-TCP granules. The functionally gradient FA/β-TCP composites could be used to design implants.