Surface Modification and Planar Defects of Calcium Carbonates by Magnetic Water Treatment

Abstract

Powdery calcium carbonates, predominantly calcite and aragonite, with planar defects and cation–anion mixed surfaces as deposited on low-carbon steel by magnetic water treatment (MWT) were characterized by X-ray diffraction, electron microscopy, and vibration spectroscopy. Calcite were found to form faceted nanoparticles having 3x (0114) commensurate superstructure and with well-developed {1120} and {10 14} surfaces to exhibit preferred orientations. Aragonite occurred as laths having 3x (011) commensurate superstructure and with well- developed (011) surface extending along [100] direction up to micrometers in length. The (hkil)-specific coalescence of calcite and rapid lath growth of aragonite under the combined effects of Lorentz force and a precondensation event account for a beneficial larger particulate/colony size for the removal of the carbonate scale from the steel substrate. The coexisting magnetite particles have well-developed {011} surfaces regardless of MWT.