Glass Science: Reports From R.M. Hovhannisyan Et Al Highlight Recent

GLASS SCIENCE; REPORTS FROM R.M. HOVHANNISYAN ET AL HIGHLIGHT RECENT RESEARCH IN GLASS SCIENCE

Science Letter
July 22, 2008

According to recent research from Yerevan, Armenia, "An insufficient
level of investigations on barium titanium borate system both
in crystalline and in glassy states has stimulated the present
research. The phase diagram of the ternary BaO-TiO2-B2O3, system
have been constructed revealing six ternary eutectic and seven
peritectic compositions in the ternary system and two new binary
eutectic compositions in the BaO-B2O3 corrected system."

"The phase diagram in the pseudo-binary barium borate-barium titanate
system is revised. The new crystalline 2BaO.TiO2.B2O3 compound is
revealed at the same glass composition crystallisation. It melted
incongruently at 940 degrees C with the formation of melt and
barium titanate. The x-ray characteristics of 2BaO.TiO2B2O3 are
reported. It has orthorhombic or tetragonal crystal symmetry and
lattice constants (A): a-11.84, b-9.64, c-18.24, Z=21. The influence
of various methods of melt casting on the glass forming ability in
the ternary BaO-TiO2-B2O3 system is investigated. The expanded glass
formation area changes from stable glass forming barium tetraborate
up to binary dibarium borate and tip to barium dititanate," wrote
R.M. Hovhannisyan and colleagues (see also Glass Science).

The researchers concluded: "A clear correlation between glass forming
ability and eutectic areas is revealed in the investigated system."

Hovhannisyan and colleagues published their study in Physics
and Chemistry of Glasses – European Journal of Glass Science and
Technology Part B (Mutual influence of barium borates, titanates
and borontitanates on phase diagram and glass formation in the
BaO-TiO2-B2O3 system. Physics and Chemistry of Glasses – European
Journal of Glass Science and Technology Part B, 2008;49(2):63-67).

For additional information, contact R.M. Hovhannisyan, Institute
Materials Science Agh, 17 Charents St., Yerevan 375025, Armenia.

Publisher contact information for the Physics and Chemistry of Glasses
– European Journal of Glass Science and Technology Part B is: Society
Glass Technology, Unit 9, Twelve O Clock Court, 21 Attercliffe Rd.,
Sheffield S4 7WW, S Yorkshire, England.

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