纳米TiO2颗粒对SnAgCu钎料组织与性能的影响

研究了纳米TiO2颗粒对SnAgCu钎料组织和性能的影响.结果表明:微量的纳米TiO2颗粒可以增加SnAgCu钎料的润湿铺展面积,显著提高SnAgCu焊点的拉伸力和剪切力.添加过量时焊点的力学性能会有一定程度的下降.经过优化分析发现,纳米TiO2颗粒的最佳添加量为0.1％(质量分数,下同).SnAgCu-0.1TiO2相对SnAgCu钎料基体组织得到明显的细化,树枝晶的间距下降62.5％.经过热循环测试,发现0.1％TiO2可以显著提高SnAgCu焊点的抗热疲劳特性.主要归因于纳米颗粒对位错的钉扎作用,因而阻止了裂纹在钎料基体内部的扩展.

Effect of Nano-particles TiO2 on the Microstructures and Properties of SnAgCu Solders

The effect of nano-particles TiO2 on the microstructures and properties of SnAgCu solders was investigated. The results indicate that adding a small amount of nano-particles TiO2 can improve the wettability of SnAgCu solders, and the mechanical properties of solder joints can be enhanced significantly; however, excessive nano-particles would reduce the properties. It can be found that the optimum content of nano-particles is 0.1 wt% for SnAgCu solders, when the matrix microstructure of solders may be refined obviously, and the dendrite-arm spacing of SnAgCu solders is decreased by 62.5% after soldering. Moreover, during thermal cycling tests, the SnAgCu solder joints show superior thermal fatigue resistance with the addition of 0.1wt% TiO2 because the particles restrict the movement of dislocations, thus hindering the propagation of cracks in matrix microstructure.