超细银粉的聚集状态与银膜微观结构演化的关系

Agglomeration State of Superfine Silver Powder with Their Sintering Film Evolution Microstructure

通过对三种不同聚集状态的银粉及烧结后对应微观结构变化分析,说明在无压自然堆积情况下,银粉聚集状态对微观结构及收缩程度有更大的影响。通过颗粒接触堆积状态对烧结微观的演化过程分析,得到造成烧结微观结构差异的根本原因在于固相烧结扩散路径的长短及颗粒接触数,进而影响到形成的孔洞能否驱除,而影响银膜的致密度。因此,要获得致密烧结膜,在考虑银粉平均粒度的同时,应将堆积密度作为一个更重要的参数。

The relation of metal powder agglomeration state with sintered body structure is investigated by analyzing the original and sintered microstructures of three kinds of different agglomerate silver powder. The results show that there is some effect of the particle diameter on the pressure for neck connection formation among the particles in the sintering process, but the agglomerate situation of the silver powder has more important influence on the sintering microstructure and the contraction extent at the initial sintering stage without pressure. The analysis of the sintering evolution indicates that the basic reason for difference in sintered microstructure of the silver powder is the length of diffusion path and the number of connected particles in solid sintering. It relates to the eliminate situation of the holes in sintered product and impacts on the film density. Therefore, besides the mean particle diameter of the silver powder, the bulk density of silver powder should be considered as the more important factor.