论文部分内容阅读
研究了纳米γ-Al2O3粉末对氧化铝纤维烧结行为的影响. 在纤维挤压成型过程中，纳米粉体填入到微米颗粒形成的孔隙中，当加入量为40wt%时，纤维素坯相对密度由65%提高到80%. 由于成型密度高、气孔分布窄、孔径小而有利于烧结，在较低的烧结温度下可以达到理论密度. 全部采用纳米γ-Al2O3粉挤压的纤维烧结后具有较大的径向收缩率，在1200°C烧结即可达到完全致密.“,”The effect of adding nanocrystalline γ-Al2O3 powders on the sintering behavior of alumina fibers was investigated. The nanocrystalline powders will be stuffed into the pores formed from the packing of micron-sized alumina powders when the fiber is extruded. In the case of 40% nanocrystalline γ-Al2O3 in the mixed powders, the relative green density increases from 65% to 80%. The fiber can be sintered to near theoretical density at relatively low temperature because it is of higher density, narrower pore size distribution and smaller mean pore size. The diametric shrinkage of the fibers extruded from the nanocrystelline γ-Al2O3 is higher than that made from micron-sized powders. γ-Al2O3 phase is transformed to α-Al2O3 during sintering process.