Cu含量对Sn基无铅钎料组织、界面反应影响

研究了Cu含量对Sn-xCu(x=0.7%,2%)、Sn-9Zn-xCu(x-0.2%,10%)两种无铅钎料的基体组织以及与Cu基板短时间钎焊时界面金属间化舍物(IMC)生长行为的影响.结果表明,当Sn-Cu钎料中Cu的含量为2%时,基体中IMC租化为块状的Cu6Sn5相;对于Sn-9Zn-xCu钎料合金,2%Cu元素的加入使得Sn-9Zn基体中长针状的富Zn相转化为Cu5Zn8相以及细小的富Zn相,而当Cu含量达到10%时,钎料基体中的IMC为CuZn相与Cu6Sn5相.在260℃短时间钎焊下,Cu含量的增加加速了Sn-xCu/Cu界面IMC的粗化和生长;而对于Sn-9Zn-xCu/Cu,Cu含量的增加却明显降低了界面IMC的生长速率.同时分析、讨论了界面IMC随钎焊时间变化的生长行为.     

超细氧化物颗粒对Sn\|58Bi钎料组织及性能影响

研究了分别添加1%Al2 O3 、Fe2 O3 、SiO2 、TiO2 超细粉末对Sn-58Bi共晶钎料的润湿性、钎焊接头微观组织及力学性能影响.结果表明,氧化物粉末的添加对钎料熔点影响不大,但钎料润湿性及钎焊接头剪切强度明显提高;明显细化钎焊接头基体组织及界面金属间化合物颗粒大小,并且界面金属间化合物层厚度也有一定减薄;另外,可抑制钎焊时焊点表面Bi的氧化,因此焊点表面光亮度也有明显提高.     

半导体激光软钎焊Sn-Ag-Cu焊点微观组织

采用90 W半导体激光焊接系统对Sn-Ag-Cu无铅钎料在纯铜基板上进行钎焊试验. 针对在不同激光输出功率下形成的微焊点形貌, 分析Sn-Ag-Cu钎料在纯铜基板上的润湿、铺展规律和微焊点的微观组织特征. 通过分析比较在激光软钎焊和红外再流焊2种再流焊加热方式的Sn-Ag-Cu钎料微焊点的微观组织, 发现： 当采用半导体激光软钎焊时存在最佳输出功率, 在此功率下得到的微焊点组织均匀, 晶粒细小, 没有产生空洞缺陷, 力学性能最佳.     

低熔点铝基钎料的性能

采用真空感应熔炼炉制备低熔点Al-Si-Cu-Zn-Sn多元合金钎料,以Cu为主要降低钎料熔点的元素,Zn和Sn作为既降低钎料的熔化温度,又提高钎料的润湿性和流动性的元素.通过对钎料的性能测试表明:该钎料液相线温度为528.8℃,可在560℃钎焊6063铝合金,钎焊接头剪切强度达到母材抗拉强度的80%,并且该钎料具有良好的润湿性和流动性,可以用于锻铝及部分硬铝合金的钎焊.     

时效处理对Sn-Ag-Cu-Bi无铅钎料显微组织和力学性能的影响

主要研究了时效处理对Sn-3Ag-0.5Cu、Sn-3Ag-0.5Cu-1Bi、Sn-3Ag-0.5Cu-3Bi无铅钎料显微组织和力学性能的影响,并根据试验结果讨论了Bi元素的作用.试验结果表明Bi的加入提高了钎料的抗拉强度,但降低了其延伸率.通过在不同温度下时效处理,在含Bi的钎料中,Bi在Sn基体中析出,而含Bi的钎料表现出相对稳定的力学性能.这可归因于Bi的固溶强化与弥散强化作用的转化.     

Sn-Zn-Cu/Cu界面反应及剪切强度

为探讨Cu的加入对Sn-Zn钎料性能的影响,研究了Sn-Zn-xCu与Cu箔钎焊界面处金属间化合物(IM C)成分、形貌及剪切强度.试验结果表明,含0~1%Cu时,Sn-Zn-xCu钎料与Cu母材钎焊界面处IM C主要为层状Cu5Zn8相;在含2%~6%Cu时,为Cu6Sn5相和Cu5Zn8相共同组成;在含8%Cu时,为Cu6Sn5相.这是由于合金基体中生成的Cu-Zn化合物阻碍了Zn向Cu界面处扩散,进而使得界面处IM C由层状Cu5Zn8逐渐向扇贝状Cu6Sn5转变.另外,随着Sn-Zn钎料中Cu含量的增加,Sn-Zn-xCu/Cu接头剪切强度因界面IM C类型的变化以及钎料合金自身强度的提高而使得钎焊接头剪切强度明显提高.     

快速凝固Al-Cu钎料钎焊铝Cu对钎缝组织的影响

研究了快速凝固钎料中Cu元素在铝合金基体中的扩散现象和机制.采用快速凝固的方法制备出了Al-Cu合金的薄带,用差热分析法(DTA)测量了钎料熔点.根据熔点利用真空钎焊用Al-Cu钎料焊接纯铝,然后使用扫描电镜和能谱分析仪分析了焊缝的显微组织,对Cu元素的扩散现象进行观察,并分析了Cu的扩散行为.实验结果表明,由于快冷钎料组织均匀,表面能高,因此熔点比普通钎料低,且熔化区间窄.随着钎焊温度的升高和保温时间的延长,Cu的扩散效果越来越好;在同一温度下钎焊时,快冷钎料中Cu的扩散能力明显强于普通钎料.     

Au-Ag-Si系钎料合金与Ni的润湿性

通过分析相图,采用中频感应真空熔炼制成液相点温度在450～500℃之间Au-10．22Ag-3．25Si, Au-14．02Ag-3．28Si和Au-18．47Ag-3．27Si 3种不同成分的Au-Ag-Si系钎料合金。分别在其液相点以上20,40和60℃及流动氢气保护下进行钎料在Ni板上的铺展试验,通过分析铺展面积及润湿角,研究其与Ni的润湿性;采用背散射电子相观察钎料与Ni润湿后的界面组织。研究结果表明:Au-Ag-Si系钎料合金与Ni润湿性良好,随着钎焊温度的增加,铺展面积增加,浸润角减小;钎料合金与Ni润湿后,出现润湿环现象;润湿环主要由Au元素组成;钎料与Ni润湿后,在界面处形成Ni3Si金属间化合物,Ni3Si的形成在一定程度上可提高钎料焊接强度。     

超声波辅助钎焊铜与石墨的组织及性能

采用四元合金Ag30Cu25Zn4Ti作为活性钎料,在大气中利用超声波辅助钎焊技术对铜和石墨进行了钎焊.通过改变超声波作用时间和方式,研究了不同超声波作用时间下钎料氧化膜破碎的效果,及其与TiC反应层形貌之间的关系.采用扫描电子显微镜对钎焊接头的微观组织进行了观察,最后对钎焊的接头进行了力学性能分析.结果表明:随着超声波作用时间的延长,液态钎料中的氧化膜逐渐减少,最终完全消除;与此同时,TiC反应层的厚度也在逐渐增加,最终趋于稳定.钎焊接头的组织由铜侧到石墨侧依次主要为Cu/Cu-Zn金属间化合物,Ag基固溶体和Cu基固溶体/TiC/石墨,钎焊接头的剪切强度最大值为18 MPa,界面的结合主要是超声波作用下活性元素Ti在石墨侧的偏聚形成TiC反应层而形成的.     

微量Ag对Sn0.7Cu力学性能影响

SnCu共晶钎料在波峰焊领域被公认为SnPb共晶及近共晶钎料的最佳替代合金之一,但其熔点高,力学性能不良。本文采用合金化原理,在Sn0.7Cu合金中添加微量的Ag形成SnCuAg三元合金来改善合金性能。结果表明:当Ag质量分数小于0.2%时,随Ag含量增加,SnCuAg钎料抗拉强度和剪切强度逐渐提高;当Ag质量分数为0.2%时,SnCuAg抗拉强度较基体提高35.5%,剪切强度较基体提高46.5%。当Ag质量分数大于0.2%时,钎料合金的力学性能有所下降,这主要与新相Ag3Sn弥散强化作用及母材界面金属间化合物有关。     

Effects of phosphorus addition on the properties of Sn-9Zn lead-free solder alloy

This article explores the effects of phosphorus addition on the wettability between Sn-9Zn solder alloy and Cu substrates, the oxidation behavior and the corrosion behavior of Sn-9Zn solder alloy. Spreading test was used to characterize the wettability of Sn-9Zn-xP solder alloys to Cu substrates. The oxidation and corrosion behaviors of Sn-9Zn-xP solder alloys were determined by means of weight gaining, and secondary ion mass spectrometry was used to analyze the oxygen content. The role and mechanism of P in the solder alloys were also discussed. It is found that the addition of P can significantly improve the wettability of the solder alloys. Incorporating P into Sn-9Zn solder alloy obviously decreases the oxygen content and enhances the oxidation and corrosion resistance. Microstructure observations show that an appropriate amount of P can greatly refine coarse rod-like Zn-rich phases in Sn-9Zn solder alloy.     

Effect of indium addition on the microstructural formation and soldered interfaces of Sn-2.5Bi-1Zn-0.3Ag lead-free solder

The microstructural formation and properties of Sn-2.5Bi-xIn-1Zn-0.3Ag (in wt%) alloys and the evolution of soldered interfaces on a Cu substrate were investigated. Apart from the relatively low melting point (about 195℃), which is close to that of conventional eutectic Sn-Pb solder, the investigated solder presents superior wettability, solderability, and ductility. The refined equiaxial grains enhance the mechanical properties, and the embedded bulk intermetallic compounds (IMCs) (Cu₆Sn₅ and Cu₅Zn₈) and granular Bi particles improve the joint reliability. The addition of In reduces the solubility of Zn in the β-Sn matrix and strongly influences the separation and growth behaviors of the IMCs. The soldered interface of Sn-2.5Bi-xIn-1Zn-0.3Ag/Cu consists of Cu-Zn and Cu-Sn IMC layers.     

温度与镀层对Sn0.7Cu焊料合金润湿性的影响

主要研究了真空状态下,焊接温度为530,560和590 K时,Sn-0.7Cu焊料合金在镀Cu、镀Ni、镀Ni/Ag和镀Ni/Au基板上的润湿性.结果表明:提高钎焊时的焊接温度,有助于降低液态Sn-0.7Cu焊料合金的表面张力,从而增大Sn-0.7Cu焊料合金在焊接基板上的润湿性.在相同的焊接条件下,Sn-0.7Cu焊料合金在镀Ni/Ag和镀Ni/Au基板上的润湿性比其在Cu和镀Ni基板上的润湿性好.     

Ag对Sn-57Bi无铅钎料组织和性能的影响

研究了在Sn-57Bi近共晶合金的基础上加入少量的Ag后对Sn-57Bi钎焊料铸态组织、抗拉强度和Sn-57Bi／Cu焊接性能的影响。试验结果表明，ωAg=0．1％～1．0％可使合金的共晶组织变细，β-Sn枝晶相的尺寸变小，提高其抗拉强度；使Sn-57Bi／Cu接头的剪切强度有所提高。     

无铅焊料Sn-9Zn—xLa的制备及性能

采用粉末冶金技术成功制备了La含量为x(其中x=0.1%～0.5%)的无铅焊料Sn-9Zn-xLa,应用DTA,SEM,XRD等技术分析了焊料的熔点,形貌,微结构,成分,焊料与Cu基板的粘附性等性能,并获得这些性能随La添加量而变化的规律.研究表明:添加微量稀土元素La能较大程度的改善无铅焊料润湿等方面的性能,Sn-9Zn-xLa有望替代传统PbSn合金,成为微电子器件封装焊接材料.     

Characterization of Cu3P phase in Sn3.0Ag0.5Cu0.5P/Cu solder joints

This article reports the effects of phosphorus addition on the melting behavior, microstructure, and mechanical properties of Sn3.0Ag0.SCu solder. The melting behavior of the solder alloys was determined by differential scanning calorimetry. The interracial micro- structure and phase composition of solder/Cu joints were studied by scanning electron microscopy and energy dispersive spectrometry. Thermodynamics of Cu-P phase formation at the interface between Sn3.0Ag0.5Cu0.5P solder and the Cu substrate was characterized. The results indicate that P addition into Sn3.0Ag0.5Cu solder can change the microstructure and cause the appearance of rod-like CuaP phase which is distributed randomly in the solder bulk. The Sn3.0Ag0.5Cu0.5P joint shows a mixture of ductile and brittle fracture after shear test- ing. Meanwhile, the solidus temperature of Sn3.0Ag0.5Cu solder is slightly enhanced with P addition.     

Effects of nano-sized Ag reinforcing particulates on the microstructure of Sn-0.7Cu solder joints

Composite solders were prepared by mechanically dispersing different volumes of nano-sized Ag particles into the Sn-0.7Cu eutectic solder. The effects of Ag particle addition on the microstructure of Sn-0.7Cu solder joints were investigated. Besides, the effects of isothermal aging on the microstructural evolution in the interfacial intermetallic compound (IMC) layer of the Sn-0.7Cu solder and the composite solder reinforced with 1vol% Ag particles were analyzed, respectively. Experimental results indicate that the growth rate of the interfacial IMC layer in the Ag particles reinforced composite solder joint is much lower than that in the Sn-0.7Cu solder joint during isothermal aging. The Ag particles reinforced composite solder joint exhibits much lower layer-growth coefficient for the growth of the IMC layer than the corresponding solder joint.