Место издания:Moscow. “Pero” Publisher .Electronic edition Moscow, Russia
Первая страница:184
Последняя страница:184
Аннотация:Calcium phosphate powders with different Ca to P ratio in the system Ca2P2O7–Ca(PO3)2 were
synthesized via thermal treatment of homogenized powder mixture of calcium citrate tetrahydrate
Ca3Cit2 . 4H2O (Cit = C6H5O7) and ammonium hydrophosphate (NH4)2HPO4. Properties of powder
mixtures of calcium citrate tetrahydrate Ca3Cit2
. 4H2O and ammonium hydrophosphate
(NH4)2HPO4 were studied to establish the best regime of thermal treatment. STA 409 PC Luxx
thermal analyzer (NETZSCH, Germany) were used in experiment. Heating of powder mixtures
(mass being at least 10 mg) was conducted in air (10 °C/min, 40–1000 °C). The evolved gases
composition was simultaneously monitored during the thermal analysis experiment using a
coupled QMS 403 C Aeolos quadrupole mass spectrometer (NETZSCH, Germany).
As far as all processes associated with mass loss are completed before 750 °C, temperatures in the
range of 750–900 °C can be recommended for calcium phosphate powders production. The use of
temperatures up to 800 °C makes it possible to obtain powders colored with amorphous carbon.
The use of temperatures above 900 °C leads to a noticeable increase of the particle size. The sample of powder obtained after heat treatment of aforementioned powder mixtures with pointed content of Ca2P2O7 in interval 40–60 % at temperatures of 800–900 °C, containы a metastable
phase – tromelite Ca4P6O19, in addition to the phases of Ca(PO3)2 and β-Ca2P2O7.
Acknowledgements The financial support of RFBR project # 18-29-11079.
