The influence of heat treatment conditions on the structure and properties of (As2Se3)100-x(SbSI)x glasses and composites on their basis


Purpose. Composites on the basis (As2Se3)100-x(SbSI)x glasses are suitable for creation of memory media, elements for various sensors, infrared and nonlinear optics. In this paper the results of the heat treatment conditions on the structure and properties of (As2Se3)100-x(SbSI)x glasses and composites are reported.
Methods. Differential thermal analysis (DTA), dielectric and X-ray diffraction spectroscopy. DTA curves and ε(T) dependences were carried out in the temperature ranges of 293-700 K and 200-550 K, respectively. Heating rates were equal 3, 6 and 10 K/min.
Results and discussion. It has been established that the crystallization of (As2Se3)100-x(SbSI)x glasses takes place in several stages and is accompanied by anomalies on the temperature dependences of dielectric parameters. These studies have shown that DTA curves of (As2Se3)100−x(SbSI)x glasses, produced from Th= 803 К and recorded at q=6 K/min, revealed two exothermic effects. Temperatures maxima of these effects (TМ1 and TМ2) are determined. The first effect is less pronounced due to the nucleus formation and the formation of nanocrystals in SbSI glass matrix. DTA curves of glasses recorded at q=3 K/min, have demonstrated three exothermic effects. For example, for (As2Se3)20(SbSI)80 glass the temperatures TМ1 , TМ2 and TМ3 are equal 408, 431 and 505 K, respectively. On DTA curves of glasses recorded at q=10 K/min, occured the only intensive effect at high temperatures. The structure of the phase that arises in the glass matrix at low temperature annealing (393-453 K) corresponds to the structure of the crystalline antimony sulfur iodide. The formation of triple chain groups SbS2/2I occurs as a result of the glass structural relaxation during its softening, which is accompanied by breaking and switching of homopolar and heteropolar chemical bonds in the binary groups that form the structural network of glasses. This process is accompanied by the diffusion of atoms in a distances of interatomic order. As the annealing time increases, the size of the crystalline inclusions of SbSI becomes larger. By the X-ray diffraction patterns method, the nature of crystalline inclusions, which are formed in the structural network in conditions of high-temperature annealing, is determined. It is assumed that in this case there is a partial dissociation and sublimation of iodinecontaining fragments involved in the formation of the structural network of composites and the formation of crystalline inclusions Sb2Se(S)3 and As2Se3. The results testifies about possibility of controlling the structure and properties of (As2Se3)100-x(SbSI)x composites (including nanocomposites) by choosing the heat treatment regimes

Keywords: chalcohalogenide glasses, ferroelectrics, crystallization, structure