Effects of pore structure in green compact on the microstructure of sintered electronic ceramics

1.研究了氧化铝压坯的孔结构和烧结行为。绿色压坯通过具有不同pH值的悬浮液的注浆成型制成。悬浮液中团聚体尺寸的增加增加了绿色压坯中的孔体积和尺寸，并降低了致密化速率。微观结构的发展是几乎相同的，无论孔隙体积和大小的绿色压坯。将单分散聚合物颗粒加入氧化铝粉末中并烧结，以研究大孔的致密化行为。直径小于1米的孔隙以相当大的速度收缩，其形状从球形变为透镜状。直径大于2 m的孔隙<micr>收缩缓慢，形状保持不变。在该实验中使用的氧化铝粉末的临界孔径为约1 <micr>m3。研究了针状镍锌铁氧体和氧化铁压制和挤压后的烧结行为。观察到各向异性收缩。针状颗粒改变等轴的加热后，但各向异性的孔结构保持，直到烧结的中间阶段。在烧结的最后阶段，观察到氧化铁的晶粒取向。

1. Pore structure and sintering behavior of alumina compacts were examined. The green compacts were made by slipcasting of suspensions with different pH. An increase in agglomerate size in the suspension increased pore volume and size in the green compact and reduced densification rate. The microstructure development was almost the same, irrespective of pore volume and size of the green compact.2. Monodispersed polymer particles were added to alumina powder and sintered to examine densification behavior of large pores. Pores less than 1 m in diameter shrank with a considerable rate and their shape changed from spherical to lenticular. Pores more than 2 <micr>m in diameter shrank slowly and their shape was maintained. The critical pore size for the alumina powder used in this experiment was about 1 <micr>m.3. Sintering behavior of pressed and extruded acicular NiZn-ferrite and iron oxide was examined. Anisotropic shrinkage was observed. Acicular particles changed to equiaxed ones upon heating but anisotropic pore structure was maintained until the intermediate stage of sintering. Grain orientation was observed for iron oxide during the final stage of sintering.