Microstructure and Electrochemical Characteristics of Melt-Spinning Alloy Ml(NiCoMnAl)_5

The microstructure and electrochemical characteristics of Ml(NiCoMnAl) 5 alloys prepared by both the melt spinning method and the conventional induction melting were investigated and compared. SEM and XRD studies show that the microstructure of melt spinning alloys is columnar structure. With increasing melt spinning rate, the crystal grains become finer and preferentially grow along (111)[111] direction. The melt spinning and cast alloys belong to CaCu 5 type hexagonal crystal structure. The electrochemical measurements show that the initial capacities of melt spinning alloy electrodes are all above 210 mAh·g -1 with good activation behavior, reaching their maximum capacities after two charge discharge cycles. The maximum capacity (294 mAh·g -1 ) of melt spinning (10 m·s -1 ) alloy electrodes is as the same as that of as cast alloy electrode, and stability of charge discharge cycles of all melt spinning alloy electrodes is better than that of the as cast alloy electrodes. When charged at 600 mA·g -1 , the capacity of melt spinning (10 m·s -1 ) alloy electrode could reach 65% of its maximum capacity about 45 min with high rate discharge capability; but with the cycle number increasing, the stability of its capacity is less than that electrodes of melt spinning rate.

Structure and Growth Mechanism of V/Ag Multilayers with Different Periodic Thickness Fabricated by Magnetron Sputtering Deposition

V/Ag multilayers with different periodic thicknesses were fabricated by magnetron sputtering deposition. The columnar structure and the orientation relationship of the multilayers were investigated by transmission electron microscopy, high resolution transmission electron microscopy, selected-area electron diffraction and X-ray diffraction. It was found that the multilayered structure became flatter as increasing individual layer thickness from 2 to 6 nm, and then became waved as the individual layer thickness increases to 8 nm. At the beginning of the growth, the morphology of the multilayers with small periodic thickness was influenced mainly by thermodynamic instabilities, and the morphology of the multilayers with larger periodic thickness was mainly influenced mainly by the columnar growth of V. When the waved interfaces were formed, the continuum growth of the multilayers was also influenced by the shadowing effect and the finite atomic size effect. All of these factors resulted in the columnar structure of the multilayers. Multilayers with small periodic thickness presented strong orientation relationship. Nano-hardness tests indicated that multilayers with flat sublayer morphology and clear interfaces exhibited larger hardness.

Direct Evidence for the Effect of Intermolecular Hydrogen Bonding on Organogels

In order to get direct evidence for the effect of intermolecular hydrogen bonding on the organogels, one arnide group in N-（3, 4, 5-octyloxybenzoyl）-N＇-（4＇-aminobenzoyl）hydrazine（D8） was replaced by a Schiff base group, forming N-（3,4,5-octyloxybenzoyl）-N＇-（4＇-amidobenzoyl） acylhydrazone（T8SchA）. D8 and T8SchA organogels in cyclohexane show the same hexagonal columnar structure. And the hydrogen bonding was demonstrated to be still interacting in the organogels. However, although the molecular geometry of D8 was well retained in T8SchA, the molecular dipole moment of T8SchA is bigger than that of D8 due to the reduction of the number of hydrogen bonds. Thus, the decreased gelling stability of T8SchA compared to that of D8 can only be attributed to the reduction of the number of intermolecular hydrogen bonds, which provides direct evidence that intermolecular hydrogen bonding plays an important role in stabilising organogels.