The Influence of Deformation the Corrosion Resistance of Titanium Grade2

2015 ◽  
Vol 227 ◽  
pp. 27-30 ◽  
Author(s):  
Marta Zwolińska ◽  
Agata Sotniczuk ◽  
Krzysztof Topolski ◽  
Andrzej Królikowski ◽  
Halina Garbacz
Keyword(s):  
Electron Microscopy ◽  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Room Temperature ◽  
Electrochemical Impedance ◽  
Extrusion Direction ◽  
Nacl Solution ◽  
Corrosion Properties ◽  
Transmission Electron

Severe Plastic Deformation (SDP) processes including Hydroextrusion (HE) causes the change of the mechanical properties by the introduction of a large number of defects and significant refinement of the microstructure. During the initially stages of HE microstructure becomes more elongated according to the extrusion direction. Only after a certain deformation, grains become more equiaxed. Present studies are intended to determine the influence of the titanium Grade2 microstructure and grain size distribution on its corrosion properties. All corrosion tests were conducted in a 0.9 % NaCl solution at room temperature. Electrochemical Impedance Spectroscopy (EIS) was measured after 2 and 24 hours. Also Potentiodynamic Polarization was conducted after 24 hours. Microstructures were reviled using Scanning Electron Microscopy and Transmission Electron Microscopy. Grain size distribution was determined using the program Micrometer . The results confirmed formation of titanium dioxide and very good corrosion properties of titanium Grade2 at all stages of hydrostatic extrusion.

scholarly journals The Domain and Microstructure of Resin-Bonded Magnets

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2849
Author(s):  
Marcin Jan Dośpiał
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Size ◽  
Size Distribution ◽  
Domain Structure ◽  
Grain Size Distribution ◽  
Exchange Interactions ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Scanning Electron

This paper presents domain and structure studies of bonded magnets made from nanocrystalline Nd-(Fe, Co)-B powder. The structure studies were investigated using scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Mössbauer spectroscopy and X-ray diffractometry. On the basis of performed qualitative and quantitative phase composition studies, it was found that investigated alloy was mainly composed of Nd2(Fe-Co)14B hard magnetic phase (98 vol%) and a small amount of Nd1.1Fe4B4 paramagnetic phase (2 vol%). The best fit of grain size distribution was achieved for the lognormal function. The mean grain size determined from transmission electron microscopy (TEM) images on the basis of grain size distribution and diffraction pattern using the Bragg equation was about ≈130 nm. HRTEM images showed that over-stoichiometric Nd was mainly distributed on the grain boundaries as a thin amorphous border of 2 nm in width. The domain structure was investigated using a scanning electron microscope and metallographic light microscope, respectively, by Bitter and Kerr methods, and by magnetic force microscopy. Domain structure studies revealed that the observed domain structure had a labyrinth shape, which is typically observed in magnets, where strong exchange interactions between grains are present. The analysis of the domain structure in different states of magnetization revealed the dynamics of the reversal magnetization process.

CuWO4 Nanoparticles: Investigation of Dielectric, Electrochemical Behaviour and Photodegradation of Pharmaceutical Waste

2019 ◽  
Vol 19 (11) ◽  
pp. 7026-7034 ◽  
Author(s):  
M. Thiruppathi ◽  
M. Vahini ◽  
P. Devendran ◽  
M. Arunpandian ◽  
K. Selvakumar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Electrochemical Impedance ◽  
Electrochemical Behaviour ◽  
Diclofenac Sodium ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Transmission Electron ◽  
Pharmaceutical Waste

The hydrothermally synthesized CuWO4 nanoparticles (NPs) were characterized with different analysis such as X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), High Resolution Transmission Electron Microscopy (HRTEM), Energy Dispersive X-ray Spectroscopy (EDX), Cyclic Voltammetry (CV), UV-Visible and Photoluminescence (PL) analysis. The prepared CuWO4 NPs were examined with Electrochemical Impedance Spectroscopy (EIS). SEM images show that CuWO4 NPs are highly spherical shaped morphology and porous in nature. The optical band gap of prepared CuWO4 NPs is found to be 2.12 eV. Photodegradation of diclofenac sodium (DFS) (medical waste) in the aqueous medium with CuWO4 NPs under visible light irradiation shows 98% degradation. The CuWO4 NPs was stable up to 5th cycle it can be used as a reusable photocatalyst for the DFS degradation. The electrical conductivity and dielectric properties of the CuWO4 NPs at room temperature is analyzed by EIS studies. The bulk conductivity value of the prepared nanoparticles is 1.477×10-5 S/cm at room temperature. The conductivity of CuWO4 NPs is found to be due to electrons movement. The CuWO4 NPs shows higher photocatalytic and electrocatalytic activity for decomposition of DFS and methanol electro-oxidation in alkaline medium respectively.

Formation of (Fe,Cr) carbides and dislocation structures in low-chromium steel studiedin situusing synchrotron radiation

2012 ◽  
Vol 46 (1) ◽  
pp. 181-192 ◽  
Author(s):  
E. Gözde Dere ◽  
Hemant Sharma ◽  
Richard M. Huizenga ◽  
Giusseppe Portale ◽  
Wim Bras ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Size Distribution ◽  
Room Temperature ◽  
Rapid Heating ◽  
Chromium Steel ◽  
Dispersion Parameter ◽  
Precipitate Size ◽  
Two Dimensional ◽  
X Ray ◽  
Transmission Electron

The evolution of the size distribution of (Fe,Cr) carbides and the dislocation structure in low-chromium steel is studied during quenching and rapid heating byin situsmall-angle X-ray scattering (SAXS). The two-dimensional SAXS patterns consist of streaks on top of an isotropic SAXS signal. The evolution of the size distribution of the (Fe,Cr) carbides during heat treatment is determined from the isotropic component of the SAXS patterns. The isotropic part of the SAXS patterns shows that, after austenitization and quenching to room temperature, the average precipitate radius is 4.74 nm and the dispersion parameter for the lognormal size distribution is 0.33. Subsequent rapid heating to 823 K results in an average precipitate size of 5.25 nm and a dispersion parameter of 0.26. Bright-field transmission electron microscopy and high-resolution transmission electron microscopy reveal the nearly spherical morphology of the precipitates. The microstructural evolution underlying the increase in the average precipitate size and the decrease in the dispersion parameter after heating to and annealing at 823 K is probably that at room temperature two types of precipitates are present,i.e.(Fe,Cr)23C6and (Fe,Cr)7C3precipitates according to thermodynamic calculations, and at 823 K only (Fe,Cr)7C3precipitates are present. Additional measurements have been carried out on a single crystal of ferrite containing (Fe,Cr) carbides by combining three-dimensional X-ray diffraction (3DXRD) and SAXS during rotation of the specimen at room temperature, in order to investigate the origin of the streaks at low angles in the SAXS pattern. From simulations based on the theory of SAXS from dislocations, it is shown that the measured streaks, including the spottiness, in the two-dimensional SAXS patterns correspond to a dislocation structure of symmetric low-angle tilt boundaries, which in turn corresponds to the crystallographic orientation gradient in the single crystal of ferrite as measured by 3DXRD microscopy.

Grain size distribution of nanocrystalline systems

2005 ◽  
Vol 20 (4) ◽  
pp. 353-358 ◽  
Author(s):  
Paolo Scardi ◽  
Matteo Leoni ◽  
Diego G. Lamas ◽  
Edgardo D. Cabanillas
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Size ◽  
Diffraction Pattern ◽  
Size Distribution ◽  
Domain Size ◽  
Typical Case ◽  
Line Broadening ◽  
Transmission Electron ◽  
Pattern Modeling

The diffraction pattern of nanocrystalline Ce0.9Zr0.1O2 was analyzed by whole powder pattern modeling, a recently proposed method for the study of line broadening. The main result in this typical case of study—the crystalline domain size distribution—matches closely the corresponding information obtained by transmission electron microscopy. Further information on nature and content of lattice defects is also discussed.

scholarly journals Study of the Nanometric Grain Size Distribution in Iron Compacts Obtained by Mechanical Milling

2006 ◽  
Vol 503-504 ◽  
pp. 1007-1012 ◽  
Author(s):  
Jordi Llumà ◽  
Josep Antonio Benito ◽  
Antoni Roca ◽  
Jose María Cabrera ◽  
Jose Manuel Prado
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Iron Powder ◽  
Grain Size Distribution ◽  
Mechanical Milling ◽  
X Ray Diffraction ◽  
Average Hardness ◽  
Transmission Electron ◽  
Two Temperatures ◽  
Average Size

A study has been carried out on the grain size distribution of cylindrical compacts obtained by consolidation of iron powder severely deformed by mechanical milling. Consolidation has been performed in two consecutive steps: cold and hot conditions. The hot one was done at two temperatures, namely 425 and 475°C. After milling, the iron powder has a grain size of 8 nm (± 4 nm) with an average hardness of 800 HV. After hot compaction the grain size increases up to 50 nm, especially at 475°C where a small fraction of grains reach larger values than the average. The grain size was evaluated by two different techniques, X-Ray Diffraction and Transmission Electron Microscopy. Results showed some differences between both methods. The advantage of using TEM is that grain size distribution, and not only the average size, can be obtained. Small discs were also obtained from the compacted specimen in order to fracture them on a “ball on three balls” equipment. The fracture behaviour of the samples was then studied by SEM.

SYNTHESIS AND CHARACTERIZATION OF COBALT FERRITES MAGNETIC NANOPARTICLES IN ALKANETHIOL SOLUTION

2004 ◽  
Vol 03 (04n05) ◽  
pp. 639-648
Author(s):  
W. T. KERK ◽  
J. M. LI ◽  
W. S. CHIN ◽  
A. C. H. HUAN
Keyword(s):  
Electron Microscopy ◽  
Magnetic Nanoparticles ◽  
Size Distribution ◽  
Room Temperature ◽  
Cobalt Ferrite ◽  
Homogeneous Solution ◽  
X Ray ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Cobalt Ferrites

Magnetic nanoparticles of cobalt ferrite have been synthesized in a homogeneous solution containing dodecanethiol at room temperature. The alkanethiol molecules have provided a mean to control the particle size distribution. The uniformed size distribution, crystallinity and morphology of these nanoparticles are characterized with X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). The stoichiometry of the cobalt ferrite is confirmed by both elemental analysis and Energy Dispersive X-ray (EDX). Fabrication of assembled arrays of these nanoparticles on Si (100) have been achieved by slow evaporation of the solution and studied by Atomic Force Microscopy (AFM). Magnetic properties of the nanoparticles are determined by Vibrating Sample Magnetometer (VSM) and show a magnetization (Ms) of 75.3 emu/g and a coercivity (Hc) of 1500 Oe at room temperature.

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