Structural and Optical Properties of Ti4+ Doped Sintered ZnAl2O4 Ceramics
The sintering characteristics, phase composition, microstructure and optical properties of 1:1 ZnAl2O4 spinel doped with Ti4+ from 1.125 to 4.5 mole-% synthesized through coprecipitation were investigated in this study. Effective densification was achieved at a low sintering temperature, 1350°C after 1 h. Powder XRD patterns revealed that, besides ZnAl2O4 spinel and rutile as major crystalline phases, minor Zn2Ti3O8 phase was present in the sintered system, with its extent depending on the TiO2 content and sintering temperature. SEM micrographs demonstrated a coherent and uniformly distributed fine-grained microstructure in the fracture surfaces of the sintered Ti4+ doped ZnAl2O4 spinel ceramics body.
The Tauc plot of Ti4+ doped ZnAl2O4 spinel exhibited a leftward shift of the band gap from 3.79 to 3.48 eV with increase of Ti4+ content from 0 to 4.5 mole-%. Ti4+ was observed to function as a normal grain growth accelerator during ZnAl2O4 sintering. This was probably due to enhanced grain boundary diffusion.
KeywordsZnAl2O4 based ceramics Ti4+ doping sintering optical properties Tauc band gap
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