Electron Microscopy Study of Structural Changes During Isothermal Annealing of a Ni4Mo-Based Alloy Containing Chromium

1985 ◽  
Vol 62 ◽  
Author(s):  
K. Vasudevan ◽  
E. E. Stansbury
Keyword(s):  
Electron Microscopy ◽  
Structural Changes ◽  
Isothermal Annealing ◽  
Stacking Faults ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Study Phase ◽  
Transmission Electron ◽  
Optical Microstructure ◽  
Second Phases

ABSTRACTTransmission electron microscopy has been used to study phase transformations in a Ni4Mo alloy containing 2.08 wt pct chromium following isothermal annealing at 850, 800 and 700°C. At these temperatgres, the DO22 phase forms initially, which then transforms to Ni3Mo. At 700°C, the DO22 phase forms from bands composed of Ni4Mo and Ni2Mo aligned parallel to {111} fcc planes, and is relatively stable. A second mechanism for the formation of Ni3Mo occurs at 700°C. Large Ni4Mo domains form at grain boundaries. These su~sequently transform to Ni3Mo, with the simultaneous presence of stacking faults on (010) Ni3Mo planes.These observations are correlated to the optical microstructure. Grain size influences the type, volume, and distribution of second phases. Sequences and mechanisms of transformations are related to the experimental observations.

Transmission electron microscopy study of Ge implanted into SiC

2002 ◽  
Vol 17 (2) ◽  
pp. 479-486 ◽  
Author(s):  
T. Gorelik ◽  
U. Kaiser ◽  
Ch. Schubert ◽  
W. Wesch ◽  
U. Glatzel
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Room Temperature ◽  
Structural Changes ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Transmission Electron Microscopy Study ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Means Of Transmission

Hexagonal 6H– and 4H–SiC wafers were implanted with (1−1.5) × 1016 cm−2 germanium ions at room temperature and at 700 °C with subsequent annealing between 1000 and 1600 °C. Structural changes in the SiC matrix were studied in detail by means of transmission electron microscopy (TEM). After implantation at room temperature the hexagonal SiC matrix becomes amorphous and, after annealing, recrystallizes into cubic SiC. The latter process was accompanied by the creation of voids and cracks. In case of high-temperature (700 °C) implantation, where amorphization was avoided, no polytype change in as-implanted and annealed SiC wafers was observed. In annealed samples nanocrystalline precipitates with high Ge content were observed in high-resolution TEM images.

Transmission Electron Microscopy Study of Planar Defects in Polycrystalline CdTe Thin Films

2001 ◽  
Vol 7 (S2) ◽  
pp. 556-557
Author(s):  
Y. Yan ◽  
K.M. Jones ◽  
M.M. Al-Jassim
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Stacking Faults ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Extended Defects ◽  
Transmission Electron ◽  
Cdte Thin Films ◽  
High Absorption Coefficient

CdTe is a promising photovoltaic material due to its near optimum band gap and high absorption coefficient. Polycrystalline, thin-film CdTe/CdS solar cells have demonstrated an efficiency of 15.8%. High density of extended defects is often found in polycrystalline CdTe films grown by close-spaced sublimation (CSS). So far, most investigations of defects in CdTe have focused on epitaxially grown films, and the reported extended defects are mainly lamellar twins. However, epitaxially grown films generally have a different microstructure compared to CSS grown polycrystalline CdTe thin films. in this paper, we report our study of extended defects in CSSgrown polycrystalline CdTe thin films by high-resolution transmission electron microscopy (HRTEM). We found that the extended defects are mostly lamellar twins and stacking faults. The stacking faults always propagate across the grains, without ending at a partial dislocation inside the grains.

Transmission electron microscopy study of (103)-oriented epitaxial SrBi2Nb2O9 films grown on (111) SrTiO3 and (111) SrRuO3/(111) SrTiO3

2001 ◽  
Vol 16 (2) ◽  
pp. 489-502 ◽  
Author(s):  
M. A. Zurbuchen ◽  
J. Lettieri ◽  
Y. Jia ◽  
D. G. Schlom ◽  
S. K. Streiffer ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Substrate Surface ◽  
Microscopy Study ◽  
Dark Field ◽  
Electron Microscopy Study ◽  
Cross Sectional ◽  
Plan View ◽  
Transmission Electron ◽  
Second Phases

Portions of the same epitaxial (103)-oriented SrBi2Nb2O9 film grown on (111) SrTiO3 for which we recently reported the highest remanent polarization (Pr) ever achieved in SrBi2Nb2O9 (or SrBi2Ta2O9) films, i.e., Pr = 15.7 μC/cm2, have been characterized microstructurally by plan-view and cross-sectional transmission electron microscopy (TEM) along three orthogonal viewing directions. SrBi2Nb2O9 grows with its c axis tilted 57° from the substrate surface normal in a three-fold twin structure about the substrate [111], with the growth twins' c axes nominally aligned with the three 〈100〉 SrTiO3 directions. (103) SrBi2Nb2O9 films with and without an underlying epitaxial SrRuO3 bottom electrode have been studied. Dark-field TEM imaging over a 12 μm2 area shows no evidence of second phases (crystalline or amorphous). A high density of out-of-phase boundaries exists in the films.

Factors influencing adhesive bonding at the bone/implant interface

1992 ◽  
Vol 50 (2) ◽  
pp. 1114-1115
Author(s):  
Julie A. Martini ◽  
Robert H. Doremus
Keyword(s):  
Electron Microscopy ◽  
Adhesive Bonding ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Bone Implant ◽  
Factors Influencing ◽  
Lr White ◽  
Transmission Electron ◽  
New Zealand White Rabbits ◽  
Scanning Electron

Tracy and Doremus have demonstrated chemical bonding between bone and hydroxylapatite with transmission electron microscopy. Now researchers ponder how to improve upon this bond in turn improving the life expectancy and biocompatibility of implantable orthopedic devices.This report focuses on a study of the- chemical influences on the interfacial integrity and strength. Pure hydroxylapatite (HAP), magnesium doped HAP, strontium doped HAP, bioglass and medical grade titanium cylinders were implanted into the tibial cortices of New Zealand white rabbits. After 12 weeks, the implants were retrieved for a scanning electron microscopy study coupled with energy dispersive spectroscopy.Following sacrifice and careful retrieval, the samples were dehydrated through a graduated series starting with 50% ethanol and continuing through 60, 70, 80, 90, 95, and 100% ethanol over a period of two days. The samples were embedded in LR White. Again a graduated series was used with solutions of 50, 75 and 100% LR White diluted in ethanol.

Transmission Electron Microscopy study of Bi-based superconducting phases

1990 ◽  
Vol 48 (4) ◽  
pp. 50-51
Author(s):  
J.G. Wen ◽  
K.K. Fung
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Single Crystals ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Space Groups ◽  
Superconducting Phases ◽  
Ceramic Samples ◽  
Transmission Electron ◽  
Modulated Structures

Bi-based superconducting phases have been found to be members of a structural series represented by Bi2Sr2Can−1Cun−1On+4, n=1,2,3, and are referred to as 2201, 2212, 2223 phases. All these phases are incommensurate modulated structures. The super space groups are P2/b, NBbmb 2201, 2212 phases respectively. Pb-doped ceramic samples and single crystals and Y-doped single crystals have been studied by transmission electron microscopy.Modulated structures of all Bi-based superconducting phases are in b-c plane, therefore, it is the best way to determine modulated structure and c parameter in diffraction pattern. FIG. 1,2,3 show diffraction patterns of three kinds of modulations in Pb-doped ceramic samples. Energy dispersive X-ray analysis (EDAX) confirms the presence of Pb in the three modulated structures. Parameters c are 3 0.06, 38.29, 30.24Å, ie 2212, 2223, 2212 phases for FIG. 1,2,3 respectively. Their average space groups are all Bbmb.

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