Study On The Nano-crystallization And Molding Technology Of Ge-Se-Sb Infrared Glass

Ge-Se-Sb infrared glass is a kind of excellent infrared transparent-wave materials due to its excellent infrared transmittance in the wavelength range2～15μm and high thermal stability. Compared with conventionally infrared materials, i.e., single Ge and polycrystal ZnSe, Ge-Se-Sb infrared glass can be easily prepared, and the glass lens can be fabricated through single process of precision molding method. Now, Ge-Se-Sb infrared glass has been widely used in the field of infrared detector and thermal imaging. However, due to the weakness of chemical bond and low phonon energy, the Ge-Se-Sb infrared glass has poor mechanical properties, thus limiting the development of molding technology. In present article, the structure, infrared transmittance and mechanical properties of Ge23Se67Sb10infrared glass has been investigated in detail. Micro-crystallization process is introduced to improve its mechanical properties while its infrared transmittance is not changed greatly. The precision molding process is explored and the optimized forming process can be developed. By the combination use of DSC, TMA, XRD, SEM, FTIR, Vickers micro-hardness, Archimedes test, structural characterization, performance, and microstructure of the Ge-Se-Sb infrared glass have been studied. The main conclusions can be drawn:Ge23Se67Sb10infrared glass has been prepared by traditional melt-quenching with high density and bright surface. Infrared transmittance of samples is upto about65%in the range of2-15μm wavelength, while micro-hardness is about180kgf/mm2. Average atomic coordination number of Ge23Se67Sb10infrared glass is2.56by theoretical calculation, thus the structure is deduced as three dimensional network structure. Glass transition temperature lies between270℃and290℃; and thermal stability parameters(△T、H’、Hr and S) are high, which indicate that Ge23Se67Sb10infrared glass has good thermal stability and glass forming ablity.In order to study heat-treatment process of the samples with different glass transition temperature and the effects on infrared properties and mechanical properties after heat-treatment, two group samples with glass transition temperature270℃and280℃are heated treatment respectively. The results of infrared test and XRD show that the sample with higher glass transition temperature (280℃) is relatively stable, and it is influenced slightly by heat treatment and suitable for the research of micro-crystallization. The infrared performance and mechanical performance of the sample with transition temperature280℃have been reseached, the results show that the transmittance of the sample decreases with increasing heat-treatment temperature and time especially in the mid-infrared region; with the increase of temperature and time, transmittance decreases and extended gradually to the whole infrared wavelenghths; microhardness tests show that the hardness of the samples increases first and then decreases with the increase of heat-treatment temperature. When the heat-treatment temperature is320℃, the maximum hardness is255kgf/mm2, which increases nearly40%compared with base glass. Accordingly, infrared transmission of Ge23Se67Sb10infrared glass is the highest and the micro-hardness is best, after heat treatment regime of330℃×70h.The crystallization tendency and thermal stability of Ge23Se67Sb10infrared glass were researched after introducing CsCl into infrared glass ingredient. The results of XRD and SEM show that after adding CsCl, crystallites GeSe2and Sb2Se3precipitate in the matrix of Ge23Se67Sb10infrared glass; three characteristic temperatures(Tg, Tx and Tp), thermal stablity parameters(△T, H’, Hrand S) of Ge23Se67Sb10infrared glass reduce, so the thermal stablity of infrared glass decreases and the crystallization tendency increases. As the CsCl addition increases, the precipitation of the bigger size crystallites results in decline of transmittance of the Ge23Se67Sb10infrared glass. The micro-hardness of Ge23Se67Sb10glass increases first and then decreases with the increase of CsCl addition. When the addition of CsCl is2%, the micro-hardness of the sample reaches to208kgf/mm2, which is higher than the base glass by16%.Ge23Se67Sb10infrared glass is molded with temperature320℃(60℃above glass transition temperature Tg), the molding samples have better surface quality and high replication precision of the mold cavity; infrared transmittance of the samples decrease slightly, while compactness increases significantly.