Preparation Of La₂O₃-Al₂O₃ Based Glass By Aerodynamic Levitation Method And Its Crystallization Performance

Aluminate glasses attract people's attention because of its outstanding mechanical and optical properties.La₂O₃-Al₂O₃ system of high melting point glass has the advantages of high refractive index,high thermal stability and high hardness.It is very important to simplify the optical system,reduce the system volume and weight and improve the system precision.Since such glasses on the equipment requirements are higher,it is necessary to greatly reduce the rate of instantaneous to form a glass,which is difficult to prepare by conventional methods.At present,this glass is still in the initial stage of research and development.Therefore,there are not many reports at home and abroad.But have been recognized that the potential advantages of such glasses and many scholars have begun their research.However,these studies have focused on the formation of glass and the simple optical properties and thermal properties,its structure,crystallization and rare earth doped luminescence and other aspects of the lack of adequate research.In this experiment,basic La2O3-Al2O3 glass was prepared by aerodynamic levitation method.A series of mechanical,optical and thermal properties were studied,and the glass structure and precipitation crystals were tested and analyzed.In addition,La₂O₃-Al₂O₃ glass excellent performance in the rare earth on the conversion of light also has great application prospects,which we have done a detailed study.The main results and conclusions of this experiment are as follows:?1?The xLa₂O₃-?1-x?Al₂O₃ glass was successfully prepared by aerodynamic levitation method,and the formation interval of this glass was 28%?x?55%.The samples have good high temperature resistance in the glass forming area.Its density and refractive index increased with the increase of La₂O₃,and with the sample ratio has a good consistency.The hardness of the glass for the system is increased first and then decreased,which is likely to be related to the properties of the glass.?2?Al³⁺mainly exists in the form of[AlO₄]^-and forms the main body of the glass network.With the increase of the La2O3,the network structure of the glass gradually depolymerized,[AlO₄]^-decreased[AlO₆]^3-.And La³⁺in the glass as a form of network changes exists.In addition,it also has an important role that is to provide[AlO₄]^-and[AlO₆]^3-balanced charge.?3?The results show that La₂O₃-Al₂O₃ glass has excellent up-conversion luminescence properties,and its luminous efficiency is very high and the power of La₂O₃-Al₂O₃ is higher than that of La₂O₃-Al₂O₃?-SiO₂?on the Er³⁺/Yb³⁺.Change the light color stability is better.The photon number and fluorescence lifetime analysis show that the multi-phonon non-radiological transition of La₂O₃-Al₂O₃ glass is much less than that of SiO₂ containing samples,so its red and green light ratio changes little with the power change.?4?La₂O₃-Al₂O₃ and La₂O₃-Al₂O₃-CaO system will precipitate LaAlO₃ after heat treatment,and La₂O₃-Al₂O₃-CaO system will precipitate CaLaAl₃O₇ crystal phase when the heat treatment temperature is high.Fluorescence analysis revealed that Eu³⁺enters the crystal.The ratio I₁/I₂ corresponding to the luminous intensity of ⁵D₀?⁷F₁and ⁵D₀?⁷F₂ increases with increasing temperature and time,indicating an increase in the amount of crystallization,which also corresponds to the XRD pattern.According to the TEM spectrum,it can be seen that the crystallization of the sample after the heat treatment is more dispersed,and the interplanar spacing is measured to show that the addition of Eu³⁺does not change the crystal structure.