Purpose

This paper aims to investigate the mechanism of Ni particles distribution in the liquid Sn3.5Ag melt under the external static magnetic field. The control steps of Ni particles and the Sn3.5Ag melt metallurgical process were studied. After aging, the microhardness of pure Sn3.5Ag, Sn3.5Ag containing randomly distributed Ni particles and Sn3.5Ag containing columnar Ni particles were compared.

Design/methodology/approach

Place the sample in a crucible for heating. After the sample melts, place a magnet directly above and below the sample to provide a magnetic field. Sn3.5Ag with the different morphological distribution of Ni particles was obtained by holding for different times under different magnetic field intensities. Finally, pure Sn3.5Ag, Sn3.5Ag with random distributed Ni particles and Sn3.5Ag with columnar Ni particles were aged and their microhardness was tested after aging.

Findings

The experimental results show that with the increase of magnetic field strength, the time for Ni particle distribution in Sn3.5Ag melt to reach equilibrium is shortened. After aging, the microhardness of Sn3.5Ag containing columnar nickel particles is higher than that of pure Sn3.5Ag and Sn3.5Ag containing randomly distributed nickel particles. A chemical reaction is the control step in the metallurgical process of nickel particles and molten Sn3.5Ag.

Originality/value

Under the action of the magnetic field, Ni particles in Sn3.5Ag melt will be arranged into columns. With the increase of magnetic field strength, the shorter the time for Ni particles in Sn3.5Ag melt to arrange in a column. With the extension of the service time of the solder joint, if Sn3.5Ag with columnar nickel particles is used as the solder joint material, its microhardness is better than Sn3.5Ag with arbitrarily distributed nickel particles and pure Sn3.5Ag.

中文翻译：

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外静磁场对磁性镍颗粒Sn3.5Ag焊料颗粒分布、冶金过程和显微硬度的影响

目的

本文旨在研究外静磁场作用下液态Sn3.5Ag熔体中Ni颗粒分布的机理。研究了Ni颗粒的控制步骤和Sn3.5Ag熔体冶金工艺。时效后，比较纯Sn3.5Ag、含有随机分布的Ni颗粒的Sn3.5Ag和含有柱状Ni颗粒的Sn3.5Ag的显微硬度。

设计/方法/方法

将样品放在坩埚中加热。样品熔化后，在样品正上方和正下方放置一块磁铁以提供磁场。通过在不同磁场强度下保持不同时间，得到具有不同形态分布的Ni颗粒的Sn3.5Ag。最后对纯Sn3.5Ag、随机分布的Ni颗粒Sn3.5Ag和带有柱状Ni颗粒的Sn3.5Ag进行时效处理，并测试其时效后的显微硬度。

发现

实验结果表明，随着磁场强度的增加，Ni颗粒在Sn3.5Ag熔体中分布达到平衡的时间缩短。时效后，含有柱状镍颗粒的Sn3.5Ag的显微硬度高于纯Sn3.5Ag和含有随机分布的镍颗粒的Sn3.5Ag。化学反应是镍颗粒和熔融 Sn3.5Ag 冶金过程中的控制步骤。

原创性/价值

在磁场的作用下，Sn3.5Ag熔体中的Ni颗粒会排列成柱状。随着磁场强度的增加，Sn3.5Ag熔体中Ni颗粒排成柱状的时间越短。随着焊点使用时间的延长，如果采用带有柱状镍颗粒的Sn3.5Ag作为焊点材料，其显微硬度优于任意分布的镍颗粒Sn3.5Ag和纯Sn3.5Ag。