Fabrication and Microstructure of Y3+∶CaF2 Transparent Ceramics
Y3+∶CaF2 powders were synthesized by chemical coprecipitation method,and transparent ceramics were fabricated by vacuum hot pressing sintering method.Characteristics of the as-synthesized powders were investigated by XRD,SEM and TEM techniques,the relationship between microstructure and transmittance of transparent ceramics were also analyzed.Crystal structures of as-synthesized Y3+∶CaF2 powders belong to single fluorite phase.With the Y3+doping content increases,the average particles sizes decrease and the lattice constants increase from 5.452 1 Å to 5.465 5 Å.The 5％Y3+∶CaF2 transparent ceramics sintered at 900 ℃ for 3 h exhibits the highest transmittance,and the transmittance at 500 and 1 500 nm are 73.1％and 86.4％,respectively.Microstructure of ceramics are modified by the Y3+doping content and sintering temperatures.For a low growth velocity,it is not easy to eliminate the residual pores,while for a higher growth velocity,residual pores are easily embedded within grains.Both cases will reduce the transmittance of transparent ceramics.This work provides a reference for the preparation of high-quality composite CaF2 transparent ceramics.
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