scholarly journals Atom Probe Tomographic Mapping Directly Reveals the Atomic Distribution of Phosphorus in Resin Embedded Ferritin

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Daniel E. Perea ◽  
Jia Liu ◽  
Jonah Bartrand ◽  
Quinten Dicken ◽  
S. Theva Thevuthasan ◽  
...  
2019 ◽  
Vol 515 ◽  
pp. 135-139
Author(s):  
Boran Tao ◽  
Baifeng Luan ◽  
Risheng Qiu ◽  
Qiang Fang ◽  
Lingfei Cao ◽  
...  

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Sanghita Mridha ◽  
David L. Jaeger ◽  
Harpreet Singh Arora ◽  
Rajarshi Banerjee ◽  
Sundeep Mukherjee

The atomic distribution in catalytically active metallic glass alloys, Pd43Cu27Ni10P20and Pt57.5Cu14.7Ni5.3P22.5, was investigated using three-dimensional atom probe microscopy. Atom probe analysis showed uniform distribution of constituent elements for both the starting amorphous alloys, with no phase separation. Both the crystallized alloys showed eutectic microstructure with a very sharp interface (~0.5 nm as determined from atom probe). The atomic distribution in the devitrified state is explained based on the “fragile liquid” behavior for these noble-metal glassy alloys.


2015 ◽  
Vol 158 ◽  
pp. 99-103 ◽  
Author(s):  
Sanghita Mridha ◽  
David L. Jaeger ◽  
Harpreet Singh Arora ◽  
Rajarshi Banerjee ◽  
Sundeep Mukherjee

2018 ◽  
Vol 190 ◽  
pp. 30-38 ◽  
Author(s):  
Se-Ho Kim ◽  
Phil Woong Kang ◽  
O Ok Park ◽  
Jae-Bok Seol ◽  
Jae-Pyoung Ahn ◽  
...  

Author(s):  
M.P. Thomas ◽  
A.R. Waugh ◽  
M.J. Southon ◽  
Brian Ralph

It is well known that ion-induced sputtering from numerous multicomponent targets results in marked changes in surface composition (1). Preferential removal of one component results in surface enrichment in the less easily removed species. In this investigation, a time-of-flight atom-probe field-ion microscope A.P. together with X-ray photoelectron spectroscopy XPS have been used to monitor alterations in surface composition of Ni3Al single crystals under argon ion bombardment. The A.P. has been chosen for this investigation because of its ability using field evaporation to depth profile through a sputtered surface without the need for further ion sputtering. Incident ion energy and ion dose have been selected to reflect conditions widely used in surface analytical techniques for cleaning and depth-profiling of samples, typically 3keV and 1018 - 1020 ion m-2.


Author(s):  
J. R. Michael ◽  
K. A. Taylor

Although copper is considered an incidental or trace element in many commercial steels, some grades contain up to 1-2 wt.% Cu for precipitation strengthening. Previous electron microscopy and atom-probe/field-ion microscopy (AP/FIM) studies indicate that the precipitation of copper from ferrite proceeds with the formation of Cu-rich bcc zones and the subsequent transformation of these zones to fcc copper particles. However, the similarity between the atomic scattering amplitudes for iron and copper and the small misfit between between Cu-rich particles and the ferrite matrix preclude the detection of small (<5 nm) Cu-rich particles by conventional transmission electron microscopy; such particles have been imaged directly only by FIM. Here results are presented whereby the Cu Kα x-ray signal was used in a dedicated scanning transmission electron microscope (STEM) to image small Cu-rich particles in a steel. The capability to detect these small particles is expected to be helpful in understanding the behavior of copper in steels during thermomechanical processing and heat treatment.


Author(s):  
J.A. Panitz

The first few atomic layers of a solid can form a barrier between its interior and an often hostile environment. Although adsorption at the vacuum-solid interface has been studied in great detail, little is known about adsorption at the liquid-solid interface. Adsorption at a liquid-solid interface is of intrinsic interest, and is of technological importance because it provides a way to coat a surface with monolayer or multilayer structures. A pinhole free monolayer (with a reasonable dielectric constant) could lead to the development of nanoscale capacitors with unique characteristics and lithographic resists that surpass the resolution of their conventional counterparts. Chemically selective adsorption is of particular interest because it can be used to passivate a surface from external modification or change the wear and the lubrication properties of a surface to reflect new and useful properties. Immunochemical adsorption could be used to fabricate novel molecular electronic devices or to construct small, “smart”, unobtrusive sensors with the potential to detect a wide variety of preselected species at the molecular level. These might include a particular carcinogen in the environment, a specific type of explosive, a chemical agent, a virus, or even a tumor in the human body.


Author(s):  
M.G. Burke ◽  
M.K. Miller

Interpretation of fine-scale microstructures containing high volume fractions of second phase is complex. In particular, microstructures developed through decomposition within low temperature miscibility gaps may be extremely fine. This paper compares the morphological interpretations of such complex microstructures by the high-resolution techniques of TEM and atom probe field-ion microscopy (APFIM).The Fe-25 at% Be alloy selected for this study was aged within the low temperature miscibility gap to form a <100> aligned two-phase microstructure. This triaxially modulated microstructure is composed of an Fe-rich ferrite phase and a B2-ordered Be-enriched phase. The microstructural characterization through conventional bright-field TEM is inadequate because of the many contributions to image contrast. The ordering reaction which accompanies spinodal decomposition in this alloy permits simplification of the image by the use of the centered dark field technique to image just one phase. A CDF image formed with a B2 superlattice reflection is shown in fig. 1. In this CDF micrograph, the the B2-ordered Be-enriched phase appears as bright regions in the darkly-imaging ferrite. By examining the specimen in a [001] orientation, the <100> nature of the modulations is evident.


Author(s):  
E.A. Fischione ◽  
P.E. Fischione ◽  
J.J. Haugh ◽  
M.G. Burke

A common requirement for both Atom Probe Field-Ion Microscopy (APFIM) and Scanning Tunnelling Microscopy (STM) is a sharp pointed tip for use as either the specimen (APFIM) or the probe (STM). Traditionally, tips have been prepared by either chemical or electropolishing techniques. Recently, ion-milling has been successfully employed in the production of APFIM tips [1]. Conventional electropolishing techniques are applicable to a wide variety of metals, but generally require careful manual adjustments during the polishing process and may also be time-consuming. In order to reduce the time and effort involved in the preparation process, a compact, self-contained polishing unit has been developed. This system is based upon the conventional two-stage electropolishing technique in which the specimen/tip blank is first locally thinned or “necked”, and subsequently electropolished until separation occurs.[2,3] The result of this process is the production of two APFIM or STM tips. A mechanized polishing unit that provides these functions while automatically maintaining alignment has been designed and developed.


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