用快速凝固Sn活性钎料低温连接ZnO陶瓷

在大气中成功地用快速凝固Ｓｎ基活性钎料低温连接ＺｎＯ陶瓷，接头的剪切强度明显高于用普通凝固钎料的最高达６０Ｍａ。     

超声作用下Mg-Zn-Al钎料的润湿与铺展

在大气环境中,对Mg-Zn-Al钎料进行超声振动作用下的铺展,超声时间分别为1,2,3,4s,并与钎剂作用下的钎料铺展行为进行对比。采用体视显微镜观察钎料在超声及钎剂作用下的铺展形貌。采用光学显微镜观察钎料铺展初始端、铺展末端及铺展后钎料的微观组织形貌。结果表明:超声振动作用下的Mg-Zn-Al钎料沿基体表面作受迫铺展,声空化作用于液态钎料产生的冲击波可以破碎基体表面的氧化膜,使液态钎料与母材发生润湿,母材溶解的深度仅有0.12mm。超声时间为2s时,钎料铺展面积最大。超声声空化作用破碎液态钎料在凝固期间产生的α-Mg固溶相及MgZn共晶相,使铺展后的钎料显微组织得到细化。     

第十四讲:真空工程用焊接技术

7．2．2扩散钎焊用钎料 扩散钎焊时，钎料起着决定性的作用。与一般钎焊方法相比，扩散钎焊用钎料应满足两个特殊要求：一是应含有一定量能够降低钎料熔点的降熔元素，这些元素在扩散钎焊过程中又非常容易地扩散到基材中或被基材溶解；二是降熔元素扩散或被溶解后，钎料的强度和性能应能满足设计和使用要求。     

关于液态Sn—Ag—Cu钎料润湿性能的实验研究

采用钎料改性工艺制备了Sn-3．5Ag0．6Cu合金，用润湿平衡法测试了液态Sn-3．5Ag0．6Cu钎料在铜基体表面的润湿性，研究了钎料制备工艺、钎剂卤素含量、浸渍温度和时间等因素对润湿性能的影响。结果表明：采用改性工艺可增强钎料的润湿性能，当钎剂卤素含量为0．4％（质量分数）、在270℃下浸渍2～3s时，液态Sn-3．5Ag0．6Cu钎料对铜表面的润湿性可以达到最佳状态。指出降低钎料的熔点和液态表面张力是提高润湿性的关键。     

压缩机铜管钎焊接头裂缝原因分析

采取化学成分分析、金相检验、扫描电镜(SEM)断口分析方法对压缩机铜管钎焊接头裂缝缺陷进行研究与分析,并通过在线模拟试验方法验证分析结果。结果表明,铜管钎焊接头裂缝主要原因为接头受到不均匀的二次加热出现收缩不一致,局部加热温度过高且超过钎料熔点使钎料重新熔化,钎料再次凝固时,部分空气残留在焊缝区域伴随钎料一起冷却,最终在钎料内部形成疏松和孔洞,降低钎焊接头强度;钎焊接头母材的热膨胀系数不同,使钎料在冷却过程中形成的内应力过大,最终导致铜管钎焊接头出现裂缝。     

电子和光子封装无铅钎料的研究和应用进展

对目前国内外电子和光子封装用无铅钎料研究和应用的新进展和发展趋势进行了回顾、评述和展望,重点评述了无铅钎料的种类和钎焊接头的力学性能、封装结构的可靠性和耐久性,以及目前出现的影响电子封装可靠性的一些新问题（如电迁移和锡须问题）．对光子封装钎料和相关钎焊工艺也进行了简要评述．最后,探讨了电子和光子封装无铅钎料及其可靠性和耐久性研究的发展趋势．     

钎焊工艺对Ni/BNi7+Cu9%钎缝组织及显微硬度的影响

为了改善Ni基钎料钎焊接头脆硬的共晶组织,本文采用BNi7+9%Cu复合钎料对纯镍进行真空钎焊。结果表明:温度越高,间隙越大,扩散影响区越大,钎缝区显微硬度越低,扩散影响区显微硬度越高。当钎焊接头间隙为30μm,温度960℃时,钎缝接头主要由等温凝固区、非等温凝固区和扩散影响区组成。等温凝固区为富(Cr、Cu)的γ(Ni)固溶体,非等温凝固区为γ(Ni)+Ni3P共晶组织,扩散影响区为少量的共晶组织和γ(Ni)固溶体;而温度980℃时,钎焊接头是由中心的Ni3P组织和扩散影响区的γ(Ni)固溶体组成。当钎焊接头间隙为100μm时,其扩散影响区的范围要比30μm的大,在960℃时,钎缝填充不好,有很多孔洞。     

真空电子钎焊用银钎料的研究现状

本文简述了真空电子钎焊用银钎料的特点,对银钎料的研究现状和发展方向进行了阐述,明确了目前银钎料的使用现状,对银钎料的后续研究提出了看法。     

真空技术及应用系列讲座 第十四讲:真空工程用焊接技术

(上接2006年第2期第64页)②对于不同的钎料与基材组合,其获得接头最高强度值的最佳间隙值范围各不相同,这与钎料和基材各自的物理化学性能以及在钎焊过程中的相互作用特性有密切关系。一般来说,钎料对基材的润湿性越好,这一间隙值就越小;钎料与基材相互作用强烈,间隙必须增大,因为填缝时基材的溶入会使钎料熔点提高、流动性下降。例如用铝基钎料钎焊铝合金时,基材向钎料中的溶解很强烈,为了保证填满钎缝,要求较大的间隙;相反,用银基或铜基钎料钎焊钢时,钎料与基材相互作用很弱,采用较小的间隙有助于加强钎料的毛细填缝。表12中所推荐的不同…     

新型代银钎料研究

研制出一种代银钎料，其最佳成分为：５５％～７５％Ｃｕ，５％～２０％Ａｇ，１２％Ｓｎ，８％Ｉｎ。它的润湿作用和填充间隙的能力接近或优于ＢＡｇ７２Ｃｕ。对用该种代银钎料钎焊的ＺＡ１４型平板凹台型管壳进行了性能测试。研究表明，采用快速凝固技术可将该种代银钎料制成薄带，其组织由银或富银的固溶体塑性相和其上分布的脆性相组成。     

Joining of sialon ceramics by Sn-5 at % Ti based ternary active solders

The effect of a third element, such as silver, copper, indium, nickel or aluminium, on the joining of sialon ceramics with tin-5 at % titanium based ternary active solders was investigated. The content of the third element in the Sn-based solders was varied from 5–40% for Cu, from 5–10% for Ag and Al from 5–20% for In and from 1–5% for Ni. The joining was carried out in vacuum at 1100 K for 20 min. The four point bend testing of a butt joint of a ceramic/ceramic structure with dimensions 40 mm long, 3 mm wide and 4 mm high was used to study the bond strength between the ceramic and the Sn-based solders. The results show that the bond strength of the Sn-based solder with the sialon ceramic varied from 54–103 MPa. Small additions of Cu or Ag (about 5–10%), In (about 5–10%), or Ni (about 1–3%) to the solder is beneficial, but too much Ni (more than 5%) or In (more than 10%) is detrimental. On the other hand, Al in the active solder considerably decreased the bond strength of the solders with the ceramic. Suggestions are made for the selection of the third element in order to improve the bond strength of the soft solders with the ceramic. These include a high surface energy, improving the wetting of the solder on the ceramic and strengthening of the solder. This revised version was published online in November 2006 with corrections to the Cover Date.     

Transient liquid-phase insert metal bonding of Al2O3 and AISI 304 stainless steel

Transition liquid-phase insert metal bonding of Al2O3 and AISI 304 stainless steel based materials is investigated. This joining technique allows the continuous replenishment of the active solute which is consumed by the chemical reaction that occurs at the ceramic/filler metal interface. Replenishment is facilitated by employing a sandwich of filler materials comprising tin-based filler metal and amorphous Cu50Ti50 or NiCrB interlayers. During Al2O3/AISI 304 stainless steel bonding, the highest shear strength properties are produced using a bonding temperature of 500 °C. Thick reaction layers containing defects form at the ceramic/filler material interface when higher bonding temperatures are applied. Bonding at temperatures above 500 °C also increases the tensile residual stress generated at the periphery of Al2O3/AISI 304 stainless steel joints. The shear strength of joints produced using NiCrB interlayers markedly increased following heat treatment at 200 °C for 1.5 h. Heat treatment had little influence on the shear strength of the joint produced using Cu50Ti50 interlayers. This revised version was published online in November 2006 with corrections to the Cover Date.     

Bond Strength of the Sn-Ti-Ⅹ Ternary Active Solders on Sialon Ceramic

The bond strength of the Sn based ternary active solders,Sn-5Ti with various contents of Ag,Cu,In,Ni or AI on sialon ceramic was investigated by the ceramic/ceramic joint joining.The bond strengthof Sn-STi (about 80 MPa) may increase to 90-100 MPa by small addition of Ag or Cu (about5-10%).A little Ni (about 1-3%) in the solder is slightly beneficial,but too more Ni (more than 5%)is harmful.Small addition of In is trivial,but too more In is detrimental.On the other hand,small addi-tion of AI in the active solder decreases greatly the bond strength of the solder,therefore it is veryharmful.In discussion,three suggestions for selection of the third element to increase the bondstrength of the soft solders on ceramic,i.e.with a high surface energy,benefiting to wetting on ce-ramic and strengthening the soft solder itself,have been made.     

Al-Ti合金钎焊SiC陶瓷接头界面微观结构与力学性能

SiC陶瓷具有优异的综合性能, 通过钎焊获得高强度接头是其获得广泛应用的重要前提。研究采用Al-(10, 20, 30, 40)Ti(Ti的名义原子含量10%、20%、30%、40%)系列合金, 在1550 ℃条件下, 对SiC陶瓷进行钎焊30 min。当中间层厚度为~50 μm时, SiC钎焊接头的平均剪切强度处于100~260 MPa范围内。当采用Al-20Ti合金作为钎料时, 随着中间层厚度从~100 μm减小至25 μm, 钎焊接头的平均强度逐渐提高, 且最大强度~315 MPa。同时, 钎焊中间层中(Al)相逐渐减少直至消失, 只留下Al₄C₃、TiC和(Al,Si)₃Ti相。SiC/Al-20Ti/SiC钎焊接头的断裂主要发生在靠近中间层/陶瓷界面位置的陶瓷基体内。     

The influence of brazing conditions on joint strength in Al2O3/Al2O3 bonding

The brazing of alumina ceramic to itself was performed using Ag₅₇Cu₃₈Ti₅ filler alloy. The bonding was carried out in a vacuum of 7 × 10^?3 Pa, and the joining conditions were at 1073, 1123, 1173, 1223, 1273 and 1323 K for 1.8ks under a pressure of 0.01 MPa, at 1123 K with a pressure of 0.01 MPa for 0, 0.3, 0.9, 1.8, 2.7 and 3.6 ks, and at 1123 K for 1.8 ks with pressures of 0, 0.01, 0.05, 0.10, 0.15, 0.20 and 0.30 MPa, to determine the effects of joining temperature, pressure and holding time on the joint strength. The joint strength was measured by shear tests. The interface microstructures and fractured surfaces after testing were observed by scanning electron microscopy (SEM). It was shown that the shear strength of Al₂O₃/Al₂O₃ joints was largely affected by the joining conditions; it first increased and then decreased with increasing joining temperature, pressure and holding time and depended mainly on the strength of interfacial reaction layer itself and the interface bonding strength between the reaction layer and the ceramic. The maximum joint strength was obtained when the reaction occurred under a suitable temperature, pressure and time, and the reaction layer thickness was about 2 μm. SEM observations revealed that there were four types of fracture and each kind corresponded to a different strength.     

Low temperature TLP bonding of Al2O3–ceramics using eutectic Au–(Ge, Si) alloys

In this study, Al₂O₃–ceramics were joined via TLP bonding using interlayers of eutectic Au–12Ge (wt%) and Au–3Si (wt%) solder alloys, respectively, with a melting temperature of 361 and 363 °C and Ni wetting layers. The Ni layers were part of a metallic multilayer coating (Ti/W/Ni) applied on the ceramic surface to ensure wetting and adhesion during the joining process. For comparison, a soldering process was performed as well by changing the multilayer structure to Ti/W/Au. With respect to the different joining processes the influence of the variation in wetting layers on the interface reactions, mechanical properties and re-melting temperature was analyzed by scanning electron microscopy, shear testing, and differential scanning calorimetry. It is shown that sound joint can be produced at a joining temperature of 400 °C, achieving reasonable shear strength and re-melting temperatures more than 550 °C above the initial melting temperature of the filler metal.     

Microstructure and strength of brazed joints of Ti3Al-base alloy with different filler metals

The interfacial microstructure and properties of brazed joints of a Ti₃Al-based alloy were investigated in this paper to meet the requirements of the use of Ti₃Al-based alloy in the aeronautic and space industries. The effects of different brazing fillers on the interfacial microstructure and shear strength were studied. The relationship between brazing parameters and shear strength of the joints was discussed, and the optimum brazing parameters were obtained. The brazed joints were qualitatively and quantitatively analyzed by means of EPMA, SEM and XRD. The results showed that using a AgCuZn brazing filler, TiCu, Ti(Cu,Al)₂ and Ag[s,s] were formed, the shear strength of the joint was decreased because of the formation of TiCu and Ti(Cu,Al)₂; using a CuP brazing filler, Cu₃P, TiCu and Cu[s,s] were formed at the interface of the joint, the former two intermetallic compounds decreased the shear strength. The analysis also indicated that using the TiZrNiCu brazing filler, the optimum parameters were temperature T=1323 K, joining time t=5 min, and the maximum shear strength was 259.6 MPa. For the AgCuZn brazing filler, the optimum parameters were joining temperature T=1073 K, joining time t=5 min, and the maximum shear strength was 165.4 MPa. To the CuP brazing filler, the optimum parameters were joining temperature T=1223 K, joining time t=5 min, and the maximum shear strength is 98.6 MPa. Consulting the results of P. He, J.C. Feng and H. Zhou [Microstructure and strength of brazed joints of Ti₃Al-base alloy with NiCrSiB, Mater. Charact., 52(8) (2004) 309–318], relative to the other brazing fillers, TiZrNiCu is the optimum brazing filler for brazing Ti₃Al-based alloy.     

Effect of a silicon sintering additive on solid state bonding of SiC to Nb

Pressureless-sintered (PLS) SiC was joined to Nb by solid state bonding in a vacuum. The joining strength of the PLS SiC/Nb joint increases to the saturated value of 108 MPa with increasing joining pressure at a joining condition of 1673 K and 7.2 ks. This saturated value of PLS SiC/Nb joint is higher than that of the reaction sintered (RS) SiC/Nb joint. The strength of SiC itself affects the strength of the SiC/Nb joint. The high stability of the intermediate phase Nb₅Si₃ in the interface at elevated temperature leads to the high heat resistance of the joint. The thickness of the intermediate phase Nb₅Si₃ in the PLS SiC/Nb system is lower than that of the RS SiC/Nb system at a constant joining time, although the activation energy, 452 kJ mol^–1, of growth for the phase in the PLS SiC/Nb system is almost the same as the RS SiC/Nb system, 456 kJ mol^–1. The rate constant of the growth for the phase in the PLS SiC/Nb system is lower than that in the RS SiC/Nb system. The excess silicon in RS SiC promotes the formation of the Nb₅Si₃ phase at the interface between SiC and Nb.     

Zr对(Ag-Cu-Ti)-SiCp钎焊SiC陶瓷/钛合金连接层组织结构的影响

使用Ag-Cu-Ti合金粉,SiC粉和Zr粉组成的混合粉末钎料,真空无压钎焊再结晶SiC陶瓷与Ti合金,观察Zr加入前后接头连接层组织结构的变化,研究了Zr的作用．结果表明,Zr加入前,连接层主要由Ag、SiC、Cu—Ti、Ti3SiC2、和Ti-Si相组成．Zr加入后,连接层主要由SiC、Ti1-xC、Ti-Si、AgTi和AgCu4Zr相组成．Zr的加入提高了连接层中Ti的活度,使SiC颗粒表面反应层Ti3SiC2转变,生成了Ti1-zC和TiSi相;提高了Ti与SiC颗粒的反应速度,使SiC颗粒减少;促进Ti与Ag的反应,生成了AgTi．Zr的加入导致连接层流动性的改善、连接层与SiC陶瓷界面结合强度的提高和接头热应力的降低,适量Zr的加入使接头剪切强度明显提高（达23．6MPa）．