不锈钢表面电镀锡银钎料的润湿特性

为揭示不锈钢表面电镀锡银钎料的润湿特性,借助润湿试验炉、影像式烧结点试验仪、扫描电镜、X射线衍射仪、能谱分析仪对电镀锡银钎料的润湿行为、动态铺展过程、界面组织、物相组成及润湿界面化学元素分布进行了分析。研究表明,优先铺展的前驱膜是改善电镀锡银钎料润湿性的本质原因。润湿过程中出现的前驱膜效应,主要是试验中FB102钎剂中的硼酐引起的。电镀锡银钎料与不锈钢界面出现的Cu41Sn11相过渡层,垂直于润湿界面呈柱状向钎料内生长。随着Sn含量升高,电镀锡银钎料在不锈钢表面的润湿面积呈增大趋势;与同Sn含量(2.4%~7.2%,质量分数)的传统AgCuZnSn钎料相比,电镀锡银钎料在不锈钢表面的润湿面积提高了8.1%~12.5%。当Sn含量为7.2%时,电镀锡银钎料的润湿面积高达481mm2。电镀锡银钎料与不锈钢母材的接合界面是扩散-化合物混合型形式。     

纳米Cr颗粒对Sn-Zn-Bi-In/Cu钎焊焊点性能的影响

通过向Sn-Zn-Bi-In钎料中添加不同含量的纳米Cr颗粒制成新型复合钎料Sn-5Zn-10Bi-10In-xCr(x=0％,0.1％,0.3％,0.5％,质量分数),探讨纳米C r颗粒对时效前后钎焊焊点的组织形貌、元素分布、物相组成和力学性能的影响.结果表明:纳米Cr颗粒的添加能够抑制焊点金属间化合物(IMCs)的生长,随着纳米Cr颗粒含量的增加,IMCs扩散层厚度逐渐降低;界面处IMCs扩散层靠近母材Cu一侧为Cu5 Zn8相,靠近钎料区一侧为Cu6 Sn5相;随时效时间的增加,钎料侧部分Cu5 Zn8化合物长大分解,Cu3 Sn相形成;纳米Cr颗粒抑制了时效过程中IMCs扩散层的进一步长大;随着纳米Cr颗粒含量的增加,焊接焊点的剪切强度和显微硬度均先增加后下降,Sn-5Zn-10Bi-10In-0.3Cr/Cu焊点的剪切强度和硬度最高;时效后焊件的剪切强度比时效前均有所下降,但纳米Cr颗粒的添加使焊点保持了良好的剪切强度,时效后焊点钎料区显微硬度比时效前有所上升,但也始终保持在30HV0.1以下.     

铜-钢高频感应钎焊工艺及其对接头组织和导电性的影响

以解决铜电解永久型阴极板导电杆铜-钢异种金属焊接问题为目标,采用Sn-Cu系钎料在不同钎焊工艺下对T2紫铜和316不锈钢进行铜-钢异种金属高频感应钎焊试验。利用光学显微镜、扫描电镜、能谱仪、X射线衍射仪分析研究了不同工艺参数下形成钎焊接头的微观组织、物相种类及元素分布,同时采用智能金属导体电阻率仪对铜钢焊接试样的导电性进行了检测。结果表明,不同工艺下形成的焊缝界面清晰且无明显的焊接缺陷。钎焊接头主要由铜侧扩散反应层、焊缝中心层、钢侧扩散反应层三部分组成;铜侧扩散反应层呈连续的"锯齿"状分布,主要由金属间化合物Cu_6Sn_5组成,中心层主要由锡单质、锡的氧化物和少量铜锡金属间化合物Cu_6Sn_5组成,钢侧扩散反应层生成了少量的铁锡金属间化合物Fe_(1.3)Sn。试样导电率与中心层金属间化合物Cu_3Sn的生成量和焊接温度均成反比。通过获得的最佳工艺参数能够得到焊缝成形美观、连接强度优良、导电性能良好的铜-钢钎焊接头。     

Ag颗粒增强复合钎料钎焊接头蠕变断裂及强化机理研究

测定了不同应力和温度下Ag颗粒增强复合钎料及基体钎料63Sn37Pb钎焊接头蠕变寿命,分析了Ag颗粒增强复合钎料及基体钎料钎焊接头蠕变断裂机理.表明:Ag颗粒增强复合钎料钎焊接头蠕变寿命优于基体钎料;Ag颗粒表面Ag-Sn金属间化合物形成及Ag颗粒对富Pb层阻碍作用是复合钎料钎焊接头蠕变性能提高的主要因素;钎焊接头Cu基板上一薄层富Pb相区形成是蠕变裂纹主要原因.     

合金元素对Cu/Sn-/Cu回流焊焊点界面微观结构及剪切性能的影响

选用Sn64Bi35Ag1、Sn64.7Bi35Ag0.3和Sn99Ag0.3Cu0.7三种不同的钎料进行回流焊焊接试验,研究高Bi元素、低Ag元素钎料及低Ag钎料对Sn基钎料焊点微观组织及剪切性能的影响.结果表明:各焊点界面处均生成了 一层扇贝状的Cu6Sn5金属间化合物,在含Bi元素的钎料焊点中,Bi元素在焊点界面及内部聚集,导致界面处金属间化合物层的厚度增加,大量富Bi相呈脆性,降低钎料中的Ag含量对焊点中Bi元素的富集现象有减弱作用.Sn99Ag0.3Cu0.7钎料焊点界面处的金属间化合物层厚度最小,且焊点内部形成了细小的Ag3Sn相颗粒,共晶组织呈均匀分布,使得焊点剪切性能最优,其剪切强度达20.4 MPa.     

钎焊陶瓷专用 Ag 基活性钎料的抗氧化性能

用 TGA 技术研究了 Ag_(57)Cu_(38)Ti_5活性钎料在873K 流动空气中氧化的动力学规律,并用 X射线能谱分析(EDAX)和 X 射线衍射分析研究了氧化产物的化学组成和相结构。结果表明,这种Ag 基活性钎料的氧化动力学规律精确地服从抛物线定律,在873K 时抛物线速率常数为6.29×10~(-5)mg~2cm~(-4)s~(-1)。氧化膜由 Cu_2O 和 CuO 两相组成,其中溶有少量的 Ag。与 Ag-Cu 共晶钎料的氧化性能对比,发现钎料中含有少量的 Ti,对钎料在高温下的氧化抗力不利。     

电弧作用下AlSi5钎料在镀锌钢板上铺展及界面行为研究

采用 TIG 电弧钎焊试验方法,主要研究了电流大小、电弧加热时间以及弧长对 AlSi5钎料在镀锌钢板上润湿铺展及界面行为的影响。实验结果表明：随着电流、燃弧时间和某一范围内弧长的增加,钎料在镀锌钢板上的润湿角逐渐减小,铺展面积逐渐增加,并在某一特定范围时润湿铺展性能达到最佳;随着燃弧电流的增加,界面金属间化合物的厚度呈现先增加后减小的趋势,靠近母材一侧有 Fe2 Al5相生成,钎料一侧则生成 FeAl3相;Al 元素扩散到界面处与 Fe 元素发生扩散反应形成 Fe-Al 金属化合物颗粒,在钎缝中弥散分布着 Si 元素,对钎缝有强化作用。     

机械合金化制备Ag-Cu-Sn钎料的组织和热稳定性

研究了机械合金化制备Ag-Cu-Sn三元体系形成过饱和固溶体的可能性,并对所得到的非平衡球磨产物的组织结构、热稳定性及其铺展重熔后的金相组织进行了表征。结果表明,通过控制球磨工艺和第三组元含量,可得到以过饱和固溶体为主要组成相的钎料合金粉,减少或细化脆性金属间化合物相。真空退火时,富银固溶体相较稳定,富铜固溶体相易于分解生成Cu_3Sn,银锡化合物可分解形成Ag基固溶体和富锡相,铜锡化合物的分解产物则为多种中间相,随退火温度的升高,转变顺序逐渐向铜锡原子比例增大的方向进行。以过饱和固溶体为主要组成相的钎料合金粉在重熔后虽然仍存在金属间化合物相,但金相组织明显细化。     

SnAgCu-xBi/Cu焊点界面反应及微观组织演化

本工作在Sn-3.0Ag-0.5Cu焊料中添加不同含量的Bi(0.1%,0.5%,1.0%(质量分数)),以此来研究Bi含量对Sn-3.0Ag-0.5Cu/Cu焊点的界面反应及金属间化合物微观组织演化的影响。结果发现:回流反应之后,焊点界面形成扇贝状的Cu_6Sn_5,对焊点进行时效处理后发现,在Cu_6Sn_5层与Cu基板之间又出现了一层Cu_3Sn,并且Cu_6Sn_5层的上表面及焊料中出现了颗粒状的Ag_3Sn,Ag_3Sn颗粒的数量随着时效时间的延长而增多;5d的时效处理之后,在Cu基板的上表面和Cu_3Sn层中发现了柯肯达尔孔洞,同时在大多数焊点界面的Cu_6Sn_5层的上表面和Cu_6Sn_5层中出现了裂纹,推测裂纹是由于热膨胀系数差导致的残余应力而形成的。时效过程中,焊点界面金属间化合物(IMC)层的厚度不断增加,并且IMC的平均厚度与时效时间的平方根呈线性关系。对比未添加Bi元素的Sn-3.0Ag-0.5Cu/Cu焊点发现,添加微量的Bi元素对IMC层生长有抑制作用,当Bi含量为1.0%时,抑制作用最为明显,而Bi含量为0.5%时,抑制作用最弱。Cu_6Sn_5晶粒的平均直径随着时效时间的延长而增加,且Cu_6Sn_5晶粒的平均直径与时效时间的立方根呈线性关系。     

Sb,Bi 元素对 Sn-22 Sb 高温钎料合金组织的影响

目的研究Sb和Bi元素对Sn-22Sb钎料显微组织的影响。方法制备了(Sn-22Sb)-xBi和Sn-xSb钎料合金,并分别采用差热分析和X射线衍射仪,分析了材料的熔化特征和物相。结果结果表明:Sn-22Sb钎料合金主要由灰色的β-Sn和白色块状的Sb2Sn3构成;少量的Bi使得Sn-22Sb钎料合金中Sb2Sn3金属间化合物逐渐细化和均匀化,数量却急剧增加;大量添加Sb后,使得Sn-22Sb钎料合金几乎全部变为粗大的块状β-SnSb组织,钎料合金的开始熔化温度有所提高。结论通过添加其他合金元素,降低Sn-50Sb钎料液相线温度,使其有望应用于二次回流焊。     

Premelting behavior and interfacial reaction of the Sn/Cu and Sn/Ag soldering systems during the reflow process

The early interfacial reaction and premelting characteristics of the Sn/Cu and Sn/Ag soldering systems, and the formation and morphology transition of interfacial intermetallic compounds in the two systems during the reflow soldering process were investigated by using a differential scanning calorimeter. Results show that the initial interfacial eutectic reaction arising from atomic interdiffusion in solid-state Sn/Cu and Sn/Ag systems results in the premelting at each interface of the two systems at a temperature 4.9 and 10.6?°C respectively lower than the actual melting point of pure tin, and consequently both of the Sn/Cu and Sn/Ag soldering systems exhibit morphology change of the intermetallic compound (IMC) as the solder experiences a transition from solid-state to liquid-state in a very small temperature range. The change in the interfacial energy between the solid (or liquid) Sn-rich phase and IMC phase is the essential factor leading to the morphology transition of the interfacial IMC in the Sn/Cu and Sn/Ag soldering systems.     

Sn对电真空Ag-Cu钎料组织和性能的影响

利用扫描电镜及其能谱仪、同步热分析仪以及对比实验来分析Sn对电真空Ag-Cu钎料微观组织、熔化特性和钎焊性能的影响。结果表明:Sn添加4%(质量分数,下同)时,Ag60Cu钎料中没有脆性β-Cu相生成,对钎料的加工性能影响不大;随着Sn含量的增加,Ag60Cu钎料的液相线温度逐渐降低,同时固相线温度降低幅度更大,导致熔化温度范围扩大,钎料的填缝性能变差;对于含Sn为4%的Ag60Cu钎料,与紫铜的铺展性能以及冶金结合性能都接近于BAg72Cu钎料,并可通过压力加工制成片状钎料,可以用来替代BAg72Cu片状钎料使用。     

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.     

Effect of tin on melting temperature and microstructure of Ag–Cu–Zn–Sn filler metals

Abstract

To develop low melting point filler metals for brazing TiNi shape memory alloy (SMA) and stainless steel (SS), a series of Ag–22Cu–Zn–Sn (wt-%) filler metals have been studied. Using differential thermal analysis (DTA) analysis, the melting temperatures of Ag–22Cu–Zn–Sn filler metals were determined. The results show that the increase of zinc and tin contents drastically decreases the solidus and liquidus temperatures of the Ag–22Cu–Zn–Sn filler metals and the melting temperatures of the Ag–22Cu–18Zn–Sn filler metals with 5–8 wt-%tin are < 650°C. Metallographic observations indicate that the increase of zinc and tin in the Ag–22Cu–Zn–Sn filler metals helps the formation of eutectic structure and inhibits the formation of α-Ag and α-Cu solid solutions, but the increase of tin also causes the formation of Ag₃Sn and Cu₄₁Sn₁₁ brittle compounds. The results of mechanical property tests of the laser brazed joints of TiNi SMA and SS show that the proper increase of zinc and tin in Ag–22Cu–Zn–Sn filler metals is favourable for improving the strength of the laser brazed joints of TiNi SMA and SS.     

Thermodynamics and phase diagrams of lead-free solder materials

Many of the existing and most promising lead-free solders for electronics contain tin or tin and indium as a low melting base alloy with small additions of silver and/or copper. Layers of nickel or palladium are frequently used contact materials. This makes the two quaternary systems Ag–Cu–Ni–Sn and Ag–In–Pd–Sn of considerable importance for the understanding of the processes that occur during soldering and during operation of the soldered devices. The present review gives a brief survey on experimental thermodynamic and phase diagram research in our laboratory. Thermodynamic data were obtained by calorimetric measurements, whereas phase equilibria were determined by X-ray diffraction, thermal analyses and metallographic methods (optical and electron microscopy). Enthalpies of mixing for liquid alloys are reported for the binary systems Ag–Sn, Cu–Sn, Ni–Sn, In–Sn, Pd–Sn, and Ag–Ni, the ternary systems Ag–Cu–Sn, Cu–Ni–Sn, Ag–Ni–Sn, Ag–Pd–Sn, In–Pd–Sn, and Ag–In–Sn, and the two quaternary systems themselves, i.e. Ag–Cu–Ni–Sn, and Ag–In–Pd–Sn. Enthalpies of formation are given for solid intermetallic compounds in the three systems Ag–Sn, Cu–Sn, and Ni–Sn. Phase equilibria are presented for binary Ni–Sn and ternary Ag–Ni–Sn, Ag–In–Pd and In–Pd–Sn. In addition, enthalpies of mixing of liquid alloys are also reported for the two ternary systems Bi–Cu–Sn and Bi–Sn–Zn which are of interest for Bi–Sn and Sn–Zn solders.     

Diffusionslöten von Aluminium mittels PVD applizierter Lotzusatzwerkstoffe

Diffusion brazing of aluminium by PVD applied filler metals Diffusion brazing of aluminium and aluminium alloys precoated with filler metal components enables fluxless wetting and obtains braze joints of high strength at moderate brazing temperatures. Previously deposited components of filler metals on the base materials as thin film, using Arc‐PVD‐process lead during a subsequently diffusion brazing process to the formation of a local liquid phase (transient liquid phase). The liquid phase is formed from the deposited thin film material and the base material and is solidified isotherm due to diffusion procedures. In doing so braze joints of higher melting point than brazing temperature can be realised. In this work, vacuum brazing of the two systems, Al‐Cu and Al‐Cu‐Si have been investigated. Cu and Al‐Cu‐Si were deposited on the base material using Arc‐PVD‐process. The base materials were pure aluminum and EN‐AW6060. Metallographic and scanning electron microscope analyses proved that the braze seam area after the completed diffusion brazing process shows similar structure and composition as the base material.     

Evolution behavior of δ phase in Cu12Sn2Ni alloy and the corresponding effects on alloy property

With the increase of tin content in tin bronze, the rise of δ phase made the strength, hardness of tin bronze increase and the ductility decrease sharply, that difficult to process. In this paper, the Cu12Sn2Ni alloy was prepared by centrifugal casting, the microstructure and phase formation before and after heat treatment were observed by x-ray diffraction, scanning electron microscope, and transmission electron microscope. The results showed that the as-cast sample microstructure was composed of equiaxed grains rather than coarse dendrites. centrifugal casting inhibits tin diffusion to form metastable phase β′-Cu_13.7Sn. The as-cast sample had good deformability and its tensile strength and elongation were 381.9 MPa and 12.4 %, respectively, which are higher than the mechanical properties of gravity casting. The tensile strength and elongation of the sample after furnace cooling at 620 °C/8 min are 439.5 MPa and 24.4 %, respectively, the increase was 16.6 % and 85.07 %, compared with the as-cast samples, due to the solid solution strengthening, the second phase strengthening and the homogenization of the microstructure.     

In含量对SnBi36Ag0.5无铅焊料合金性能的影响

为了研究In的添加对合金显微组织、熔化特性、润湿性和力学性能的影响.按质量比将纯锡、铋锭、银锭和铟锭在400℃熔化,保温6h,搅拌均匀后在320℃浇铸,制备成SnBi36Ag0.5Inx(x=0％、0.1％、0.2％、0.3％、0.4％、0.5％)焊料合金.利用X射线衍射仪、光学金相显微镜(OM)、扫描电镜能谱(SEM...