Study On The Luminescent Properties Of CMAS Glass-ceramic Doped With RE

This paper that is based on the requirements of the white light LED luminous performance is aimed to study the structure and properties of glass ceramics doped with RE. With turning the blast furnace slag into resources, we studied the structure,luminescence properties, luminescence mechanism and the relationship between them of the Ca O-Mg O-Al₂O₃-Si O₂ glass ceramics doped with Eu or Eu/Tm/Tb in air or reducing atmosphere.In the research, the simulated blast furnace slag was used to replace blast furnace slag in order to avoid the complexity of the blast furnace slag and to study the relationship between structure and luminescence properties easily.The transparent glass of Ca O-Mg O-Al₂O₃-Si O₂ was prepared by high temperature melt-water quenching method.The structure and luminescence properties of glass and blast furnace slag were studied by DSC and fluorescence spectrum. The result shows that the glass' s temperature of the crystal exothermic peak increases and the crystal exothermic peak becomes relative sharply with the increasing of the heating rate. The crystal index is 1. 54 that is less than 3.So the crystal form of the glass is the surface crystallization.In air atmosphere, the glass ceramics of Ca O-Mg O-Al₂O₃-Si O₂ doped with Eu³⁺can be excited by 365 nm effectively. The emission peak is at 592 nm, 618 nm, 650 nm and702nm, which is in red light region and belong to the energy level transition of Eu³⁺ 5D0?7FJ?J=1, 2, 3, 4?. When the concentration of Eu³⁺ is 1.25 percent and the crystal time is 12 hours, the intensity of luminescence achieves the maximum. The crystalline phase and the shape of emission peak in the sample doped with NH4F?Ba F₂ or Ca F₂ does not change,and all of the doped materials are beneficial to enhance the luminous intensity.In reducing atmosphere, the glass ceramics of Ca O-Mg O-Al₂O₃-Si O₂ doped with Eu2+ and Eu³⁺can be excited by 261 nm and 324 nm effectively. The emission peak is at400-600nm?Eu2+?and 592nm/618nm/50nm/702 nm, which is in green light region and red light region. The emission peaks that is in the green region and red light region belong to the energy level transition of Eu2+4f?5d and Eu³⁺ 5D0?7FJ?J=1, 2, 3, 4? respectively.When the concentration of Eu³⁺ is 1.25 percent and the crystal time is 12 hours, the luminous intensity achieves the maximum. The crystalline phase and the shape of emission peak in the sample doped with NH4 F, Ba F₂ or Ca F₂ does not change, and all of the doped materials are beneficial to enhance the luminous intensity of Eu2+and Eu³⁺.The white light glass ceramics of Ca O-Mg O-Al₂O₃-Si O₂ doped with 1.25 percent Eu³⁺, 0.25 percent Tm³⁺, and 1 percent Tb³⁺ were prepared in air atmosphere. The glassceramics can be excited by 242 nm. There are mainly blue emission peak, green emission peak and red emission peak. The white light glass ceramics doped with 1.25 percent Eu³⁺and different concentrations of Tb³⁺ were prepared in reducing atmosphere. The glass ceramics emit blue, green and red spectra excited by 242 nm and emit blue-green and red spectra excited by 380 nm. When the concentration of Eu₂O₃ is constant and the concentration of Tb³⁺increases from 1 percent to 1.25 percent, the emission peaks of Tb³⁺,Eu³⁺, and Eu2+ in the sample are enhanced to a certain extent.In summary, the luminescent glass ceramics of Ca O-Mg O-Al₂O₃-Si O₂ doped RE designed and prepared according to blast furnace slag are not only used in the illumination white LEDs, but also provide a new way for the high value utilization of blast furnace slag.