Effects Of Nucleation Agent On Structure And Properties Of Selenium Based Infrared Glass

As the excellent microwave transparent material for Mid-infrared, chalcogenide glass has the advantages of high transmittance, good chemical stability, and it has a wide application prospects in the field of optical and optoelectronic materials. However, the disadvantages of weakly chemical bonds and poor mechanical properties limit its development. Microcrystallization of chalcogenide glass is an effective method to improve mechanical properties. The microcrystallization of Ge23Se67Sb10infrared glass was studied in this study. Effects of the nucleation agent (CsCl and RbI) and thermal treatment on the microstructure, thermal stability, optical and mechanical properties of Ge23Se67Sb10infrared glass were studied by using DSC, XRD, SEM, Fourier Infrared Spectrum analysis and micro Vikers hardness method. The research results are following:With the increased addition of RbI, the glass transition temperature of Ge23Se67Sb10declines, the thermal stability decreases, the crystal appeares in the sample and the size increases gradually, a large number of cross-shaped crystals appear at last; at the same time, the infrared transmittance of Ge23Se67Sb10decreses; the Vichers hardness increases first and then decreases and the fracture toughness is improved. The hardness reached to the largest, i.e.1980.45Mpa, when the RbI was1%, and the infrared transmittance was about50%at the range of8～12μm wavelength. The99Ge23Se67Sb10-1RbI is considered to be the best glass with excellent performances.With the increase of CsCl, the glass transition temperature and the thermal stability of Ge23Se67Sb10declines, the grain appeares in the internal of glass and the size increases gradually; the infrared transmittance decreases with the increase of CsCl, the Vickers hardness increases first and then decreases and the fracture toughness is increasing. A large number of grains with small size appeared and distributed equally when the content of CsC1was1%, at this point, the Vickers harness reached to the largest, i.e.2040.46MPa, and the transmittance was approximate60%in the range8-12μm. The99Ge23Se67Sb10-1CsCl is considered to be the best glass with excellent performances.The values of△T, H of Ge23Se67Sb10glass with RbI are larger than the same content of CsCl of Ge23Se67Sb10glass, the thermal stability and glassy ability of (100-x)Ge23Se67Sb10-xRbI are better than (100-x)Ge23Se67Sb10-xCsCl glass. In the view of the structure of nucleation agent and the mechanism of microcrystalline generated in the infrared glass, the crystallization behavior in the glasses after introducing CsCl nucleation agent is easier than that in the glasses after introducing RbI nucleation agent, which is in well agreement with experimental result.When the heat-treated temperature is lower than310℃, the organization of99.5Ge23Se67Sb10-0.5CsCl changes slowly and the number of small grain changes unsignificantly with the increasing of holding time. The infrared transmittance decreases slightly and the mechanical properties remain unchanged. However, as heat-treated temperature is larger than310℃, the microstructure, infrared transmittance and the mechanical properties are quite different. As the holding time increases, the interal crystals within the glass matrix become larger and microstructure transites into completely ceramic. The infrared transmittance decreases dramatically to0, and mechanical properties reduce. The fracture toughness of99.5Ge23Se67Sb10-0.5CsCl glasses, subjected to heat treatment of290℃for70h, reach10.94MPa-mm1/2, which improves by29%as compared with the glasses without heat treatment and35%as compared with Ge23Se67Sb10original glasses. After heat treated at290℃for70h, the infrared transmittance of99.5Ge23Se67Sb10-0.5CsCl glasses is55%in the wavelength range8-12μm.