Strengthening Ge-Sb-Se-Te Chalcogenide Glass By Microcrystalliztion Technique

Chalcogenide glass has a series of excellent optical properties such as low phonon energy,wide infrared transmission range,high linear and nonlinear refractive index,thus it is widely used.However,the disadvantages of mechanical properties and thermal shock resistance of chalcogenide glass hinder the preparation,processing and application of chalcogenide glass.Adding nucleating agent to the glass matrix or heat-treating the glass to precipitate nanocrystalline particles in the glass can effectively improve the mechanical properties and thermal shock resistance of the glass.In this paper,different contents of nucleating agents（CsI,CsCl）were added to Ge₂₀Sb₁₀Se₆₅Te₅ glass,and the optimal cooling method was determined by XRD analysis.The effects of different contents of nucleating agent on the physical properties such as glass hardness and density were studied.The optical properties such as infrared transmittance and transmittance range of the samples were tested by Fourier transform infrared spectrometer and ultraviolet-visible light spectrophotometer.To study the thermodynamic properties of the glass and explore the influence of different heat treatment processes on the properties of 96Ge₂₀Sb₁₀Se₆₅Te₅-4CsI glass,differential scanning calorimeter was used to test the DSC curve of the sample,and the thermal mechanical analyzer was used to test the dynamic linear expansion coefficient of the sample.The main conclusions are as follows:（1）The glass prepared by cooling in a salt bath has a bright surface and no cracks,and is a typical amorphous structure.With the increase of CsI and CsCl content,the thermal stability of the glass decreases,and the hardness and density tend to decrease.（2）Adding CsI and CsCl nucleating agents to Ge₂₀Sb₁₀Se₆₅Te₅ glass has little effect on the infrared transmittance of the glass.With the increase of CsI content,the short-wave cut-off wavelength of Ge₂₀Sb₁₀Se₆₅Te₅-CsI glass shifts to the short-wave direction,that is,a blue shift occurs moving.With the increase of CsCl content,the short-wave cut-off wavelength of Ge₂₀Sb₁₀Se₆₅Te₅-CsCl glass,moves to the short wave direction first,then to the long wave direction,that is,the first blue shift and then red shift.（3）Adding CsI and CsCl to Ge₂₀Sb₁₀Se₆₅Te₅ glass,the kinetic ideal glass transition temperature of the glass decreases,and the crystallization activation energy of most glass components increases.Adding CsI,except for the 98Ge₂₀Sb₁₀Se₆₅Te₅-2CsI glass,the glass transition activation energies of the other glass components are reduced to different degrees.After adding CsCl,except for the 98Ge₂₀Sb₁₀Se₆₅Te₅-2CsCl glass,the glass transition activation energies of the other glass components are all different degrees of increase.With the increase of CsI and CsCl contents,the average linear expansion coefficientαof Ge₂₀Sb₁₀Se₆₅Te₅-CsI/CsCl glass increases to different degrees.（4）With the increase of heat treatment temperature and time,the infrared transmittance of96Ge₂₀Sb₁₀Se₆₅Te₅-4CsI glass decreased.Among them,the infrared transmittance of the samples at 280°C/20 h,290°C/70 h,310°C/20 h and 310°C/40 h still remained above 50%.For samples at 300°C/70 h,310°C/70 h,320°C/20 h and 320°C/40 h,the transmittance at wavelengths of2.5 to 4μm is almost 0,and the maximum transmittance at wavelengths of 11 to 15μm is about30%.After being kept at 310℃for 40 h,the micro-Vickers hardness and fracture toughness of the sample are 160.56 kgf·mm^-2 and 0.82 kgf·mm^-1/2,respectively,and the brittleness is 195.01mm^1/2.Compared with the samples without heat treatment,the micro-Vickers hardness is increased by about 19%,and the fracture toughness is increased by about 78%.It is the best heat treatment process for preparing 96Ge₂₀Sb₁₀Se₆₅Te₅-4CsI glass-ceramics.