Electron Microscope Study of Cation-Deficient Chalcogenide Spinels

1982 ◽  
Vol 21 ◽  
Author(s):  
Y. Komura ◽  
S. Takeda
Keyword(s):  
Electron Microscope ◽  
X Ray ◽  
Disordered Structures ◽  
Spinel Compounds ◽  
Vacancy Ordering ◽  
Resolution Electron ◽  
The Matrix ◽  
Lattice Images ◽  
Image Characteristic ◽  
High Resolution Electron Microscope

ABSTRACTHigh-resolution electron microscope observations were carried out on the cation-deficient spinel compounds Ga2/3Cr2S4 and InCr5/3S4. X-ray analysis of both compounds indicates that there exist 1/3 vacancy per formula unit in 8a positions. It was also found that the vacancy ordering occurs in Ga2/3Cr2S4 below about 1100°C, as well as in InCr5/3S4. Lattice images of vacancy ordered and disordered structures were obtained. In some electron micrographs of ordered InCr5/3 S4, several domains of disordered region were observed in between the matrix of the ordered structure. In a [110] image, characteristic lattice defects were observed on the (110) plane.

Electron microscopy and diffraction studies of polyimides

1983 ◽  
Vol 41 ◽  
pp. 28-29
Author(s):  
O.C. de Hodgins ◽  
K. R. Lawless ◽  
R. Anderson
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Structural Features ◽  
Inert Atmosphere ◽  
Polyimide Films ◽  
Resolution Electron ◽  
The Matrix ◽  
High Resolution Electron Microscope ◽  
Diffraction Patterns ◽  
Polymeric Samples

Commercial polyimide films have shown to be homogeneous on a scale of 5 to 200 nm. The observation of Skybond (SKB) 705 and PI5878 was carried out by using a Philips 400, 120 KeV STEM. The objective was to elucidate the structural features of the polymeric samples. The specimens were spun and cured at stepped temperatures in an inert atmosphere and cooled slowly for eight hours. TEM micrographs showed heterogeneities (or nodular structures) generally on a scale of 100 nm for PI5878 and approximately 40 nm for SKB 705, present in large volume fractions of both specimens. See Figures 1 and 2. It is possible that the nodulus observed may be associated with surface effects and the structure of the polymers be regarded as random amorphous arrays. Diffraction patterns of the matrix and the nodular areas showed different amorphous ring patterns in both materials. The specimens were viewed in both bright and dark fields using a high resolution electron microscope which provided magnifications of 100,000X or more on the photographic plates if desired.

Identification of T1 phase in Al-Li-Cu alloy (2090)

1992 ◽  
Vol 50 (1) ◽  
pp. 188-189
Author(s):  
J.S. Kim ◽  
S. S. Baek ◽  
G. H. Kim ◽  
C. H. Chun
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Zone Axis ◽  
The Other ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cu Alloy ◽  
Resolution Electron ◽  
High Resolution Electron Microscope ◽  
Optical Laser

In Al-Li-Cu alloy(2090) the extra spots in the Selected Area Diffraction Pattern (SADP) of [112]α zone axis have been argued. Huang and Ardell described that the extra spots were originated from T1 variants tilted to electron beam. Rioja and Ludwiczak, however, presented that die precursor of T1 termed T1' was present in alloy(2090) and generated the extra spots. Rioja and Ludwiczak explained die existence of extra spots as making the simulated SADP diagrams and analyzing x ray diffraction lines of T1'. The existence of T1' has been inconsistent with the other papers. Huang and Ardell's model has been well recognized in present. The investigations on the extra spots had mainly been restricted in [112]α SADP. In the present paper, the extra spots from [110]αand [100]α zone axes were investigated using High Resolution Electron Microscope (HREM) and optical laser diffractometer.

300kv high-performance analytical TEM (H-9000)

1987 ◽  
Vol 45 ◽  
pp. 108-109
Author(s):  
H. Kobayashi ◽  
H. Sato ◽  
K. Miyauchi ◽  
T. Onai ◽  
K. Shii ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
High Performance ◽  
Image Resolution ◽  
X Ray ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Analytical Microscopy ◽  
High Resolution Electron Microscope

Higher voltage operation has many advantages for transmission electron microscopy.These advantages include better TEM image resolution and ease of specimen imaging. For analytical microscopy, the higher voltage operation has advantages such as higher source brightness, and better spatial resolution.We reported development of a 300kV ultra high resolution electron microscope. At this time, we would like to report an analytical type 300kV electron microscope.We have incorporated a side entry specimen stage which permits ±45° specimen tilt and is convenient for characteristic x-ray detection. We have also incorporated an analytical objective polepiece which has Cs of 2. 5mm, Cc of 2. 3mm and theoretical TEM image resolution of 0.23nm.

Hrem of metal/metal multilayer materials

1986 ◽  
Vol 44 ◽  
pp. 404-405
Author(s):  
A.K. Petford-Long ◽  
C.-H Chang ◽  
M.B. Stearns ◽  
M.A. Kadin
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Structural Information ◽  
Si Substrate ◽  
Multilayered Structures ◽  
Optical Elements ◽  
X Ray ◽  
Resolution Electron ◽  
Metal Metal ◽  
High Resolution Electron Microscope

Multilayered structures (MLS) containing thin (<10nm) metallic layers of W or Mo with C or Si are undergoing development for use as x-ray reflectors and other x-ray optical elements. The two metals used are sputtered or evaporated in alternate layers onto a crystalline Si substrate (eg. [2]). The x-ray reflectance properties of these materials have been extensively studied, but until recently only indirect structural evidence has been available to allow a correlation between reflectance and structure to be made. A JEM 4000EX ultra-high resolution electron microscope has been used in this study to image the MLS and provide direct structural information.

Crystal Structures Of L-Nb205 AND L-Ta205

1977 ◽  
Vol 35 ◽  
pp. 188-189
Author(s):  
Sumio Iijima
Keyword(s):  
Electron Microscope ◽  
Complex Nature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Resolution Electron ◽  
Unit Cells ◽  
System 2 ◽  
High Resolution Electron Microscope ◽  
Diffraction Patterns ◽  
Phase Relationships

Although structures of tantalum pentoxides have been extensively studied, they have not been fully understood because of the complex nature of their X-ray diffraction patterns. In this study we made some observations on crystals of L-Ta2O5 and L-Nb2O5 using a high resolution electron microscope. The latter structure has been believed to be isostructural with L-Ta2O5. The samples were prepared by Dr. Roth at NBS and were parts of the products used for determining phase relationships in niobium pentoxides (1) and the Ta2O5-Ta2WO8 system (2).According to the X-ray data both structures have orthorhombic unit cells with a = 6.2, b = 29.3, c = 3.9Å. The structures are based on the U03-type and the b spacings are nearly 8 times those of the subcell. Electron diffraction (E.D.) patterns of L-Nb2O5 and L-Ta3O5 crystals showing a*-b* reciprocal sections confirmed generally the results of X-ray works (Figs, la and lc).

scholarly journals The Preparation and Characterization ofβ-SiAlON Nanostructure Whiskers

2008 ◽  
Vol 2008 ◽  
pp. 1-6 ◽  
Author(s):  
Pengli Dong ◽  
Xidong Wang ◽  
Mei Zhang ◽  
Min Guo ◽  
Seshadri Seetharaman
Keyword(s):  
Electron Microscope ◽  
Diameter Distribution ◽  
Growth Mechanisms ◽  
X Ray Diffraction ◽  
Vapor Liquid Solid ◽  
X Ray ◽  
Transmission Electron ◽  
Resolution Electron ◽  
High Resolution Electron Microscope ◽  
Sintering Method

Two kinds ofβ-SiAlON nanostructure whiskers, rod-like and wool-like whiskers, were synthesized by pressure-less sintering method at 1773 K for 5 hours. The whiskers synthesized were characterized by powder X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and high-resolution electron microscope (HREM) techniques. It was found that diameter distribution of rod-like whiskers was about 80–250 nm, while it was about 45–55 nm in diameter for the wool-like whiskers. The growth mechanisms ofβ-SiAlON nanostructure whiskers are discussed by the vapor-solid (VS) and vapor-liquid-solid (VLS) mechanisms, respectively.

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