Porous hydroxyapatite microspheres formed by a situ conversion process

Porous hydroxyappatite (HAP) microspheres were prepared by a situ Li-Ca-B glass conversion process.The phase composition,morphology and pore structure on the shell wall were investigated using XRD,SEM and FTIR.The results showed that the resulting microspheres possessed good internal porous structure.After heat treated at 600℃ for 2h,HAP is transformed from amorphous to crystal structure.Meanwhile,HAP is partially decomposed to Ca3(PO4)2.Furthermore,the formation mechanism of the porous HAP microsphere was also suggested.On immersing in phosphate solution,Ca-P-OH hydrate was in situformed on the surface of the glass and precipitated in the position occupied by Ca2+,while the pores were formed in the position occupied by Li+ and B3+.These porous HAP microspheres may be useful for drug delivery.