Optical and Structural Studies of Binary Compounds by Explosive Laser Irradiation and Heat Treatment

10.5772/21407 ◽  
2011 ◽  
Author(s):  
S. Kar
Keyword(s):  
Heat Treatment ◽  
Laser Irradiation ◽  
Structural Studies ◽  
Binary Compounds

Influence of Heat Treatment on the Anelastic Properties of MgB2

2010 ◽  
Vol 660-661 ◽  
pp. 832-836
Author(s):  
Marcos Ribeiro da Silva ◽  
Carlos Roberto Grandini
Keyword(s):  
Heat Treatment ◽  
Grain Boundaries ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Crystalline Lattice ◽  
Relaxation Processes ◽  
Mechanical Spectroscopy ◽  
Critical Temperatures ◽  
Dislocation Movement ◽  
Binary Compounds

The discovery of the superconductivity of MgB2 was of great importance, because this material is one of the few known binary compounds and has one of the highest critical temperatures (39° K). As MgB2 is a granular compound, it is fundamentally important to understand the mechanisms of the interaction of the defects and the crystalline lattice, in addition to the eventual processes involving the grain boundaries that compose the material. In this sense, the mechanical spectroscopy measurements constitute a powerful tool for this study, because through them we can obtain important information about phase transitions, the behavior of interstitial or substitutional elements, dislocations, grain boundaries, diffusion, instabilities, and other imperfections of the lattice. For this paper, the samples were prepared using the PIT method and were characterized by density, X-ray diffraction, scanning electron microscopy, electric resistivity, magnetization, and mechanical spectroscopy. The samples were measured in their as-cast condition and after an ultra-high-vacuum heat treatment. The results showed complex spectra, in which were identified relaxation processes due to dislocation movement, interaction among interstitial elements and dislocations, auto-diffusion, and movement of grain boundaries. Some of these processes disappeared with the heat treatment.

EFFECT OF NANOCRYSTALLIZATION ANNEALING ON MAGNETIC PROPERTIES AND MAGNETOIMPEDANCE OF CO-BASE RIBBONS

2012 ◽  
Vol 05 ◽  
pp. 841-846
Author(s):  
AMIR KEYVANARA ◽  
REZA GHOLAMIPOUR ◽  
SHAMSEDIN MIRDAMADI ◽  
FARZAD SHAHRI ◽  
HOSSEIN SEPEHRI AMIN
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Magnetic Properties ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Melt Spun ◽  
Melt Spun Ribbons ◽  
Nanocrystalline Phases

Melt spun ribbons of Co 64 Fe 4 Ni 2 B 19 Si 8 Cr 3 alloy have been prepared and the nanocrystallization process was carried out by the heat treatment of the as spun ribbons above the crystallization temperature. Structural studies of the samples have been performed by transmission electron microscopy and X-ray diffraction. Magnetic properties of the samples and magnetoimpedance measurements were investigated and it was revealed that magnetic properties and magnetoimpedance of the samples deteriorate by the formation of nanocrystalline phases.

Electrical Properties of Solid Phase Crystallized Silicon Films

2001 ◽  
Vol 664 ◽  
Author(s):  
Tadashi Watanabe ◽  
Hajime Watakabe ◽  
Toshiyuki Sameshima
Keyword(s):  
Heat Treatment ◽  
Electrical Conductivity ◽  
Energy Density ◽  
Laser Irradiation ◽  
Carrier Mobility ◽  
Crystalline Silicon ◽  
Solid Phase ◽  
Laser Energy ◽  
Silicon Films ◽  
Laser Energy Density

ABSTRACTIn this study, the carrier mobility and density for solid phase crystallized (SPC) silicon films fabricated at 600 °C for 48 hours are analyzed by free carrier optical absorption. The carrier mobility is 40 cm2/Vs for SPC films doped with 6×1019-cm−3-phosphorus atoms. This analysis suggests the SPC films have fine crystalline grains closed to single crystalline silicon. In addition, initial carrier density was 3×1019 cm−3, which increased to 6×1019 cm−3by XeCl excimer laser irradiation of 500mJ/cm2. The inactivated regions in SPC films are reduced by laser irradiation. However, the electrical conductivity after laser irradiation for SPC films doped with 6×1018-cm−3-phosphorus atoms decreased from 3.3 to 0.018 S/cm as laser energy density increased to 500mJ/cm2. On the other hand, the electrical conductivity increased from 14.7 to 31.3 S/cm with similar increase of laser energy density after H2O vapor heat treatment at 260°C for 3 hours with 1.3 MPa. Furthermore, the characteristics of n-channel TFTs fabricated with initial SPC films as well as SPC films which was irradiated by laser at 425mJ/cm2 are also researched. The threshold voltage is decreased from 3.8 to 2.0 V by laser irradiation. Threshold voltages of both cases are decreased from 3.8 to 2.4 V for no-laser irradiation and from 2.0 to 0.8 V for laser irradiation, after H2O vapor heat treatment at 310°C for 1 hour with 9.0MPa. Based on the above trial, the defect reduction method combining laser irradiation and H2O vapor heat treatment has proved to be very effective for SPC films and SPC TFTs.

Influence of Femtosecond Laser Irradiation and Heat Treatment on Precipitation of Silver Nanoparticles in Glass

2003 ◽  
Vol 20 (6) ◽  
pp. 932-934 ◽  
Author(s):  
Zeng Hui-Dan ◽  
Qiu Jian-Rong ◽  
Jiang Xiong-Wei ◽  
Qu Shi-Liang ◽  
Zhu Cong-Shan ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Silver Nanoparticles ◽  
Femtosecond Laser ◽  
Laser Irradiation ◽  
Femtosecond Laser Irradiation

On-Machine Heat Treatment System Using YAG Laser: Laser Hardening of Micro-Cutting Edge

2010 ◽  
Vol 447-448 ◽  
pp. 203-207 ◽  
Author(s):  
Keiji Ogawa ◽  
Heisaburo Nakagawa ◽  
Akira Ohtsuka
Keyword(s):  
Heat Treatment ◽  
Machine Tool ◽  
Laser Irradiation ◽  
Cutting Edge ◽  
Laser Hardening ◽  
Treatment System ◽  
Yag Laser ◽  
Micro Cutting ◽  
Laser Quenching ◽  
Machining Center

This paper describes the laser hardening of micro-cutting edges using an on-machine heat treatment system with a YAG laser. Various laser conditions were evaluated to perform laser quenching on a machine tool without melting at the edges. We also investigated the influence of the motion accuracy of the machining center on the quenching characteristic of micro-cutting edges after laser irradiation. We clarified that we could quench both the straight and curved corner parts by arranging proper laser irradiation conditions considering the motion accuracy of the machining center.

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