无氧铜镀层对激光封焊裂纹的影响

Effect of finishes of oxygen-free copper on laser welding cracks

关键词:  激光焊接  裂纹  化学镀镍  电镀镍

Key words:  laser weld  cracks  electroless plating nickel  electroplating nickel

摘要:

采用300 W的Nd：YAG激光器系统分析了微波组件无氧铜壳体表面镀层对壳体激光封焊裂纹的影响.首先采用五因素四水平正交试验法并通过设置多脉冲波形优化焊接工艺参数，从而可获得成形美观、组织均匀的焊缝.分析发现，无氧铜表面镀层工艺的差异对焊缝质量有重要影响.化学镀镍时以单质形式存在的P元素极易汽化且可形成多种低熔点的化合物，焊接时焊缝会有裂纹产生；电镀镍时不含P元素，焊缝则没有裂纹出现.气密性检测显示，采用此参数激光封焊无氧铜微波组件的气密性小于5×10^-9 （Pa·m³/s），产品一次合格率在95%以上.

Abstract:

Utlilizing 300 W Nd:YAG laser with the wavelength of 1.06 μm for laser weld to study the effect of electroless plating and electroplating on the weldability of oxygen-free copper shell microwave module. Based on the orthogonal test of five factors and four levels as well as setting multiple-pulse waves to match laser weld technological parameters, the typical laser weld technological parameters are established. By using the above-mentioned typical parameters, a beautiful, homogeneous microstructural, and sealed weld seam can be obtained. It is studied that the difference of electroplating technology has great effect on the quality of weld seam. When electroless plating nickel, there exists P can vaporize easily and form multiple low-melting compounds, which increases the tendency of cracks during solidification. When electroplating nickel, there existis no any P, which can form well-shaped weld seam without cracks. The seal test shows that the air impermeability of oxygen-free copper microwave module is below 5×10^-9Pa·m³/s, the one-off qualified rate of product is above 95%.