ИСТИНА

Polycrystalline ceramic samples with nominal composition M10(PO4)6(CuxOH1-x-d)2 + (3-2x)CuOy (M = Ca, Sr, y = 1, 0.5) were synthesized by a solid-state treatment in air at 1150°C. Grinded samples were heated at the fixed temperature in the range 800-1400°C in air, in flowing air with the controlled water amount, in flowing oxygen and in flowing argon. Obtained samples were searched by powder X-ray diffraction, diffuse reflectance spectroscopy and magnetic susceptibility measurement methods.It was shown that the copper doped hydroxyapatite is in phase equilibrium with CuO or Cu2O in a wide range of thermodynamic parameters used. the amount of copper solubility x was determined. It was demonstrated that the main part of copper in the apatite exists in a diamagnetic state with oxidation state +1 and only minor part of it is paramagnetic. The cell parameters and cell volume grow with the channels copper content increasing. The copper content limit x grows with the annealing temperature arising and reaches the value 0.58 for the calcium and 0.67 for the strontium apatite. The copper content limit slightly increases with the oxygen partial pressure decreasing for the strontium samples whereas it exhibits a maximum at p(O2) = 0.21 bar for the calcium analogue. The reduced water vapor pressure promotes the grows of x. The chemical processes proceeding in equilibrium system that explain such a complex p-T behavior of the solid solution limits were proposed.