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

摘要: Abstract Conditions for the synthesis of vaterite without additives have been investigated ( T  = 30 – 90 °C, stirring velocity = 200–600 rpm). The obtained different CaCO 3 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 Rietveld method. To describe patterns, two structural models employed. Their relative abundance found to change temperature synthesis. optimal conditions preparing pure (≥ 99 wt.%) at 60 °C 600 rpm. This is first time such high additives. under which formed, their microstructural features, are discussed. In addition, nanoindentation measurements on synthesized calcite firstly reported. elastic modulus higher than that E  = 16–48 GPa  = 9–35 GPa, respectively), whereas range in hardness be same both H  = 0.4–2.8).