Yang Wenchao, Qin Weiou, Wu Jingwu, Feng Junli, Zhan Yongzhong
School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China.
State Key Laboratory of Featured Metal Materials and Life-Cycle Safety for Composite Structures, Nanning 530004, China.
Materials (Basel). 2023 Feb 13;16(4):1550. doi: 10.3390/ma16041550.
The application of Sn-Bi series solder is limited due to the brittleness of Bi phase. Sn-20Bi solder with less Bi element content has great research prospects, but it needs modification to make it a substitute for traditional Sn-Pb solder. In this article, we mixed graphene nanosheets with nanometer Sn powder by means of ultrasonic oscillation, and Sn-20Bi-GNS ( = 0.01, 0.02, 0.04, 0.06, and 0.1 wt.%) solder alloys were prepared by the melt-casting method. The effects of graphene nanosheets (GNSs) on the microstructure, physical properties, mechanical properties, and corrosion resistance of solder alloys were investigated. Scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were used to determine the microstructural morphology and composition. The results showed that the melting point, density, and wettability of the solder decreased slightly with the addition of GNSs. The addition of GNSs as a second phase refined the solder structure and improved the tensile strength of the molten Sn-20Bi composite solder to 99.6 MPa, while elongation decreased with the addition of GNSs. Furthermore, GNSs prevented the MC Sn-20Bi-GNSs/Cu intermetallic compound layers' growth by interfering with atomic diffusion and grain boundary movement. In addition, the addition of 0.02 wt.% GNSs enhanced the shear strength of MC Sn-20Bi solder joints to 46.3 MPa. The electrochemical experimental results show that the surface corrosion products of MC Sn-20Bi-GNSs under 3.5% NaCl solution were SnO(OH)Cl, with MC Sn-20Bi-0.01GNSs exhibiting the best corrosion resistance.
由于铋相的脆性，Sn-Bi系焊料的应用受到限制。铋元素含量较低的Sn-20Bi焊料具有很大的研究前景，但需要对其进行改性，使其成为传统Sn-Pb焊料的替代品。在本文中，我们通过超声振荡将石墨烯纳米片与纳米锡粉混合，并采用熔铸法制备了Sn-20Bi-GNS（=0.01、0.02、0.04、0.06和0.1 wt.%）焊料合金。研究了石墨烯纳米片（GNSs）对焊料合金微观结构、物理性能、力学性能和耐腐蚀性的影响。利用扫描电子显微镜、能谱、X射线衍射和X射线光电子能谱来确定微观结构形态和成分。结果表明，随着GNSs的加入，焊料的熔点、密度和润湿性略有下降。作为第二相的GNSs的加入细化了焊料结构，将熔融态Sn-20Bi复合焊料的拉伸强度提高到99.6 MPa，而伸长率则随着GNSs的加入而降低。此外，GNSs通过干扰原子扩散和晶界移动来阻止MC Sn-20Bi-GNSs/Cu金属间化合物层的生长。另外，加入0.02 wt.%的GNSs将MC Sn-20Bi焊点的剪切强度提高到46.3 MPa。电化学实验结果表明，MC Sn-20Bi-GNSs在3.5% NaCl溶液中的表面腐蚀产物为SnO(OH)Cl，其中MC Sn-20Bi-0.01GNSs具有最佳的耐腐蚀性。
