Epitaxial Crystal Growth of Nitratine on Calcite (10.4) Cleavage Faces at the Nanoscale

Abstract

In this article, we present a study of the epitaxial growth of nitratine (NaNO3) on calcite (CaCO3) from ethanolic solutions. By using sodium nitrate saturated solutions in ethanol we were able to observe the initial stages of nitratine crystallization on calcite (10.4) cleaved surfaces with atomic force microscopy (AFM). Although the oriented epitaxial growth of nitratine crystallites on calcite is independent from the solvent used (water, ethanol, or mixtures of them), the use of ethanolic solutions saturated with respect to nitratine is preferable for surface imaging in the AFM fluid cell. Additional nanotribology AFM experiments allowed us to measure shear strengths necessary to remove crystallites of nitratine from calcite (10.4) faces. On the basis of both AFM observations and measured shear strengths, the mechanism of epitaxial growth of nitratine on calcite (10.4) is discussed.