| Summary: | 碩士 === 國立臺北科技大學 === 材料及資源工程系所 === 94 === To semitransparent ceramics, grain size, pore and second phases make great influence to reflection and scattering behavior of the light. It is a very important subject to control grain size, improve the sintered bulk density, reduce the porosity and suppress the second phase for producing a semitransparent ceramics.
In this study, small amount of Nb2O5 was added to Al2O3 using solid-state method. The effects of Nb element addition and different preceding treatment conditions on the densification and microstructure evolution of α phase Al2O3 powders were studied. Three type of powders APD-100-A, B and C were used as raw materials. The results show 0.4mol% Nb2O5 is helpful for APD-100-B and C powder to obtain fine density sintered at 1350℃ for 2h. The relative density ( ) is 97.1% and 98.2% respectively. And APD-100-C powder can obtain 99.9% of relative density at 1650℃ for 2h. Moreover, Nb additive enhanced the grain growth and reduced the grain bounding and the scattering of the light, and therefore improved the material transparency.
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