Fabrication of porous ceramics with well-controlled open pores by sintering of fibrous hydroxyapatite particles

Porous hydroxyapatite (Ca-10(PO4)(6)(OH)(2); HAp) ceramics with various por osity values were fabricated by sintering fibrous HAp particles prepared fr om the aqueous solutions in the Ca(NO3)(2)- (NH4)(2)HPO4-(NH2)(2)CO-HNO3 sy stem by the homogeneous precipitation method using urea. The total porositi es, total pore volumes, median pore sizes and specific surface areas of the resulting ceramics were controlled in the range of 16.7 to 55.0%, 0.04 to 0.36 cm(3) . g(-1), 0.28 to 0.78 mu m and 0.29 to 2.90 m(2) . g(-1), respec tively, by changing the compaction pressures (20, 30 and 40 MPa) and firing temperatures (1000 degrees C, 1100 degrees C, 1200 degrees C and 1300 degr ees C). Most of the pores in the resulting ceramics were regarded as the op en pores.