Aqueous processing of hydroxyapatite

This paper describes a study of the dispersion of hydroxyapatite (OHAp) powder in aqueous media. The slurry stability is achieved by utilizing a combination of a commercially available dispersant, polyacrylic acid sodium salt (PAA-Na) and ethylenediaminetetraacetic acid, tetrasodium salt, dihydrate (EDTA·4Na·2H2O). Adsorption, sedimentation and rheology measurements have been performed to investigate the suspensions properties. It was shown that HAp slurries could be stabilized at pH 10.50 with the PAA-Na concentration around 0.45 wt%. Rheological measurement confirmed that well dispersed slurries could be obtained with the solid content as high as 63 vol%. After sintering, the relative density of HAp sheets reached 98.8%. The as sintered HAp samples exhibited excellent properties for cell attachment and proliferation. Results showed that the aqueous processing technique is effective for preparation HAp samples for biological applications.