No abstract

Conditions for hydroxyapatite (HAP) synthesis in aqueous solutions by hydrolysis of α Са 3 (РО 4 ) 2 were studied. Temperature exerts a substantial effect on the rate of α Ca 3 (PO 4 ) 2 hydrolysis and also changes the morphology of the reaction products. At 40 °C, the plate like intersecting (perpendicular to the surface of the initial particles) crystals of HAP grow. Their maximum size after the 24 h hydrolysis is 1-2 µm. Needle like HAP crystals are formed upon boiling of the suspension. The morphology observed for the HAP particles agrees well with the conclusions obtained by analysis of the kinetics of tricalcium phosphate hydrolysis.

No abstract

A continuous preparation method for nanoscopic calcium phosphate ceramics is presented. The influence of processing parameters (temperature, time) on the properties of calcium phosphates was studied. Crystallinity, structure, and morphology are important for an application as biodegradable implant material in bone contact. The samples were studied in detail using X-ray powder diffraction, infrared spectroscopy, atomic absorption spectroscopy, photometry, scanning electron microscopy, and transmission electron microscopy. All calcium phosphate precipitates are non-stoichiometric, calcium-deficient hydroxyapatites.

No abstract

The properties of Ca-deficient hydroxyapatite powder synthesized from calcium nitrate and ammonium hydrophosphate at 60°C, pH = 7, and Ca/P = 1.67, 1.61, and 1.48 are presented. After sintering at 1100°C for 6 h the phase composition of the ceramic based on these powders was represented by tricalcium phosphate (Ca/P = 1.48) or tricalcium phosphate hydroxyapatite (Ca/P = 1.67 and 1.61). The grain size of the ceramic was 100 -1000 nm.

No abstract

No abstract