Microanalysis of precipitates in a ferritic steel

1978 ◽  
Vol 36 (1) ◽  
pp. 618-619
Author(s):  
J.M. Titchmarsh
Keyword(s):  
Ferritic Steel ◽  
Particle Identification ◽  
Energy Dispersive ◽  
Objective Lens ◽  
Ferritic Steels ◽  
Replica Technique ◽  
X Ray ◽  
Large Numbers ◽  
Scanning Transmission ◽  
Made In

The advances in recent years in the microanalytical capabilities of conventional TEM's fitted with probe forming lenses allow much more detailed investigations to be made of the microstructures of complex alloys, such as ferritic steels, than have been possible previously. In particular, the identification of individual precipitate particles with dimensions of a few tens of nanometers in alloys containing high densities of several chemically and crystallographically different precipitate types is feasible. The aim of the investigation described in this paper was to establish a method which allowed individual particle identification to be made in a few seconds so that large numbers of particles could be examined in a few hours.A Philips EM400 microscope, fitted with the scanning transmission (STEM) objective lens pole-pieces and an EDAX energy dispersive X-ray analyser, was used at 120 kV with a thermal W hairpin filament. The precipitates examined were extracted using a standard C replica technique from specimens of a 2¼Cr-lMo ferritic steel in a quenched and tempered condition.

Quantitative elemental analysis of bacterial polyphosphate bodies using scanning transmission electron microscopy and energy-dispersive x-ray spectroscopy

1996 ◽  
Vol 54 ◽  
pp. 802-803
Author(s):  
J. Goldberg ◽  
H. Gonzalez ◽  
T.E. Jensen ◽  
W.A. Corpe
Keyword(s):  
Elemental Composition ◽  
Bulk Sample ◽  
Energy Dispersive ◽  
Mode Analysis ◽  
Objective Lens ◽  
X Ray ◽  
Scanning Transmission ◽  
Tem Mode ◽  
Cell Components ◽  
Polyphosphate Bodies

The elemental composition of polyphosphate bodies (PPB's) has been determined qualitatively previously using energy dispersive x-ray spectrometers (EDX) and in bodies isolated from cells. In this present study we determine in several bacteria their quantitative elemental composition using EDX in conjunction with a STEM.Bacteria were grown as previously described or were collected from natural sources. Portions of each sample were air dried on formvar coated grids. Separate samples were fixed and embedded in Epon. For x-ray analysis cells of interest were first located using the TEM mode. The microscope was then switched to the STEM mode. Analysis of cell components was carried out in the spot mode (75 kV) of the STEM. The spot diameter at 100,000x is approximately 20nm. The objective lens current was adjusted so a total x-ray count of 600 to 1,000 cps was attained for the 100 sec. count time. Spectra were collected on a PGT IMIX (EDX). The data was analyzed using a bulk sample analysis program (ZAF method) in standardless mode (w/w). Latex spheres of known density (1.05 g per cu cent) and volume were analyzed to obtain a standard (mass/weight).

Energy Dispersive X-Ray Measurements of thin Metal Foils

1976 ◽  
Vol 34 ◽  
pp. 426-427
Author(s):  
J. Bentley ◽  
E. A. Kenik
Keyword(s):  
Materials Science ◽  
Energy Dispersive Spectrometer ◽  
Thin Foil ◽  
Thin Metal ◽  
Energy Dispersive ◽  
Thin Specimen ◽  
X Ray ◽  
Metal Foils ◽  
Small Probe ◽  
Scanning Transmission

Instruments combining a 100 kV transmission electron microscope (TEM) with scanning transmission (STEM), secondary electron (SEM) and x-ray energy dispersive spectrometer (EDS) attachments to give analytical capabilities are becoming increasingly available and useful. Some typical applications in the field of materials science which make use of the small probe size and thin specimen geometry are the chemical analysis of small precipitates contained within a thin foil and the measurement of chemical concentration profiles near microstructural features such as grain boundaries, point defect clusters, dislocations, or precipitates. Quantitative x-ray analysis of bulk samples using EDS on a conventional SEM is reasonably well established, but much less work has been performed on thin metal foils using the higher accelerating voltages available in TEM based instruments.

Comparison of high-angle take-off and low-angle take-off EDX detector geometry of the HF-2000 FE-TEM

1993 ◽  
Vol 51 ◽  
pp. 252-253
Author(s):  
Y. Sato ◽  
T. Hashimoto ◽  
M. Ichihashi ◽  
Y. Ueki ◽  
K. Hirose ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Field Emission ◽  
Solid Angle ◽  
Energy Dispersive ◽  
Objective Lens ◽  
X Rays ◽  
High Angle ◽  
X Ray ◽  
Detector Geometry

Analytical TEMs have two variations in x-ray detector geometry, high and low angle take off. The high take off angle is advantageous for accuracy of quantitative analysis, because the x rays are less absorbed when they go through the sample. The low take off angle geometry enables better sensitivity because of larger detector solid angle.Hitachi HF-2000 cold field emission TEM has two versions; high angle take off and low angle take off. The former allows an energy dispersive x-ray detector above the objective lens. The latter allows the detector beside the objective lens. The x-ray take off angle is 68° for the high take off angle with the specimen held at right angles to the beam, and 22° for the low angle take off. The solid angle is 0.037 sr for the high angle take off, and 0.12 sr for the low angle take off, using a 30 mm2 detector.

Simultaneous determination of trace elements in lavage fluids from human bronchial alveoli by energy dispersive x-ray fluorescence. 1: Technique and determination of the normal reference interval.

1985 ◽  
Vol 31 (4) ◽  
pp. 551-555 ◽  
Author(s):  
E A Maier ◽  
F Rastegar ◽  
R Heimburger ◽  
C Ruch ◽  
A Pelletier ◽  
...  
Keyword(s):  
Trace Elements ◽  
Analytical Procedure ◽  
Reference Interval ◽  
Lavage Fluid ◽  
Energy Dispersive ◽  
Polypropylene Film ◽  
Internal Standards ◽  
X Ray ◽  
Large Numbers

Abstract We have applied energy dispersive x-ray fluorescence to the analysis of broncho-alveolar lavage fluids, to determine the concentration of several elements simultaneously with manipulation of the sample minimized. A 20-microL sample of a homogenized lavage fluid, to which two internal standards (containing Y and V) have been added, is deposited on a polypropylene film, 4 microns in thickness, and analyzed by x-ray fluorescence. We report the analytical procedure, the detection limits, and the reproducibility. The normal concentration range for trace elements is reported for a selected population. The simplicity and rapidity of the method, and the possibility of automating measurements, make this procedure suitable for screening large numbers of lavage specimens and to establish the diagnosis of some pneumoconioses.

Multi-Variate Analysis of Trace Elements from XRF Studies for Classification According to Origin

1992 ◽  
Vol 46 (5) ◽  
pp. 843-847 ◽  
Author(s):  
C. T. Yap
Keyword(s):  
Principal Component Analysis ◽  
Trace Elements ◽  
Geographical Origin ◽  
Principal Component ◽  
Energy Dispersive ◽  
Fluorescence Technique ◽  
X Ray ◽  
Elegant Method ◽  
Variate Analysis ◽  
Made In

The concentrations of twelve trace elements (Mn, Fe, Co, Ni, Cu, Zn, As, Rb, Sr, Y, Zr, and Nb) in 143 pieces of Chinese porcelain made in Jingdezhen, China and elsewhere were obtained with the use of the energy-dispersive x-ray fluorescence technique. An elegant method of multi-variate analysis, known as principal component analysis, was successfully employed in fingerprinting the geographical origin of the porcelain samples.

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