The Synthesis And Properties Of Gadolinium Aluminate Phosphors And Transparent Ceramics

In rare earth aluminate system,lanthanum aluminate series has excellent optical properties,mechanical properties and stable physical and chemical properties,which has a very wide range of applications in the field of optical materials.As a kind of lanthanum alumnate series,GdAlO3 can improve the high-temperature mechanical properties of alumina effectively by compositing with alumina,in addition to being used as a functional material matrix.The luminescent material with rare earth aluminate as the based has high luminous efficiency and good chemical stability characteristics,and it has been brought to the attention of people.Matrix material GAP was mixed with different ions Tb3+,Eu3+ to synthesis aluminate phosphor powders.The samples synthesized at 1200? have full of pure GAP phase.The luminous intensity of GdAlO3:xTb is strengthened and then weakened with the increase of Tb3+ ion incorporation and the sample which has the maximum luminous intensity was doped with Tb3+ ions with amount of 0.1 mol.The luminous intensity of GdAlO3:xEu is strengthened with the increase of Eu3+ ion incorporation,which shows that suitable amount Eu3+ can improve the crystallization of the sample.In this paper GAP powders are prepared by molten salt method,and the influence of reaction temperature,phase composition of raw materials on the microstructure and morphology of GAP is all studied.The GAP powders are also prepared by two-step molten salt synthesis.The research shows that the molten salt synthesis can reduce the reaction temperature significantly compared with solid state method.The GAP has been generated at 900?,and the pure GAP phase is generated at 1200?.The phase composition of raw materials has little influence on the phase and morphology of the GAP.The GAM crystal with orientation can be prepared by molten salt method,and the sample orientation degree is increased with the increase of temperature.Homogeneous rod GAM crystal with anisotropy can be obtained after insulation 1200? for 8h.The GAP with plate-like structure can be prepared with GAM and A1203 by two-step molten salt synthesis.We use the hot-pressing sintering to get GAP transparent ceramics in the experiment.The results show that,the density of Ceramics increases rapidly in the range of 1200?-1250?and when it comes to 1250? ceramics begin sintering.we got a relative density up to 96.4%after insulation 1400? for 30 min.In the two-step hot-pressing sintering for preparing GAP ceramics,the IR transmittance of the sample which using powders prepared by molten salt method can arrives to the highest of 56%,and the IR transmission even can reach 56.3%after that decarbonizing in 1300? which is the best condition.