Investigation of the Phase Equilibria of Sn-Cu-Au Ternary and Ag-Sn-Cu-Au Quaternary Systems and Interfacial Reactions in Sn-Cu/Au Couples

The phase equilibria of the Sn-Cu-Au ternary, Ag-Sn-Cu-Au quaternary systems and interfacial reactions between Sn-Cu alloys and Au were experimentally investigated at specific temperatures in this study. The experimental results indicated that there existed three ternary intermetallic compounds (IMCs) and a complete solid solubility between AuSn and Cu₆Sn₅ phases in the Sn-Cu-Au ternary system at 200°C. No quaternary IMC was found in the isoplethal section of the Ag-Sn-Cu-Au quaternary system. Three IMCs, AuSn, AuSn₂, and AuSn₄, were found in all couples. The same three IMCs and (Au,Cu)Sn/(Cu,Au)₆Sn₅ phases were found in all Sn-Cu/Au couples. The thickness of these reaction layers increased with increasing temperature and time. The mechanism of IMC growth can be described by using the parabolic law. In addition, when the reaction time was extended and the Cu content of the alloy was increased, the AuSn₄ phase disappeared gradually. The (Au, Cu)Sn and (Cu_,Au)₆Sn₅ layers played roles as diffusion barriers against Sn in Sn-Cu/Au reaction couple systems.     

Hillock and Whisker Growth on Sn and SnCu Electrodeposits on a Substrate Not Forming Interfacial Intermetallic Compounds

Intermetallic compound (IMC) formation at the interface between the tin (Sn) plating and the copper (Cu) substrate of electronic components has been thought to produce compressive stress in Sn electrodeposits and cause the growth of Sn whiskers. To determine if interfacial IMC is a requirement for whisker growth, bright Sn and a Sn-Cu alloy were electroplated on a tungsten (W) substrate that does not form interfacial IMC with the Sn or Cu. At room temperature, conical Sn hillocks grew on the pure Sn deposits and Sn whiskers grew from the Sn-Cu alloy electrodeposits. These results demonstrate that interfacial IMC is not required for initial whisker growth.     

Synthesis and materials characterization of Li2MnO3-LiCrO2 system nanocomposite electrode materials

A series of Li[Cr_xLi_(1−x)/3Mn_2(1−x)/3]O₂, (0.2 ≤ x ≤ 0.4) with nanocomposite structures was synthesized by a solution method with subsequent quenching. The sample structures were investigated by X-ray diffraction (Rietveld refinement), electron diffraction and HRTEM. According to co-indexed electron diffraction patterns and HRTEM images, Li[Cr_0.211Li_0.268Mn_0.520]O₂ was found to be composed of solid solution powders and Li[Cr_0.290Li_0.240Mn_0.470]O₂ and Li[Cr_0.338Li_0.225Mn_0.436]O₂ of nanocomposite powders indexed in monoclinic and hexagonal structure. Among the three compounds, the nanocomposite Li[Cr_0.290Li_0.240Mn_0.470]O₂ cathode prevented spinel-like structural transformation during cycling and delivered a good reversible capacity of about 195 mAh/g.     

抛光型SLAM系统灵敏度研究

以片式电子材料元器件作为无损检测分析对象,以提高激光扫描声学显微镜(SLAM)系统灵敏度为目标,详细分析了入射声波在抛光型分层介质中的传播规律,建立了抛光型样品自由界面动态波纹振幅数学模型。经综合分析获得了提高系统响应的方法,为进一步改进SLAM提供了理论依据。     

Hydrothermal Synthesis and Characterization of a Novel Organic Inorganic Hybrid Compound [Co(dien)_2](dienH_3)(H_3O)_7[P_2Mo_5O_(23)]_2·14H_2O

A new compound,[Co(dien)2](dienH3)(H3O)7[P2Mo5O23]2·14H2O, has been hydrothermallly synthesized by using Na2MoO4,CoCl2, H3PO4 and dien, and structurally characterized by elemental analysis, X-ray powder diffraction analysis, SEM, IR and TG analysis. The results show that the compound is composed of a polyanion [P2Mo5O23]212- , complex [Co(dien)2]2 cation, protonated [dienH3]3 , and forteen crystallization water molecule.     

Ratio of Fe-Al compound at interface of steel-backed Al-graphite semi-solid bonding plate

The ratio of Fe-Al compound at the bonding interface of solid steel plate to Al-7graphite slurry was used to characterize the interfacial structure of steel-Al-7graphite semi-solid bonding plate quantitatively. The relationship between the ratio of Fe-Al compound at interface and bonding parameters (such as preheat temperature of steel plate, solid fraction of Al-7graphite slurry and rolling speed) was established by artificial neural networks perfectly. The results show that when the bonding parameters are 516 ℃ for preheat temperature of steel plate, 32.5% for solid fraction of Al-7graphite slurry and 12 mm/s for rolling speed, the reasonable ratio of Fe-Al compound corresponding to the largest interfacial shear strength of bonding plate is obtained to be 70.1%. This reasonable ratio of Fe-Al compound is a quantitative criterion of interfacial embrittlement, namely, when the ratio of Fe-Al compound at interface is larger than 70.1%, interfacial embrittlement will occur.     

纯棉复合组织织物上机工艺优化

为了在喷气织机上顺利生产不同浮长的复合组织织物,对所用经纱的强力、强力不匀率、千米细节提出了质量要求,并结合实例介绍了复合组织织物织造各工序的工艺实践。     

提高造纸用高岭土粘浓度及分散特性的研究

通过调节高岭土矿浆的pH值到8.5—9,使用6种分散剂单独或复配应用的方法,改变高岭土浆料的分散特性,提高粘浓度。结果表明:单独使用时,分散效果聚丙烯酸钠>萘磺酸钠>胶易素1>六偏磷酸钠>胶易素2>单宁酸;复配使用时,六偏磷酸钠与萘磺酸钠以质量比1∶1配合为最佳,可以将高岭土浆料粘浓度从69.7%提高至71.3%。     

氧化铁/绢云母复合光催化剂降解次甲基蓝

采用水热合成法，在绢云母表面沉淀一层氧化铁薄膜，制备成氧化铁/绢云母复合光催化剂。并以次甲基蓝为降解物，重点探讨了催化剂后处理方式、体系H2O2浓度和催化剂添加量对光催化效率的影响。结果证明，复合光催化剂煅烧前比煅烧后降解效果更好；体系H2O2浓度为0.5%、光催化剂用量为5 g/L时，降解效果最佳。     

单排小桩复合桩墙支护结构设计计算方法

复合桩墙支护结构是一种由水泥土桩墙和竖向小桩通过钢筋砼压顶板联合构成的新型复合型支护结构体系.本文在全面总结复合桩墙支护体系结构类型及其计算模型基础上,结合现场试验研究和数值模拟,提出了单排小桩复合水泥土桩墙支护体系基于整体计算模式的设计计算方法,为同类型基坑工程的设计和施工提供了一定的技术参考.