Effects of Zn addition on mechanical properties of eutectic Sn-58Bi solder during liquid-state aging

Interfacial reaction, tensile strength and creep resistance of Sn-58Bi-x Zn(x=0, 0.7, mass fraction, %) solder samples during liquid-state aging were investigated. The coarsening of Bi and the growth of Cu-Sn intermetallic compounds(IMCs) in Sn-58Bi-0.7Zn solder sample were both effectively suppressed. With the addition of 0.7% Zn, ultimate tensile strengths(UTSs) of the Sn-58 Bi solder slabs were respectively increased by 6.05% and 5.50% after reflow soldering and liquid-state aging, and those of the Cu/Sn-58Bi/Cu solder joints were also increased by 21.51% and 29.27%, respectively. The increase in strengthening effect of Cu/Sn-58Bi-x Zn/Cu solder joints could be attributed to the fracture surface which was changed from the Cu/IMC interface to the IMC/solder interface due to the finer Bi grain. Nanoindentation results revealed that the creep behavior of Sn-58Bi-0.7Zn solder was significantly improved compared with that of the eutectic Sn-58 Bi solder after reflow soldering and liquid-state aging.

均匀颗粒成形中金属射流断裂因素的研究

利用自行搭建的均匀颗粒成形设备(UniformDropletSpray–UDS)对Sn-37%Pb金属射流在外加扰动,外加电场,环境氧浓度3个因素影响下的断裂方式进行了初步研究。实验结果表明:外加扰动控制金属射流断裂的形态和均匀度;外加电场给金属液滴加载电荷,通过库仑排斥作用避免了射流断裂后形成的液滴间的相互凝聚现象;环境氧浓度通过影响金属射流的表面张力和氧化层生长速度控制金属射流的断裂。

基于SPR和干涉模式复合增强窄带钙钛矿光电探测器

制备了一种基于银岛膜表面等离激元共振的窄带钙钛矿光电探测器,通过钙钛矿与银岛膜之间的薄膜干涉实现了窄带增强。利用前驱液温度调控晶粒尺寸,通过钙钛矿厚度调控光传播路径,增强了窄带响应,实现了中心波长为490 nm、峰值半峰全宽为110 nm的窄带光探测,其上升和下降时间分别为247 ms和266 ms,响应光电流为0.151μA,外量子效率为159%,响应度为0.6 A·W^(-1),归一化探测率为2.73×10^(13)cm·Hz^(1/2)·W^(-1)。