Sn-58Bi-(0~3)Ga/Cu润湿剪切性能及界面化合物的研究

采用熔炼铸造法制备了Sn-58Bi-(0~3)Ga焊料合金,研究了Ga元素含量对合金熔化特性、润湿和剪切性能的影响,并利用扫描电镜研究了Sn-58Bi-(0~3)Ga/Cu基体界面特征。结果表明,Ga元素的添加降低了合金的熔点,增大了合金的熔程,相比于Sn-58Bi合金,Sn-58Bi-1Ga焊料合金在铜基体的铺展率显著下降,剪切强度略有提高,随着Ga含量提高至2%、3%,合金的铺展率略有下降,剪切强度显著降低;Sn-58Bi/Cu界面主要组成元素为Sn和Cu,Sn-58Bi-(1~3)Ga/Cu界面上出现了明显的Ga和Cu元素偏聚界面层,结合特征点的能谱成分分析,确定了界面化合物的组成。     

P元素对Sn-0.7Cu焊料合金性能的影响

为了研究P元素含量对合金微观组织、熔程、润湿性和抗氧化性能的影响,将纯锡和中间合金Sn-10Cu及Sn-3.5P按质量比在270 ℃熔化,保温20 min后搅拌均匀,浇铸冷却后制备成Sn-0.7Cu-xP(x=0~0.1)焊料合金.通过光学显微镜观察焊料合金的显微组织,分别利用X射线衍射仪(XRD)和差示扫描量热分析仪(DSC)对焊料合金进行了物相分析和熔点测定,采用润湿平衡法测定焊料的润湿性,用静态刮渣法测定焊料的抗氧化性.研究表明：焊料合金晶粒随着P元素含量的升高而增加;焊料合金的熔程随着P元素含量的升高先增加后降低;焊料的润湿时间随着P元素含量的增加先减小后增大,润湿力随着P元素含量的增加而减小,在P含量为0.001%时润湿性较好;P元素含量为0.01%时,Sn-0.7Cu的抗氧化性能较好.     

无铅焊料的盐雾腐蚀性能研究

无铅焊料已经进入实用化研究阶段，Sn-3Ag-0．5Cu及sn-8Zn-3Bi等几种典型合金在-些电子产品中已经得到实际应用。然而对于上述无铅焊料的腐蚀性却报道较少。选取Sn-3Ag-0．5Cu、Sn-8Zn-3Bi及Sn-8Zn-3Bi—Nd合金进行盐雾腐蚀实验，对腐蚀表面进行宏观及微观分析，并与传统的sn—Pb焊料对比，考察焊料合金的耐腐蚀性能。结果表明：Sn-3Ag-0．5Cu具有比传统Sn—Pb焊料更优越的耐腐蚀性能；Sn-8Zn。3Bi合金由于组织中存在更为粗大的初生Zn相易于优先腐蚀而导致抗盐雾腐蚀性能不良，因此在腐蚀开始阶段腐蚀速率相对Sn-8Zn-3Bi—Nd合金更快，但后者初生相数量更多，因此在更长时间腐蚀后腐蚀量更大。     

稀土Ce对SnAgCu合金显微组织及剪切强度的影响

研究了稀土Ce对Sn-3.0Ag-0.5Cu合金显微组织及焊点剪切强度的影响规律.利用扫描电镜对铸态合金及焊点显微组织和断口形貌进行了观察和分析,利用能谱仪对铸态合金组分进行测试,采用力学试验机测试焊点的剪切强度.研究表明:当Ce添加量为0.25%时,铸态合金显微组织中β-Sn相与Ag3Sn相明显细化,出现了少量的Sn-Ce相及Ce的偏聚区;采用气雾化粉末所配制的焊膏进行回流焊,添加Ce后,焊点基体组织比未添加时明显优化;经过气雾化制粉,Ce向粉末表面富集并极易氧化,导致焊粉氧含量升高,使得回流焊接后焊料/Cu界面IMC层附近孔洞增加,焊点剪切强度降低.     

63Sn-37Pb和Sn-0.7Cu钎料的力学性能

对63Sn-37Pb和Sn-0.7Cu两种钎料进行了单轴拉伸试验、纯扭试验和纯扭疲劳试验.结果表明,钎料拉伸和纯扭时的应力应变关系有很强的应变速率相关性.弹性模量和剪切模量受应变速率的影响很小.钎料的屈服强度、剪切屈服强度、抗拉强度和抗剪强度也受应变速率的影响.钎料是剪切型破坏材料,并且发生循环软化.     

Bi对Sn-0.7Cu无铅焊料微观组织和性能的影响

研究了Bi对Sn-0.7Cu焊料合金的微观组织、物理性能、润湿性能以及力学性能的影响.结果表明,在Sn-0.7Cu焊料合金中添加适量Bi后,合金的微观组织和性能有较明显的变化,Bi的加入能够降低焊料合金的熔点,提高润湿性能,同时对合金的力学性能也有很大影响,Bi能显著提高合金的抗拉强度,但合金的塑性会有所降低.     

Ce的添加对SnAgCu系钎料组织和性能的影响

通过向Sn-0.3Ag-0.7Cu系无铅焊料中添加微量稀土Ce,研究不同稀土含量对Sn-0.3Ag-0.7Cu合金的熔化温度和润湿性的影响,同时利用扫描电子显微镜(SEM)对焊料的显微组织进行了分析.实验结果表明,添加Ce对焊料的熔化温度影响不大,但对合金的润湿性和微观组织影响较大.当ω(Ce)=0.10%时,焊料合金的综合性能较好.     

Sn-Bi-Sb无铅焊料研究

开发了一种新型无铅焊料-Sn-Bi-Sb软焊料.Bi和Sb含量均影响Sn-Bi-Sb无铅焊料的力学性能,其中Bi是影响合金力学性能的主控元素.Sn-1.38Bi-0.49Sb焊料是获得最优综合力学性能的最佳成分焊料,其拉伸强度为55.4MPa,延伸率为35.9%,扩展率为80.6%,熔化温度为225～229℃,相对成本为1.478.实验结果表明,Sn-1.38Bi-0.49Sb无铅焊料不仅具有良好的物理和力学性能,而且成本较低.     

Ni元素对Sn-9Zn-3Bi无铅钎料显微组织和性能的影响

利用真空箱式电阻炉制备了Sn-9Zn-3Bi-xNi无铅钎料合金,并对其显微组织和主要性能(熔点、熔程、抗氧化性、润湿性、剪切强度)及钎焊接头断口形貌进行了分析。结果表明,少量Ni的加入可以细化Sn-9Zn-3Bi合金的显微组织,而对其熔点影响较小。当Ni添加量为0.1%和0.5%时,钎料的熔程变化不大,Ni添加量为1%时,钎料的熔程增大比较明显。随着Ni添加量增多,无铅钎料的抗氧化性能和润湿性能提高。Ni添加量在0.1%和0.5%时,钎焊接头的剪切强度变化不大,但韧性增加;Ni添加量在1%时,钎焊接头的剪切强度略有增大,但韧性降低。     

Sn-2Ag-2.5Zn低银含量合金焊料界面反应

共晶Sn-Ag-Cu无铅焊料由于成本和可靠性问题导致应用受到限制,将Sn-2Ag-2.5Zn低银含量合金焊料与不同基板焊接,研究焊接后界面反应以及随后不同时效处理条件下的组织形貌变化及可靠性。Sn-2Ag-2.5Zn焊料由直接熔炼法制成焊球,将焊球置于焊接强度测试仪中与基板加热焊接,随后将焊点置于加热炉中进行时效处理。结果表明:焊料与裸Cu基板焊接,时效处理后在界面处形成Cu₅Zn₈和Ag₃Sn致密双层IMC结构,双层结构相互阻隔,限制铜锡IMC的发展。焊料与电镀有Ni阻挡层Cu基板焊接,焊接界面形成薄层Ni₃Sn₄金属化合物,时效1 000 h后Ni₃Sn₄的厚度约为1 μm,Ni阻挡层的厚度保持在2~3 μm, Ni阻挡层的阻挡效果稳定。Sn-2Ag-2.5Zn焊料在长时效处理中损耗性能优良,耐热时效处理性好,焊料连接的质量较好,界面可靠性较高,对环境污染少。Sn-2Ag-2.5Zn焊料中低银含量使得成本大幅下降,不容易形成粗大的金属间化合物Ag₃Sn,性能有所改善,是一种非常有应用前途的合金焊料。     

铜导线表面热浸镀PbSn合金镀层的组织与性能

为了改善铜导线的可焊性和耐蚀性,采用热浸镀技术在铜导线表面制备Pb40Sn60和Pb37Sn63两种成分的低熔点合金镀层,利用扫描电镜(SEM)、能谱分析(EDS)、X射线衍射(XRD)等分析手段和电阻率检测实验、拉伸实验、中性盐雾实验等方法,系统研究其微观组织、相成分、电阻率、力学性能及耐蚀性。结果表明:Pb40Sn60和Pb37Sn63两种成分的合金镀层均由α相和β相两相组成,镀层的电阻率分别约为2.6832×10^-3,2.5929×10^-3Ω·m,均高于铜基体。铜导线热浸镀Pb40Sn60和Pb37Sn63两种成分合金镀层后的表面硬度分别为13.4,12.6HV0.2;抗拉强度分别为193,180 MPa;伸长率分别为35%和37%,与铜基体相比均降低。铜导线表面热浸镀PbSn合金镀层具有良好的导电性、力学性能及耐腐蚀性等综合性能。随着Pb含量的降低或Sn含量的增加,PbSn合金镀层中α相的相对量减少、β相的相对量增大,其电阻率、硬度和强度降低,塑性略有增大,耐蚀性增强。Pb40Sn60比Pb37Sn63合金镀层的腐蚀速率较高,分别为2.44×10^-2,3.65×10^-3 g·cm^-2·a^-1,耐腐蚀性较差。PbSn合金镀层中α相比β相的腐蚀程度更为严重,α相比β相的耐蚀性要差。     

Tensile properties and wettability of SAC0307 and SAC105 low Ag lead-free solder alloys

In this article, the tensile properties of low Ag lead-free solder alloys, SAC0307 and SAC105, are examined under various strain rates and temperatures. The wettability of these solders on Cu pad is also characterized by using different fluxes. The SAC305 and Sn37Pb solder alloys are also studied for comparison. Our results show that the properties of all solder alloys are dependent on the strain rate and temperature. The ultimate tensile strength increases monotonously with the increment of strain rate. Both SAC0307 and SAC105 alloys possess lower strength and higher elongation ratio than SAC305 and Sn37Pb alloys. For all the fluxes used in this study, the SAC0307 and SAC105 alloys show the similar wettability to SAC305, whereas worse than that of Sn37Pb alloy. Increasing the activity of the flux does not improve the wettability of the SAC solder alloys on Cu pad effectively.     

Investigation of microstructures and tensile properties of a Sn-Cu lead-free solder alloy

In recent years, the pollution of environment from lead (Pb) and Pb-containing compounds in microelectronic devices attracts more and more attentions in academia and industry, the lead-free solder alloys begin to replace the lead-based solders in packaging process of some devices and components. In this work, microstructures and mechanical properties of the lead-free solder alloy Sn99.3Cu0.7(Ni) are investigated. This paper will compare the mechanical properties of the lead-based with lead-free solder alloys (Sn99.3Cu0.7(Ni) and 63Sn37Pb). The tensile tests of lead-based and lead-free solder alloys (Sn99.3Cu0.7(Ni) and Sn63Pb37) were conducted at room and elevated temperature at constant strain rate; the relevant tensile properties of Sn99.3Cu0.7(Ni) and Sn63Pb37 were obtained. Specifically, the tensile strength of this lead-free solder- Sn99.3Cu0.7(Ni) in 25^∘C, 50^∘C, 75^∘C, 100^∘C, 125^∘C was investigated; and it was found that tensile strength of the lead-free solder decreased with the increasing test temperature at constant strain rate, showing strong temperature dependence. The lead-free solder alloy Sn99.3Cu0.7(Ni) was found to have favorable mechanical properties and it may be able to replace the lead-based solder alloy such as Sn63Pb37 in the packaging processes in microelectronic industry.     

温度对Cu颗粒增强复合钎料蠕变性能的影响

蠕变性能是影响钎焊接头可靠性的重要指标之一.采用搭接面积为1 mm2的单搭接钎焊接头,在恒定载荷下,测定了Cu颗粒增强锡铅基复合钎料钎焊接头的蠕变寿命,分析并讨论了温度对该复合钎料蠕变寿命的影响.结果表明:Cu颗粒增强的锡铅基复合钎料的蠕变抗力优于传统63Sn37Pb共晶钎料;钎焊接头蠕变寿命随温度的升高而降低,并且温度对复合钎料钎焊接头蠕变寿命的影响较传统63Sn37Pb钎料明显.     

Effect of trace additions of Sn on microstructure and mechanical properties of Al–Cu–Mg alloys

The work is aimed at investigating the influence of trace additions of Tin (Sn) on the microstructure, mechanical properties and age-hardening behavior of Al–6.2%Cu–0.6%Mg alloy system. Al–6.2%Cu–0.6%Mg alloys containing varying weight percentages (from 0 to 0.1 wt.%) of Sn were prepared by casting technique. The mechanical properties and microstructure of these alloys were investigated in the as-cast as well as different heat treated conditions. The composition of the different phases present in the microstructure was determined by energy dispersive X-ray (EDS) analysis. The average grain size of the annealed alloy was found to be maximum with trace content of 0.06 wt.% Sn. The hardness and strength of the alloy increased but the ductility reduced with increase in Sn content up to 0.06 wt.%. Precipitation hardening behavior of the alloys was investigated by analyzing the aging time required to attain the peak hardness value. Addition of trace percentage of Sn was observed to have no significant influence on the peak ageing time of the investigated alloy system.     

Influence of Thermal Cycling on the Microstructure and Shear Strength of Sn3.5Ag0.75Cu and Sn63Pb37 Solder Joints on Au/Ni Metallization

The influence of thermal cycling on the microstructure and joint strength of Sn3.5Ag0.75Cu （SAC） and Sn63Pb37 （SnPb） solder joints was investigated. SAC and SnPb solder balls were soldered on 0.1 and 0.9 μm Au finished metallization, respectively. After 1000 thermal cycles between -40℃ and 125℃, a very thin intermetallic compound （IMC） layer containing Au, Sn, Ni, and Cu formed at the interface between SAC solder joints and underneath metallization with 0.1 μm Au finish, and （Au, Ni, Cu）Sn4 and a very thin AuSn-Ni-Cu IMC layer formed between SAC solder joints and underneath metallization with 0.9 μm Au finish. For SnPb solder joints with 0.1 μm Au finish, a thin （Ni, Cu, Au）3Sn4 IMC layer and a Pb-rich layer formed below and above the （Au, Ni）Sn4 IMC, respectively. Cu diffused through Ni layer and was involved into the IMC formation process. Similar interfacial microstructure was also found for SnPb solder joints with 0.9μm Au finish. The results of shear test show that the shear strength of SAC solder joints is consistently higher than that of SnPb eutectic solder joints during thermal cycling.     

Bi-Pb-Sn-Cd易熔合金的设计与性能研究

根据铋基合金的特点与合金相图,设计了不同成分的Bi Pb Sn Cd易熔合金;并利用差热分析仪、X射线衍射仪及力学检测设备等研究了成分对合金熔点、组织和抗拉强度的影响。结果表明,设计的易熔合金由Bi、Pb7Bi3、Sn和Cd等物相组成;合金的熔点均在72℃左右。随Cd、Bi元素含量的增加,液相线温度逐渐降低;Cd元素对合金熔程、抗拉强度的影响最大,Sn元素次之,Pb元素的影响最小。正交试验表明,Bi 30Pb 15Sn 9Cd合金的综合性能最佳。     

Effects of small amounts of Ni/P/Ce element additions on the microstructure and properties of Sn3.0Ag0.5Cu solder alloy

The purpose of this study is to investigate the effects of small amounts of Ni, P and Ce element additions on the microstructure and properties of Sn3.0Ag0.5Cu solder alloy. The results indicate that adding trace amounts of Ni, P or Ce element has little influence on the melting temperature of Sn3.0Ag0.5Cu solder alloy. Adding Ni or Ce element cannot improve the wettability and anti-oxidization of the Sn3.0Ag0.5Cu solder alloy, but it can depress the interfacial intermetallic compounds growth due to the high temperature aging and then improves the shear strength of the solder joint. In addition, the P element addition not only significantly increases the maximum wetting force and decreases the wetting time of the solder, but also improves the anti-oxidation property of the Sn3.0Ag0.5Cu solder. At the same time, adding P element also increases the hot cracking sensitivity of the solder surface in the solidification. However, it is noted that adding Ni or Ce element can depress the formation of the hot carking. The reason may be related to the modification of the microstructure of the solder alloys due to trace amounts of Ce or Ni elements additions. The adding elements change the microstructure of Sn3.0Ag0.5Cu solder alloy.     

Effects of trace amount addition of rare earth on properties and microstructure of Sn–Ag–Cu alloys

Ternary lead free solder alloys Sn–Ag–Cu were considered as the promising alternatives to conventional SnPb alloys comparing with other solders. In the present work, effects of trace amounts of rare earth Ce on the wettability, mechanical properties and microstructure of Sn–Ag–Cu solder have been investigated by means of scanning electron microscopy and energy dispersive X-ray analysis systematically. The results indicate that adding trace amount of rare earth Ce can remarkably improve the wettability, mechanical strength of Sn–Ag–Cu solder joint at different temperature, especially when the content of rare earth Ce is at about 0.03%, the tensile strength will be 110% times or more than that of the lead free solder joint without rare earth Ce addition. Moreover, it was observed that the trace amount of rare earth Ce in Sn–Ag–Cu solder may refine the joint matrix microstructure, modify the Cu₆Sn₅ intermetallic phase at the copper substrate/solder interface, and the intermetallic compound layer thickness was reduced significantly. In addition, since rare earth Ce possesses a higher affinity to Sn in the alloy, adding of rare earth Ce can also lead to the delayed formation and growth of the intermetallic compounds of Ag₃Sn and Cu₆Sn₅ in the alloy.