| Transparent yttria(Y2O3) ceramic has a wide range of applications as functional and structural material. In addition to use as excellent high-temperate infrared material and electronic material, it is often used as reaction vessel and refractory because of its corrosion resistance and high temperature stability. With the addition of Nd, yttria ceramic can also be used as laser host material. Therefore, the preparation of high-performance Y2O3 ceramic has important theoretical and applied value.In this paper, ultra-fine yttria powder with 100nm is used as raw material. The effects of rheological behavior of slurry on the green body and sintering densification of yttria are studied systematically. The effects of different types of dispersants(NaPAA and NH4PAA), different amount(mass percentage) and different solid content on the slurry properties are studied. After slip casting and drying, the green body are sintered by presintering at 1400℃and at 1700℃in vacuum. Then the effects of shrinkage, relative density and porosity on the light transmittance of Y2O3 ceramic are also analyzed.The results show that NaPAA and NH4PAA can both be used as effective dispersant for ultra-fine yttria. With the content of dispersant increasing, viscosity of slurry decreased significantly.NaPAA is used as dispersant, the pH value of slurry is around 11, the solid content of ultra-fine yttria slurry can reach to 45wt% when the content of NaPAA is 1.0wt%. Then the slurry shows good stability and rheological behavior. The relative density of sintered body is up to 99.36%, and the pore in sample is less. The light transmittance is best which more than 30% when the wavelength in the 800nm.NH4PAA is used as dispersant, the pH value of slurry is around 11, the content of dispersant is 3.9wt%, the solid content of ultra-fine yttria slurry can also reach to 45wt%. Meanwhile the rheological behavior of slurry keeps good. The relative density of sample with 3.6wt% NH4PAA can achieve to 98.74% after sintering.In this experiment, the slip casting methods and sintering of ultra-fine powder Y2O3 are explored preliminarily, to lay a foundation for further study on the high-density and high transparency of Y2O3 ceramic. At the same time, it also provides a reference for the slip casting of other ultra-fine ceramic powders. |
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