Effect of Solidification Conditions on Structure and Properties of Rapidly-Solidified Sn-7.5wt%Sb Alloy

The effect of cooling speed on structure and properties of the rapidly-solidified Sn-7.5wt%Sb has been investigated. The samples in this study were prepared using a single roller melt spinning technique with two speeds: 15.7 and 30.7 m/s, respectively. The results showed formation of the intermetallic compound SnSb. This intermetallic compound changes in the amount which precipitated in the two samples. This behavior tends to affect the properties of these two samples. Also higher cooling speed tends to reduce the crystallite size, which in turn reduces the melting point of the resulting alloy compared to that of the lower cooling speed.     

Chen系统的动力学行为及其吸引子结构的研究

利用受控Chen系统,并基于镜像操作方法,发现Chen吸引子是由左、右两个吸引子所组成的复合结构,且左、右吸引子均可由极限环生成.采用一维时间序列相空间重构技术和系统混沌的定量判据准则,揭示出Chen系统从规则运动转化到混沌运动所具有的普适特征:Chen系统可通过Pomeau-Manneville途径走向混沌,且其间歇性与Hopf分岔和倍周期分岔有关,在这些途径上既可观察到锁相和准周期运动,也可观察到类Chen吸引子、Chen系统和Lorenz系统之间的过渡吸引子和类Lorenz吸引子.     

辐照交联聚氯乙烯电缆绝缘料配方研究

使用聚氯乙烯树脂、增塑剂、敏化剂、稳定剂、抗氧剂、填充剂等添加剂,通过对电线电缆辐照交联聚氯乙烯绝缘料配方体系、工艺性能等方面进行试验研究,获得了性能优良的辐照交联聚氯乙烯绝缘料,可适用于辐照交联聚氯乙烯绝缘料的生产。     

Phase and Microstructure Analysis of Cu-Cr-Zr Alloys

Phases of Cu-（0.4%-2.0%） Cr-（0.05%-0.16%） Zr alloys were analyzed in both as cast and deformed state. Solute-rich clusters of Cr, which was supposed to form during aging treatment, were observed in as cast state; along with the morphology character, corresponding preferential orientation of Cr phase in as cast state was also investigated. Precipitates were observed to distribute in the matrix with a bimodal distribution, viz. coarse precipitates with dimension larger than several hundred nanometers and fine precipitates with size of 2- 10 nm. Three types of intermetallics, the common compound of Cu51Zr14, correspondingly infrequent Cu5Zr and rare Cu5Zr3, were characterized in different samples.     

钢包铜复合线的制备研究

介绍了3种钢包铜复合导电柱的复合坯制备方法，探索了3种复合坯的制备工艺（1）液固相复合法；（2）直接装配法：（3）特殊装配法，对制备出的钢包铜复合导电柱复合界面组织致密性、界面结合状态及密封性能的影响。试验表明：前两种工艺制备的复合线材其结合面有局部结合不紧密，在界面未形成冶金结合状态，致使复合界面经氦检漏有漏气现象；第三种工艺制备的钢包铜复合线经气密性等综合性能试验，达到了使用要求。     

激光熔覆在金属间化合物涂层材料制备中的应用

在分析金属间化合物涂层材料特点的基础上，综述各种激光熔覆合成金属间化合物涂层的研究现状，分析各种金属间化合物涂层的组织及性能，研究表明激光熔覆合成的金属间化合物涂层均具有优异的耐磨、耐腐蚀、抗氧化等性能。     

The effect of microwave on preparation of kaolinite/dimethylsulfoxide composite during intercalation process

Since there are hydrogen bonds and no exchangeable ions between the layers of kaolinite, the intercalation reaction of organics is difficult. We induct microwave techniques into the preparation of kaolinite/organics intercalation compound. We studied the microwave effect for the inserted piece (dimethylsulfoxide), intercalation rate and intercalation speed and discussed intercalation compound by Fourier-transformed infrared spectroscopy, X-ray diffraction (powder method), thermal analysis (TG/DTA) and transmission electron microscopy. The result shows that microwave radiation can greatly shorten reaction time. XRD shows the intercalation rate can reach above 80% after 40 min reaction. FTIR proves the hydrogen bonds are formed between DMSO molecules and the inner surface hydroxyls of kaolinite and a TEM micrograph shows that microwave radiation can accelerate an exfoliation effect, which makes stacking layers of kaolinite delaminated as well as a reduction of the particle size dimensions.     

Intermetallic compound formation between lead-free solders (Sn) and Cu or Ni electrodes

A kinetic model based on the principle of maximum degradation rate of the total system free energy, MDR law using thermodynamic data, is proposed and successfully applied to the selection of the first intermetallic compound (IMC) phase in Cu/Sn and Ni/Sn diffusion couples. The first phases predicted with this model for Cu/Sn and Ni/Sn are Cu₆Sn₅ and Ni₃Sn₄, respectively, resulting in good agreement with experimental observations.     

高能球磨Si还原V2O5的固相反应

采用机械还原的方法以Si／V2O5为原料直接制VO2／SiO2复合陶瓷粉，主要探讨了高能球磨实现固相反应的动力学条件。利用X射线衍射仪和扫描电镜分析了不同球磨时间粉末的物相、形貌及结构变化，结果表明，球磨25hV2O5衍射峰消失，36h发生固相还原反应生成新相VO2。随着球磨的进行，V2O5的层状结构断裂，表面吸附小颗粒更均匀化，晶格常数发生明显改变，为室温下发生固相还原反应提供新增表面能、减小反应物之间的接触距离以及歧变能。     

On the advantages of using a hypoeutectic Sn-Zn as lead-free solder material

Hypoeutectic Sn-Zn may be a better choice than the eutectic Sn-9Zn as a lead-free solder. We checked the non-equilibrium melting behaviors of a series of Sn-Zn alloys (2.5-9 wt.% Zn) by differential thermal analysis, and found that at a heating rate of 5 °C/min, Sn-6.5Zn behaves the same way as the eutectic Sn-9Zn in melting. Dipping and spreading tests were carried out to characterize the wettability of Sn-Zn alloys on Cu. Both tests indicated that Sn-6.5Zn has significantly better wettability to Cu than Sn-9Zn does. The reaction layers formed during the spreading tests were examined. For all samples with 2.5-9 wt.% Zn, two reaction layers are formed at the interface, a thick and flat Cu₅Zn₈ layer adjacent to Cu and a thin and irregular Cu-Zn-Sn layer adjacent to the alloy. The total thickness of the reaction layers between the alloy and Cu was found to remarkably decrease with decrease of the Zn concentration.