国产黄铜引脚器件焊接可靠性问题分析研究

Analysis and Research on Soldering Reliability of Domestic Brass Pin Devices

针对基材为黄铜合金的2种不同镀层结构的引脚可焊性进行了对比研究。结果表明:黄铜镀金结构的引脚基材中,Zn元素极易扩散到引脚表面并发生氧化,进而导致润湿性不良现象,搪锡后表面不光亮,微观上呈现出表面焊锡凹凸不平,焊接后有焊点反润湿现象。而黄铜镀铜、镀镍和镀金结构的引脚能有效阻止基材中的Zn元素向最外镀层的扩散,润湿良好,表面光亮,去金完全。通过对搪锡前后镀层结构、界面化合物组成和引脚表面元素的种类及价态等方面进行分析对比,探究出了镀层结构对引脚表面润湿性的影响机理,提出了镀层结构优化途径,以解决润湿不良的问题,促进进口器件的国产化替代工作。

The solder abilities of brass pins with two different plating materials are compared and studied. The results show that the Zn element in the brass pins with single gold plating layer was very easy to diffuse to the pins surface and oxidized, which resulted in the poor solder wettability. The pins surface were not clean and bright after degolding and pre-tinning. The surface solder morphology was uneven in microscopy, and there is dewetting phenomena occurred after soldering. However, the Zn element diffusion could be prohibited effectively for the brass pins with Cu-Au plating or Cu-Ni-Au plating layers, and got the good wetting surface which was shining after de-golding perfectly. Comparison analysis on the plating layers configuration, the intermetallic compounds composition, and the surface elements sorts was performed before and after pre-tinning. Accordingly, the influence mechanisms of the plating configurations on the pins surface wettability were studied systemically. The poor solder wettability problem were solved through plating layers optimization, the domestic replacement of imported devices is improved.