Morphology-controlled Growth of Manganese Oxide Electrodes

2011 ◽  
Vol 1333 ◽  
Author(s):  
Banafsheh Babakhani ◽  
Douglas G. Ivey
Keyword(s):  
Manganese Oxide ◽  
Thin Sheet ◽  
Microstructural Characterization ◽  
Electrochemical Analysis ◽  
Retention Rates ◽  
Thin Sheets ◽  
Si Substrates ◽  
Oxide Electrodes ◽  
Deposition Parameters

ABSTRACTManganese oxide electrodes are synthesized by anodic deposition on Au coated Si substrates from acetate-containing aqueous solutions. By changing the deposition parameters including deposition current density, electrolyte composition, pH and temperature, a series of nanocrystalline manganese oxide electrodes with various morphologies (non–uniform continuous coatings, rod–like structures, aggregated rods and thin sheets) is obtained. Detailed microstructural characterization of as-deposited electrodes is conducted using scanning electron microscopy (SEM).Electrochemical analysis using cyclic voltammetry showed that manganese oxide electrodes with rod–like and thin sheet morphology exhibit enhanced electrochemical performance by improving manganese oxide utilization. The highest specific capacitance (~230 F g−1) and capacitance retention rates (~88%) are obtained for manganese oxide thin sheets after 250 cycles in 0.5M Na2SO4 at 20 mV s−1.

Characterization of Tensile and Compressive Behavior of Microscale Sheet Metals Using a Transparent Micro-Wedge Device

2011 ◽  
Author(s):  
James Magargee ◽  
Jian Cao ◽  
Rui Zhou ◽  
Morgan McHugh ◽  
Damon Brink ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Thin Sheet ◽  
Thin Sheets ◽  
Stainless Steel Sheet ◽  
Sheet Metals ◽  
Compressive Behavior ◽  
Buckling Modes ◽  
Full Field ◽  
Compressive Loads

The cyclic and compressive mechanical behavior of ultra-thin sheet metals was experimentally investigated. A novel transparent wedge device was designed and fabricated to prevent the buckling of thin sheets under compressive loads, while also allowing full field strain measurements of the specimen using digital imaging methods. Thin brass and stainless steel sheet metal specimens were tested using the micro-wedge device. Experimental results show that the device can be used to delay the onset of early buckling modes of a thin sheet under compression, which is critical in examining the compressive and cyclic mechanical behavior of sheet metals.

Characterization of Tensile and Compressive Behavior of Microscale Sheet Metals Using a Transparent Microwedge Device

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
James Magargee ◽  
Jian Cao ◽  
Rui Zhou ◽  
Morgan McHugh ◽  
Damon Brink ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Thin Sheet ◽  
Thin Sheets ◽  
Stainless Steel Sheet ◽  
Sheet Metals ◽  
Compressive Behavior ◽  
Buckling Modes ◽  
Full Field ◽  
Compressive Loads

The cyclic and compressive mechanical behavior of ultrathin sheet metals was experimentally investigated. A novel transparent wedge device was designed and fabricated to prevent the buckling of thin sheets under compressive loads, while also allowing full field strain measurements of the specimen using digital imaging methods. Thin brass and stainless steel sheet metal specimens with thicknesses on the order of 10–100 μm were tested using the microwedge device. Experimental results show that the device can be used to delay the onset of early buckling modes of a thin sheet under compression, which is critical in examining the compressive and cyclic mechanical behavior of sheet metals.

Microstructural characterization of CoPtCr/Cr thin film disks by cross-section TEM and elongated probe micro-diffraction

1991 ◽  
Vol 49 ◽  
pp. 762-763
Author(s):  
M.A. Parker ◽  
K.E. Johnson ◽  
C. Hwang ◽  
A. Bermea
Keyword(s):  
Magnetic Recording ◽  
Electron Probe ◽  
Microstructural Characterization ◽  
Crystallographic Structure ◽  
Recording Media ◽  
Layer By Layer ◽  
Cross Sectional ◽  
New Techniques ◽  
Polished Side

We have reported the dependence of the magnetic and recording properties of CoPtCr recording media on the thickness of the Cr underlayer. It was inferred from XRD data that grain-to-grain epitaxy of the Cr with the CoPtCr was responsible for the interaction observed between these layers. However, no cross-sectional TEM (XTEM) work was performed to confirm this inference. In this paper, we report the application of new techniques for preparing XTEM specimens from actual magnetic recording disks, and for layer-by-layer micro-diffraction with an electron probe elongated parallel to the surface of the deposited structure which elucidate the effect of the crystallographic structure of the Cr on that of the CoPtCr.XTEM specimens were prepared from magnetic recording disks by modifying a technique used to prepare semiconductor specimens. After 3mm disks were prepared per the standard XTEM procedure, these disks were then lapped using a tripod polishing device. A grid with a single 1mmx2mm hole was then glued with M-bond 610 to the polished side of the disk.

Electron microscope characterization of MOCVD-grown gap layers on Si

1986 ◽  
Vol 44 ◽  
pp. 724-725
Author(s):  
K.M. Jones ◽  
M.M. Al-Jassim ◽  
J.M. Olson
Keyword(s):  
Atmospheric Pressure ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Organic Chemical ◽  
Lattice Match ◽  
Si Substrates ◽  
Metal Organic ◽  
Good Lattice ◽  
Antiphase Domains

The epitaxial growth of III-V semiconductors on Si for integrated optoelectronic applications is currently of great interest. GaP, with a lattice constant close to that of Si, is an attractive buffer between Si and, for example, GaAsP. In spite of the good lattice match, the growth of device quality GaP on Si is not without difficulty. The formation of antiphase domains, the difficulty in cleaning the Si substrates prior to growth, and the poor layer morphology are some of the problems encountered. In this work, the structural perfection of GaP layers was investigated as a function of several process variables including growth rate and temperature, and Si substrate orientation. The GaP layers were grown in an atmospheric pressure metal organic chemical vapour deposition (MOCVD) system using trimethylgallium and phosphine in H2. The Si substrates orientations used were (100), 2° off (100) towards (110), (111) and (211).

Microstructural Characterization of Au-Ge-Ni based ohmic contacts to GaAs/AlGaAs modfet device

1987 ◽  
Vol 45 ◽  
pp. 326-327
Author(s):  
A.K. Rai ◽  
A.K. Petford-Long ◽  
A. Ezis ◽  
D.W. Langer
Keyword(s):  
Contact Resistance ◽  
Ohmic Contact ◽  
Ohmic Contacts ◽  
Microstructural Characterization ◽  
Almost Everywhere ◽  
Spacer Layer ◽  
Good Contact ◽  
The Relationship ◽  
Lower Contact

Considerable amount of work has been done in studying the relationship between the contact resistance and the microstructure of the Au-Ge-Ni based ohmic contacts to n-GaAs. It has been found that the lower contact resistivity is due to the presence of Ge rich and Au free regions (good contact area) in contact with GaAs. Thus in order to obtain an ohmic contact with lower contact resistance one should obtain a uniformly alloyed region of good contact areas almost everywhere. This can possibly be accomplished by utilizing various alloying schemes. In this work microstructural characterization, employing TEM techniques, of the sequentially deposited Au-Ge-Ni based ohmic contact to the MODFET device is presented.The substrate used in the present work consists of 1 μm thick buffer layer of GaAs grown on a semi-insulating GaAs substrate followed by a 25 Å spacer layer of undoped AlGaAs.

Microstructural characterization of a cast RENi5-based alloy

1993 ◽  
Vol 51 ◽  
pp. 1176-1177
Author(s):  
G. M. Micha ◽  
L. Zhang
Keyword(s):  
Electron Microscopy ◽  
Rare Earth ◽  
Microstructural Characterization ◽  
Binary Compound ◽  
Nickel Metal ◽  
Cast Material ◽  
Nickel Metal Hydride ◽  
Transmission Electron ◽  
Cast Condition

RENi5 (RE: rare earth) based alloys have been extensively evaluated for use as an electrode material for nickel-metal hydride batteries. A variety of alloys have been developed from the prototype intermetallic compound LaNi5. The use of mischmetal as a source of rare earth combined with transition metal and Al substitutions for Ni has caused the evolution of the alloy from a binary compound to one containing eight or more elements. This study evaluated the microstructural features of a complex commercial RENi5 based alloy using scanning and transmission electron microscopy.The alloy was evaluated in the as-cast condition. Its chemistry in at. pct. determined by bulk techniques was 12.1 La, 3.2 Ce, 1.5 Pr, 4.9 Nd, 50.2 Ni, 10.4 Co, 5.3 Mn and 2.0 Al. The as-cast material was of low strength, very brittle and contained a multitude of internal cracks. TEM foils could only be prepared by first embedding pieces of the alloy in epoxy.

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