Technology Business Journal
March 10, 2009

MATERIALS SCIENCE;
Findings from Yerevan State University provide new insights into
materials science

According to a study from Yerevan, Armenia, "The early growth of
calcium hydroxide (CH) crystals in cement solution is investigated by
soft X-ray transmission microscopy imaging. Aquantitative analysis of
the successively recorded images of the hydration process enabled to
evaluate the supersaturation ratio of solution, growth rates, both
kinetic and diffusion coefficients, and concentrations of solute
molecules at {10 (1) over bar0} and {0001} facets of the CH crystals."

"It is concluded that the difference in obtained concentrations of
solute molecules at these facets may be associated with solubility
anisotropy of crystallographic facets of the CH. The interfacial
energy of the CH nuclei in aqueous solution is evaluated to be 0.114
J/m(2) that by an order of magnitude is smaller than the average free
surface energy of this phase," wrote V.S. Harutyunyan and colleagues,
Yerevan State University.

The researchers concluded: "The proposed theoretical approach is
universal and, in potential, may be applied to any precipitating phase
in a supersaturated solution."

Harutyunyan and colleagues published their study in the Journal of
Materials Science (Investigation of early growth of calcium hydroxide
crystals in cement solution by soft X-ray transmission
microscopy. Journal of Materials Science, 2009;44(4):962-969).

For more information, contact V.S. Harutyunyan, Yerevan State
University, Dept. of Solid State Physics, Yerevan 375049, Armenia.

Publisher contact information for the Journal of Materials Science is:
Springer, 233 Spring St., New York, NY 10013, USA.