Preparation And Luminescent Properties Of M:MgAl₂O₄?M=Mn,Cr? Ultrafine Powders

In 1995,Ikesue et al.Firstly obtained Nd:YAG transparent ceramic laser materials,and the research of transparent polycrystalline ceramics instead of single crystals as laser materials has attracted wide attention.At present,there are few reports on the study of transparent polycrystalline ceramics.Hanamura has studied the Mg Al₂O₄ single crystal doped with Mn and found that it can be used as visible light band laser material.Therefore,the preparation of high quality Mg Al₂O₄ spinel ultrafine powder,and transition metal doping on the luminescent properties,research is particularly important to provide high-quality raw materials for the subsequent sintering powder of polycrystalline Mg Al₂O₄ ceramic laser material.In this paper,the precursor of pure spinel Mg Al₂O₄ ultrafine powder was synthesized by chemical co-precipitation method,and the effect of the addition of modifier and the use of different drying methods on the powder was studied.In the end,the precursor was prepared by precipitation azeotropic distillation method and adding modifier at the same time,and then the high quality pure spinel Mg Al₂O₄ ultrafine powder was successfully prepared by grinding and 1150 degrees celsius.The Mn²⁺/Cr³⁺ single doped Mn²⁺ and Cr³⁺ double doped spinel Mg Al₂O₄ ultrafine powders were synthesized by the process,and the luminescent properties of the powders were studied.The main conclusions are as follows:?1?Mn²⁺ doped Mg_1-x Al₂O₄:x Mn²⁺?x = 1% 15%?superfine powder in green emitting light when the excitation wavelength was 450 nm 520 nm,fluorescence quenching concentration as high as 10%,which is the best luminescence of Mg0.9Al₂O₄:0.1Mn²⁺ powder.?2?Cr³⁺ doped Mg Al_2?1-y?O₄:y Cr³⁺?y = 0.1% 1%?ultrafine powder in the excitation wavelength of red emitting light obtained by 694 nm 425 nm and 545 nm,the fluorescence quenching concentration as high as 0.5%,which is the best luminescence of Mg Al1.99O4:0.005Cr³⁺ powder.?3?Mn²⁺,Cr³⁺double doped Mg_0.9Al_2?1-y?O₄:0.1Mn²⁺,y Cr³⁺?y = 0.1% 0.7%?at the excitation wavelength of 450 nm 525 nm 694 nm in green and red,red emission peak of 694 nm by 425 nm,450 nm and 525 nm stimulate.Compared with the luminous intensity of the powder in Mn²⁺/Cr³⁺doped enhanced green Cr³⁺doping concentration reached 0.5% on the fluorescence quenching of red light intensity increased with the increase of doping concentration,concentration quenching effect does not appear.That is,Mg0.9Al1.99O4:0.1Mn²⁺,0.005Cr³⁺ powder luminous intensityis best.?4?the energy transfer between Mn²⁺ and Cr³⁺ exists in the mutual absorption of radiation,Mn²⁺and Cr³⁺in the samples of Mgx Al_2?1-y?O₄:x Mn²⁺,y Cr³⁺ interact with each other as excitation centers and sensitization centers.