Papers by Keyword: Annealing Effect

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Authors: Masataka Satoh, Tomoyuki Suzuki, Shohei Miyagawa
Abstract: The annealing behavior of the N+ implantation-induced defects in 4H-SiC(0001) has been investigated by means of Rutherford backscattering spectrometry in the annealing temperature range from 200 to 1000 oC. The samples are multiple-implanted by N+ ions with energy range from 15 to 120 keV at a total dose of 2.4 x 1015 /cm2. Three annealing stages are observed by isochronal annealing; first stage from 200 to 400 oC, second stage from 400 to 600 oC and third stage from 600 to 1000 oC. The 80 percent of the N+ implantation-induced defects are annealed out at the temperature above 600 oC. The annealing mechanism of the defects in each stage is discussed.
Authors: Junya Sumita, Taiju Shibata, Masahiro Ishihara, Tatsuo Iyoku, Nobumasa Tsuji
Abstract: Graphite materials are used for structural components in the core of high temperature gas-cooled reactors (HTGRs) because of their excellent thermo/mechanical properties. When the core temperature is raised at an accident, the thermal stress of the components is induced, and it enhances the fracture probability of them. In general, the thermal conductivity of graphite is decreased by neutron irradiation due to irradiation-induced defects preventing heat conduction by phonon. It is hence expected that decreased thermal conductivity is recovered to some extent by thermal annealing at the accident. Therefore, the consideration of the thermal annealing effect is placed as much important subject in the fracture/strength evaluation of the graphite components at the accident. In the present study, the thermal stress and the fracture probability of graphite components influenced by the thermal annealing were investigated by a finite element method (FEM) analysis. It was shown that the annealing effect decreases the thermal stress and a certain level of the fracture probability.
Authors: Jian Huang, Marianne Gilbert, Jeremy Bowman
Abstract: This paper investigated the effect of outer polypropylene (PP) skin thickness on the density and calculated hardness of a polyethylene (PE) core pressure pipe. Density of PE pipes with different PP skin thicknesses (including a PE pipe without a skin) was compared and found that the density distribution can be described well by an exponential function and it increased and flattened with increased PP thickness, which was equivalent to a PE layer 2~3 times as thick. Thermal analysis showed that the density increment is derived from the thermal insulation provided by the PP skin and allowed annealing occur during pipe cooling, particularly close to the outer wall. According to the crystallinity and hardness relationship, the relative strengthening effect on hardness and its relationship with PP layer thickness was quantified.
Authors: Yi Si
Abstract: The deformation and mechanical properties of Zr-based bulk metallic glasses (BMGs) under a nanoindenter and the effect of cooling rate, the effect of cooling rate, tungsten fiber addition and annealing on them have been studied by means of a nanoindentation instrument and a scanning electron microscope (SEM). The results indicate that the deformation of Zr-based BMGs under a nanoindenter is characterized by multiple shear bands and viscous flow which confirms the existence of a amount of plastic deformation. For pure quenched Zr-based BMGs, the larger the size of samples or the nearer the location away from the surface of a same sample, the smaller the values of microhardness (Hv) and elastic modulus (E); Annealing and tungsten fiber addition enhance the values of Hv and E; meanwhile, they also significantly change morphology around a nanoindenter and the amount of plastic deformation. The mechanism of plastic deformation is preliminarily analyzed.
Authors: A.A. Haidry, P. Durina, M. Tomasek, J. Gregus, P. Schlosser, M. Mikula, M. Truhly, T. Roch, T. Plecenik, A. Pidik, M. Zahoran, P. Kus, A. Plecenik
Abstract: One of the potential applications of TiO2 is its use in gas sensor technology. The aim of this work was to study the gas sensing properties of TiO2 thin films in combination with the effect of post-deposition annealing treatment. Titanium dioxide thin films with thickness 100 nm were prepared by the reactive dc magnetron sputtering. The thin films were deposited on sapphire substrate from a titanium target in an oxygen atmosphere. The samples were then post-annealed in air in the temperature range 600 °C 1000 °C. Crystal structure, surface topography and absorption edge of the thin films have been studied by X-ray Diffraction technique, Atomic Force Microscopy and UV-VIS Spectroscopy. It was found that the phase gradually changed from anatase to rutile, the grain size and roughness tended to increase with increasing post-annealing temperature. The effect of these factors on gas sensing properties was discussed. For electrical measurements comb-like Pt electrodes were prepared by standard photolithography and the films were exposed to different concentrations of H2 gas up to 10000 ppm in synthetic air at various operating temperatures from 200 °C to 350 °C.
Authors: Samir Sani Abdulmalik, Rosli Ahmad
Abstract: Friction stir processing is a novel process evolved to fabricate surface metal matrix composites. Rice husk ash (RHA) is an agro-industrial waste and by product of rice husk. The feasibility of incorporating RHA powder into aluminium alloy AA6061-0 as reinforcement particles to make surface matrix composite via FSP is reported in this paper. The optical micrographs revealed a homogeneous distribution of RHA particles which were well bonded with the matrix in both first and fourth-passes of the FSP due to mechanical stirring. Microhardness of the stir zone SZ with the RHA particles of I-pass increased to about 106 HV, 40% higher than that of the base material 66 HV by dispersed RHA particles.
Authors: Jing Li, Xiao Dong Zhao
Abstract: Indium tin oxide thin film (ITO film) has been deposited onto the quartz glass by a sol-gel process, followed by annealing in air. The temperature range from 200 to 800 °C and the annealing effect on the optical, electrical and structural properties of ITO films has been studied in detail. ITO Films with a thickness of 100nm had an optical transparency up to 90% in the wavelength range of visible spectrum. The ITO film showed minimum resistivity of 1.65×10-3Ω.cm-1 when annealing temperature was 600°C in air. the rapid annealing process may contribute to the electrical property of ITO film for the densification of the micro structure. but the process may lead to the decrease of transparency for the reflection caused by grain boundary.
Authors: Kazuhiko Ohmori, Tomonori Umeda, Takuya Sakaguchi, Masaaki Doi, Pan Huayong, Hidefumi Asano, Nobuo Tanaka, Masaaki Matsui
Abstract: Annealing effect on the magnetic properties of Fe-Pt nanoparticle was investigated. Fe-Pt nanoparticles were synthesized by the chemical reduction of H2PtCl6 and the decomposition of Fe(CO)5 in the presence of PVP polymers. The samples were annealed at several temperatures from 350°C to 600°C and the structural and magnetic properties were studied by TEM, XRD and magnetization measurements. FePt nanoparticles as-synthesized showed super-paramagnetism and annealed samples at temperatures more than 400°C, ferromagnetism. The crystal structure of as-synthesized sample was disordered fcc, but chemically ordered fct, when it was annealed at more than 400°C. The annealing effects are the concatenation or agglomeration of nanoparticles accompanied with the increase in particle diameter and with the ordering of the FePt superlattice. The critical diameter for emergence of ferromagnetism of FePt particle has been considered to be 3.6 to 5.6 nm in mean diameter, under the existence of the ordered L10 phase The blocking temperature as a function of the annealing temperature was investigated.
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