INVESTIGATION OF THE REGION OF EXAMINATION OF MELTS IN SYSTEMS In - ВVI (ВVI - S, Se, Te) BY THE ACOUSTIC METHOD

. The temperature dependences of the propagation velocity of ultrasound in exfoliating melts of the In-S, In-Se and In-Te systems have been studied. Supercritical phenomena have been found, consisting in an anomalous decrease in the speed of ultrasound with decreasing temperature as one approaches the delamination dome in a short temperature range. It has been established that these anomalies increase gradually as the melt concentration approaches the critical one. The coordinates of the critical point have been established.