铜焊技术在阴极保护测试桩中的应用

在阴极保护测试桩施工中,测试电缆和钢管的连接直接影响阴极保护系统的运行测试。为了解决铝热焊容易造成虚接的问题,陕京二线管道工程引进了国外铜焊技术,该铜焊技术焊点牢固,不会产生虚接,焊点热影响区小,管道母材金相组织不会受到破坏。文章介绍了该铜焊工艺、操作注意事项以及常见问题与处理。     

镀银的铜引线与PCB焊盘平行微隙焊时的界面行为

研究了平行微隙焊过程中镀银的铜引线分别与PCB板上的裸铜焊盘及镀锡铜焊盘的接头特性.结果表明,对于Ag/Cu接头,接头的界面处两侧的Cu向中间的Ag处扩散较多.对于Ag/Sn/Cu接头,由于界面处Sn的分布受两侧的Cu向中间的Ag处扩散的影响,造成了Sn在界面处顶部和底部含量较高,中间含量低的分布.虽然Sn膜很薄,但是Sn的局部熔化导致了引线周围裂纹的产生,对接头的强度影响很大.Ag/Sn/Cu接头的拉伸强度低于Ag/Cu接头.因此利用平行微隙焊将镀银引线焊接到PCB板上时,建议采用裸铜焊盘而尽量不要采用镀锡焊盘.     

加入银和锡的四元磷铜焊料液相面探讨——关于低熔点磷铜焊料的研究（第三报）

本文探讨了古Ag和Sa的铜碑焊料的液相面，同时还研究了在铜母材上Cu—Ag-Sn。P四元合金焊料的扩展性和浸蚀性。用P当量预测初晶相，P当量大于8．38的焊料结晶出Cu3P初晶相。P当量小于8．38的焊料合金结晶出Cu固涪体初晶相。初始相也可以通过焊料的电子浓度预测，还可以通过Sn P含量的电子浓度与Cu Ag古量的电子浓度比预测。Cu母材的侵蚀深度总是随Sn、Ag和P含量成线性增加。     

Influence of laser energy input mode on joint interface characteristics in laser brazing with Cu-base filler metal

The flange butt joints of 1 mm-thick galvanized steel sheets were brazed with CuSi3 as filler metal at different laser heating modes. The microstructures and element distributions of joint interface were investigated by SEM and EDS. The results show that there is no obvious interface layer with the circular individual beam heating and lamellar Fe-Si intermetallic compound layer is found with dual-beam laser spot heating. With the irradiation of rectangular laser spot, the joint interface layer is also formed. The layer thickness is larger than that of dual-beam brazing and the layer shape is flat so that intermetallic compounds trend to grow into cellular crystals. Moreover, the interface layer shape also depends on its position in the joint. Under the high heat input, dendritic or granular intermetallic compounds dispersively distribute in brazing seam adjacent to the interface, which is caused by the melting or dissolving of the base metal. According to the results, the brazing quality can be controlled by laser heating mode and processing parameters.     

醋酸对晶体硅太阳电池组件影响

主要阐述醋酸对晶体硅太阳电池组件中涂锡铜带的影响,醋酸对太阳电池的腐蚀特性以及对太阳电池组件性能的影响。实验结果表明：（1）稀醋酸使涂锡铜焊带发生电化学腐蚀,产生氧化黄变,此腐蚀对其电阻率影响较小;（2）稀醋酸腐蚀电池片表面银电极和铝背场,使银电极变黑,铝背场与硅片的附着力下降,对电池片造成损害影响其电性能;（3）组件在湿热试验过程中EVA发生老化反应,产生的醋酸会有腐蚀封装其中的涂锡铜焊带和太阳电池,使串联电阻Rs增大,填充因子FF降低,组件输出功率降低。     

Effects of Al2O3 Particulates on the Thickness of Reaction Layer of Al2O3 Joints Brazed with Al2O3-Particulate-Contained Composite Filler Materials

In order to understand the rate-controlling process for the interracial layer growth of brazing joints brazed with active composite filler materials, the thickness of brazing joints brazed with conventional active filler metal and active composite filler materials with different volume fraction of AI203 particulate was studied. The experimental results indicate although there are Al2O3 particulates added into active filler metals, the time dependence of interracial layer growth is t^2 as described by Fickian law for the joints brazed with conventional active filler metal. It also shows that the key factor affecting the interracial layer growth is the volume fraction of alumina in the composite filler material compared with the titanium weight fraction in the filler material.     

Preparation of Ti-based amorphous brazing alloy

A new kind of amorphous active brazing alloy foil with the composition of Ti40Zr25Ni15Cu20 was successfully synthesized using melt spinning in roll forging machine in argon atmosphere. The amorphous structure and composition were examined by X-ray diffraction, differential thermal analysis and energy dispersive X-ray detector. The results show that the Ti40Zr25Ni15Cu20 amorphous alloy foil has excellent wettability on Si3N4 ceramic and demonstrate a strong glass forming ability. The reduced glass transition temperature （Trg） and the temperature interval of supercooled liquid region before crystallization are 0.76 and 78 K, respectively.     

Interfacial reaction product and mechanical properties of the electron beam brazed K465 Ni-based superalloy joints

Ni-based superalloy K465 is brazed with BNi-2 filler metal by vacuum electron beam brazing (VEBB). In process of VEBB, effects of processing primary parameters on shear strength of joints are investigated. Microstructure of the brazed joint with BNi-2 filler metal is studied by means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The results show that the structure of brazed seam consists of a large amount of Ni-based γ solid solution, Ni3Al (γ′), Ni3B, WB, CrB, and a small quantity of WC, NbC. The maximum shear strength of the joint is 398 MPa when the beam current of welding is 2.6 mA, heating time is 480 s and focused current is 1 800 mA.     

发电电动机定子线棒故障检修

介绍了十三陵蓄能电厂发电电动机定子绕组线棒故障情况,阐述了半导体硅胶弹性固定工艺的发电电动机定子绕组检修工艺,为同类型机组提供参考。