TITLE:
Crystallization of amorphous boron by the calorimetric method
AUTHORS:
Tengiz Machaladze, Madona Samkharadze, Nino Kakhidze, Maia Makhviladze
KEYWORDS:
Amorphous boron; α, β-Rombohedric Crystalline Phase; Calorimeter; Thermogram
JOURNAL NAME:
Open Journal of Inorganic Chemistry,
Vol.4 No.1,
January
23,
2014
ABSTRACT:
The kinetics of formation of crystal boron was studied by X-ray structure and
differential-thermal analyses. The enthalpy of transition of amorphous boron
to crystal boron with formation of an intermediate non-equilibrium phase was
determined by the calorimetric method. Studies were carried out by using the
differential scanning calorimeter SETARAM. Amorphous boron received by diboron
cracking was used as the starting material. The test sample is cha- racterized
by stability even at a high temperature. When heated, amorphous boron first
transforms to crystal boron of α-modification,
and during a further heating, there occur several phase transitions, which
means the transition of α-rhombohedric
crystal boron to the β'and β''metastable states. Studies of various
modifications were carried out by radiographic and electro-optic methods. The
high sensitiveness of the calorimeter made it possible to control temperature
in the oven, make records and detect even the smallest thermal effects.