氧化铝粉料的颗粒级配对成型行为和烧结行为的影响

Effect of Bimodal Particle Size Distribution on Compaction Efficiency and Sintering Behavior of Alumina Powders

研究了颗粒级配对超细氧化铝粉体成型行为和烧结行为的影响．发现两种颗粒直径之比约为2的氧化铝粉体，一定比例混合后可获得比同样条件下单独的粉体高得多的成型密度.在细颗粒体积百分数约为33％时，应用压滤成型工艺（45MPa）获得的素坯相对密度高达72％．研究了压滤和干压成型方法对成型素坯密度及其烧结的影响．压滤成型的素坯，由于成型密度高、气孔分布窄、孔径小而有利于烧结，在较低的温度下可以达到理论密度，烧结体晶粒细小均匀，无明显缺陷；这一条件下于压成型（300MPa）得到的素坯由于有较宽的气孔尺寸分布，影响烧结，并且烧结体中有较大的气孔，不能完全致密．应用新的烧结理论对此进行了解释．

The effcct of bimodal partiele size distribution on the compact cfficiency and sintering behavior ofsubmicron-sized alumina powder was investigated For two types of submicroll alumina powders with sizeratio of about 2, collsidcrably lligller compact densitics, as compared to their individuaJs, were obtainedwhen mixed in proper volumc ratios. In the casc of 33% fine particls in the mixed powder, the relativegreen density of abovc 72% was achieved by pressure filtration. Different consolidation techniqucs, namelypressure filtration.and drying press, were found to yield compacts with different properties. Green compactsby pressure filtration, which had highcr density, narrower pore size distribution and smaller mean poresize than those by dry-pressing, can be sintered to theorctical density with fine microstructure at relativelylow temperature. The sintering behavior and the microstructure developed for the compacts by differentcompaction techniques were discussed with newly developed theory of sintering thermodynamics