Study On Fabrication And Properties Of Cerium-Doped Lutetium Aluminum Garnet Films And Lutetium Oxyorthosilicate/Lutetium Pyroilicate Ceramics

Due to excellent optical properties,high density and rapid attenuation,cerium-doped yttrium aluminum garnet has good application prospects in the fields of medical imaging,high-energy physics,laser illumination,laser display,etc.cerium-doped yttrium silicate single crystal has been applied on a large scale in nuclear medicine PET-CT.As the core material of PET-CT,it accounts for 30%of the cost of PET-CT(single PET-CT is priced at 20 million RMB,and average inspection fee per person is 8,000-10,000 yuan).This paper is devoted to the preparation of yttrium-doped aluminum garnet film and lutetium oxyorthosilicate/lutetium pyroilicate ceramics,and their properties are studied.Cerium-doped aluminum garnet(Lu3Al5O12:Ce,LuAG:Ce)films were prepared on a sapphire(Al2O3)substrate by using sol and nitrate solution as precursor solution by ultrasonic spray pyrolysis and immersion coating process.The effects of annealing temperature,annealing atmosphere,Ce3+ doping amount on the phase and optical properties of the films were investigated.The SiO2@Lu(OH)CO3 core-shell structure powders were deposited on the surface of SiO2 microspheres by urea uniform precipitation process.After calcination,spherical strontium silicate(LSO)or strontium silicate(LPS)powders were obtained.LSO/LPS ceramics were prepared by spark plasma sintering(SPS).The effects of Lu/Si ratio,calcination temperature,etc.on the properties of powders and ceramics were investigated.The main conclusions of this paper are as follows:(1)LuAG:Ce films were prepared on sapphire substrate by ultrasonic spray pyrolysis process with Lu3+ and Ce3+sol as precursor solution.With the increase of annealing temperature,the grain size increased and the luminescence intensity increased.After annealing at 1500℃,the films consist of LuAG phase.No impurity phase was found by X-ray diffraction,and the grain size were 300～800nm.The luminescence intensity of the films after annealing in the carbon atmosphere were 1.58 times that of the annealed films of the air atmosphere.The precursor solution was composed of nitrates containing Lu3+,Al3+ and Ce3+n(Lu+Ce):n(Al)=3:5,and the LuAG:Ce films were doped at a high concentration,and the Ce3+doping amount was 3.0 mol.%,the luminous intensity was 1.5 times that of 0.5 mol.%of the films.(2)LuAG:Ce films were prepared on a sapphire substrate by sol-impregnation pulling process.When the number of layers was 8 layers,the LuAG:Ce films had a grain size of 300～800 nm.The luminescence intensity was 2.6 times that of the 2-layer films.The transmittance at 515 nm can be up to 94%.(3)The SiO2@Lu(OH)CO3 spherical powders with core-shell structure were successfully prepared by urea uniform precipitation process.As the RLu/si ratio increases,the particle size increases and the dispersibility decreases.After calcination at 1200℃,the RLu/Si=1.00 sample consists of LSO phase,which remains substantially spherical in shape.After the powders were sintered by spark plasma,the relative densities of the yttrium silicate and the yttrium silicate ceramics were as high as 99.8%(RLu/Si=2.00)and 99.3%(RLu/Si=1.00)respectively.