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- Author or Editor: V. Parvanova x
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Abstract
The phase diagram of the system GeSe2-SnTe is studied by means of X-ray diffraction, differential thermal and measurements of the microhardness and the density of the material. The unit-cell parameters of the intermediate phases α-3GeSe2SnTe (phase A) and GeSe22SnTe (phase B) are determined as follows for phase A: a=0.7955 nm, b=0.6969 nm, c=0.6064 nm, α=91.47, β=85.90 for phase B: a=0.6063 nm. The phase α-3GeSe2SnTe melts congruently at 500C and a polymorphic transition of the phase takes place at T α?↔β=400C and the phase GeSe22SnTe at 385C decomposes to the peritectoidal reaction at α-3GeSe2SnTe+SnTe.
Abstract
The phase diagram of the system Ag4SSe-SnTe is studied by means of X-ray diffraction, differential thermal and metallographic analyses and measurements of the microhardness and the density of the material. This diagram is divided into two eutectic-type subdiagrams by the composition Ag4SSe·2SnTe. The unit-cell parameters of the intermediate phases 3Ag4SSe·SnTe (phase A) and 
-Ag4SSe·2SnTe (phase B) are determined as follows: for phase A: a=0.7851 nm, b=0.7196 nm, c=0.6296 nm, =101.32°, 
=85.90°,
=111.36°; for phase B: a=0.3662 nm, b=0.3303 nm, c=0.3343 nm, =90.74°, =108.94°,
=91.91°. The phase Ag4SSe·2SnTe melts congruently at 615°C and a polymorphic transition of the phase takes place at T
-
=110°C.
Barium peroxytitanate, Ba2[Ti2(O2)4(OH)4(H2O)4], was synthesized and its thermal decomposition in the temperature range from 298 to 1173 K was investigated. The intermediates at 423, 533, 773 and 873 K were identified by means of quantitative analysis, IR spectroscopy and X-ray diffraction analysis. On the basis of the data obtained, a scheme of its thermal decomposition was suggested.
