无钎剂加压钎焊接头特性

阐述了微电子器件表面组装无钎剂加压钎焊新方法。利用研制的加压钎焊设备进行引线焊接并对试件进行了拉剪试验。试验结果表明，加压钎焊接合部强度高于普通软钎焊接合部强度的２倍。采用热电偶实时测量焊接劈刀强度，并利用电子探针对接合部元素的分布进行了分析。     

基于有限元法的聚碳酸酯激光焊接性能研究

为了揭示焊接参量对焊接质量的影响机理,优化焊接工艺参量,利用超景深显微镜和拉伸试验机对不同功率、焊接速率和材料厚度参量下的焊接强度进行了观察和测试。采用ABAQUS建立3维轴对称物理模型,对焊接过程中的温度分布进行了有限元模拟,并通过正交试验获得了各参量对焊接质量的影响规律。结果表明,激光功率是影响焊接强度的首要因素,其次是焊接速率,材料厚度影响最小;焊接过程中焊接温度越高,焊缝的宽度越大,可能导致熔池材料分解,焊缝中的气泡增多,影响焊接强度。     

CBGA、CCGA植球植柱焊接返工可靠性研究

多功能、高性能、高可靠及小型化、轻量化是集成电路发展的趋势。以航空航天为代表的高可靠应用中,CBGA和CCGA形式的封装需求在快速增长。CLGA外壳/基板植球或植柱及二次组装之后的使用过程中,常出现焊接不良或其他损伤而导致电路失效,因此需要进行植球植柱焊接返工。在返工过程中,除对焊接外观、焊接层孔隙等进行控制,研究返工过程对植球植柱焊盘镀层的影响也是保证焊接可靠性的重要工作。一次返工后焊盘表面镀金层已不存在,镀镍层也存在被熔蚀等问题,这都对返工工艺及返工后的电路可靠性提出了挑战。文章主要研究返工中镀镍层熔蚀变化趋势以及随返工次数增加焊球/焊柱拉脱强度和剪切强度的变化趋势,并分析返工后电路植球植柱的可靠性。     

激光透射焊接聚碳酸酯的有限元分析

为了研究激光透射焊接塑料过程中温度分布对焊接显微结构和强度的影响,采用ABAQUS软件,建立了使用激光透射焊接技术焊接聚碳酸酯(PC)的三维有限元热分析模型,通过子程序DFLUX和FORTRAN语言编程实现超高斯型热源的动态加载,有限元分析得到激光透射连接过程中温度场的分布。结果表明:当激光功率P=40 W,焊接速度v=40 mm/s时,焊接温度达到333.8℃,焊接强度最高(1.3 kN),焊接质量最好;当焊接速度v=10 mm/s时,最高温度达到589.5℃,拉伸强度为0.4 kN。当激光功率为40 W,焊接速度为100 mm/s时,焊接温度达到165.5℃,拉伸强度为0.74 kN。焊缝成形的好坏主要与焊接温度有关,可通过选择合适的工艺参数对这些缺陷进行控制。     

PP塑料激光透射焊接剪切强度测试方法研究

提出一种新的激光焊接接头剪切强度测试方法:即将现有的两块板材、一条焊缝的试样制备方法,改变为四块板材、四条焊缝的试样制备方法。选取透明聚丙烯(PP)和不透明PP板条试样进行了验证性试验,按照两种塑料焊接强度测试方法在万能材料试验机上试验观测,对测量结果和数据进行和分析证明:双搭的焊接剪切强度测试方法因为没有附加力矩的作用,不会改变焊接面受力状态,因此在拉伸剪切过程中没有角度偏转,而单搭的测试方法存在附加力矩带来的角度偏转;在相同能量密度区间,测试得到的双搭剪切断裂强度值高于单搭焊接的试样的值。这是因为单搭焊接焊缝的断裂的是不同步的,而双搭焊接断裂是同步的。     

激光摆动模式对铝/钢焊接接头成形特征及组织、强度的影响

铝、钢金属在物理化学性质上的巨大差异使得铝/钢异种接头的优质连接成为焊接领域的难点。采用摆动激光热源实现了6061铝合金和316L不锈钢搭接接头的良好连接,研究了激光摆动模式、摆动频率对接头成形质量、界面组织结构及拉剪强度的影响。结果表明:摆动激光能够增加铝/钢界面的连接面积,减小接头的熔深,有效抑制焊缝中的气孔、裂纹等缺陷;同时,摆动激光能使界面温度均匀并增强对熔池的搅拌作用,降低界面处的冶金反应,有效抑制界面脆硬金属间化合物的产生;摆动激光焊接接头的界面组织主要为Fe(Al)固溶体及少量弥散分布的针状FeAl3相;摆动激光焊接接头的最大拉剪强度可达117.5 N/mm,相比于常规激光焊接接头提高了约45%,接头断裂位置为不锈钢与焊缝交界处。     

2195-T8铝锂合金激光填丝双面焊熔池行为与接头力学性能研究

铝锂合金以其质轻、高强、耐腐蚀等优势成为新一代航空航天应用材料,与其他铝锂合金相比,2195-T8铝锂合金焊接性能最优。基于液体火箭贮箱连接处的焊接需求,采用激光填丝双面焊接可以获得质量较好的接头。针对焊接过程中熔池内流体流动与温度的变化,建立了热-流耦合数学模型,通过数值模拟的方法对2195-T8铝锂合金焊接过程进行了研究,而后开展了接头轴向拉伸强度测试实验,阐明了焊接速度与填丝速度对熔池成形、流动与热输入的影响,并得到了不同焊接工艺参数下的最高接头强度。研究结果表明：4组不同焊接工艺参数下,第一面焊接与第二面焊接的熔池内流体流动趋势基本一致,主要为熔池左侧的顺时针涡流与右侧的逆时针涡流;提高焊接速度或填丝速度可以改善熔池成形质量,降低熔池热输入,细化焊缝熔合区中以柱状晶为代表的晶粒,进而有效提升接头力学性能;通过对4组不同焊接工艺参数的数值模拟与实验结果进行对比分析,最终得到熔池成形质量最好、热输入最小的焊缝,其接头轴向拉伸强度高达426.4 MPa,为母材强度的72.6%,对应的焊接速度与填丝速度分别为50 cm/min、1.8 m/min。     

不锈钢CO2激光焊接等离子体行为特性实验研究

采用3.5kW Slab CO₂激光焊接不锈钢,利用高速摄像观测焊接等离子体形态,采用光谱仪探测等离子体光谱,并利用相对强度法计算等离子体电子温度。结果表明:在氦气保护下,等离子体高度随时间周期性振荡,振荡频率约为530Hz;熔池表面附近等离子体的温度为8392K左右。进一步分析表明,等离子体对入射激光的吸收不足10%;等离子体周期性振荡对焊接过程稳定性影响不明显。     

晶圆级封装微凸点脱落失效分析

随着晶圆级封装的技术发展,其可靠性倍受关注,微凸点的制备作为晶圆级封装实现高密度引出端的关键技术,其制备过程及可靠性至关重要,明确微凸点相关失效的原因对于提升微凸点的可靠性十分关键。针对晶圆级微凸点的拉脱异常失效进行了分析,采用SEM和FIB等分析手段,确定凸点拉脱强度由不足是UBM金属层失效所致,针对UBM失效的根本原因进行了分析,确定存放环境中的水汽对UBM种子金属的侵蚀情况,明确了失效机理,并提出了相关的改进措施,对于提高晶圆级封装微凸点制备的可靠性具备一定的指导作用。     

P1小型继电器的进一步研制

电子设备小型化的新技术和总趋势使得有必要继续对PC板上的元件进行设计修正。因此,有必要使机电继电器成为SMD,并满足高灵敏度和高绝缘强度的要求。在带引出脚的标准P1小型继电器的基础上,采用耐高温塑料,可以开发出适合所有常规焊接方法的SMD品种。因此,尽管尺寸很小,MRP1满足现代小型继电器的所有要求,例如:     

高比能水体系锂电池研究

实现水溶液锂电池的关键技术是如何保护金属锂电极不与水反应。提出了一种保护金属锂电极,其不仅在有机电解液体系稳定而且在水溶液中也可稳定工作,这种锂电极可以用于水体系锂电池。该研究制备了双层锂离子电解质保护的金属锂电极,其外层采用的LAGP（Li1＋x＋yAlxGe2-x SiyP3-yO12）玻璃陶瓷电解质相对于包括水溶液等电解液是稳定的,该玻璃陶瓷电解质的电导率达到0.57 mS cm^-1。通过交流阻抗评估发现不同电解质间的界面阻抗是水体系锂电池内阻的主要来源。最终采用双层保护金属锂电极制备的水体系锂空气电池和锂水电池可以稳定工作。     

Catalytically Induced Robust Inorganic-Rich Cathode Electrolyte Interphase for 4.5 V Li||NCM622 Batteries

Tailoring inorganic components of cathode electrolyte interphase (CEI) and solid electrolyte interphase (SEI) is critical to improving the cycling performance of lithium metal batteries. However, it is challenging due to complicated electrolyte reactions on cathode/anode surfaces. Herein, the species and inorganic component content of the CEI/SEI is enriched with an objectively gradient distribution through employing pentafluorophenyl 4-nitrobenzenesulfonate (PFBNBS) as electrolyte additive guided by engineering bond order with functional groups. In addition, a catalytic effect of LiNi_0.6Mn_0.2Co_0.2O₂ (NCM622) cathode is proposed on the decomposition of PFBNBS. PFBNBS with lower highest occupied molecular orbital can be preferentially oxidized on the NCM622 surface with the help of the catalytic effect to induce an inorganic-rich CEI for superior electrochemical performance at high voltage. Moreover, PFBNBS can be reduced on the Li surface due to its lower lowest unoccupied molecular orbital , increasing inorganic moieties in SEI for inhibiting Li dendrite generation. Thus, 4.5 V Li||NCM622 batteries with such electrolyte can retain 70.4% of initial capacity after 500 cycles at 0.2 C, which is attributed to the protective effect of the excellent CEI on NCM622 and the inhibitory effect of its derived CEI/SEI on continuous electrolyte decomposition.     

宽温、高压工作电解液的研制

介绍了混合溶剂体系,高压(350~400 V)、宽温(40 ~ +105℃)工作电解液的研制。发现以癸二酸铵作主溶质,添加适当副溶质GPA及优质添加剂的电解液具有耐腐蚀、高闪火电压、高氧化效率及高稳定等特点。用此电解液制作CD293X(400 V 220 mF)规格的电容器通过了105℃、1 000 h负荷寿命试验和105 ℃、500 h的高温贮存试验。     

日立7180E生化分析仪电解质模块性能评价指标的研究

目的：评价日立7180E自动生化分析仪电解质模块测定K＋,,Na＋,Cl-离子的精密度、稳定性、线性和携带污染率。方法：采用日立公司配套试剂和病人血清,用该仪器测定K＋,Na＋,Cl-离子,对精密度、稳定性、线性及携带污染率等指标进行了评价。结果：批内及稳定性的变异系数均小于1%,批间变异系数均小于1.5%,携带污染率...     

PLC和变频器在锌电解行车中的应用

目前大部分老锌电解行车的电气控制系统,均采用简单的继电器控制,即使采用了变频器,也是用简单的端子控制速度,这样的效果不是很好,速度调整不灵活,控制精度存在问题。经过PLc灵活控制变频器速度,行车的启停均很平稳,精度很高,能满足生产需求。本文重点介绍PLC和变频器在新锌电解多功能行车中的应用。     

Modified Solid Electrolyte Interphases with Alkali Chloride Additives for Aluminum–Sulfur Batteries with Enhanced Cyclability

Aluminum–sulfur batteries employing high-capacity and low-cost electrode materials, as well as non-flammable electrolytes, are promising energy storage devices. However, the fast capacity fading due to the shuttle effect of polysulfides limits their further application. Herein, alkaline chlorides, for example, LiCl, NaCl, and KCl are proposed as electrolyte additives for promoting the cyclability of aluminum–sulfur batteries. Using NaCl as a model additive, it is demonstrated that its addition leads to the formation of a thicker, Na_xAl_yO₂-containing solid electrolyte interphase on the aluminum metal anode (AMA) reducing the deposition of polysulfides. As a result, a specific discharge capacity of 473 mAh g⁻¹ is delivered in an aluminum–sulfur battery with NaCl-containing electrolyte after 50 dis-/charge cycles at 100 mA g⁻¹. In contrast, the additive-free electrolyte only leads to a specific capacity of 313 mAh g⁻¹ after 50 cycles under the same conditions. A similar result is also observed with LiCl and KCl additives. When a KCl-containing electrolyte is employed, the capacity increases to 496 mA h g⁻¹ can be achieved after 100 cycles at 50 mA g⁻¹. The proposed additive strategy and the insight into the solid electrolyte interphase are beneficial for the further development of long-life aluminum–sulfur batteries.     

Interfacial and Interphasial Chemistry of Electrolyte Components to Invoke High-Performance Antimony Anodes and Non-Flammable Lithium-Ion Batteries

Electrolytes play a pivotal role to determine the electrode performances in lithium-ion batteries (LIBs). However, understanding the function of electrolyte components at the molecular scale remains elusive (e.g., salts, solvents, and additives), particularly how they arrange themselves and affect properties of the bulk, liquid-solid interfaces, and electrolyte decomposition, rendering a bottleneck for improving the electrolytes. Herein, the function of electrolyte components is thoroughly studied, from Li⁺ solvation structure in the bulk electrolyte, Li⁺ (de-)solvation behaviors at the electrolyte-solid interfaces, until the formation of solid electrolyte interphase (i.e., SEI) layer on the electrodes. Furthermore, a detailed model by taking into account the effects of solvent, additive, lithium salt, and concentration on the electrochemical properties of the Li⁺-solvent-anion complex to elucidate the electrode performances are depicted. As the ultimate benefit of this study, a completely new non-flammable ether-based electrolyte and stabilizing the promising antimony (Sb) anodes can be designed. Remarkably, a high-performance Sb anode that is superior to previous reports is obtained. This study provides a graphical model to unravel interfacial and interphasial behaviors of electrolyte components in LIBs, which is also significant for developing other metal-ion batteries.     

Elastic Interfacial Layer Enabled the High-Temperature Performance of Lithium-Ion Batteries via Utilization of Synthetic Fluorosulfate Additive

The key to producing high-energy Li-ion cells is ensuring the interfacial stability of Si-containing anodes and Ni-rich cathodes. Herein, 4-(allyloxy)phenyl fluorosulfate (APFS), a multi-functional electrolyte additive that forms a mechanical strain-adaptive solid electrolyte interphase (SEI) comprising LiF and polymeric species, and a thermally stable cathode–electrolyte interface containing S O and S F species. The radical copolymerization of vinylene carbonate (VC) with APFS via electrochemical initiation creates a spatially deformable polymeric SEI on the SiG-C (30 wt.% graphite + 70 wt.% SiC composite) anode, with large volume changes during cycling. Moreover, the APFS-promoted interfacial layers reduce Ni dissolution and deposition. Furthermore, APFS deactivates the Lewis acid PF₅, thereby inhibiting hydrolyses that produce unwanted HF. These results indicate that the combined use of VC with APFS allows capacity retentions of 72.5% with a high capacity of 143.5 mAh g⁻¹ in SiG-C/LiNi_0.8Co_0.1Mn_0.1O₂ full cells after 300 cycles at 45 °C.     

Electrolyte‐Regulated Solid‐Electrolyte Interphase Enables Long Cycle Life Performance in Organic Cathodes for Potassium‐Ion Batteries

Organic cathode materials as economical and environment‐friendly alternatives to inorganic cathode materials have attracted comprehensive attention in potassium‐ion batteries (KIBs). Nonetheless, active material dissolution and mismatched electrolytes result in insufficient cycle life that definitely hinders their practical applications. Here, a significantly improved cycle life of 1000 cycles (80% capacity retention) on a practically insoluble organic cathode material, anthraquinone‐1,5‐disulfonic acid sodium salt, is realized, in KIBs through a solid‐electrolyte interphase (SEI) regulation strategy by ether‐based electrolytes. Such an excellent performance is attributed to the robust SEI film and fast reaction kinetics. More importantly, the ether‐electrolyte‐derived SEI film has a protective inorganic‐rich inner layer arising from the prior decomposition of potassium salts to solvents, as revealed by X‐ray photoelectron spectroscopy analysis and computational studies on molecular orbital energy levels. The findings shed light on the critical roles of electrolytes and the corresponding SEI films in enhancing performance of organic cathodes in KIBs.     

Optimized electrolyte for electrochemical capacitance-voltage profiling of carrier concentration in In0.49Ga0.51P

Electrolyte characterization and optimization for the electrochemical capacitance-voltage profiling of carrier concentration in In_0.49Ga_0.51P is presented. The conditions for operation under minimum electrolyte interference are found based on the complex impedance analysis of an electrolyte-semiconductor junction. Carrier concentration results obtained with the optimized electrolyte are shown to both provide good etch depth control and to agree with Hall measurements. The same optimization scheme may be used for the characterization of other semiconductor material.