Glass formation, density, microhardness, and optical properties of As-Si-Te chalcogenide alloys

The As-Si-Te glasses are IR transparent, have relatively high glass transition temperatures among the chalcogenide glasses, and thus have been considered suitable in high temperature IR-optical applications. Sixty one As-Si-Te alloys of various compositions were prepared, and their glass formation, glass transition temperatures, density, microhardness, and IR transmittance were experimentally determined. By quenching the As-Si-Te melt in air, glasses can be formed in the As-Si-Te system. Some of the as-quenched alloys are completely amorphous, and some are partially amorphous and partially crystalline. Most notably, some As-Si-Te alloys exhibit volatility. Although the As-Si-Te glasses have good IR transmittance, the oxygen impurities in the glasses cause IR absorption at the wave numbers of 690 cm(-1) and 960 cm(-1). Their glass transition temperature (T-g) decrease with Te contents, and the highest T-g found in this study is at 394 degrees C for the AS(0.2)Si(0.4)Te(0.4) The densities of As-Si-Te alloys increase with higher silicon content. The microhardness of As-Si-Te alloys is relatively high among chalcogenide glasses and its Value increases with increasing silicon content. (C) 1999 Elsevier Science B.V. All rights reserved.