Characterization of vaterite synthesized at various temperatures and stirring velocities without use of additives

0446212 - ÚTAM 2016 RIV CH eng J - Článek v odborném periodiku
Ševčík, Radek - Pérez-Estébanez, Marta - Viani, Alberto - Šašek, Petr - Mácová, Petra
Characterization of vaterite synthesized at various temperatures and stirring velocities without use of additives.
Powder Technology. Roč. 284, November (2015), s. 265-271. ISSN 0032-5910. E-ISSN 1873-328X
Grant CEP: GA ČR(CZ) GP14-20374P; GA MŠMT(CZ) LO1219
Klíčová slova: synthesis * vaterite * Rietveld method * morphology * nanoindentation
Kód oboru RIV: AL - Umění, architektura, kulturní dědictví
Impakt faktor: 2.759, rok: 2015
http://www.sciencedirect.com/science/article/pii/S0032591015005239

Conditions for the synthesis of vaterite without additives have been investigated (T = 30 – 90 °C, stirring velocity=200–600 rpm). The obtained different CaCO3 polymorphs were characterized with Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRPD) and scanning electron microscopy (SEM). Quantitative phase analysis (QPA) was performed by the Rietveld method. To describe vaterite diffraction patterns, two structural models were employed. Their relative abundance was found to change with the temperature of synthesis. The optimal synthesis conditions for preparing pure vaterite (≥99 wt.%) were found at 60 °C and 600 rpm. This is the first time pure vaterite is obtained at such high temperature without additives. The conditions under which the different polymorphs formed, and their microstructural features, are discussed. In addition, nanoindentation measurements on synthesized vaterite and calcite are firstly reported. The vaterite elastic modulus is higher than that of calcite (E = 16–48 GPa and E = 9–35 GPa, respectively), whereas the range in hardness was found to be the same for both polymorphs (H=0.4–2.8).
Trvalý link: http://hdl.handle.net/11104/0248204