Micro-crystallization And Fine Molding On The Chalcogenide Glasses

Chalcogenide glass with a good IR transmittance in the wavelength region from 2 to 15μm and chemical stability has broad uses in many fields such as infrared laser power delivery, thermal imaging and chemical sensing. It can be used to manufacture optical components by molding, which can enhance the productivity and reduce cost. More and more attentions have been paid on the research of it. The improvement of the mechanical properties is the key to expand the application of chalcogenide glasses. In this study, IR transmitting glass-ceramics have been prepared by microcrystalline of Ge23Se67Sb10 glass to improve their mechanical properties. The structure, properties and the nano-crystallization of Ge23Se67Sb10 chalcogenide glass have been systematically studied by XRD, FTIR spectra, DSC, SEM and TMA analysis, et al. At the same time, compression molding of chalcogenide glass has been researched preliminary.The IR transmittance of the Ge23Se67Sb10 is higher than 58% in the wavelength region from 2 to 15μm. Adding Al to chalcogenide glass can eliminate most of absorption bands, but small impurity absorption peaks are found in the infrared spectra of 4.2μm (2380cm-1) and 4.55μm (2190cm-1) in infrared transmission spectrum, which results from Se-H and H2Se bonds.It has been measured that the Ge23Se67Sb10 glass transition temperature, the crystallization onset temperature and crystallization peak temperature of Ge23Se67Sb10 are 285.30℃,437.45℃, and 457.16℃respectively by DSC. The Vicker hardness of the Ge23Se67Sb10 first increases, then decreases with increasing load, which results from the indentation size effect. With 25g load, the max Vickers hardness is 199.1 Kg/mm2. The thermal expansion coefficient of Ge23Se67Sb10 is 15.96×lO-6K-1 during 200-360℃.The chalcogenide glass-ceramics made by micro-crystallization have good optical properties and mechanical properties. Research has shown that the optimum crystallization craft of Ge23Se67Sb10 is annealing the sample at 310℃for 40h. The IR transmittance of glass-ceramics is higher than 50% in the wavelength region from 2 to 15μm. The Vickers hardness of glass-ceramics is 251.5 kg/mm2, which is increased by 26% than the Ge23Se67Sb10 glass sample. The thermal expansion coefficient of the glass-ceramics is 9.35×10-6K-1, down by 41 percent over the original sample.The rough lens with excellent surface quality can be cast by fine molding process.