Study On Preparation And Sintering Process Of Nd³⁺doped Sr₅?PO₄?₃F Nanoparticles

Rare-earth doped high transparency polycrystalline ceramics have recently emerged as promising candidates for next generation laser gain media in modern applied laser physics and optics.Current research in the field of laser ceramics focuses on cubic polycrystalline materials(e.g.,Y₃Al₅O₁₂,Y₂O₃,Lu₂O₃,CaF₂),This is mainly due to the crystal structure restrict the development of low symmetry system materials.However,considering the luminescence center,When the rare earth luminescent ions are in the high symmetry environment in the cubic system,the electric dipole transition is forbidden.The field environment will reduce the intensity and efficiency of the luminescence.Therefore,the low symmetry system has more potential for development and will be the focus of future research.The rare-earth doped fluorapatite materials(M₅?PO₄?₃F,M=Ca or Sr,space group P⁶_3/m)have attracted considerable attention recently due to its large absorption,stimulated emission cross-section and long fluorescence lifetime.The development of solid-state laser materials is ultimately used as a nuclear fusion ignition material,the Livermore National Laboratory?LLNL?has used fluorapatite as one of the candidates for nuclear fusion.Therefore,it is particularly important to study it.In this paper,The Nd:Sr₅?PO₄?₃F nanoparticles were synthesized by co-precipitation method and the sintering process was explored.The main research contents are as follows:1.The Sr₅?PO₄?₃F nanoparticles were synthesized by a chemical co-precipitation method,and the effects of mixing modes and reaction temperature on the particle's morphology were investigated by XRD,FT-IR,SEM and TEM.The results revealed that the particle's morphology tended to transform from nanorods to nearly spherical particles when the mixing modes changed from droplet mixing to quick mixing.In addition,with the increase of temperature,the particles have a tendency to grow into rods in the fast mixing mode.2.The 5%Nd:Sr₅?PO₄?₃F nanoparticles were synthesized by co-precipitation method,the reaction concentration is 0.03mol/L,and the effects of mixing modes on the particle's morphology and optical properties were investigated.The results revealed that the powders prepared in different mixing modes are not only different in the morphology,but also in the light intensity.The luminescence performance in the fast mixing mode is stronger than the droplet mode.3.The 3%Nd:Sr₅?PO₄?₃F transparent ceramics were prepared by spark plasma sintering using the powders prepared by rapid mixing as raw material with the reaction concentration is 0.03 mol/L.The effects of sintering temperature and heating rate on ceramics were investigated.The results show that when the sintering temperature is 950?,and the heating rate is 50?/min,The ceramics have clear signs of transparency,indicating that the synthetic raw materials can be transparent by spark plasma sintering.With hot pressing sintering as contrast sintering,a number of micron grade rod appear in the ceramic section when the sintering temperature is950?,indicating that the particles also tend to be rod in the process of sintering,and the phenomenon of the micron rod is related to pressure.