Phase equilibria in the GeSe2-SnTe system

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 alpha-3GeSe(2).SnTe (phase A) and GeSe2.2SnTe (phase B) are determined as follows for phase A: alpha=0.7955 nm, b=0.6969 nm, c=0.6064 nm, alpha=91.47degrees, beta=85.90degrees; for phase B: alpha=0.6063 nm. The phase alpha-3GeSe(2).SnTe melts congruently at 500degreesC and a polymorphic transition of the phase takes place at Talpha<---->beta=400degreesC and the phase GeSe2.2SnTe at 385degreesC decomposes to the peritectoidal reaction at alpha-3GeSe(2).SnTe+SnTe.