Influence of surface finish and annealing treatment on oxidation behavior of Ti-48Al-8Cr-2Ag alloy

The effect of surface finish and annealing treatment on the oxidation behavior of Ti-48Al-8Cr-2Ag (molar fraction, %) alloy was investigated at 900 and 1 000 °C, respectively in air. Thermal gravimetric analysis (TGA) was conducted for the characterization of oxidation kinetics. The microstructures of oxide scales were studied by scanning electron microscopy (SEM) and transmission election microscopy (TEM) techniques. Unfavorable effect of the annealing treatment on the oxidation behavior of the coating was also investigated. The results indicate that the oxidation behavior of the alloy is influenced by surface finish and annealing treatment. The oxidation rate of ground sample is lower than that of the polished alloy at 1 000 °C in air. The former forms a scale of merely Al₂O₃, and the latter forms a scale of the mixture of Al₂O₃ and TiO₂. Annealing can improve the formation of TiO₂. Foundation item: Project(2007430028) supported by the Science and Technique Foundation of Henan Educational Committee, China     

Parameter fitting of constitutive model and FEM analysis of solder joint thermal cycle reliability for lead-free solder Sn-3.5Ag

The experimental tests of tensile for lead-free solder Sn-3.5Ag were performed for the general work temperatures range from 11 to 90 °C and strain rate range from 5×10⁻⁵ to 2×10⁻² s⁻¹, and its stress—strain curves were compared to those of solder Sn-37Pb. The parameters in Anand model for solder Sn-3.5Ag were fitted based on experimental data and nonlinear fitting method, and its validity was checked by means of experimental data. Furthermore, the Anand model was used in the FEM analysis to evaluate solder joint thermal cycle reliability. The results show that solder Sn-3.5Ag has a better creep resistance than solder Sn-37Pb. The maximum stress is located at the upper right corner of the outmost solder joint from the symmetric center, and thermal fatigue life is predicted to be 3.796×10⁴ cycles under the calculated conditions. Foundation item: Project(50376076) supported by the National Natural Science Foundation of China     

纳米压印光刻工艺的研究进展和技术挑战

图形化技术是微纳制造过程的核心工艺之一.目前,作为微纳加工主流工艺的光学光刻技术由于受曝光波长衍射极限的物理限制,其技术复杂性和设备制造成本大幅增加.纳米压印将传统的模板复型原理应用到微观制造领域,以其高分辨率、高效率、低成本和工艺过程简单的特点,引起了各国研究人员的广泛关注.作为一种接触式几何约束流变成形方式,纳米压印必然衍生出许多新的挑战性问题.在阐述纳米压印工艺构成要素的基础上,对目前的若干主要压印技术工艺变种进行了简要综述,总结出了纳米压印所涉及的基本理论问题,并对纳米压印在集成电路制造中所面临的挑战进行了分析.     

连续高速电镀技术在集成电路引线框架生产中的应用

介绍了集成电路引线框架镀层特点及其卷对卷式连续高速局部电镀银技术。分析了高速镀银工艺条件，并与传统氰化物镀银工艺进行了比较。简单介绍了局部电镀技术的原理及方法。     

Propene Oxidation on Ag(111): Spectroscopic Evidence of Facile Abstraction of Methyl Hydrogen

Reactions of propene on an oxygen-modified Ag(111) surface were investigated by means of temperature-programmed reaction spectra and reflection--adsorption infrared spectroscopy (RAIRS) at 100 K. In the presence of oxygen adatoms, interactions of propene with the substrate are strengthened. The reaction between propene and oxygen adatoms (0.086 monolayer) produces not only total oxidation products (CO₂ and H₂O), but also partial oxidation products (CO and acetone). The formation of chemisorbed hydroxyl groups is identified by RAIRS when coadsorbed propene and oxygen adatoms are annealed to 200 K. The formation of hydroxyl is ascribed to the abstraction of methyl hydrogen by oxygen adatoms.     

综合物化探方法在内蒙古张家沟银铅锌矿床勘查中的应用

本文在野外勘探成果的基础上结合室内研究总结了张家沟银铅锌矿矿床的地球物理及地球化学特征,归纳了张家沟银铅锌矿矿床地质、地球物理、地球化学找矿标志,提出了该区地球物理综合找矿方法技术集成,进一步提出了张家沟银铅锌矿床找矿方向,应注意岩体内外接触破碎带两侧次级羽状纵张裂隙带及磁力推测断裂构造汇部位,特别是负磁异常区域并伴有土壤地化异常部位的含矿性研究。     

活性炭纤维负载Ag3PO4光催化剂的可见光催化性能

用湿化学沉淀法将Ag3PO4沉积在活性炭纤维(ACF)上制备复合光催化剂Ag3PO4/ACF,采用BET比表面积法和扫描电子显微镜分析对样品进行表征,通过在可见光下降解橙Ⅱ检测样品的光催化活性.结果表明,Ag3PO4/ACF的光催化活性比纯Ag3PO4提高了32％,主要是Ag3PO4/ACF具有更为精细的Ag3PO4晶体束,且分布更均匀,对污染物的吸附能力增强以及Ag3PO4与ACF有紧密的接触界面.Ag3PO4/ACF对橙Ⅱ的降解率随着投加量的增大而提高,最佳投加量为1 000mg/L.随着染料初始pH的增大,Ag3PO4/ACF对橙Ⅱ的降解率逐渐下降,强酸环境较有利于降解染料废水.在Ag3PO4/ACF循环使用4次后,其对橙Ⅱ的降解率由99％下降到59％.     

铬银共掺杂改性纳米TiO2光催化剂及其光催化性能研究

以钛酸四丁酯为原料,利用溶胶凝胶法制备了Cr/Ag共掺杂的TiO2纳米材料.采用XRD、SEM、EDS等测试分析技术对掺杂纳米TiO2粉体进行了表征;以甲基橙为降解物,在太阳光照射条件下研究了掺杂对光催化活性的影响.研究结果表明:掺杂后的纳米TiO2的光催化性能明显提高,优于纯TiO2.当共掺杂的比例为Cr 1.0%/Ag 0.5%时,样品的效果最佳,对甲基橙的3h降解率达到97.63%.     

银系TiO_2光催化无机抗菌材料的制备及抗菌性能测试

为探讨银离子缓释的载体制备及载银抗菌剂的抑菌功能,采用浸渍提拉法制备银系无机抗菌材料,通过银离子的抗菌机理,调试银离子浓度对抗菌性能的影响.实验证明将TiO2与银、铜等离子复合发挥相互补充的抗菌作用,具有明显的抑菌功能.     

微-纳米复合陶瓷超声振动磨削的塑性-脆性 转变特征研究

基于工件超声振动磨削的单磨粒运动模型,建立超声振动磨削单磨粒最大切削厚度agm ax公式;基于压痕断裂力学,给出硬脆材料超声振动磨削塑性-脆性转变临界条件,进行超声振动磨削与普通磨削对比试验,应用SEM和AFM分析陶瓷磨削表面微观形貌特征,重点研究磨削参数对其塑性-脆性转变特征的影响。研究结果表明,砂轮平均磨粒尺寸是影响塑性-脆性转变最为主要的因素,砂轮速度对其影响次之,磨削深度对塑性-脆性转变的影响最小;得出只有当agm ax小于临界切削深度agc时,才能实现硬脆材料塑性域磨削的重要结论。