Energy Dispersive X-ray Analysis System Research Articles

Authigenic iron oxide formation in the estuarine mixing zone of the Yangtze River

Estuaries are elementary geochemical fronts where river water and seawater mix. Within this mixing zone, iron and other non-conservative elements can undergo complex reactions to form new solid phases. In order to understand authigenic iron oxide formation in the Yangtze River Estuary, two onsite water-mixing sets of experiments were conducted, one by mixing variable amounts of unfiltered Yangtze River water with filtered East China Sea water of different salinity (set 1), the other by mixing variable amounts of filtered Yangtze River water with filtered East China Sea water of different salinity (set 2). In set 2, the minerals newly formed in the course of mixing were investigated by means of a scanning electron microscope fitted with an energy-dispersive X-ray analytical system. It was found that ferrihydrite and lepidocrocite were formed in these mixing experiments, coexisting in nearly equal amounts. These iron oxides appear as aggregated particles with a large grain-size range of several microns to more than 100 μm. The electrolytic properties of seawater played an important role in the formation of these authigenic iron oxides. Kaolinite and organic aggregates were also found in the experimentally mixed pre-filtered waters. Amounts of newly formed suspended matter (set 2) were one to three orders of magnitude lower than those of total suspended matter (TSM) (set 1). This implies that newly formed minerals represent only a very small proportion of TSM in the estuarine mixing zone of the Yangtze River.

Avaliação da zona de transição interfacial pasta-agregado leve em concretos com sílica ativa e látex SBR

Este trabalho aborda o efeito da sílica ativa e do látex de estireno-butadieno (SBR) na zona de transição entre a argila expandida (agregado leve) e a matriz de cimento Portland. Para a avaliação da zona de transição utilizou-se um microscópio eletrônico de varredura (MEV) associado a um sistema de análise quantitativa (espectrografia de Raios-X por dispersão de energia - EDS). No concreto de referência a zona de transição apresentou espessura de 30mim. Com a inclusão de sílica ativa ou de látex SBR nos concretos observou-se a redução da espessura da zona de transição para valores entre 20 e 25mim. Entretanto os menores valores da espessura da zona de transição, entre 8 e 15mim, foram obtidos para os concretos com sílica ativa e látex SBR.

走査型電子顕微鏡を用いたモード測定

We propose a new modal analysis method using a scanning electron probe microanalyzer with an energy dispersive X-ray analytical system. The procedure is based on the multipoint analysis software of EDAX® Inc. The analysis points are selected as equal interval grids in the secondary electron image (SEI), which covers 3.2 × 2.45 mm2 area as the maximum. The mineral identification of each X-ray spectrum can be done by the combination of the assemblage and content of mineral forming elements. This method can identify most of rock-forming minerals easily, what is an advantage comparing with the conventional modal analysis method under the optical microscope. To obtain the reliable modal data, we can adjust grid intervals depending on the grain size of rock forming minerals and the numbers of the beam acquisition areas depending on the degree of heterogeneity of samples. This technique is available for the rock sample with average grain size between 0.2 and 2.0 mm by the restriction of the minimum enlargement size of the SEI. The new method gives the concordant modal data to those obtained by the conventional point-counting method by several beam acquisition areas for homogeneous samples and by a few tens beam acquisition areas for heterogeneous samples.

Effect of porous lightweight aggregate on strength of concrete

The microstructure of interfacial zone (IZ) of one kind of lightweight aggregate concrete was studied using Scanning Electron Microscope (SEM) equipped with an energy dispersive X-ray analysis system, as well as through back-scattered electron imaging (BSEI). This paper examined the topography of the IZ and the characteristic of the surface pores of the lightweight aggregate concrete. We demonstrate that the ‘Wall Effect’ does not exist on surface of the porous lightweight aggregate, resulting in a better bond than the normal concrete. A thin porous ettringite layer of 5–10 μm was found at the IZ of LWC. The formation of IZ of LWC was partly due to the lack of wall effect at the IZ and partly due to the interlocking of the cement paste onto the rough surface pores of the lightweight aggregate. However, it was likely that the large pore size of the ettringite network (0.3 to 1 μm) at the IZ of the lightweight concrete (LWC) weakens the strength of concrete.

Fracture in sintered Sm-Co permanent magnetic materials

The bending strength and fracture toughness of sintered Sm−Co permanent magnetic materials are measured. A scanning electron microscope equipped with an energy dispersive X-ray analysis system is employed to investigate the bending fractography. The fracture behavior and micromechanism are discussed. The fracture behavior of sintered Sm−Co permanent magnetic materials exhibits cleavage fracture. Some Sm-rich impurities are found in fracture plane, suggesting that the Sm-rich impurities help reduce the cleavage brittleness of sintered Sm−Co permanent magnetic materials. The possible methods for improving the strength and toughness are also proposed.

Microchemical transformation of bioactive glass particles of narrow size range, a 0-24 months study.

Previous studies demonstrated the capacity of bioactive glass particles of narrow size range (300-355 microm, Biogran) to stimulate bone tissue formation without contact with pre-existing bone tissue. Chemical interactions between the bioactive glass and the surrounding tissue fluids caused the glass transformation. This study quantifies the time-dependent transformation process. Particles were implanted in the jaws of beagle dogs and resected after 1, 2, 3, 6, 12 and 24 months. Microchemical analysis was performed using a scanning electron microscope equipped with an energy dispersive X-ray analysis system. After one month, Na-ions were leached out and the particles transformed into two layers. In the center, a Si-rich gel was found on the outer surface, a Ca- and P-rich shell. After two months, the concentration levels of the outer Ca- and P-rich shell remained. In the center the Si-concentration decreased and the Ca and P concentration increased. After three months, Si disappeared completely from the center of the particle, while the Ca and P concentration increased. At one and two years, the Ca and P concentrations in the transformed particles equalled those of bone tissue, turning the transformed particle into a chemical equivalent of the bone mineral phase.

Detoxification of cadmium in tobacco plants: formation and active excretion of crystals containing cadmium and calcium through trichomes.

In tobacco (Nicotiana tabacum L.), long and short trichomes can be distinguished morphologically. The established function of long trichomes is to exude a sticky gum containing diterpenes, whereas that of short trichomes is not known. When tobacco seedlings were exposed to toxic levels of cadmium (Cd), growth was retarded, but trichome number was increased up to 2-fold in comparison with untreated samples. Observation by variable-pressure scanning electron microscopy (VP-SEM) indicated that large crystals of 150 microm in size were formed on head cells of both short and long trichomes. An energy-dispersive X-ray analysis system fitted with VP-SEM revealed the crystals to contain amounts of Cd and calcium (Ca) at much higher concentrations than in the head cells themselves. Transmission electron microscopy demonstrated crystal formation in amorphous osmiophilic deposits in vacuoles. When seedlings were treated with Cd in the presence of Ca, tolerance was increased in proportion to the increase in Ca concentration. These results indicate that tobacco plants actively exclude toxic Cd by forming and excreting Cd/Ca-containing crystals through the head cells of trichomes.

Incorporation of Zinc in Electroless Deposited Nickel-Phosphorus Alloys I. A Comparative Study of Ni-P and Ni-Zn-P Coatings Deposition, Structure, and Composition

The impact of zinc incorporation on the chemical composition of electroless Ni-Zn-P coatings and the elements distribution through the thickness was studied. Ni-Zn-P alloy was deposited on various metal substrates (Al, Fe, Au) with and without electroless Ni-P underlayer. The employed bath formulation and the substrates with a Ni-P intermediate layer allowed direct comparison between the binary Ni-P and Ni-Zn-P alloy coatings. A reduction in phosphorus content and deposition rate due to zinc inclusion was observed. Some physical characteristics (morphology, structure, magnetic properties) of Ni-Zn-P coatings were assessed in parallel with those of Ni-P. The localization of Zn mainly at the grain boundaries together with P was proved by transmission electron microscopy combined with energy dispersive X-ray analysis system. The particular role of the steel substrate is discussed as a source of iron, subsequently included in electroless Ni-P and Ni-Zn-P coatings. © 2001 The Electrochemical Society. All rights reserved.

Estimation of cobalt coating layer thickness on acicular Fe3O4powder using HR-TEM

The thicknesses of cobalt coating layers grown on four different types of acicular Fe3O4particles were estimated from the analysis of lattice images and from the determination of the Co depth profile using high-resolution transmission electron microscopy (HR-TEM) coupled with an energy dispersive X-ray (EDX) analysis system. It was observed that the coating thickness might vary with the crystallite size resulting from the growth mechanism of the coating layer. In this study, two different layer thicknesses, 40 Å and less than 10 Å, were evidenced for crystallite sizes of 390 Å and 350 Å, respectively.

Typical Application In A Metallurgical Failure Analysis Laboratory

Metallurgical failure analysis is generally straight forward in many cases. However, there are times when it is difficult to really discern the fracture characteristics due to surface degradation, improper handling, or subsequent mechanical damage from improper planning.Dr. Alan Tettleman, a founder of Failure Analysis and Associates, in San Jose, CA, once told me you can not properly conduct any product failure analysis without metallography, and especially without scanning electron microscopy. In many ways, I agree with him. There are obvious times, however, when various physical properties and deformations are apparent. Those are generally when a consultant is not required. As in your field, there are many references that assist the usage and implementation of the scanning electron microscope and energy dispersive x-ray analysis system. Many of the references introduce the procedure and some of the cautionary steps that should be taken in preparation of samples and in the interpretation of the fracture.

Role of the primary silicon particle on the dry sliding wear of hypereutectic aluminium-silicon alloy A390

The wear behavior of hypereutectic aluminium-silicon alloy A390 was investigated using a pin-on-disc wear machine under dry sliding conditions. The wear tests were performed within a load range of 10 to 300N at a constant sliding velocity of 0.5 m/sec. The microstructural and compositional changes that took place during wear were characterized by scanning electron microscopy (SEM) equipped with an energy dispersive X-ray analysis (EDXA) system. Based on the metallographic observations the role of the primary silicon particles was suggested. In a low pressure region, primary silicon particles supported the applied load and wear occurred mainly in the matrix. Thus the wear loss did not show much variation with the applied load. In the mid-load range, primary silicon particles did not yet fracture and thus supported the applied load in part. Transition from oxidative to metallic wear occurs mainly in the matrix and the increase of wear loss becomes sharper than that in a low pressure region. In the high pressure region, the fractures of primary silicon Particles occurred and wear loss increased sharply.

Influence of a cellulosic ether carrier on the structure of biphasic calcium phosphate ceramic particles in an injectable composite material

An injectable composite material based on biphasic calcium phosphate (BCP) and a nonionic cellulose ether has been elaborated for use in percutaneous surgery for spine fusion. This paper reports the characterization results of this material by spectroscopic techniques including X-ray diffraction (XRD), infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) fitted with an energy dispersive X-Ray analysis system and high-resolution transmission electron microscopy (HR-TEM). From FTIR and XPS results, it was observed that the adhesion between the polymer and the ceramic might be insured by oxygen bridging developed through an ionic bonding between calcium ions and (C;O) groups of the polymer. Moreover, XPS showed attraction of Ca 2+ ions in the polymer matrix, while the ceramic surface was modified in a HPO 2- 4-rich layer. These results suggest a possible dissolution/precipitation process at the interface ceramic/polymer. HR-TEM observations supported this hypothesis, showing a light contrasted fringe at the surface of the ceramic grains in the composite paste. As well, changes in the XRD spectra could indicate a small decrease in the crystal size of the BCP powder through the contact to polymer solution. In addition, SEM observation showed a decrease of the initial BCP granulometry. Aggregates of 80–200 μm seemed to be mostly dissociated in micrograins. The ceramic grains were coated with and bonded between each other by the polymer matrix, which acted as spacer in between the ceramic grains, creating a macroporous-like material structure.

Microstructural Changes in Al–Cu–Mn Alloy Reinforced with SiC Particles on Holding at High Temperatures

The microstructural changes were investigated in an Al-Cu-Mn alloy reinforced with SiC particles after being kept in the liquid or semi-solid state. The microstructural and compositional changes were characterized by differential thermal analysis (DTA), X-ray diffraction, and scanning electron microscopy (SEM) equipped with an energy dispersive X-ray analysis (EDXA) system. The solidification behavior of the monolithic alloy is followed by the Al-Cu-Mn ternary system while its composites showed the Al-Cu-Mn-Si quaternary system due to the rejection of Si from SiC particles after being kept in the liquid or semi-solid state. SiC particles were attacked heavily and a large amount of reaction product, Al 4 C 3 was formed. The extent of reaction was calculated from the contents of Si in matrix by the DTA method for determining the liquidus. The result was compared with the quantitative metallography.

ICP-OES and SEM-EDX Analysis of dust and powder produced by the laser-processing of a Cr-Ni-Steel alloy

In this investigation we compared the analytical results obtained by inductively coupled plasma optical emission spectroscopy (ICP-OES) and a scanning electron microscope with an energy dispersive X-ray analysis system (SEM-EDX). The powder and dust, obtained by laser-processing of CRN-14301 steel, was analysed to classify the powder and dust for its final waste disposal. For this reason we analysed the elemental content of the samples. The samples consisted of a mixture of metals and their oxides.

Reference Methods For Analyzing For Asbestos In Various Media

Abstract Microscopy remains the primary tool for the analysis and quantification of asbestos in occupational and environmental studies. The American Society for Testing and Materials (ASTM) has recently approved two new Standard Methods for the analysis of asbestos in settled dust. Both methods require the use of a transmission electron microscope (TEM) equipped with an energy dispersive x-ray analysis system. Other methods curently in use require the use of a polarized light microscope {PLM) or phase contrast microscope (PCM).

Environmental dust analysis in opencast mining areas

Abstract An atmospheric dust database has been set up for the western end of the South Wales Coalfield. This, the first of its kind in the UK, comprises dust data from British Standard 1747 four-way directional gauges, a window ledge sampler and an experimental frisbee deposit gauge. X-Ray diffraction was used to characterize the dust on the basis of mineralogy. Scanning electron microscopy was used to examine particle size and shape and an energy dispersive X-ray analysis system was used to locate coal particles. For 18 months, a total of 15 directional and three frisbee gauges were used to collect dust on and around the Ffos Las opencast coal site in South Wales, UK. Additionally, two more directional gauges have been installed in the Brecon Beacons and at Exeter in south-west England to provide data from outside the coal mining area. Processed data from the X-ray diffractograms, along with the weather data from an onsite weather gauge, are input to a geographical information system (ArcInfo), where they can be manipulated statistically. Rose diagram plots for the area can thus be presented, giving the mineralogical contents of dust from the four directions of each sampling station, set in a spatial context. A series of these plots introduces the temporal element. This new dust data technology already shows considerable potential for use in nuisance complaints, planning applications, site licence renewals and for the implementation of future European environmental protection legislation.

ガス中蒸発法によるナノ複合粒子の作製

Iron-nickel and iron-magnesium nanocomposite particles were prepared by evaporation of coat material (nickel or magnesium) onto flying iron nanoparticles, which were produced by gas-evaporation technique. They were studied by means of a transmission electron microscope (TEM) and a scanning electron microscope (SEM) equipped with an energydispersive X-ray analysis system. For the iron-nickel system, the presence of nickel atoms was confirmed only by the analysis with SEM, while for the other one, magnesium particles sticking to chain-like iron particles were observed by means of TEM.

New achievements in industrial applications of nuclear track microfilters

Nuclear Track Microfilters (NTMF) have been applied to analyse the prime loop water of a nuclear power reactor for its content of plutonium and solid contaminants. After filtrating a few liters of prime loop water and subsequent drying of the filters, the α-activity of the loaded filters has been measured. The Pu content in the original water and in the filtrate were determined also, using conventional Pu chemistry. First results show that the filters are capable of retaining a major fraction of the Pu present in the sample. Thus, α-spectrometry of the loaded filters could be a method to routinely determine the Pu content of the prime loop water in spite of certain difficulties in the sampling which will be discussed in the paper.Solid contaminants have their origin in the corrosion of those materials which are in contact with the coolant. Using the scanning electron microscope (SEM), these particles can be found as filter load. Their elemental composition can be determined with the help of an energy-dispersive X-ray analysis system (EDXA) attached to the SEM.

Microanalysis of individual silver halide microcrystals

There is a considerable interest for the study of the elemental distribution and composition in silver halide photographic emulsions, particularly for the microanalysis of individual microcrystals. In this work, elemental distributions and contents of tabular and cubic silver halide microcrystals were obtained by backscattered electron imaging (BSEI), scanning transmission electron imaging (STEI), x-ray mapping and x-ray microanalysis in a scanning electron microscope (STEM) combined with energy-dispersive x-ray analysis (EDX).Several kinds of silver halide microcrystals were prepared, After removing the gelatin, repeated centrifugation and washing in distilled water, the grains were resuspended and dispersed onto carbon coated 50 mesh copper grids. All analyses were carried out on a JEOL 1200 EX electron microscope equipped with detectors for backscattered, secondary and transmitted electrons and an energy dispersive x-ray analysis system. An image processing system was used for acquiring and processing BSE images, STE images and x-ray maps. The role of the image processing computer system (IBAS Kontron) is twofold: it allows to optimize the acquisition conditions and to process the images afterwards.

Microstructural and thermal stability of a Ti-43AI alloy containing dispersoids of titanium di-boride

Ti-43Al (atomic percent) alloy containing a dispersion of 7 vol pct TiB2 particles was exposed to various thermal treatments to determine the stability of TiB2 in an ⇌2 + β-phase matrix. No new phases were detected at the particle/matrix interfaces even after thermal exposure at 1473 K for 7 days. The absence of an Al peak in the energy dispersive X-ray analysis system (EDS) spectra from TiB2 particles chemically extracted from the specimens aged at 1473 K for 7 days indicated no diffusion of Al from the matrix to the particles. These results indicate that TiB2 is stable in an α2+ β matrix at 1473 K.