Ізотермічні перерізи при 770 K та склоутворення у системах AgCl(I) – Ga2S3 – La2S3

Abstract

For the investigation of the phase equilibria in the systems AgCl(I) – La2S3 – Ga2S3 30 samples were synthesized for each of system. The samples were studied by X-ray diffraction (XRD) and differential thermal analyses (DTA). Diffraction patterns were recorded on DRON 4-13 diffractometer, CuKα radiation, step scan 0.05º, exposure time 2 s. The analysis of the diffraction patterns was performed using PowderCell-2 software package. The DTA curves were recorded using Pt/Pt-Rh thermocouples at a combination of a Thermodent regulated heating furnace and a H307-1 XY recorder set. Phase equilibria in AgCl(I) – La2S3 – Ga2S3 system at 770 K were built from the X-ray analysis results. In the quasiternary systems, small one-phase regions are formed based on Ga2S3, S.G. Cc, a = 1.1136 (2), b = 0.6407 (2), c = 0.7038 (3) nm, b = 121.22°, La2S3, S.G. Pnma, a = 0.7560 (3), b = 0.4291 (1), c = 1.5850 (2) nm, AgCl, S.G. F-43m, a = 0.5617 (5) nm, AgI, S.G. F-43m, a = 0.6485 (5) nm. In addition in the quasiternary systems the existence of two quasibinary systems AgCl(I) – LaGaS3 and AgCl(I) – La3Ga1,67S7 was found. They triangulate quasiternary systems on three subsystems AgCl(I) – La2S3 – LaGaS3, AgCl(I) – LaGaS3 – La3Ga1,67S7, AgCl(I) – La2S3 – La3Ga1,67S7. In the La2S3 – Ga2S3 system, the existence of ternary compounds LaGaS3, orthorombic system, S.G. Pna21, а = 1,5175(3), b = 1,0568(6), с = 1,2829(7) nm, β = 137,56 ̊, La3Ga1,67S7, structural type Ce3Al1,67S7, S.G. P63, a = 0,9935(3), c = 0,6013(6) nm was confirmed. There are very small one-phase regions based on them. The quaternary compounds were not found. The glasses in the AgCl(I) – Ga2S3 – La2S3 systems have orange-red color, transparent. The glass-forming regions in the AgCl(I) - Ga2S3 - La2S3 systems locate within the 50-75 mol.% Ga2S3 in the system La2S3 – Ga2S3 and extend into the concentration triangle till 5 mol.% AgCl(I). The values of the Hruby factor for the glassy specimens located within the range of 50-75 mol% Ga2S3 in the La2S3 – Ga2S3 system were found and found out that they are not significant and these samples do not have high glass-forming ability. But the samples obtained three years ago retain their glassy conditions and can be used in semiconductor technology. Keywords: AgCl(I) - La2S3 - Ga2S3; phase eguilibrium; glass formation; isothermal sections; chalcogenides.