Cr对Sn-3.0Ag-0.5Cu无铅焊料抗氧化性能的影响

研究了Cr元素对液态Sn-3.0Ag-0.5Cu(SAC305)焊料在280℃下表面抗氧化性能的影响,并通过扫描电镜(SEM)、俄歇电子能谱(AES)分析了焊料的表面氧化,探讨了Cr改善合金抗氧化性能的机制及其对SAC305无铅焊料显微组织和润湿性能的影响。结果表明,Cr元素的加入可有效提高焊料的抗氧化性,Cr元素在熔融的焊料表面易于生成Cr2O3,其先于Sn氧化形成一种保护性的致密氧化膜,阻碍了焊料的进一步氧化。当焊料中Cr的质量分数达到0.1%(质量分数)时,焊料表面的氧化膜光滑致密,SAC305-0.1Cr液态焊料具有很好的抗氧化性能。另一方面,Cr的加入降低了焊料的润湿性能,随着Cr含量的不断增加,焊料的铺展面积逐渐减少。微量P元素的添加可以改善SAC305-0.1Cr焊料的润湿性。     

新型无铅焊料Sn-Ag-Cu-Cr-X的性能研究

传统的SnPb钎料由于Pb的毒性即将被禁止在微电子连接上使用, 加上现在集成电路小型化、微型化以及高密度化的趋势;对所要开发的无铅钎料性能要求愈来愈高.以 Sn-3.0Ag-0.5Cu钎料为母合金, 添加了不同含量的合金元素Cr以及微量的合金元素Al或P, 得到了一种新的Sn-3.0Ag-0.5Cu-Cr-P, 测得熔点在217 ℃左右, 抗拉强度达46 Mpa, 电导率在8.2(106 S·m-1)以上, 并具有很好的抗氧化性能.     

微量Ga元素对低银系无铅钎料抗氧化性能的影响

电子封装波峰焊从有铅到无铅的转换过程中,由于无铅钎料中锡含量比传统Sn37Pb钎料高,导致波峰焊过程中氧化渣的产生量很大。其不仅造成生产中的浪费,还会影响焊接质量。控制钎料氧化渣的产生量是当前无铅波峰焊技术必须要解决的一个重要问题。研究了目前常用的Sn-0.3Ag-0.7Cu无铅钎料在模拟波峰炉中的抗氧化情况。主要研究了微量Ga元素的加入对该钎料抗氧化性的影响。通过钎料的润湿实验和氧化锡渣的产出量的比较可以发现微量Ga元素的加入可以提高钎料的抗氧化性能,Ga元素的最佳含量是0.02%(质量分数),Sn-0.3Ag-0.7Cu-0.020Ga的抗氧化有效温度范围是320℃以下,有效时间控制在120 min以下。利用俄歇能谱AES分析表明,微量元素Ga在焊料表面富集,O原子浓度的降低。热力学分析表明:Ga元素会在合金中优先氧化,阻碍钎料的进一步氧化;动力学分析表明:在保护膜内高价Ga离子使表面层离子排列空位增加并使电导率降低,是产生抗氧化性的原因。     

添加微量稀土元素对Sn-Ag-Cu系无铅焊料性能的影响

以Sn-3．0Ag-0．5Cu（质量分数，％）焊料为母合金，探讨了微量稀土元素Ce、Er、Y和Sc对Sn—Ag—Cu合金物理性能、润湿性能以及力学性能的影响。试验结果表明：稀土元素对焊料的性能有不同的影响，添加微量Ce元素可以更好地改善焊料综合性能。     

微量Si元素对Sn-0.7Cu钎料组织及钎焊性能的影响

研究了Si元素对Sn-0.7Cu钎料合金钎焊性能的影响。采用感应熔炼工艺制备出Sn-0.7Cu-x Si (x=0,0.1,0.3,0.5,0.75,1.0；%，质量分数)钎料合金，通过扫描电镜(SEM)、能谱仪(EDS)、显微硬度计及万能拉伸实验验机等分析测试方法研究了Sn-0.7Cu-x Si钎料微观组织、界面形貌、熔化特性及力学性能。研究结果表明：加入0.1%的Si元素后，晶粒明显细化，共晶相增多，界面层厚度降低，此时硬度及抗拉强度达到最大值(HV_0.025 11.38,37 MPa)；随着Si含量的继续增加，Sn-0.7Cu-x Si钎料合金晶粒逐渐粗化，共晶组织减少，同时过量黑色的Si颗粒聚集，界面处化合物层厚度不断增加；钎料的熔点随着Si含量的增加无明显变化，过冷度逐渐降低，当Si元素添加量超过0.5%后趋于稳定，相比于Sn-0.7Cu钎料合金降低了46.5%;Sn-0.7Cu-x Si钎料合金的润湿性随着Si含量的增加先升高后降低，在Si元素含量为0.5%处润湿面积最大(93.71 mm²)，显微硬度及剪切强度逐渐降低。     

Al_xCoCrFeNi_2Ti_y高熵合金高温氧化行为的研究

利用非自耗真空电弧熔炼技术制备AlxCoCrFeNi2Tiy(x=0、0.2,y=0、0.5、1)多主元高熵合金,研究了不同含量Al和Ti元素对合金在800、900℃空气中氧化行为的影响。结果表明,所制备合金均有较好的高温抗氧化性能,在800、900℃空气中的氧化动力学曲线均基本符合抛物线规律。随着Al含量的增加,合金的高温抗氧化性能增强;当合金中有Al存在时,其高温抗氧化性能随着Ti含量的增加而减弱,但当合金中无Al存在时,合金的高温抗氧化性能随着Ti含量的增加先增强后减弱。Al0.2CoCrFeNi2合金的高温抗氧化性能最佳,Al0.2CoCrFeNi2Ti0.5次之。     

Zr对Ag-Cu-Ti钎料合金显微组织与力学性能的影响

通过非自耗电弧熔炼与氩气保护浇铸,制备Ag-50Cu-4Ti基钎料合金。采用差热分析(DSC)、X射线衍射(XRD)、显微组织观察及力学性能测试方法,研究Zr含量对基体钎料合金显微组织与力学性能的影响。结果表明,Zr含量的增加并不明显影响钎料合金的熔化温度,其熔点均为783℃左右。随Zr含量的提高,基体合金的显微组织发生明显变化,Zr的添加可降低基体合金中针状Cu3Ti相的体积分数与尺寸,促进弥散分布的(Cu,Ag)5(Ti,Zr)相形成,从而提高合金的维氏硬度与剪切强度。高温氧化实验表明,含Zr合金表现出相对基体合金更为优异的高温抗氧化性能。     

典型添加元素对Sn-Zn系钎料性能的影响

Sn-Zn钎料被认为是传统Sn-Pb共晶钎料的最佳替代合金之一,它以低廉的成本、较好的力学性能以及其共晶成分与Sn-37Pb钎料熔点相近等优点引起了人们的广泛关注,但其润湿性、抗氧化性、抗腐蚀性不够理想.阐述了Bi、A1、In、Ag、Cu及稀土元素(RE)等典型添加元素对Sn-Zn钎料各种性能的影响,以期为Sn-Zn钎料的研究开发和应用提供参考.     

高Al低密度钢的高温氧化行为

为观察Fe-Mn-Al-C系高Al低密度钢在高温下的抗氧化性能,采用氧化增重法测定了4种合金在950~1 100℃下的氧化动力学曲线。通过SEM观察氧化层形貌特征,利用线扫描能谱分析氧化后合金元素的变化,分析了28Mn-10Al合金氧化膜发生膨胀破裂的原因。结果表明,Al元素提高钢的抗氧化性,而Mn元素则降低Al的抗氧化性。抗氧化性较好的28Mn-12Al、20Mn-10Al合金表层未发现Fe的氧化,而氧化严重的28Mn-8Al合金氧化层Fe元素含量较高。28Mn-12Al合金抗氧化性最好,氧化膜的连续性及致密性优于其他3种合金,氧化物连续且晶粒细小,在氧化过程中具有一定的防护作用。     

TiAl基合金高温抗氧化研究进展

综述了TiAl基合金高温抗氧化研究进展,包括TiAl基合金氧化热力学/动力学、氧化膜组成和结构及其形成过程,以及提高合金高温抗氧化性的措施。研究结果表明,TiAl基合金高温氧化动力学一般遵循抛物线规律,且受到合金相组成和组织形貌的影响。氧化膜由外向内,主要呈TiO_2/Al_2O_3/Al_2O_3+TiO_2结构,氧化膜与基体界面处易形成降低合金抗氧化性的Z相(Ti_5Al_3O_2)和氮化产物(TiN,Ti_2AlN)。TiAl基合金中添加适量的Nb,Y,Si,Cr,Mo等元素,在改善力学性能的同时,可明显降低合金高温氧化增重。采用表面处理技术,包括表面离子注入、表面渗透扩散处理以及磷化处理等,可在合金表面形成保护层,显著提高TiAl基合金高温抗氧化性能,然而保护层的稳定性尚需提高。采用涂层技术,包括富Al涂层、陶瓷涂层以及新兴的复合涂层等,可有效地阻止氧向内扩散,抑制TiAl基合金在高温下的氧化行为。     

Effect of Rare-Earth (La,Ce, and Y) Additions on the Microstructure and Mechanical Behavior of Sn-3.9Ag-0.7Cu Solder Alloy

In this article, we report on the microstructure and mechanical properties of Ce- and Y-containing Sn-3.9Ag-0.7Cu solders. The microstructures of both as-processed solder and solder joints containing rare-earth (RE) elements (up to 0.5 wt pct) are more refined compared to conventional Sn-3.9Ag-0.7Cu, with decreases in secondary Sn dendrite size and spacing and a thinner Cu₆Sn₅ intermetallic layer at the Cu/solder interface. These results agree well with similar observations seen in La-containing solders reported previously. The monotonic shear behavior of reflowed Sn-3.9Ag-0.7Cu-X(Ce, Y)/Cu lap shear joints was studied as well as the creep behavior at 368 K (95 °C). The data were compared with results obtained for Sn-3.9Ag-0.7Cu and Sn-3.9Ag-0.7Cu-XLa alloys. All RE-containing alloys exhibited creep behavior similar to Sn-3.9Ag-0.7Cu. Alloys with Ce additions exhibited a small decrease in ultimate shear strength but higher elongations compared with Sn-Ag-Cu. Similar observations were seen in La-containing solders. The influence of the RE-containing intermetallics (CeSn₃ and YSn₃) that form in these alloys on the microstructural refinement, solidification behavior, and mechanical performance of these novel materials is discussed.     

合金元素对Sn-9Zn基无铅钎料润湿性和组织的影响

研究了分别添加混合轻稀土、磷和铋对Sn-9Zn共晶合金在铜基上的润湿性能及对钎料内部显微结构和钎料/铜界面的影响。研究结果表明:Bi、RE和P都能有效地改善Sn-9Zn基合金钎料在铜基上的润湿性;且添加RE和P对钎料/铜界面无明显的影响,也不改变Sn-9Zn钎料内部的扫把状共晶结构;而添加Bi促进了Sn-9Zn合金中锌的富集析出。     

Microstructures and properties of SnZn-xEr lead-free solders

The Sn9Zn eutectic alloy is the nontoxic lead-free solders alternative having a melting temperature which is closest to that of the eutectic SnPb alloy. In order to improve the properties of SnZn lead-free solders, 0-0.5 wt.% of rare earth Er was added to the base alloys, and the microstructures were studied. Results showed that the addition of rare earth Er could enhance the wettability of SnZn solders, with 0.08%Er addition, the spreading area gave an 19.1% increase. And based on the mechanical testing, it was found that the tensile force and shear force of SnZn-xEr solder joints could be improved significantly. Moreover, the oxidation resistance of SnZn0.08Er solder was better than that of SnZn solder. In addition, it was found that trace amounts of rare earth Er could refine the microstructures of SnZn solders, especially for Zn-rich phases, and excessive amount of rare earth Er led to a coarse microstructure.     

Effect of Microalloying on Wettability, Oxidation and Solidification Morphology of Sn-9Zn Alloy

EutecticorcloseneareutecticSn Pballoysare extensivelyusedinelectronicinterconnectionand packagingbecauseoftheirlowmeltingtemperatures, excellentwettabilitytocoppersubstratesandlow cost.Existingproductionlinesaredesignedonbasis ofSn Pbsolders.Withtheaccele…     

Microstructural analysis of lead-free solder alloys

Among the many issues related to the performance of lead-free solder alloys, the dependence of their mechanical properties on the microstructure and the stability of the microstructure stability are some of the most important issues. A comprehensive understanding of the process-microstructure-property relationships is essential. Toward that goal, a microtextural analysis is performed using orientation imaging microscopy (OIM) for alloy Sn-3.8Ag-0.7Cu (wt pct) processed at four different temperatures. Sn-3.8Ag-0.7Cu is one of the most promising lead-free solder alloys that has shown superior mechanical properties to other candidate lead-free solder alloys. However, a comprehensive understanding of their microstructure and the dependence of microstructure on processing conditions are still lacking. In the present work, a detailed microstructure characterization with respect to phase compositions, grain size and size distributions, texture, and orientation relationships between various phases are performed. The measured microstructural features are correlated with the soldering temperatures.     

微量Ge对Sn-0.7Cu高温钎焊界面组织的影响

测试了Sn-0.7Cu和Sn-0.7Cu-0.012Ge钎料在不同钎焊温度下的润湿性,研究了Ge元素对老化过程中钎焊界面金属间化合物(IMC)层生长速率的影响。结果表明:2种钎料的润湿性相差不大,但添加了Ge元素的Sn-0.7Cu-0.012Ge钎料在不同钎焊温度下的漫流性得到了明显的改善,相应提高了约4.00%~5.00%;250℃和350℃钎焊温度下,Sn-0.7Cu/Cu钎焊界面IMC在150℃的老化条件下的生长速率分别为3.24×10-18m2/s和2.50×10-17m2/s,Sn-0.7Cu-0.012Ge/Cu钎焊界面IMC的生长速率分别为2.66×10-18m2/s和1.48×10-17m2/s。Ge元素在钎焊界面处富集,提高了界面IMC的致密性,阻碍了原子的扩散,在一定程度上抑制了界面IMC层的粗化与增厚。     

Dissolution and interface reactions between the 95.5Sn-3.9Ag-0.6Cu, 99.3Sn-0.7Cu, and 63Sn-37Pb solders on silver base metal

Dissolution and intermetallic compound (IMC) layer development were examined for couples formed between 99.9 silver (Ag) and molten 95.5Sn-3.9Ag-0.6Cu (wt pct), 99.3Sn-0.7Cu, and 63Sn-37Pb solders, using a range of solder temperatures and exposure times. The interface reactions that controlled Ag dissolution were sensitive to the solder composition. The Ag₃Sn IMC layer thickness and interface microstructure as a whole exhibited nonmonotonic trends and were controlled primarily by the near-interface solder composition. The kinetics of IMC layer growth were weakly dependent upon the solder composition. The processes of Ag dissolution and IMC layer growth were independent of one another.