Journal Article

Physical and nanomechanical properties of the synthetic anhydrous crystalline CaCO3 polymorphs: vaterite, aragonite and calcite

Ševčík, Radek, Viani, Alberto, Šašek, Petr

2018

Overview

The synthetic anhydrous crystalline CaCO 3 polymorphs—vaterite, aragonite and calcite—were tested using dilatometry and nanoindentation. Microstructural changes in the samples before and after measurements were observed under scanning electron microscope and their phase composition quantified with X-ray powder diffraction with the Rietveld method. The thermal expansion coefficients of vaterite and the hardness and elastic modulus of synthetic aragonite are reported for the first time. The physical and nanomechanical properties were measured under similar conditions for each CaCO 3 polymorph. Aragonite, calcite and vaterite showed volumetric thermal expansion coefficient at 303 K of 49.2(8), 48.6(2) and 44.1(3) 10 −6  K −1 , respectively. The elastic modulus increased from 5(4), 16(7) to 31(8) GPa for aragonite, calcite and vaterite, respectively. Average hardness was found lower than values from the literature, ranging from 0.3 to 1.3 GPa. The results are considered of interest for the design of CaCO 3 -based materials for applications.

• Publisher: Springer US,Springer Nature B.V
• Subject: Aragonite / Calcite / Calcium carbonate / Ceramics / Characterization and Evaluation of Materials / Chemistry and Materials Science / Classical Mechanics / Crystal structure / Crystallinity / Crystallography and Scattering Methods / Dilatometry / Electron microscopes / hardness / Materials Science / microstructure / Modulus of elasticity / Nanoindentation / Phase composition / Polymer Sciences / Rietveld method / scanning electron microscopes / Solid Mechanics / Thermal expansion / vaterite / X ray powder diffraction / X-ray diffraction