Open-cell hydroxyapatite (HA) foams, produced through the novel technique o
f gelcasting foams with relative porosities ranging from 0.72 to 0.90, were
characterized for pore-size distribution, surface area, permeability, comp
ressive strength, elastic modulus, and microstructural features. The porous
structure, which is composed of an array of spherical cells interconnected
through windows, had a mode pore diameter in the range 17-122 mum, as demo
nstrated by mercury porosimetry, The BET specific surface area increased fr
om 1.5 to 3.8 m(2)/g as the sample porosity increased. The compressive stre
ngth and elastic modulus were in the range 1.6-5.8 MPa and 3.6-21.0 GPa, re
spectively. The permeability constants, k(1) (Darcian) and k(2) (non-Darcia
n), were strongly dependent on porosity fraction and varied widely, from 1.
22 x 10(-11) to 4.31 x 10(-10) m(2) and from 1.75 x 10(-6) to 8.06 x 10(-5)
m, respectively. This combination of properties make the HA foams suitable
for a variety of potential applications in the biomedical field, preferent
ially nonloading, including materials for bone repair, carriers for control
led drug-delivery systems, and matrixes for tissue engineering.