Papers by Keyword: Scanning Electron Microscope (SEM)

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Authors: Ya Ming Huang, Qiang Fu, Chun Xu Pan
Abstract: Electron backscatter diffraction (EBSD) has been developed as a novel technique for characterizing crystallographic textures in recent years. The present paper proposes an “in-situ-tracking” approach using SEM and EBSD to examining the microstructural development and grain boundary variation of stainless steel during elevated 1200 °C service. The results revealed that in addition to the coarsened grains the fraction of low angle grain boundaries (LABG) became increased and flattened obviously during service. Comparing to the regular high temperature service (below 900 °C), the present “recovery and recrystallization” process was accelerated due to dislocation fastened movement and intensive interaction. However, the grain growth mechanism still meet the well-accepted dislocation model of subgrain combination.
Authors: Ourania Menti Goudouri, Eleana Kontonasaki, Nikolaos Kantiranis, Xanthippi Chatzistavrou, Lambrini Papadopoulou, Petros Koidis, Konstantinos M. Paraskevopoulos
Abstract: Melt derived bioactive glass- porcelain system is reported to be bioactive but with a slow rate of bioactivity. The aim of this work is to fabricate and characterize bioactive glass/dental porcelain composites produced by the sol-gel method. Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and X-ray Diffractometry (XRD) were used to characterize the fabricated materials. The FTIR spectra and the XRD patterns confirm the presence of both constituents in the mixtures, while the dominant crystal phases in bioactive glass/dental porcelain specimens are leucite and wollastonite.
Authors: Andreea Carmen Bărbînţă, Romeo Chelariu, Marcelin Benchea, Carmen Iulia Crimu, Sorin Iacob Strugaru, Corneliu Munteanu
Abstract: Ti-Nb-Zr-Ta alloys represent a new generation of biomaterials with possible applications in the orthopedic field, being developed in order to eliminate the negative aspects of the current orthopedic biomaterials, which consist mainly in a low biocompatibility with human tissues and high values of modulus of elasticity compared to the human bone. This paper presents a comparative study of new titanium alloys, corresponding to the Ti-Nb-Zr-Ta system: Ti-21Nb-6Zr-15Ta and Ti-25Nb-10Zr-8Ta, which were analyzed by scanning electron microscopy, X-ray diffraction and microindentation. The both alloys are classified as near-β alloys. The addition of alloying elements such as Ta, Nb and Zr represents a good solution for lowering modulus of elasticity, which is an important factor for reducing bone resorption and therefore for preventing implant failure.
Authors: Heidi Nordmark, Alexander G. Ulyashin, John Charles Walmsley, Randi Holmestad
Abstract: Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) have been used to compare hydrogen defects formed in p doped [001] oriented Cz silicon samples which are H+ plasma treated , H+ implanted or Si+ implanted + H+ plasma treated. Samples were studied as processed and after annealing at 250°C, 450°C and 600°C. It is found that 1 hour H+ plasma treatment at 250°C produces a low density of large defects (~100 nm) in prefered {111} plans close to the surface. H+ implantation at a dose of 3x1016 cm-2 produces high density of small (~ 20 nm) mostly {100} platelets that after 1 hour annealing at 450°C result in microcrack formation. Lower H+ implantation doses form very few microcracks at this temperature. Silicon implantation with a dose of 1015 cm2 followed by 1 hour H+ plasma treatment at 250°C and 1 hour annealing at 450°C produces similar microstructure and microcracks as the 3x1016 cm2 H+ implantation dose.
Authors: Mária Svéda, András Roósz, Gábor Buza, László Kuzsella
Abstract: The aim of this research work is to investigate the sliding properties of the monotectic surface layers developed by a laser surface-treatment technology. The coatings-remelting technology has been chosen from the laser surface treatment methods. The surface of Al-Si alloy was coated with a lead layer by galvanizing, then the basic material and the surface layer were remelted together by using laser beam produced a monotectic Al- Pb surface layer. The structure of monotectic surface layer has been determined by means of a light microscope and scanning electron microscope. The sliding properties of the basic material (as cast, nearly eutectic Al-Si alloy), the Al-Si-Pb monotectic surface layer as well as the Al-Cu-Sn sliding bearing (Al-Cu matrix and Sn sliding layer) used in the gas industry have been investigated.
Authors: G. Vourlias, N. Pistofidis, D. Chaliampalias, F. Stergioudis
Abstract: One of the most effective methods for the protection of ferrous substrates from corrosion is zinc hot-dip galvanizing. Although this method has many advantages, it is characterized by a very negative effect on the environment. In the present work Zn coatings were formed with thermal spraying, pack cementation and fluidized bed reactor, which are friendlier to the environment. Their microstructure was characterized with X-ray diffraction and scanning electron microscopy, while their corrosion performance was estimated with exposure in a salt spray chamber. From this investigation it was deduced that CVD coatings are composed by two layers referring to Γ-Fe11Zn40 and δ-FeZn10 phase of the Fe-Zn phase diagram. By contrast the thermal coatings are very porous and composed by pure Zn. However, the corrosion performance of all coatings is similar. This conclusion is very important because it verifies that hot-dip galvanizing could be replaced by the other coating methods.
Authors: Tehreem Kanwal, Rub Nawaz Shahid, Naeem Ul Haq Tariq, Fahad Ali, M. A. Rafiq, Muhammad Iqbal, J.I. Akhter, Bin Awais Hasan
Abstract: The ceramic-metal composites that have all phases continuous throughout the structure are known as Interpenetrating Phase Composites (IPCs) and they have many applications in various fields. In this investigation ZrO2-Ni IPCs of varied compositions were synthesized using tubular furnace and microwave furnace routs. Samples were Characterized using BET surface area, Pycnometer density, dilatometry and scanning electron microscopy. The Electrical parameters of the composites were measured using impedance spectrometer. Results indicate that threshold percolation reached at 40 volume percent of Ni in both cases. Moreover, no significant difference was observed in BET surface area and CTE of composites prepared by conventional and microwave sintering processes.
Authors: E. Wolf, U. Geissler, D. Klinger, A. Voigt
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