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1.
通过成分设计形成了Sn-Zn-Bi-Ag系钎料合金。针对微电子产业的应用要求研究了钎料的物理性能,分析了Sn-Zn-Bi-Ag系钎料中合金元素对钎料物理性能的影响。发现:Sn-Zn-Bi-Ag系钎料的合金元素中Bi、Ag含量(质量分数)的增加会使钎料的密度增大,而Zn含量对钎料的密度影响不大。Zn含量5.0%~6.5%,Bi含量1.5%~3.0%,Ag含量0.5%~0.8%范围的Sn-Zn-Bi-Ag钎料具有较好的润湿性能。Sn-Zn-Bi-Ag系钎料中Bi含量不高时,钎料的电阻率均比传统Sn-37Pb钎料小。随着Bi含量的增加,钎料的电阻率有明显增大的趋势。 相似文献
2.
稀土改性的Sn-58Bi低温无铅钎料 总被引:1,自引:0,他引:1
研究了微量稀土对Sn-58Bi低温钎料的改性作用.试验添加质量分数为0.1 ?组混合稀土的无铅材料,并对比Sn-58Bi和Sn-58Bi0.5Ag合金.观察了钎料显微组织的变化并做了定量分析,采用DSC测试了钎料的熔化温度,同时测量了钎料的润湿性能、接头强度与硬度.结果表明,微量稀土添加细化了Sn-58Bi钎料合金的显微组织,对钎料的熔化温度几乎没有影响,能显著改善Sn-58Bi钎料的润湿性能和接头剪切强度,而且改善的程度优于添加微量Ag对Sn-58Bi钎料的作用. 相似文献
3.
Sn-Sb-Cu(Bi)系无铅钎料的研究 总被引:1,自引:0,他引:1
本文研究了Sn-Sb-Cu(Bi)系无铅钎料的润湿性、显微组织以及熔化特性,对Sb、Cu、Bi等元素在Sn基钎料中的作用进行了阐述,发现了几种有应用潜力的合金,有望取代现有广泛使用的SnAg(Cu)系钎料. 相似文献
4.
在BiSbCu钎料中添加Sn,分析Sn对BiSbCu钎料合金钎焊工艺性能的主要指标——钎料熔点和铺展面积的影响。结果表明:在Bi5Sb2Cu钎料合金中加入Sn可以显著降低钎料的熔点和显著增强钎料合金的铺展性能。当Sn的质量分数为10%时,Bi5Sb2Cu钎料的铺展面积为26.22 mm2,钎焊工艺性能最好。 相似文献
5.
在BiSbCu钎料中添加Sn,分析Sn对BiSbCu钎料合金钎焊工艺性能的主要指标——钎料熔点和铺展面积的影响.结果表明:在Bi5Sb2Cu钎料合金中加入Sn可以显著降低钎料的熔点和显著增强钎料合金的铺展性能.当Sn的质量分数为10%时,Bi5Sb2Cu钎料的铺展面积为26.22 mm2,钎焊工艺性能最好. 相似文献
6.
7.
研制开发熔点在250~450℃之间的高温无铅软钎料一直是钎焊领域一大难题。熔点为300℃左右的Bi5Sb2Cu钎料因润湿性能和导电性能不良而受到限制。本文通过在Bi5Sb2Cu中添加不同含量Sn形成新型BiSbCuSn四元合金,来改善Bi5Sb2Cu合金的润湿性能和物理性能。结果表明:在Bi5Sb2Cu钎料合金中添加2-↑10wt.%Sn,BiSbCu钎料合金熔点呈下降趋势且幅度较大,但仍在250~450℃之间,润湿性能和导电性能明显改善。当Sn含量为10wt.%时,(Bi5Sb2Cu)10Sn钎料合金润湿性能和导电性能最好。 相似文献
8.
9.
表面封装用无铅软钎料的接头强度及熔点范围的研究 总被引:6,自引:1,他引:5
研究了Bi的添加量,对电子表面封装(SMT)用Sn-Ag近共晶无铅软钎料钎焊接头抗拉强度和熔点及熔点范围的影响。随着Bi含量的增加,钎焊接头抗拉强度也随着增加,同时钎料的液固相线温度均降低。当Bi的含量达到5%时,抗拉强度增加快;Bi的添加量大于5%时,抗拉强度上升缓慢。在Bi的含量增加时,熔点温度范围也逐渐变宽,使得凝固时间变长,这对于表面组装中的电子元件与器件的焊接是非常不利的。故在Sn-Ag近共晶无铅软钎料中Bi的添加量,应加以适当的控制。 相似文献
10.
11.
It was reported in a previous study that the Sn-6Bi-2Ag-0.5Cu solder alloy had great potential to replace leaded alloys. This alloy was prepared by mechanical alloying, and had the advantage of providing a high percentage of supersaturate solution of bismuth in tin. In the present paper, the microstructural evolution of surface-mount joints during aging was examined. In the as-soldered joints, small bismuth and Ag3Sn particles of about 1 mum in size were found to be finely dispersed in a nearly pure tin matrix with a small amount of eta-Cu6Sn5 phase in the bulk of solder. During aging, microstructural evolution of solder joints occurred. These include Cu-Sn intermetallic compound (IMC) layer growth at the interface between solder and copper pad on the printed circuit board, as well as bismuth phase and Ag3Sn phase coarsening. The shear strength of the solder joints decreased parabolically with the increase in IMC layer thickness, such that taus=22.22-radic22.05(t-1.88), where taus is the shear strength in MPa and t (>1.88) is the total IMC layer thickness in micrometers. The microstructure of solder appeared to be stable under aging at elevated temperatures up to about 160degC. Above this temperature, brittle and porous IMC epsiv-Cu3Sn appeared at the copper/eta-Cu6Sn 5 interface. Fracture was found to occur at the Cu-Sn IMC layer-solder interface and in the bulk of solder 相似文献
12.
Effects of Trace Amounts of Rare Earth Additions on Microstructure and Properties of Sn-Bi-Based Solder Alloy 总被引:3,自引:0,他引:3
Wenxing Dong Yaowu Shi Zhidong Xia Yongping Lei Fu Guo 《Journal of Electronic Materials》2008,37(7):982-991
The effect of trace amounts of rare earth additions on the microstructure and properties were studied for the Sn-58Bi and
Sn-58Bi-Ag solder alloys. At the same time, the intermetallic compounds (IMCs) in the solder alloys and intermetallic layer
(IML) thickness at the solder/Cu substrate interface were investigated, both as-reflowed and after high-temperature aging.
The results indicate that adding trace amounts of rare earth (RE) elements has little influence on the melting temperature
and microhardness of the solders investigated, but adding RE elements improves the wettability and shear strength of the Sn-58Bi
and Sn-58Bi-Ag solder alloys. In addition, it was found that the addition of RE elements not only refines the microstructure
and size of the IMC particles, but also decreases the IML thickness and shear strength of the Sn-58Bi solder joint after high-temperature
aging. Adding trace amounts of RE elements is superior to adding trace amounts of Ag for improving the properties of the Sn-58Bi
solder. The reason may be related to the modification of the microstructure of the solder alloys due to the addition of trace
amounts of RE elements. 相似文献
13.
Poon N.M. Wu C.M.L. Lai J.K.L. Chan Y.C. 《Advanced Packaging, IEEE Transactions on》2000,23(4):708-714
In this study, two lead-free solder alloys, namely 50 tin-50 bismuth (Sn-Bi) and 96.5 tin-3.5 silver (Sn-Ag), were studied for their use in surface mount solder joints. They have been considered as potential replacements for 63 tin-37 lead (Sn-Pb) solder. All joints were subjected to various cycles of thermal shock with temperature ranging from -25 to 125/spl deg/C. Shear tests were conducted on joints with and without thermal shock treatment. Another thermal shock cycle (-25 to 85/spl deg/C) was carried out on Sn-Bi solder joints for comparison. Their performance against thermal shock was compared with eutectic Sn-Pb solder by evaluating their residual shear strength and studying their microstructural change. For the Sn-Ag solder, a fine rod-like Ag/sub 3/Sn intermetallic was formed in the solder matrix after the thermal shock. On the other hand, Bi-rich and Sn-rich phases appeared in the Sn-Bi solder after the -25 to 125/spl deg/C thermal shock. Moreover, fine cracks were observed along the Bi-rich grain-like phase boundary. These were not observed in the Sn-Bi solder with the -25 to 85/spl deg/C thermal shock treatment. Voids and cracks were also observed in the joint of Sn-Bi solder alloy after 1000 thermal shock cycles. In addition, the thickness of intermetallic compound (IMC) of three solder alloys gradually grew with the number of thermal shock cycles. These defects reduced the strength of solder joint and led to thermal fatigue failure. In general, the shear strength is found to decrease with increasing number of thermal shock cycles. The Sn-Ag solder was better than the Sn-Bi solder in terms of residual thermal shock shear strength. Sn-Bi solder showed good properties when it was treated with the -25 to 85/spl deg/C thermal shock. It has a strong potential to replace Sn-Pb solder in low temperature applications such as consumer electronics. The Sn-Ag solder is suitable for high temperature applications. 相似文献
14.
Yoshiharu Kariya Yasunori Hirata Masahisa Otsuka 《Journal of Electronic Materials》1999,28(11):1263-1269
Quad Flat Pack (QFP) Leads/Sn-3.5Ag-X (X=Bi and Cu) joint was thermally cycled between 243 K and 403 K or 273 K and 373 K,
and both metallographic examination and mechanical pull test were performed to evaluate thermal fatigue damage of the joint.
The addition of bismuth drastically degrades the thermal fatigue resistance of Sn-3.5Ag solder. On the other hand, the pull
strength of Sn-3.5Ag-Cu solder joints slightly decreased with increasing number of thermal cycles, though it still remains
higher in comparison to that for conventional Sn-37Pb or bismuth containing solder joint. The behavior observed here reflects
the isothermal fatigue properties of bulk solder, because thermal fatigue crack initiates at the surface of solder fillet
and propagates within the fillet in an early stage of fatigue damage. Furthermore, the lead phases lying at the interface
between lead-frame and bismuth containing solder joint may promote the crack propagation at the interface, resulting in the
extremely low thermal fatigue resistance of the joint. 相似文献
15.
The Sn-0.7%Cu alloy has been considered as a lead-free alternative to lead-tin alloys. In this work, various small amounts
of rare earth (RE) elements, which are mainly Ce and La, have been added to the Sn-0.7%Cu alloy to form new solder alloys.
It was found that the new alloys exhibit mechanical properties superior to that of the Sn-0.7%Cu alloy. In particular, the
addition of up to 0.5% of RE elements is found to refine the effective grain size and provide a fine and uniform distribution
of Cu6Sn5 in the solidified microstructure. Tensile, creep, and microhardness tests were conducted on the solder alloys. It was found
that significant improvements of the tensile strength, microhardness, and creep resistance were obtained with RE element addition.
Upon aging at 150°C for 20 h, the microstructure of Sn-Cu-RE is more stable than that of the Sn-Cu alloy. 相似文献
16.
The thermal property of lead-free Sn-8.55Zn-1Ag-XAl solder alloys and their wetting interaction with Cu 总被引:1,自引:0,他引:1
The wetting behaviors between the quaternary Sn-8.55Zn-1Ag-XAl solder alloys and Cu have been investigated with the wetting
balance method. The Al contents, x, of the quaternary solder alloys investigated were 0.01–0.45 wt.%. The results of differential
scanning calorimeter (DSC) analysis indicate that the solders exhibit a solid-liquid coexisting range of about 7–10°C. The
solidus temperature of the quaternary Sn-8.55Zn-1Ag-XAl solder alloys is about 198.2°C, while the liquidus temperatures are
205–207°C. The experimental results showed that the wettability of the Sn-8.55Zn-1Ag-XAl solder alloys is improved by the
addition of Al. The mean maximum wetting force of the solders with Cu is within 0.75–1.18 mN and the mean wetting time is
around 1.0–1.1 sec, better than the ∼1.3 sec of eutectic Sn-9Zn and Sn-8.55Zn-1Ag solder alloys. The addition of Al also depresses
the formation of ε-Ag-Zn compounds at the interface between Sn-8.55Zn-1Ag-XAl solders and copper. 相似文献
17.
Ratchev P. Vandevelde B. Verlinden B. Allaert B. Werkhoven D. 《Components and Packaging Technologies, IEEE Transactions on》2007,30(3):416-423
The fracture toughness of bulk Sn, Sn-Cu, Sn-Ag, and Sn-Ag-Cu lead-free solders was measured as function of the temperature by means of a pendulum impact test (Charpy test). A ductile to brittle fracture transition was found, i.e., a sharp change in the fracture toughness. No transition was found for the eutectic Sn-Pb. The transition temperature of high purity Sn, Sn-0.5%Cu and Sn-0.5%Cu(Ni) alloys is around -125degC. The Ag-containing solders show a transition at higher temperatures: in the range of -78 to -45degC. The increase of the Ag content shifts the transition temperature towards higher values, which is related to the higher volume fraction of SnAg particles in the solder volume. At fixed volume fraction, smaller particle size shifts the transition temperature towards higher values. Therefore, a careful microstructure control is needed during the solder solidification after reflow in order to decrease the low temperature brittleness hazard. 相似文献
18.
Wenxing Dong Yaowu Shi Yongping Lei Zhidong Xia Fu Guo 《Journal of Electronic Materials》2009,38(9):1906-1912
In the present work, solidification cracks in Sn-Ag-Cu solder joints were investigated. Experimental results indicate that
solidification cracks existed in significant numbers in the miniature Sn-Ag-Cu solder joints. In order to create solidification
cracks in the miniature solder joints during solidification and evaluate the susceptibility of Sn-Ag-Cu alloys to solidification
cracking, a copper self-restraint specimen was designed, which can simulate the process of solidification crack formation.
The solidification crack susceptibility of the Sn-Ag-Cu solder alloy was evaluated using the total crack length of the solder
joint. In addition, the effect of trace amounts of elemental additions on solidification cracking of Sn-Ag-Cu solder joints
was studied. It was found that adding trace amounts of Ni or Ce could depress the solidification cracks in Sn-3.0Ag-0.5Cu
solder joints. However, P additions aggravated the formation of solidification cracks. 相似文献
19.
在无铅组装工艺中,大多数电路板组装厂优先采用低成本焊料合金。没有添加剂的锡铜无铅焊料本身存在局限性,可是添加某种成份后,就能克服锡铜焊料通常所遇到的不足之处。文章分析了几种锡铜焊料相对于SAC焊料的特点,并叙述了它们在波峰焊和手工焊接工艺中的应用情况。 相似文献
20.
This study describes tests in which solder composition, substrate metallization, temperature, and dwell time were combined
in a factorially designed experiment to determine the effect of those factors on solder spread area. Measure of spread area,
reflowed solder shape, solder microstructure, and solder and interface chemistry were taken in order to provide insight about
the wetting mechanism(s). The reactivity of Au vs Cu metallization with solder was found to be a major factor in increasing
spread area. The role of increasing tin content is to increase spread and spread rate. A similar effect is seen by increasing
temperature. Time allowed for spread is a minor contributor to the spread area. Segregation of the tin and bismuth solder
components during the wetting process was observed which indicated the role of bismuth as a carrier species. Analysis of variance
methods based on the statistically designed experiments1a’lb were used to show how to generate a model which estimates the spread area as a function of the tested factors. 相似文献