Cu—Zn—Al合金贝氏体的三个生长阶段及其精细结构研究

利用透射镜研究了Ｃｕ－Ｚｎ－Ａｌ合金贝氏体α１相在相变过程中的精细结构变化，发现贝氏体的生长经历三个阶段：初生态、中间态和退化态。初生贝氏体内不含层错亚结构，α１依台阶机制长大到一定程度后，内部出现层错；随转变进一步进行，α１内的层错结构逐渐消失，发生“过退火”，最终向平衡相转变。     

Cu—Zn—Al合金中贝氏体的扫描隧道显微镜分析

本文用扫描隧道显微镜（ＳＴＭ）在大气中研究了Ｃｕ－２７．２ｗｔ．％Ｚｎ－４．７ｗｔ．％Ａｌ合金中的贝氏体的精细结构，并与透射电镜（ＴＥＭ）及扫描电镜（ＳＥＭ）下的形态进行了比较，发现Ｃｕ－Ｚｎ－Ａｌ合金中虫氏体是由亚片条或亚单元组成，亚单元由超亚单元构成，进而为贝氏相变机制的再认识提供了重要的实验基础，并在此基础上提出Ｃｕ－Ｚｎ－Ａｌ合金中贝氏体的形成模型。     

添加Ni—Fe或Ni—Cr合金对Mo粉末压坯烧结行为的影响

添加少量纯Ｎｉ粉不仅可以降低Ｍｏ的烧结温度,而且也大大地提高烧结密度。例如,添加２％的纯Ｎｉ粉可以使Ｍｏ在相应烧结温度一半时达到９４％的相对密度。烧结Ｍｏ坯的工与烧结温度有很强的关系,其烧结过程中的活化能,与Ｍｏ的体弥散能相比迅速下降,在相当短的时间内即完成整个烧结过程。     

硅片上电镀铅锡合金工艺

介绍了硅片上电镀铅锡合金工艺,并对镀液中各成分的作用及影响镀层质量的因素进行了探讨.     

关于Cu—Zn—Al贝氏体相变的阶段性—亚结构与体转变激活能

从Ｃｕ－Ｚｎ－Ａｌ合金相变产物的形貌与亚结构的特征着手分析了贝氏体相变的阶段性。测定了贝氏体相变阶段的体转变激活能并讨论了贝氏体相变的性质。     

Cu、Zn掺杂对Co2Y软磁铁氧体性能的影响

介绍了通过掺杂Cu、Zn离子对Co2Y(Ba2Co2Fe12O22)型平面六角结构软磁铁氧体的成相及其性能的影响。采用传统的固相反应法制备样品，Ba2Co1.2-xZnxCu0.8Fe12O22(x=0-1.2)的合成温度低，成相温度范围比较宽，易于成相。在甚高频段，对Ba2Co1.2-xZnxCu0.8Fe12O22的磁性能、介电性能及改善进行了深入的探讨。     

化学镀Cu—Ni合金

概述了PH=5—10的化学镀Cu—Ni合金工艺,用以取代传统的以HCHO为还原剂的强碱性化学镀Cu工艺,特别适用于刚性印制板,挠性印制板磁带自动粘结等电子部品的制造。     

化学镀Cu—Ni合金工艺

概述了ＰＨ５－１０的化学镀Ｃｕ－Ｎｉ合金工艺。特别适用于制造刚性印制板（ＲＰＣ）、挠性印制板（ＦＰＣ）和磁带自动粘结带（ＴＡＢ）等电子部品。     

Solid-State Reactions between Cu(Ni) Alloys and Sn

Solid-state interfacial reactions between Sn and Cu(Ni) alloys have been investigated at the temperature of 125°C. The following results were obtained. Firstly, the addition of 0.1 at.% Ni to Cu decreased the total thickness of the intermetallic compound (IMC) layer to about half of that observed in the␣binary Cu/Sn diffusion couple; the Ni addition decreased especially the thickness of Cu₃Sn. Secondly, the addition of 1 to 2.5 at.% Ni to Cu further decreased the thickness of Cu₃Sn, increased that of Cu₆Sn₅ (compared to that in the binary Cu/Sn couple) and produced significant amount of voids at the Cu/Cu₃Sn interface. Thirdly, the addition of 5 at.% Ni to Cu increased the total thickness of the IMC layer to about two times that observed in the binary Cu/Sn diffusion couple and made the Cu₃Sn disappear. Fourthly, in contrast to the previous case, the addition of 10 at.% Ni to Cu decreased the total IMC (Cu₆Sn₅) thickness again close to that of the Cu/Sn couple. With this Ni content no voids were detected. The results are rationalized with the help of␣the thermodynamics of the Sn-Cu-Ni system as well as with kinetic considerations.     

Interfacial reactions in the Sn-(Cu)/Ni,Sn-(Ni)/Cu,and Sn/(Cu,Ni) systems

Specimens with the Sn/Cu/Sn/Ni/Sn/Cu/Sn structure reacted at 200°C are prepared and examined. The Cu₆Sn₅ and Cu₃Sn phases are formed at the Sn/Cu interface, and the Cu₆Sn₅ and Ni₃Sn₄ phases at the Sn/Ni interface. The reaction path in the original Cu/Sn/Ni part of the specimen is Cu/Cu₃Sn/Cu₆Sn₅/Sn/Cu₆Sn₅/Ni₃Sn₄/Ni. The peculiar phenomenon of the Cu₆Sn₅ phase forming at both sides of the Sn phase is illustrated using the Sn-Cu-Ni phase diagram with a very wide compositional-homogeneity range of the Cu₆Sn₅ phase. Interfacial reactions at 240°C between pure Sn and (Cu,Ni) alloys of various compositions are determined. The Cu₆Sn₅ phase is formed when the NI content is less than 30 wt.%, and the Ni₃Sn₄ phase is formed when the Ni content is higher than 40 wt.%. When the Ni content is between 35 wt.% and 40 wt.%, both Cu₆Sn₅ and Ni₃Sn₄ phases are formed. It is also noticed that the formation of the Cu₃Sn phase at the Sn/(Cu,Ni) interface is suppressed with more than 1wt.%Ni addition in the substrate.     

Diffusion Behavior of Zn During Reflow of Sn-9Zn Solder on Ni/Cu Substrate

Reflow behavior of Sn-Zn solder on Ni/Cu substrate was investigated in an infrared (IR) reflow furnace using different heating rates from 180 °C/min to 36 °C/min. Energy dispersive spectroscopy (EDX) studies of the reflowed samples showed increased diffusion of Zn from the solder to the intermetallic compound (IMC) layer with a decrease in heating rate. Higher interfacial activity and affinity of the Zn in the formation of the IMC with the lowering of the heating rate were further demonstrated by electron probe microanalyzer (EPMA) results. The Zn diffusion behavior was related to its higher reactivity and smaller size in comparison with Sn, phase separation during heating, and affinity of Zn to form Ni-Sn-Zn and Ni-Zn intermetallic compounds.     

Hermetic Packaging Using Eutectic SnPb Solder and Cr/Ni/Cu Metallurgy Layer

We have developed an easy, low-cost, and low-temperature optoelectronic hermetic packaging technology utilizing the eutectic SnPb solder and the Cr/Ni/Cu bonding pad. Bonding characteristics of the design were investigated in three different setups: silicon-silicon, silicon-glass, and glass-glass samples. Hermeticity was achieved at 200 degC without flux for all samples during the final bonding process. The bonding pads did not dewet during or after the reflow process. By utilizing the eutectic SnPb solder, the self-alignment process can be achieved. Because the bonding process was conducted through visual alignment, original misalignment was estimated to be more than 100 mum. The surface tension of melting solder during the reflow process allowed the samples to self-align and obtain a misalignment of less than 20 mum after solidification, which was 4% of the entire solder width. The bonding strength of the three setups ranged from 3 to 10 MPa. Among the three setups, glass-glass samples appear to have the strongest bonding strength. This low-temperature and cost-effective soldering process has demonstrated its feasibility and potential utilization in optoelectronic packaging     

Interfacial Reactions of Sn, Sn-3.0Ag-0.5Cu, and Sn-9Zn Lead-Free Solders with Fe-42Ni Substrates

Interfacial reactions between Sn, Sn-3.0 wt.%Ag-0.5 wt.%Cu (SAC), and Sn-9 wt.%Zn (SZ) lead-free solders and Fe-42 wt.%Ni (alloy 42) substrates at 240°C, 255°C, and 270°C were investigated in this study. FeSn₂, (Fe,Ni, Cu)Sn₂, and (Ni,Fe)₅Zn₂₁ phases were formed, respectively, at the interface in the Sn/alloy 42, SAC/alloy 42, and SZ/alloy 42 couples. As the reaction time and temperature were increased, the layered intermetallic compound (IMC) assumed two distinct structures, i.e., a thicker layer and a pillar-shaped IMC, in all couples. The IMC thickness of these couples increased with the increase of reaction time and temperature. The IMC thickness was also proportional to the square root of the reaction time. The interfacial reaction mechanism of these couples was diffusion controlled.     

Sn-9Zn/Cu 焊点界面反应及其化合物生长行为

通过扫描电镜(SEM)等手段研究了Sn-9Zn/Cu在不同浸焊时间与时效时间等条件下的界面反应及其金属间化合物(IMC)生长行为。结果表明:在浸焊后,Sn-9Zn/Cu钎焊接头界面形成了扇贝状的界面化合物Cu5Zn8,IMC层厚度随着浸焊时间与时效处理时间的增加而增加,未时效处理的焊点界面IMC与铜基板接触的一面较为平直,而与钎料接触的一侧呈现出锯齿状,随着时效时间的增加,界面变得越来越不平整;另外在IMC层与焊料之间产生裂缝现象,分析认为是由于钎料与IMC之间的热膨胀系数差异导致热应力形成裂缝。浸焊600 s后的试样在时效15 d后IMC层与Cu基板接触侧产生了与初始金属间化合物Cu5Zn8不同的三元化合物Cu6(Sn,Zn)5。     

Effect of Cr additions on interfacial reaction between the Sn-Zn-Bi solder and Cu/electroplated Ni substrates

Intermetallic compounds (IMCs) growth on the Sn-8Zn-3Bi (-Cr) solder joints with Cu and electroplated Ni substrates was investigated after aging at 150 °C. It was found that the IMCs were the Cu₅Zn₈ and Ni₅Zn₂₁ at the solder/Cu and solder/Ni interface, respectively. The IMCs growth rate at the Sn-8Zn-3Bi-Cr/Cu and Ni interface was slower than that at Sn-8Zn-3Bi/Cu interface (about 1/2 times) and Sn-8Zn-3Bi/Ni interface (about 1/4 times) during aging. The reason may be that Cr reacts with Zn and forms the Sn-Zn-Cr phase which block the diffusion of Zn atom to the interface and slow down the IMCs growth rate.     

Intermetallic reactions in reflowed and aged Sn-9Zn solder ball grid array packages with Au/Ni/Cu and Ag/Cu pads

During the reflowing of Sn-9Zn solder ball grid array (BGA) packages with Au/Ni/Cu and Ag/Cu pads, the surface-finished Au and Ag film dissolved rapidly and reacted with the Sn-9Zn solder to form a γ₃-AuZn₄/γ-Au₇Zn₁₈ intermetallic double layer and ε-AgZn₆ intermetallic scallops, respectively. The growth of γ₃-AuZn₄ is prompted by further aging at 100°C through the reaction of γ-Au₇Zn₁₈ with the Zn atoms dissolved from the Zn-rich precipitates embedded in the β-Sn matrix of Sn-9Zn solder BGA with Au/Ni/Cu pads. No intermetallic compounds can be observed at the solder/pad interface of the Sn-9Zn BGA specimens aged at 100°C. However, after aging at 150°C, a Ni₄Zn₂₁ intermetallic layer is formed at the interface between Sn-9Zn solder and Ni/Cu pads. Aging the immersion Ag packages at 100°C and 150°C caused a γ-Cu₅Zn₈ intermetallic layer to appear between ε-AgZn₆ intermetallics and the Cu pad. The scallop-shaped ε-AgZn₆ intermetallics were found to detach from the γ-Cu₅Zn₈ layer and float into the solder ball. Accompanied with the intermetallic reactions during the aging process of reflowed Sn-9Zn solder BGA packages with Au/Ni/Cu and Ag/Cu pads, their ball shear strengths degrade from 8.6 N and 4.8 N to about 7.2 N and 2.9 N, respectively.     

Interfacial Reactions Between Sn-Zn Alloys and Ni Substrates

Interfacial reactions between Sn-Zn alloys and Ni substrates after annealing at 463 K have been studied. Only one intermetallic compound (IMC), γ-Ni₅Zn₂₁, was observed at the Sn-Zn/Ni interfaces, although other IMC(s) in the Ni-Sn and Ni-Zn system can stably exist at this temperature. Taking into account nucleation along with diffusion kinetics, formation of the reaction product has been reasonably modeled. In addition, growth kinetics for the reaction layer has been quantified. The results indicate that the growth rate of the γ-Ni₅Zn₂₁ layer increases with Zn content, and that the layer growth obeys a parabolic law with annealing time, implying a diffusion-controlled mechanism.     

Reactions of Sn-3.5Ag-Based Solders Containing Zn and Al Additions on Cu and Ni(P) Substrates

In this study we consider the effect of separately adding 0.5 wt.% to 1.5 wt.% Zn or 0.5 wt.% to 2 wt.% Al to the eutectic Sn-3.5Ag lead-free solder alloy to limit intermetallic compound (IMC) growth between a limited volume of solder and the contact metallization. The resultant solder joint microstructure after reflow and high-temperature storage at 150°C for up to 1000 h was investigated. Experimental results confirmed that the addition of 1.0 wt.% to 1.5 wt.% Zn leads to the formation of Cu-Zn on the Cu substrate, followed by massive spalling of the Cu-Zn IMC from the Cu substrate. Growth of the Cu₆Sn₅ IMC layer is significantly suppressed. The addition of 0.5 wt.% Zn does not result in the formation of a Cu-Zn layer. On Ni substrates, the Zn segregates to the Ni₃Sn₄ IMC layer and suppresses its growth. The addition of Al to Sn-3.5Ag solder results in the formation of Al-Cu IMC particles in the solder matrix when reflowed on the Cu substrate, while on Ni substrates Al-Ni IMCs spall into the solder matrix. The formation of a continuous barrier layer in the presence of Al and Zn, as reported when using solder baths, is not observed because of the limited solder volumes used, which are more typical of reflow soldering.