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.     

微量Nd对Sn-9Zn钎料特性及焊点组织与性能的影响

研究Sn-9Zn中添加微量稀土元素Nd对合金显微组织和铺展性能的影响,对比分析Sn-9Zn-xNd(x=0,0.1,0.5)钎料/Cu焊点界面微观特征及力学性能。结果表明:微量Nd元素在Sn-9Zn合金中能够显著细化组织,但添加量为0.5%时合金中形成了"十字状"NdSn3金属间化合物(IMC)。钎焊温度较低或时间较短时,微量Nd添加能够改善Sn-9Zn合金在Cu基板上的铺展性能;但是在温度较高或时间较长的钎焊工艺条件下,由于Nd元素的严重氧化导致钎料铺展性能明显下降。在Sn-9Zn中添加0.1%Nd,在界面处形成了均匀细密分布的"毛绒状"共晶组织,能够提高焊点结合性能;Nd添加量为0.5%时,成分偏聚引起的组织不均匀导致焊点力学性能下降。     

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.     

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.     

Sn-8Zn-3Bi无铅钎料的抗氧化性

为了提高Sn-8Zn-3Bi合金钎料的抗氧化性,在Sn-8Zn-3Bi合金基础上,通过加入少量的其他合金元素(A1,P)以提高钎料的抗氧化性.少量A1的加入降低了Sn-8Zn-3Bi钎料的氧化量,而加入P的Sn-8Zn-3Bi钎料在加热过程中不仅没有质量增加,反而出现减重现象.通过扫描电镜和X射线衍射等分析手段研究样品的表面微观结构和显微组织,探讨了A1,P的抗氧化机理.分析结果表明:A1通过在合金表面形成一层致密的氧化膜,阻止钎料直接接触周围空气,从而达到了降低氧化速率的目的;P通过自身不断被氧化而消耗钎料表面的O原子,从而保护元素Sn和Zn不被氧化.     

Influence of Cu content on the mechanical properties and corrosion resistance of Mg-Zn-Ca bulk metallic glasses

(Mg_66.2Zn_28.8Ca₅)_100?xCu_x (at%, x = 0, 1, 3, and 5) bulk metallic glasses (BMGs) of 2 mm in diameter were prepared by the conventional copper mold injection casting method. Besides, the influence of Cu content on the microstructure, thermal stability, mechanical properties, and corrosion behavior of Mg-Zn-Ca BMGs was investigated. It is found that the addition of Cu decreases the glass-forming ability of Mg-Zn-Ca BMGs. Crystalline phases are precipitated at a higher Cu content, larger than 3at%. The compressive fracture strength of Mg-Zn-Ca BMGs is enhanced by the addition of Cu. With the formation of in-situ composites, the compressive strength of the Mg-Zn-Ca alloy with 3at% Cu reaches 979 MPa, which is the highest strength among the Mg-Zn-Ca alloys. Furthermore, the addition of Cu also results in the increase of corrosion potential and the decrease of corrosion current density in Mg-Zn-Ca BMGs, thereby delaying their biodegradability.     

Optimization of mechanical properties of Sn-3.8Ag-0.7Cu alloys by the additions of Bi,In and Ti

Bi, In and Ti were added to Sn-3.8Ag-0.7Cu (SAC387) solder alloy to optimize the mechanical performance. The alloying effects of Bi, In and Ti on the microstructure, thermal and mechanical properties of SAC387 based solder alloys were investigated. The results demonstrate that adding 3.5 ?wt % of Bi could refine the microstructure, optimize the thermal properties, and improve the tensile strength. Meanwhile, the ductility of the solder alloys reduced evidently. Adding 2.8 ?wt % of In into SAC387–3.5 ?wt %Bi alloy could increase both the strength and ductility, which is attributed to the beneficial effect of In addition, as adding In could improve the solubility of Bi in the β-Sn matrix. Meanwhile, the melting point was reduced, and the wettability improved with the addition of In. Introducing amounts of Ti into SAC387–3.5 ?wt % Bi-2.8 ?wt % In alloy could further increase the strength. However, the ductility was significantly reduced when 0.8 ?wt % of Ti was added due to the formation of the coarse Ti₂Sn₃ phase. The undercooling was remarkably reduced with the addition of Ti. The nanoindentation tests demonstrate that the hardness increased mainly due to the hardening effect of the Bi addition. Among all the samples prepared, alloy SAC387–3.5 ?wt % Bi exhibited the highest creep resistance at the ambient temperature. Further adding In and Ti into SAC387–3.5 ?wt % Bi alloys reduced the creep resistance of the solder alloys. The mechanism associated with the different mechanical responses is also discussed in this study.     

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.     

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。     

Interfacial intermetallic compound growth and shear strength of low-silver SnAgCuBiNi/Cu lead-free solder joints

The growth rule of the interfacial intermetallic compound (IMC) and the degradation of shear strength of Sn-0.8Ag-0.5Cu-2.0Bi-0.05Ni (SACBN)/Cu solder joints were investigated in comparison with Sn-3.0Ag-0.5Cu (SAC305)/Cu solder joints aging at 373, 403, and 438 K. The results show that (Cu_1?x,Ni_x)₆Sn₅ phase forms between the SACBN solder and Cu substrate during soldering. The interfacial IMC thickens constantly with the aging time increasing, and the higher the aging temperature, the faster the IMC layer grows. Compared with the SAC305/Cu couple, the SACBN/Cu couple exhibits a lower layer growth coefficient. The activation energies of IMC growth for SACBN/Cu and SAC305/Cu couples are 111.70 and 82.35 kJ/mol, respectively. In general, the shear strength of aged solder joints declines continuously. However, SACBN/Cu solder joints exhibit a better shear strength than SAC305/Cu solder joints.     

Sn-8Zn-3Bi-P无铅钎料微观组织及性能

研究了Sn-8Zn-3B i-xP钎料的抗氧化性、熔点、组织及力学性能.热重分析表明:P元素的加入显著降低了钎料熔体表面的氧化量;采用俄歇能谱分析氧化层的成分和厚度,发现含P的钎料表面形成的ZnO层厚度明显降低,约为80 nm;对合金进行差热分析发现少量P的加入并不改变钎料的熔点和熔程;P的加入对钎料合金的强度几乎没有影响,但却降低了合金的塑性,这是因为含P合金中有粗大的富Zn相形成,断口分析显示在Zn相与Sn相晶界上容易出现裂纹,从而导致钎料的塑性下降.     

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.     

界面反应及界面张力对Sn-Zn-Bi焊料润湿性的影响

通过合金化的方式得到了Sn-Zn-Bi三元及Sn-Zn-Bi-Nd四元无铅焊料,采用润湿平衡法测量了其润湿力和润湿时间,并对润湿后的焊料/Cu界面组织进行了分析.结果表明:Bi元素不参与焊料/Cu界面的扩散反应,但能够通过吸附作用降低界面张力,从而提高焊料在Cu基底上的润湿力;Zn元素优先向焊料/Cu界面进行扩散形成Cu5Zn8金属间化合物,且扩散层随焊料中Zn含量的提高而增长,此时固-液界面张力方向发生改变,润湿力提高,但润湿时间延长;Nd元素的作用类似于Bi,既能提高焊料的润湿力,也能够缩短润湿时间,是一种改善Sn-Zn基焊料润湿性的有效元素.     

Corrosion behavior of as-cast Mg–8Li–3Al+xCe alloy in 3.5wt% NaCl solution

Mg–8Li–3Al+xCe alloys (x = 0.5wt%, 1.0wt%, and 1.5wt%) were prepared through a casting route in an electric resistance furnace under a controlled atmosphere. The cast alloys were characterized by X-ray diffraction, optical microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The corrosion behavior of the as-cast Mg–8Li–3Al+xCe alloys were studied under salt spray tests in 3.5wt% NaCl solution at 35°C, in accordance with standard ASTM B–117, in conjunction with potentiodynamic polarization (PDP) tests. The results show that the addition of Ce to Mg–8Li–3Al (LA83) alloy results in the formation of Al₂Ce intermetallic phase, refines both the α-Mg phase and the Mg₁₇Al₁₂ intermetallic phase, and then increases the microhardness of the alloys. The results of PDP and salt spray tests reveal that an increase in Ce content to 1.5wt% decreases the corrosion rate. The best corrosion resistance is observed for the LA83 alloy sample with 1.0wt% Ce.     

基于 NiTi 温敏形状记忆纳米结构调控的润湿性研究

NiTi 合金是常见的形状记忆合金,有着良好的形状记忆效应、超弹性、耐腐蚀性和生物相容性,在生物医疗、 航空航天和微机电等领域有着广泛的应用。 目的 研究 NiTi 合金表面不同纳米级结构的润湿性能,改善 NiTi 合金 在工作环境下的磨损情况,提高 NiTi 合金的使用寿命。 方法 使用分子动力学方法模拟周期性边界条件下 NiTi 合 金的形状记忆效应,研究在不同温度下 NiTi 合金原子的微观结构演化;同时基于 NiTi 合金温度响应下不同的微观 结构,建立液滴静态接触角仿真,研究 NiTi 合金表面在不同微观结构下的润湿性能。 结果 发现 NiTi 合金在不同温 度响应下发生相变,从而使 NiTi 合金的表面原子排列发生改变,展示了温度诱发 NiTi 合金的相变和逆相变行为以 及在原子尺度下的微观结构演化,再以不同温度响应下发生相变和逆相变的 NiTi 合金表面作为基底,发现其表面 的润湿性也发生了改变和恢复。 结论 NiTi 合金随温度响应发生相变,微观结构发生改变,其表面的润湿性能也发 生改变;而且 NiTi 合金随温度逆相变,微观结构恢复到初始状态,其表面润湿性也能随之恢复到初始状态;NiTi 合 金在相变过程中的奥氏体和马氏体含量会影响 NiTi 合金表面润湿性能,因此能够通过温度进行 NiTi 合金表面在 微观结构下润湿性的自适应调控。     

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.     

Ameliorating mechanical properties and reducing anisotropy of as-extruded Mg-1.0Sn-0.5Ca alloy via Al addition

Effects of Al addition to a Mg–Sn–Ca ternary alloy on its microstructure and tensile properties after extrusion were studied via extrusion of Mg-1.0Sn-0.5Ca-xAl (x ​= ​0, 0.8, 2.4 ​wt%) sheets and analysis of the extruded materials. The results showed that Al addition not only refined the grain size (from 9.8 ​± ​0.7 ​μm to 8.3 ​± ​0.4 ​μm and 7.6 ​± ​0.5 ​μm) but also accelerated the generation of more second phase (from 0.98 to 1.72 and 4.32%). Except for the CaMgSn and Mg₂Ca in Mg-1.0Sn-0.5Ca alloy, new phase (Mg, Al)₂Ca appeared after Al addition. The addition of Al into Mg–Sn–Ca alloy induced the textural variation from an initially ED-split double-peaked texture to a weakened texture, i.e., divergent elliptical texture, due to the effect of particle stimulated nucleation. This eventually contributed to the improvement of mechanical anisotropy as well as the higher Hc value and n-value. For the strain hardening behavior when tension along the TD, the prolonged stage Ⅱ of Al-modified alloys was closely connected with the additional TD textural components, accelerating the activation of more basal slip. The decreased θⅢ0 in stage Ⅲ of Al-modified alloys is beneficial to the grain refinement and the emergence of more second phase.     

Sn-Zn基无铅焊接材料的界面反应和润湿性能

总结了近年来Sn-Zn基与不同成分基板的界面反应的研究现状,概括了界面反映的主要生成物是Cu6Sn5和Cu5(Zn,Sn)两种化合物.同时总结了提高Sn-Zn基无铅焊料润湿性能所作的工作,指出在添加剂中加入金属有机物可能会成为提高焊料润湿性能的一个途径.     

Cu-Zn-Al2O3 nanocomposites:study of microstructure,corrosion,and wear properties

Alumina nanoparticles were added to a Cu-Zn alloy to investigate their effect on the microstructural, tribological, and corrosion properties of the prepared alloys. Alloying was performed using a mixture of copper and zinc powders with 0vol% and 5vol% of α-Al nanopowder in a satellite ball mill. The results showed that the Cu-Zn solid solution formed after 18 h of mechanical alloying. The mechanically alloyed powder was compacted followed by sintering of the obtained green compacts at 750℃ for 30 min. Alumina nanoparticles were uniformly distributed in the matrix of the Cu-Zn alloy. The tribological properties were evaluated by pin-on-disk wear tests, which revealed that, upon the addition of alumina nanoparticles, the coefficient of friction and the wear rate were reduced to 20% and 40%, respectively. The corrosion properties of the samples exposed to a 3.5wt% NaCl solution were studied using the immersion and potentiodynamic polarization methods, which revealed that the addition of alumina nanoparticles reduced the corrosion current of the nanocomposite by 90%.     

硬脂酸改性处理TC4钛合金微弧氧化膜层耐蚀性的研究

在Ti₆Al₄V合金微弧氧化膜层上采用硬脂酸改性处理实现了陶瓷膜层的疏水化转变，显著提高了钛合金的耐蚀性能。利用接触角测试仪、扫描电子显微镜（SEM）、能谱仪（EDS）和傅里叶变换红外光谱仪（FT-IR）对膜层的润湿性、稳定性、微观结构和化学组成进行了分析，并通过动电位极化曲线和电化学阻抗分析了其腐蚀行为。结果表明，改性处理得到的疏水微弧氧化膜层试样能有效修复微弧氧化膜层缺陷，提高钛合金的耐蚀性能，说明硬脂酸改性处理与微弧氧化技术相结合有助于拓宽微弧氧化技术在钛合金上的应用。