Growth and Thermal Stability of Thin Niobium Overlayers on (0001) Sapphire Substrates

1995 ◽  
Vol 403 ◽  
Author(s):  
T. Wagner ◽  
M. Lorenz ◽  
P. A. Langjahr ◽  
M. Ruhle
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Transmission Electron Microscopy ◽  
Deposition Temperature ◽  
High Energy ◽  
High Energy Electron ◽  
Epitaxial Relationship ◽  
Sapphire Substrates ◽  
Transmission Electron ◽  
Thermal Stability Of

AbstractThin Nb films were deposited by MBE on (0001)α-Al2O3 in UHV. At a substrate temperature of 800°C, reflection high energy electron diffraction (RHEED) revealed that the film grew with the orientation relationship (planes of similar symmetry are parallel to each other): (0001)α-Al2O3 ‖ (111)Nb; [2110]α-Al2O3 ‖ [110]Nb. Investigations with conventional transmission electron. microscopy (CTEM) revealed that the film was not perfectly epitaxial after deposition. Small Nb grains with different orientations were embedded in the epitaxial Nb film. During annealing at temperatures well above the deposition temperature, secondary grain growth of the small embedded Nb grains occured, leading to a different epitaxial relationship between the Nb film and the sapphire: (0001)α-Al2O3 ‖ (110)Nb; [0110]α-Al2O3 ‖ [001]Nb.

Strengthening Mechanism and Thermal Stability of Spray Formed H13 Steel

2019 ◽  
Vol 295 ◽  
pp. 49-56
Author(s):  
Zhan Zhan Zhang ◽  
Wan Zhen Wang ◽  
Yun Bo Chen ◽  
Miao Hui Wang ◽  
Chang De Zhao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Transmission Electron Microscopy ◽  
Strengthening Mechanism ◽  
H13 Steel ◽  
Tempering Temperature ◽  
Transmission Electron ◽  
Tempering Treatment ◽  
Hardness Values ◽  
Thermal Stability Of

The aim of this work is to study the strengthening mechanism and thermal stability of spray formed H13 steel. The microstructure and hardness of spray formed H13 steels are investigated by electron microscopy, transmission electron microscopy and hardness measurementscanning. The calculated results demonstrate that tensile strength, impact energy and hardness values of sprayed-formed H13 steel are higher than that of as-cast H13 steel when the tempering temperature is 600 °C after quenched at 1050 °C. Compared with as-cast H13 steels, tempered spray-formed H13 steels possess supernal high-temperature temper resistant stability. The chemical composition of the carbides in spray-formed steels is V and Cr rich spherical carbides are hardly influenced by the tempering treatment.

Structural and Chemical Properties of MBE Grown Niobium Overlayers on (110) Rutile

1996 ◽  
Vol 441 ◽  
Author(s):  
J. Marien ◽  
T. Wagner ◽  
M. Rühle
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Defect Structure ◽  
Chemical Properties ◽  
High Energy ◽  
Initial Growth ◽  
High Energy Electron ◽  
Transmission Electron ◽  
Different Temperatures ◽  
And Chemical Properties

AbstractThin Nb films were grown by MBE in a UHV chamber at two different temperatures (50°C and 950°C) on the (110) surface of TiO2 (rutile).At a growth temperature of 50°C, reflection high energy electron diffraction (RHEED) revealed epitaxial growth of Nb on rutile: (110)[001] TiO2 ¦¦ (100)[001] Nb. In addition, investigations with Auger electron spectroscopy (AES) revealed that a chemical reaction took place between the Nb overlayer and the TiO2 substrate at the initial growth stage. A 2 nm thick reaction layer at the Nb/TiO2 interface has been identified by means of conventional transmission electron microscopy (CTEM) and high-resolution transmission electron microscopy (HRTEM).At a substrate temperature of 950°C, during growth, the Nb film was oxidized completely, and NbO2 grew epitaxially on TiO2. The structure and the chemical composition of the overlayers have been investigated by RHEED, AES, CTEM and HRTEM. Furthermore, it was determined that the reaction of Nb with TiO2 is governed by the defect structure of the TiO2 and the relative oxygen affinities of Nb and TiO2.

Thermal stability of laser-induced modified volumes in Si as studied by in situ and ex situ heating experiments

Microscopy ◽  
2018 ◽  
Vol 67 (2) ◽  
pp. 112-120
Author(s):  
Hiroyasu Saka ◽  
Hiroyuki Iwata ◽  
Daisuke Kawaguchi
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Transmission Electron Microscopy ◽  
Laser Beam ◽  
Ex Situ ◽  
Dislocation Theory ◽  
Tail Region ◽  
Transmission Electron ◽  
Thermal Stability Of

Abstract Radiation of a permeable laser beam into Si induces considerable modification of structures. Thermal stability of the laser-induced modified volumes (LIMV’s) was studied comprehensively by means of in situ and ex situ heating experiments using transmission electron microscopy. The behavior in the tail region of a LIMV can be understood by dislocation theory, while that of a void formed at the very focus of a laser beam cannot be understood easily.

scholarly journals Encapsulated Molecules in Carbon Nanotubes: Structure and Properties

2001 ◽  
Vol 675 ◽  
Author(s):  
Richard Russo ◽  
Brian W. Smith ◽  
B.C. Satishkumar ◽  
David E. Luzzi ◽  
Harry C. Dorn
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Thermal Stability ◽  
Transmission Electron Microscopy ◽  
Single Walled Carbon Nanotubes ◽  
Structure And Properties ◽  
One Dimensional ◽  
Transmission Electron ◽  
Walled Carbon Nanotubes ◽  
Thermal Stability Of

ABSTRACTWe encapsulate a number of fullerenes inside single-walled carbon nanotubes (SWNTs) including La2@C80 and ErxSc3–xN@C80(x=0–3). The structural properties of these nanoscopic hybrid materials are described using high resolution transmission electron microscopy and electron diffraction. It is found that the encapsulated fullerenes self-assemble into long, one-dimensional chains. The thermal stability of these supramolecular assemblies are studied and large variations are found. The behavior is nominally consistent with the mass of the encapsulated metallofullerenes.

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