Microporous Ceramics Based on β-Tricalcium Phosphate.

Microporous ceramic material, based on β-tricalcium phosphate β-Ca₃(PO₄)₂ with grain size 2–5 μm, pore size smaller than 10 mm, and density 1.22 g/cm³ corresponding to ~40% of the theoretical density (3.07 g/cm³) of β-Ca₃(PO₄)₂, was obtained from a powder mixture with a given molar ratio Ca/P = 1.5 after firing at 1100 °C. A homogenized powder mixture of synthetic dicalcium hydrogen phosphates with the molar ratio Ca/P = 1 and calcium citrate tetrahydrate Ca₃(C₆H₅O₇)₂·4H₂O with the molar ratio Ca/P = ∞ was used for microporous ceramic preparation. The phase composition of calcium phosphate powder, synthesized from an aqueous solution of phosphoric acid H₃PO₄ and calcium carbonate CaCO₃ powder, included brushite CaHPO₄·2H₂O as the predominant phase. Formation of β-tricalcium phosphate β-Ca₃(PO₄)₂ during firing occurred due to the heterophase interaction of the products of thermal decomposition of the components of the starting powder mixture, namely, calcium pyrophosphate Ca₂P₂O₇ and calcium oxide CaO. The formation of arch-like structures from β-tricalcium phosphate β-Ca₃(PO₄)₂ grains, which were tightly sintered together, hindered the shrinkage of ceramics. The microporous ceramics obtained, based on β-tricalcium phosphate β-Ca₃(PO₄)₂, can be recommended as a biocompatible and biodegradable material for treatment of bone defects and as a substrate for bone-cell cultivation. [ABSTRACT FROM AUTHOR]