Preparation of Lead–Calcium Hydroxyapatite Solid Solutions by a Wet Method Using Acetamide

Lead–calcium hydroxyapatite solid solutions with different Pb/(Pb+Ca) molar ratios (XPb) were prepared by a wet method using acetamide (AA). The crystal phase and structure of the products depended on the aging period (ta), Pb/(Pb+Ca) molar ratio ([XPb]), and AA concentration ([AA]) of the starting solution. At [AA]=1.6 mol dm-3 and ta=6 days, the large needle-like PbCaHap particles were formed from solutions at [XPb]=0–0.6 and 0.9–1. Under the other AA concentrations and aging periods, pure PbCaHap particles could be obtained in a narrower region of [XPb]; e.g., PbCaHap was formed from solutions at [AA]=0.8 mol dm-3, ta=6 days, and [XPb]= 0–0.1, 0.4–0.5, and 0.9–1.