共查询到20条相似文献,搜索用时 15 毫秒
1.
Alexander I. Berner Michael Y. Beregovsky Moshe M. Eizenberg 《Mikrochimica acta》2000,132(2-4):461-465
A method for quantitative analysis of Ti-Si-Ge/Si-Ge/Si structures with submicron thick layers by energy dispersive spectroscopy
(EDS) in transmission electron microscopy (TEM) and Auger electron spectroscopy (AES) was developed. Quantitation of the results
of both AES and EDS techniques was performed on the basis of a single reference specimen for the Ti-Si-Ge system comprising
a uniform layer of the Ti(Si0.85Ge0.15)2 phase on a silicon substrate. The reference sample was prepared by the same procedure as the samples used in the study, and
was thoroughly characterized by X-ray diffractometry, transmission electron microscopy and energy dispersive spectroscopy
in scanning electron microscopy. Using this reference sample the elemental sensitivity factors relative to Si were found for
both techniques, which enable us to obtain the elemental depth distributions for the studied samples. Good agreement between
the results obtained by EDS/TEM, AES and supplementary techniques was found. 相似文献
2.
Werner Grogger Ferdinand Hofer Bernd Kraus Irmgard Rom Werner Sitte Peter Warbichler 《Mikrochimica acta》2000,133(1-4):125-129
Energy-filtering transmission electron microscopy (EFTEM) is more and more becoming an important nanoanalytical technique
in both materials science and biology. The main advantage of the method lies in the possibility to obtain two-dimensional
chemical information from large specimen areas as well as from features on a nanometer scale. Due to its excellent lateral
resolution it is perfectly suited for the investigation of nanometer sized features (e.g. interfaces).
In this paper we will show how EFTEM can be used to characterize the interface between a Pt layer and a NiO crystal as part
of a coulometric titration cell. In addition to elemental distribution maps electron energy-loss spectra (EELS) across the
interface (EELS linescans) have been acquired to obtain quantitative compositional profiles. By employing these methods the
following interfacial layers could be identified, all of which containing Pt, Ni and O in different proportions: 13 nm Pt-rich,
32 nm Ni-rich and 29 nm Pt-rich. The origin of these is discussed in terms of displacement reactions. 相似文献
3.
Multianalytical Study of Patina Formed on Archaeological Metal Objects from Bliesbruck-Reinheim 总被引:1,自引:0,他引:1
Michael Wadsak Ina Constantinides Guido Vittiglio Annemie Adriaens Koen Janssens Manfred Schreiner Freddy C. Adams Philippe Brunella Michel Wuttmann 《Mikrochimica acta》2000,133(1-4):159-164
Patinas naturally formed on archaeological bronze alloys were characterized using light microscopy (LM), micro energy dispersive
X-ray fluorescence analysis (μ-EDXRF), time of flight secondary ion mass spectrometry (TOF-SIMS) and scanning electron microscopy
in combination with energy dispersive X-ray microanalysis (SEM/EDX). The examinations carried out on cross-sections of samples
have shown that in all samples the copper content in the corrosion layer is lower than in the bulk, while an increase of tin
and lead could be observed. Two different types of corrosion were found: first type, a corrosion formation leading to a three
layer structure was observed on lead bronze. The outer layer consists mainly of Cu(II) compounds and soil material, followed
by a fragmented layer of cuprous oxide and the surface layer of the alloy, where a depletion of copper and an enrichment of
tin and high amounts of Cl could be detected. The second type of corrosion is characterized by a two layer structure on the
tin bronze sample consisting of an outer layer with copper containing corrosion products and a layer with cracks, which reveals
a depletion of copper whereas tin and lead are enriched. Also high amounts of Si were detected in this surface layer. 相似文献
4.
John F. W. Bowles 《Mikrochimica acta》2002,138(3-4):125-131
Naturally formed geological materials are not constrained in the number of elements which may be present and a wide range
of concentrations can be expected. Oxides are a frequent component and water may be present. The particular problems posed
for quantitative analysis in some representative applications are described and solutions suggested. Critical testing of the
results for consistency with mineral formulae and for repeatability provides confidence in those results.
Examples of applications of quantitative analysis of minerals are used to show the variety of problems encountered in electron
microbeam analysis and how the analytical results can be used to determine the conditions (time, pressure, temperature) of
the minerals or the rocks in which they occur. 相似文献
5.
Concentration profiles of sputtered and pulsed laser deposited nanoscale Co/Cu multilayers have been measured by EDXS and
EELS line scans in scanning mode at electron microscopic cross section foils and by AES depth profile analysis. The interpretation
of the results has been supported by model calculations. After deposition, the pulsed laser deposited multilayers are stronger
mixed than the sputtered layers. They decompose during annealing. 相似文献
6.
Harry Podlesak Uta Faust Bernhard Wielage Michael Quast Peter Mayr Heinz-Rolf Stock 《Mikrochimica acta》2000,133(1-4):285-288
Detailed examinations were made by AES depth profiling, SEM, TEM and electron diffraction to get information about the relation
between treatment conditions and the state of plasma-nitrided aluminium. The chemical composition and the elemental depth
distribution were proofed to be depending on gas phase mixture, pressure and temperature during plasma treatment. The admixture
of hydrogen during presputtering for surface cleaning and during nitriding results both in an improved nitriding behaviour
and in a reduction of the formation of conical-shaped particles at the surface. The microstructure of the nitride layer isn’t
depending on tested process conditions significantly. Surface and interface between layer and substrate are roughly in a scale
of a few ten nanometers owing to sputtering effects. The main phase inside the layer is nanocrystalline AlN of the known hexagonal
modification. In addition, some crystallites of remaining aluminium are present as a second phase. In contrast to nitrogen-implanted
aluminium no preferred lattice orientation of the AlN phase was evident. 相似文献
7.
Stephen J. B. Reed 《Mikrochimica acta》2000,132(2-4):145-151
“Trace” elements may be defined as elements whose concentrations are of a similar order to the detection limit. In WD analysis
the detection limit is a function of the ‘figure of merit’ P2/B, where P is the pure-element peak intensity and B the background intensity. With normal analysis conditions detection limits
of ∼100 ppm are typical, but substantial improvements can be achieved by using higher values of accelerating voltage and beam
current. Long counting times are also advantageous, but should preferably be divided into relatively short alternating peak
and background measurements to minimise the effect of instrumental drift. Using separate routines for trace and major element
analysis is desirable owing to their different requirements. As the statistically defined detection limit is reduced, errors
due to background nonlinearity and interferences (overlaps) from other elemental peaks become more probable. Spectrum simulation
is useful for optimising background offsets and choice of crystal to minimise interferences, and estimating interference corrections
when these are necessary. ‘Blank’ standards containing none of the trace elements of interest are also useful for quantifying
background nonlinearity. 相似文献
8.
In the present experiments the high temperature successive deposition (HTSD) of Al and Pt and the half shadowing technique
producing wedge shaped area with increasing quantity of deposited Pt are applied for studying the initial stages of solid
phase reaction producing amorphous Al2Pt phase. The nucleation of Al2Pt phase results in a decoration pattern which could be related to the characteristic local oxide coverage of the Al crystal
surface developing by kinetic segregation of oxygen species during the Al film deposition. In the area of larger amount of
deposited Pt, where the Al2Pt phase is continuous Kirkendall voids are present.
The samples were investigated in plane by transmission electron microscopy (TEM) and selected area electron diffraction (SAED)
and analysed by energy dispersive X-ray spectroscopy (EDX). 相似文献
9.
It is shown in this paper that – in contrast to the accepted belief in the literature – it is possible to determine if a
minority component is located on the dodecahedral, octahedral or tetrahedral sites in a garnet single crystal. Previous literature
regarded the dodecahedral sites indistinguishable form the tetrahedral sites. Our prediction about the separability is based
upon dynamical Bloch-wave calculations and proved experimentally in a transmission electron microscope (TEM) on two different
natural garnets (almandine and grossular). The crystallographic positions of the minority components are determined in an
ALCHEMI experiment that makes use of the channeling of electrons in special directions of a single-crystal sample. 相似文献
10.
Infrared reflection spectroscopy (specular reflection, attenuated total reflection) has been applied in combination with
spectroscopic ellipsometry and electron microscopy to analyze the surface structure of plasma-treated Si(100) surfaces. It
is shown that plasma treatments in oxygen and fluorine or chlorine-containing gases cause the formation of a thin surface
layer having thicknesses of a few nanometers. The layer was identified to consist of SiO2 for treatments in an oxygen plasma. Analyses of layers formed by treatments in a fluorine-containing plasma do not confirm
the generally assumed model. Different Si-F vibration modes were identified in the surface layer caused by a SF6 plasma. They correlate, however, with SiF and SiF2 molecules. There are no indications of the existence of the generally assumed SiF4. Neither has SiOF2 been proven in layers produced by etching in a SF6/O2 plasma. 相似文献
11.
Alessandro Borghi Davide Agnella Elena Belluso Roberto Cossio Raffaella Ruffini 《Mikrochimica acta》2000,132(2-4):479-487
The occurrence of compositional and microtextural relics within metamorphic rocks can provide useful information on the pressure-temperature
history of the host rock. The grain-size of these microstructures, such as coronitic reaction microtextures, is mostly too
fine to be detected by optical microscopy. Therefore, a more detailed analytical approach is needed. In this paper multiple
electron beam techniques including the acquisition of X-ray multi-element maps, micro and nano-analysis performed by SEM/EDS
and TEM/STEM-EDX systems were applied to a specific petrological problem related to metamorphism. Fine-grained decompressional
reaction microtextures of an eclogitic sample (Mt. Rosa Nappe, Western Alps) are described and discussed. 相似文献
12.
Some analytical techniques are able to produce images, making if possible to obtain a large amount of information. Working
with images, the pixels can be treated like objects in a data matrix. In this way, a multi-way PCA of micrograph images was
applied to the internal surface of a Teflon coil used for microwave sample digestion. This Teflon coil was used for 120 h
and had been attacked with different acids. It was cut into 3 pieces (namely: initial, medium and central portions) in order
to obtain 7 micrographs (2 for initial, 2 for medium and 3 for the central part). A micrograph of a piece from a new Teflon
coil was used for comparison. With these 8 micrographs, it was possible to establish a three-dimensional arrangement. After
multi-way PCA was applied to the Teflon surface images, was possible to group a great amount of information and to characterise
different parts of this coil.
Received March 3, 2000. Revision July 28, 2000. 相似文献
13.
Alessandro Borghi Roberto Cossio Filippo Olmi Raffaella Ruffini Gloria Vaggelli 《Mikrochimica acta》2002,139(1-4):17-25
A comparison between major and trace element concentrations in garnet performed by electron microprobe (EPMA) technique is
reported. Quantitative spot analyses and X-ray maps of major elements (Fe, Mg, Mn, Ca) and the trace element yttrium in garnets
from metamorphic rocks are presented. The selected garnet samples come from meta-pelitic and meta-basic specimens belonging
to the tectonic unit of the Monte Rosa Nappe (Western Alps).
In the metapelites, the quantitative Y distribution maps display a prominent increase at the core, the Y abundance varying
by over two orders of magnitude, from about 80 ppm (rim) to over 2100 ppm (core). The Y profiles show well defined patterns
with sharp features that do not correlate with major element distributions. A roughly comparable pattern can be supposed only
with Mn. The Y distribution suggests that the diffusion of Y through the garnet is very slow compared to the major elements,
thus the Y results are suitable for geothermometric estimates.
In the metabasites, the Y spatial distribution is characterised by an increasing content from the core to the rim, displaying
a zoning pattern opposite to the metapelite garnet. Quantitative EPMA analyses range from 1100 ppm at the rim to values lower
than the detection limit at the core.
Therefore, the Y content in the garnet can be related to several chemical and physical variables such as the bulk rock composition
and the phase assemblage. In particular, in the xenotime-bearing metapelitic system the Y distribution seems to be correlated
with metamorphic peak temperature. 相似文献
14.
Extra-ordinary mechanical features and high corrosion resistance are essential qualities of CrNi-steels and nickel base alloys.
The corrosion resistance of these materials fundamentally depends on their surface conditions. Tarnish colours and welding
scale, formed during thermal treatment or joining, are removed by pickling components made of these alloys with sulphuric
acid, nitric acid and hydrofluoric acid as well. By this kind of surface refinement several million tons per annum of aggressive
waste waters are produced, that cause high environmental risks and not acceptable employee endangerings. Therefore, a project
was promoted by the DECHEMA e.V. to replace hydrofluoric acid by organic complexing agents. The related surface analytical
examinations are reported in this publication. 相似文献
15.
The iodine-azide reaction induced by eight thiosemicarbazones was investigated. Inducing properties of thiosemicarbazones
are different and depend on the parent carbonyl compound used for synthesis. The inductor coefficients of the examined thiosemicarbazones
vary from 61 to 176. Optimum conditions for the determination of microamounts of thiosemicarbazones are given. The detection
limit for the determination by the back-titration method depends on the inducing activity and is 0.9 μg for phenyl-thiosemicarbazones
and 2 μg for diethyl-thiosemicarbazone in a 5-mL sample, and this corresponds to a concentration of 0.9 × 10−6 mol/L and , respectively. The automatic titration with the diluted iodine solution decreases the detection limit to about 50 ng in a
10-mL sample.
Received October 28, 1998. Revision April 9, 1999. 相似文献
16.
Klaus van Benthem Stephan Krämer Wilfried Sigle Manfred Rühle 《Mikrochimica acta》2002,138(3-4):181-193
An understanding of the correlation between microstructures and properties of materials require the characterization of the
material on many different length scales. Often the properties depend primarily on the atomistics of defects, such as dislocations
and interfaces. The different techniques of transmission electron microscopy allow the characterization of the structure and
of the chemical composition of materials with high spatial resolution to the atomic level: high resolution transmission electron
microscopy allows the determination of the position of the columns of atoms (ions) with high accuracy. The accuracy which
can be achieved in these measurements depends not only on the instrumentation but also on the quality of the transmitted specimen
and on the scattering power of the atoms (ions) present in the analyzed column.
The chemical composition can be revealed from investigations by analytical microscopy which includes energy dispersive X-ray
spectroscopy, mainly quantitatively applied for heavy elements, and electron energy-loss spectroscopy. Furthermore, the energy-loss
near-edge structure of EELS data results in information on the local band structure of unoccupied states of the excited atoms
and, therefore, on bonding. A quantitative evaluation of convergent beam electron diffraction results in information on the
electron charge density distribution of the bulk (defect-free) material.
The different techniques are described and applied to different problems in materials science. It will be shown that nearly
atomic resolution can be achieved in high resolution electron microscopy and in analytical electron microscopy. Recent developments
in electron microscopy instrumentation will result in atomic resolution in the foreseeable future. 相似文献
17.
Alejandro Marcó Ramón Compañó Roser Rubio Pilar Domènech Albert Palangues Miguel Maestro 《Mikrochimica acta》2002,140(1-2):131-139
Four inter-comparison exercises on organic elemental analysis were carried out between 1997 and 2001 by the Department of
Analytical Chemistry of the University of Barcelona, together with the Microanalysis Service and the Institute of the Marine
Sciences, which both belong to the CSIC in Barcelona, and the University of A Coru?a. More than sixty laboratories participated
in these exercises. Here we describe the design and characteristics of the trials, the samples and the homogeneity tests applied.
We report the results obtained for the analysis of carbon, hydrogen, nitrogen, sulphur and oxygen, their statistical analysis,
and the most relevant aspects of the technical discussion meetings.
Received December 20, 2001; accepted March 18, 2002; published online July 22, 2002 相似文献
18.
The determination of the concentration of light elements, such as carbon, nitrogen and oxygen, in e.g. atmospheric aerosol
particles is important to study the chemical behaviour of atmospheric pollution. The knowledge of low-Z element concentrations gives us information on the speciation of nutrients (species having nutritional value for plants)
and toxic heavy metals in the particles. The capability of the conventional energy-dispersive EPMA is strongly limited for
the analysis of low-Z elements, mainly because the Be window in the EDX detector hinders the detection of characteristic X-rays of light elements
such as C, N, O and Na. WDS is suitable for analysis of light elements, but the measurement of beam sensitive microparticles
requires the minimisation of the beam current and the measurement time. A semi-quantitative analytical method based on EPMA
using an ultra-thin window EDX detector was developed. It was found that the matrix and geometric effects that are important
for low-energy X-rays can be reliably evaluated by Monte Carlo calculations. Therefore, the quantification part of the method
contains reverse Monte Carlo calculation done by iterative simulations. The method was standardised and tested by measurements
on single particles with known chemical compositions. Beam-sensitive particles such as ammonium-sulphate and ammonium-nitrate
were analysed using a liquid nitrogen cooled sample stage. The shape and size of the particles, which are important for the
simulations, were determined using a high-magnification secondary electron image. Individual marine aerosol particles collected
over the North Sea by a nine-stage Berner cascade impactor were analysed using this new method. Preliminary results on five
samples and 4500 particles show that the method can be used to study the modification of sea-salt particles in the troposphere. 相似文献
19.
Interferences (overlaps) occurring when lines of other elements affect either peak or background measurements can cause errors
in quantitative WD analysis, but may be minimised by suitable choices of analysis conditions such as spectrometer crystal,
background offsets, and pulse-height analyser settings. Computer spectrum-simulation is much more effective than reference
to wavelength tables for investigating interferences. The ‘Virtual WDS’ simulation program developed by the present authors,
hitherto applied only to ‘ordinary’ elements (Z ≥ 11), has been extended to light elements for which evaporated multilayers are used in place of true crystals. ‘Virtual
WDS’ utilises experimentally recorded light-element K spectra and L and M spectra of heavier elements in the same wavelength
range. It is impractical to record all high-order peaks, so computed line profiles are used, with widths and intensities interpolated
from a limited set of observations. The relative positions of first and higher order peaks are affected significantly by the
refractive index of the multilayer, requiring modification of the Bragg equation. Suppression of high orders by pulse-height
analysis is less effective than for ‘normal’ wavelengths, owing to the breadth of the pulse-height distribution for low X-ray
energies. Simulation using a Gaussian expression aids optimisation of threshold and window-width settings. 相似文献
20.
Determination of the Stoichiometric Composition of High-Temperature Superconductors by ICP-OES for Production Control 总被引:1,自引:0,他引:1
A procedure to dissolve and analyse different types of high-temperature superconducting materials in order to determine their
stoichiometric com- position is described. As sample materials Y-Ba-Cu-O and (Pb)Bi-Sr-Ca-Cu-O were analysed. They were dissolved
with hydrochloric acid and analysed by simultaneous ICP-OES, which fits best for this analytical task because of its multielement
capacity, its high precision of determination and accuracy. Each of the relevant metals (Pb, Bi, Sr, Ca, Y, Ba, Cu) could
be determined successfully. The precision of the determination was found to be better than 2% relative standard deviation
and usually even below 1%. The sample preparation and determination procedure described allows a high sample throughput, which
is essential for production control. Also precursors of the superconducting materials (e.g. nitrate solutions) could be analysed
by the procedure described. 相似文献