2009 Volume 34 Issue 1 Pages 81-84
Beta-tricalcium phosphate (β-TCP) precursors were prepared by chelation of calcium ions with phosphonic acid using calcium nitrate tetrahydrate (Ca(NO3)2 4H2O) and 2-phosphonobutane-1.2.4-tricarboxylic acid (C7H11PO9; PBTA) in distilled water in the temperature range of 60-130 ℃. β-TCP powder was then synthesized by heating the precursors at various temperatures. β-TCP precursors were gelled in three reactions. First, calcium ions were chelated with carboxyl groups in PBTA. Second, chelation of calcium ions with phosphonic acid and/or the dehydrated condensation of carboxyl groups with phosphonic acid, finally, dehydrated condensation of carboxyl groups occurred in the range of 100-130 ℃. Powder obtained after heating the β-TCP precursor prepared at 130 ℃ had a single crystalline alpha-TCP phase at 600 ℃, following by a single β-TCP phase at 800 and 1000 ℃. In addition, the crystallinity of the powder improved with an increase in the preparation temperature of β-TCP precursors, which accelerated gelation. The powder obtained at 600 ℃ was formed layers with submicrometer pores among particles, and the powder obtained after heating at and above 800 ℃, the particles formed a specific three-dimensional network. The particle sizes increased with an increase in the heating temperatures.
