水洗钎剂下SnAgCuRExNi与铜引线的润湿适配性

采用润湿平衡法,选用商用水洗钎剂,研究了镍添加量及钎焊工艺参数对Sn2.5Ag0.7Cu0.1RE钎料合金在铜引线上的润湿适配性. 结果表明,当Sn2.5Ag0.7Cu0.1RE钎料合金中镍添加量为0.05%时,钎料合金显微组织明显细化;当钎焊温度为255 ℃、钎焊时间为5 s、浸渍速度为20 mm/s、浸渍深度为3 mm的情况下, 其与φ0.6×30 mm的铜引线具有较好的润湿适配性,即具有较短的润湿时间,较小的润湿角,较大的润湿力,符合润湿力、润湿时间和润湿角的相关标准,完全满足现代表面组装技术对无铅钎料润湿性能的要求.     

饰品用贵金属合金及其钎焊工艺的发展

概述了金、银两类贵金属及其钎焊工艺的发展。介绍了各类型饰品用金、银合金种类、特性和应用范围,并针对不同类型的金、银合金所适用的钎焊材料及钎焊工艺。首饰用贵金属合金所使用的钎料种类繁多,国家标准中已规定适用于各行业的银合金钎料(包括含钯钎料)48个牌号,金合金钎料19个牌号,但未进一步对饰品用贵金属钎料进行规定。近年来市场对饰品用贵金属合金的需求逐年增长,对其成分的安全无害标准亦有提升,故饰品用贵金属合金钎料的无害化、系列化和标准化已成为必然趋势,相关研究在制定行业标准、提高国际市场竞争力上具有重要意义。     

无铅无卤焊接用活性物质的研究

寻求高效无卤活性剂是实现绿色电子产品的关键.本文首次以氨基酸对甲苯磺酸盐及氨基酸酯对甲苯磺酸盐为活性剂配制了助焊剂与锡膏,并对其进行了扩展率、润湿及焊后残留物腐蚀性测试.结果表明:所得助焊剂扩展率都超过80%;所得锡膏焊点饱满,焊后残留物少,湿热试验铜板几乎无腐蚀性.这表明氨基酸对甲苯磺酸盐及氨基酸酯对甲苯磺酸盐是一类...     

Microstructure evolution and fracture behaviour of friction stir welded 6061-T6 thin plate joints under high rotational speed

6061-T6 sheets with 0.8?mm thickness were successfully welded using high-speed friction stir welding (FSW) technology. The microstructural evolution and fracture behaviour of the joints were studied. The results show that sound joints could be obtained at the investigated high rotational speed of 8000?rev?min^?1 and welding speeds of 300–1200?mm?min^?1. Compared with conventional rotational speed, the grain size in the nugget zone (NZ) is obviously refined under high rotational speed. The Mg₂Si, Al₈Fe₂Si and Al₂CuMg precipitates reprecipitated adequately in the NZ during high-speed FSW, resulting in the number of the precipitates increased significantly, and further alleviating the weld softening. The difference in weld softening leads to different fracture characteristics during the tensile process. After artificial aging, the maximum welding softening in all joints is located in the heat affected zone, and the fracture is characterised by brittle fracture.     

半导体用高纯金制备技术及应用研究进展

综述了目前制备高纯金的各种方法的原理及工艺,并对其优缺点进行了分析。化学还原分离法效率高、周期短,但酸耗大、污染严重;熔融氯化法对原料适应范围广,但存在氯化过程复杂、工艺难于精准控制和产品质量不稳定等不足;溶剂萃取法效率高、产品质量稳定,但试剂消耗大、有机污染严重和易燃易爆;电解法具有成本低、除杂效果好、产品纯度稳定性强及环境污染小的优点,但原料适应性相对较差、生产周期相对较长且会积压金。高纯金具体应用形式为键合用金丝、溅射靶材及高纯度金基合金,涉及电子、半导体及航空航天等领域。     

电解高纯金的制备与表面织构研究

用670和800 A/m²的电流密度对4N金进行电解提纯,并利用X射线衍射(XRD)和电子背散射衍射(EBSD)技术对电沉积产物的底面和表面进行极图绘制和微观组织重构。结果表明,样品纯度均达到6N以上;EBSD与XRD所得织构结果基本一致。电沉积金的表面和底面均存在织构,较大的电流密度会弱化织构。受外延生长效应和过渡生长效应的影响,2样品与阴极基板接触的表面均存在{111}纤维织构,电沉积自由表面均存在{001}纤维织构,电流密度的变化导致2样品的织构也发生变化。随着电沉积过程的进行,晶粒尺寸长大。     

急冷型Sn-Ag-Cu系钎料钎焊接头力学性能与显微组织

采用单辊法制备了急冷型Sn-Ag-Cu系钎料合金,在对其进行熔化温度特性和XRD分析检测后,进行了钎焊工艺试验,并对所得接头的抗剪强度和显微组织进行了测试分析,研究了钎焊温度对接头组织性能的影响。结果表明:在不同的钎焊温度条件下,接头界面处金属间化合物的形成及分布是不同的,并由此导致了接头抗剪强度的变化。     

Analysis of strengthening in AA6111 during the early stages of aging: Atom probe tomography and yield stress modelling

In this work, a series of aging treatments has been conducted on AA6111 alloy samples for various times at ambient temperature (so-called natural aging) and at temperatures between 60 and 180 °C (artificially aged). The time at artificial ageing was chosen such that samples with approximately the same yield stress were produced. The microstructures of these alloy samples have been carefully characterized using atom probe tomography together with advanced cluster-finding techniques in order to obtain quantitative information about the changes in distribution of both the solute clusters and early-stage precipitates that are formed. The size distribution of clusters has been mapped onto the glide plane and then the stress necessary for a dislocation to pass through the range of obstacles has been estimated using an areal glide model where the dislocation–obstacle interaction strength has been assumed to be related to the obstacle size on the glide plane. It is demonstrated that the contribution of cluster strengthening during artificial aging at higher temperatures is dominated by the high number density of small clusters (Guinier radius <1 nm), whereas the situation during room temperature natural aging is more complex.     

The embrittlement mechanism and improvement of impact strength for lead-free solder joints in BGA packaging using electrolytic Ni/Au plating

Impact strength evaluation and fracture mechanism analysis in board level of Sn–3mass%Ag–0.5mass%Cu solder joints of ball grid arrays (BGA) using electrolytic Ni/Au plating were performed. The cause of impact strength degradation of BGA solder ball joints is the existence of low density defects, which contain organic materials, in the (Cu,Ni)₆Sn₅ intermetallic compound grain boundary formed in the solder joints. These organic materials are taken in by the nickel plating film at the time of nickel plating. To improve the impact strength of the Sn–3mass%Ag–0.5mass%Cu solder joint of the BGA, it is necessary to lower the concentration of these organic materials. The contamination prevention and nickel plating bath sanitization, solder mask material selection (to minimize nickel plating bath contamination) and higher current density of nickel plating are effective to keep a lower concentration of organic materials in nickel plating film.     

Zr对Sr变质近共晶Al-Si铸造合金组织和性能的影响

分析了Zr对Sr变质近共晶Al-Si铸造合金组织的影响.结果表明,随着Zr加入量的增加,枝晶α(Al)有等轴化趋势;当Zr加入量为0.5%～0.6%时,枝晶α完全等轴化;这是由于熔体中形成了ZrAl3颗粒,在合金凝固过程中起到了异质生核作用,并且Zr对共晶硅的形态、尺寸没有明显影响;随着Zr加入量增加,合金的力学性能明显提高.     

高硅钢热轧卷板的YAG激光拼接新工艺研究

采用4kW的YAG固体激光器，利用激光切割—焊接—热处理组合工艺对Hi—B钢热轧卷板进行了试验研究，探索了在不同工艺参数条件下焊缝成形、接头力学性能的变化情况，得出了最佳工艺参数，解决了高牌号硅钢难焊的问题。     

高纯贵金属靶材在半导体制造中的应用与制备技术

高纯Au、Ag、Pt、Ru贵金属及其合金溅射靶材是半导体PVD工艺制程中的溅射源材料,广泛用于半导体制造工艺中,成为保证半导体器件性能和发展半导体技术必不可少及不可替代的材料。材料的高纯化、高性能贵金属及其合金靶材的制备(金属熔铸、热机械处理、粉末烧结、焊接等)以及贵金属靶材残靶及加工余料残屑的提纯回收利用是研究发展的重点,以实现贵金属靶材产品的高效增值。     

氟化物对自保护药芯焊丝焊接工艺性能的影响及熔敷金属中P、Si的控制

通过自制的5种药芯成分不同的自保护药芯焊丝，研究氟化钡和氟化钙的不同配比对焊接工艺性能、过渡熔滴、熔敷金属中P、Si的控制的影响。结果表明，随着：BaF2占氟化物总量的增加，立焊性能改善，焊接过程飞溅、烟尘减少，累积质量分数为50％时的熔滴的平均直径减小，而熔敷效率和Hmax／Bmax降低(Hmax为焊缝最大熔深，Bmax为焊缝最大熔宽)。BaF2比CaF2控制熔敷金属中P、Si含量的能力更强，并通过热力学分析解释了氟化物对熔敷金属中P、Si控制的机理。综合考虑焊接工艺性能和熔敷金属中P、Si的控制，药芯中选用BaF2占氟化物总量的75％～87．5％较为合适。     

缅甸某高硫高砷金矿碱浸预处理工艺研究

针对缅甸某高硫高砷金矿中毒砂和黄铁矿包裹金浸出率低的问题,采用碱浸预处理工艺处理该矿石.确定了磨矿时间、固液比等工艺条件,重点考察预处理过程中的pH、催化剂ZNT用量、时间、氧化剂用量等因素对金浸出率的影响.结果表明,用NaOH调节pH=13,磨矿细度?38μm含量占90％,再添加10 kg/t催化剂ZNT,40 kg...     

集成电路用Ti靶材和Cu62Zn38合金背板焊接技术研究

研究了高纯Ti和Cu62Zn38合金在不同的工艺条件下的扩散焊接性能和界面情况。结果表明,热等静压温度为510℃时,加工态Ti板硬度下降明显,与退火态Cu62Zn38接近;退火态Ti板和退火态Cu62Zn38两种材料硬度较为接近,而在温度接近525℃时,退火态Cu62Zn38合金硬度明显高于退火态Ti板。退火态Cu62Zn38合金与退火态高纯Ti经过焊接温度525℃,压力120 MPa,保温4 h的扩散焊接后,平均抗拉强度能达到136 MPa,焊接界面达到冶金结合,满足Ti靶材的使用要求。     

Production of high purity APT from scheelite and complex tungsten raw material with high Mo content

More than 73% of the tungsten resources in China are scheelite and 41% are high molybdenum content ores, and their dressing becomes increasingly difficult. Such situation calls for new and advanced processes that can treat complex ores and still attain high overall recovery of tungsten. The novel NaOH digestion process and selective precipitation process was developed. The former is universal for leaching tungsten from various tungsten materials,including scheelite concentrate and keeps most of the impurity elements P, As and Si in residue; while the latter is effective for removing impurities such as Mo and Sn. Combined with the traditional ion exchange process, the new process can be used to produce APT that confirms with the Chinese National Standard GB10116-88APT-0 with crystallization ratio of 95%. When treating high molybdenum scheelite concentrate from Shizhuyuan Deposit with WO3 content of 50%-55%, recovery of the new process may reach up to about 95% which is grossly the same as that from the traditional way for treating standard wolframite concentrates.     

用非晶钎料加中间层连接Si3N4陶瓷的试验

采用TiZrCuB非晶钎料并用Cu箔为中间层连接Si3N4陶瓷,研究了钎料成分、钎焊工艺和中间层厚度等对接头室温和高温强度的影响.结果表明:采用Ti40Zr25CuB0.2非晶钎料和70μm厚的Cu箔中间层,在1 323 K,30 min及0.027 MPa压力下钎焊连接Si3N4陶瓷,其接头在室温下的四点抗弯强度最高...     

用铁粉置换回收氰化金泥精炼废水中的金和银

采用铁粉置换处理山东黄金冶炼有限公司氰化金泥精炼废水,考察了铁粉用量、pH值、反应温度和置换时间等因素对金、银置换率的影响.条件实验确定的最佳工艺技术条件为:保持原液pH=0.5,铁粉用量2.5 kg/m3、反应温度60℃、置换时间30 min,金和银的置换率在95％和97％以上;在工业应用中银的置换率进一步提高到98...     

Microstructure and mechanical performance of a secondary cast aluminium piston alloy with minor element additions

The effect of individual and combined minor element additions (Sr, Sb, Mn, Cr and Al-5Ti-1B grain refiner) on microstructure and mechanical performance of a secondary cast aluminium piston alloy, with 1 wt-% Fe was investigated. It was observed that addition of Cr of up to 1% was better than a 0.53%Mn addition in improving tensile strength, impact energy and percent elongation of the alloy. The high mechanical performance recorded with addition of 1%Cr alloy was attributed to the significant reduction in porosity levels compared to all other minor element additions. It also resulted in a microstructure with fine compact intermetallic compounds. Other element additions also resulted in improved mechanical properties with 0.53%Mn performing better than 0.3%Mn + 0.2%Cr. Marginal improvements in mechanical performance were recorded with addition of 0.02%Sr (or 0.05%) and 0.02%Sb individually or in combination with 0.53%Mn. This was attributed to general increase in porosity and volume fraction of intermetallics.