ZnWO4单晶衬底上ZnO薄膜的晶核发育与形貌分析

ZnWO4单晶的a晶面与氧化锌c晶面晶格匹配很好,是制备氧化锌薄膜的优良衬底.本文采用溶胶-凝胶法在ZnWO4单晶衬底上制备出透明的ZnO薄膜.通过光学显微镜对薄膜晶核发育过程和形貌进行了详细的分析.实验结果表明:在结晶刚开始,系统将经历成核--长大的过程,随着生长过程的进行,在主晶轴上(一次轴)上又长出二次轴、三次轴等等,最后逐渐形成树枝状晶核.由于ZnO晶核是在非平衡条件下生长的,故在晶核发育过程中又出现了三种不同的生长形态--成核生长、枝晶生长和分形生长.     

TiC晶须的形貌

用气相催化无衬底化学气相沉积法制备TiC高温陶瓷晶须。经X射线物相分析、电子衍射测定和扫描电镜观测。分析了TiC晶须的形貌。     

二维锌枝晶生长行为研究

采用恒电压方法得到了不同电解质浓度和电压下金属锌二维电沉积生长的形貌分布图．在枝晶生长条件下,研究了支持电解质、全氟表面活性剂和脉冲电压等对锌枝晶生长行为的影响，并检测了电解池中Zn^2 的浓度分布．实验结果表明：支持电解质、表面活性剂和脉冲电压改变了阴极附近的电场分布和Zn^2 的浓度分布，对沉积物形貌产生很大的影响．同时发现，Zn^2 仅通过电迁移作用到达阴极附近，扩散对传质的贡献可忽略不计．     

氢气泡动态模板法制备三维多孔金膜

采用氢气泡阴极沉积法成功制备了具有枝晶结构的三维分级多孔Au膜。本文详细研究了沉积电位、沉积时间、H2SO4浓度、前驱体浓度等沉积条件对形貌的影响。由枝晶构成的三维多孔金膜(3D PGFs)也可以通过方波电位法(SWP)制备。采用扫描电子显微镜(SEM)对泡沫膜的形貌进行了表征。研究表明,由纳米簇组成的3D PGFS对葡萄糖无酶传感具有良好的催化活性。     

Stabilizing Lithium Plating by a Biphasic Surface Layer Formed In Situ

The dendritic growth of Li metal leads to electrode degradation and safety concerns, impeding its application in building high energy density batteries. Forming a protective layer on the Li surface that is electron‐insulating, ion‐conducting, and maintains an intimate interface is critical. We herein demonstrate that Li plating is stabilized by a biphasic surface layer composed of a lithium‐indium alloy and a lithium halide, formed in situ by the reaction of an electrolyte additive with Li metal. This stabilization is attributed to the fast lithium migration though the alloy bulk and lithium halide surface, which is enabled by the electric field across the layer that is established owing to the electron‐insulating halide phase. A greatly stabilized Li‐electrolyte interface and dendrite‐free plating over 400 hours in Li|Li symmetric cells using an alkyl carbonate electrolyte is demonstrated. High energy efficiency operation of the Li₄Ti₅O₁₂ (LTO)|Li cell over 1000 cycles is achieved.     

Dendrite structure of electrolytic gold deposited from molten chlorides

The structure of gold deposits produced by electrolysis of molten eutectic NaCl-KCl-CsCl at 500–700°C in an inert atmosphere is studied. The initial process on the gold cathode is the epitaxial growth of a layer up to 3 μm thick with a smoothed surface and a considerably later growth of grain boundaries. Gradually, on the protruding parts of deposit, the growth of dendrites starts. The dendrites are the major form of gold deposits. Typical gold dendrites are two-dimensional 2D〈112〉 and 2D〈112〉–〈110〉 and three-dimensional 3D〈100〉. Upon supplying air into the atmosphere above the melt at high current densities at the initial period there appears a powder comprising particles of a rounded twisted shape. Probable mechanisms leading to the formation of the “rounded” powder are discussed.     

通过枝晶间距反求薄带连铸界面的热流

根据导热微分方程，推导出了在二次枝晶间距基础上计算双辊薄带连铸界面传热热流的数学解析式，并以1Cr18Ni9Ti不锈钢作为研究对象，进行了数值计算.数值计算结果表明，随着凝固时间的增加，界面热流密度呈下降趋势；在弯月面附近热流密度下降速度很快，越靠近Kiss点，热流密度下降速度越慢；薄带连铸界面热流密度的计算数值与文献所报道的实验数据在同一个数量级上.此外，进一步的计算还表明，双辊薄带连铸属于亚快速凝固过程，这与实际情况是一致的.     

Insight of the dendrite deformation in Ni-based superalloys for increased misorientation along convergent boundaries

The dendrite growth and the associated misorientation evolution on the platform base of a single crystal investment casting were investigated. It was found that the long secondary dendrite arm(LSDA) grew through the whole platform, and a convergent boundary of dendrite arms(CBDA) formed simultaneously between the corresponding branched arms and the extended secondary arms from the blade zone. The corresponding orientation measurement confirmed that the misorientation of dendrite arms between the two sides of the CBDA monotonically increased from 5.9° at one platform edge to 33.5° at the other platform edge. Additionally, the LSDA dendrite deformation was also identified by the accumulated misorientation within the LSDA dendrite core. Furthermore, it was deduced that the increased misorientation along the CBDA was caused by the LSDA dendrite deformation, and the reason of LSDA dendrite deformation was further discussed based on the associated strain distribution around the LSDA. Because of a 33.5° misorientation along the CBDA, it was indicated that the dendrite deformation might be the formation mechanism of high angle boundary.     

助熔剂法生长的PLZST单晶的缺陷研究

本文介绍了助熔剂缓慢降温自发成核法生长的稀土掺杂锆钛锡酸铅镧(PLZST)晶体中出现的几种缺陷：包裹体、开裂、位错、枝晶,分析了这些缺陷的形成机理并提出了减少和消除这些缺陷的一些措施。     

多孔聚合物在锂金属负极保护中的研究进展

锂金属负极具有极高的理论比容量和最低的还原电位,因此锂金属电池被认为是最具潜力的高比能储能器件之一.然而,充放电过程中不受控制的枝晶生长、不稳定的界面反应与巨大的体积变化导致锂金属负极库伦效率低与循环稳定性差,同时枝晶刺穿隔膜也会带来安全隐患,这些问题极大地制约着锂金属电池的实际应用.多孔聚合物由于比表面积大、密度低、...