Scanning Electron Microscopy and Energy Dispersive Analysis Applied to Forensic Science

1976 ◽  
Vol 34 ◽  
pp. 386-387
Author(s):  
G. Judd
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Chemical Composition ◽  
Forensic Science ◽  
Energy Dispersive ◽  
Energy Dispersive Analysis ◽  
Physical Evidence ◽  
Police Investigations ◽  
Large Numbers ◽  
Scanning Electron

Analysis of physical evidence in police investigations by electron optical techniques has been performed in several laboratories in recent years. These studies have evolved in stages from exploratory evaluation of the viability of first SEM and then EDA analyses of samples, to extensive programs investigating certain classes of evidence materials, to detailed cataloging of the features and the results of large numbers of individual analyses within a class, to the ultimate test of the techniques, application in criminal investigations. During these studies, the following different general characteristics of the analyses emerged - analyses dependent upon the topography, those dependent upon the composition, and those dependent upon both composition and topography. In the experiences in our investigations (l-3), the number of analyses requiring some information from chemical composition were far greater than originally expected.

scholarly journals Joining of γ-TiAl Alloy to Ni-Based Superalloy Using Ag-Cu Sputtered Coated Ti Brazing Filler Foil

Metals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 723 ◽  
Author(s):  
Sónia Simões ◽  
Carlos Tavares ◽  
Aníbal Guedes
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Scanning Electron Microscopy ◽  
Chemical Composition ◽  
Tial Alloy ◽  
Energy Dispersive ◽  
X Ray ◽  
Base Materials ◽  
Intermetallic Particles ◽  
Scanning Electron

Joining γ-TiAl alloy to Ni-based superalloy Hastelloy using Ag-Cu sputtered coated Ti foil as brazing filler was investigated in this study. Brazing experiments were performed at 900, 950, and 980 °C with a dwelling stage of 10 min in vacuum. The microstructure and the chemical composition of the resulting interfaces were analyzed by scanning electron microscopy (SEM) and by energy dispersive X-ray spectroscopy (EDS), respectively. Sound joints were produced after brazing at 980 °C, presenting a multilayered interface, consisting mainly of Ti-Al and Ti-Ni-Al intermetallics close to the γ-TiAl alloy, and of Ti-rich, Ti-Ni, and Cr-Ni-Mo rich phases near Hastelloy. The hardness of the interface, ranging from around 300 to 1100 HV0.01, is higher than both base materials, but no segregation of either Ag solid solution or coarse intermetallic particles was observed. Therefore, the developed brazing filler also avoids the need to perform post-brazing heat treatments that aim to eliminate detrimental extensive segregation of either soft phases or of hard and brittle compounds.

scholarly journals Relationship Between the Surface Chemical Composition of Implants and Contact With the Substrate

2015 ◽  
Vol 41 (1) ◽  
pp. 17-21 ◽  
Author(s):  
Mariana Lima da Costa Valente ◽  
Antonio Carlos Shimano ◽  
Elcio Marcantonio Junior ◽  
Andréa Candido dos Reis
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Chemical Composition ◽  
Surface Characterization ◽  
Structural Changes ◽  
Testing Machine ◽  
Energy Dispersive ◽  
Machined Surface ◽  
X Ray ◽  
Scanning Electron

The purpose of the study was to use scanning electron microscopy and energy dispersive x-ray spectrometry to assess possible morphologic and chemical changes after performing double-insertion and pullout tests of implants of different shapes and surface treatments. Four different types of implants were used—cylindrical machined-surface implants, cylindrical double-surface–treated porous implants, cylindrical surface-treated porous implants, and tapered surface-treated porous implants—representing a total of 32 screws. The implants were inserted into synthetic bone femurs, totaling 8 samples, before performing each insertion with standardized torque. After each pullout the implants were analyzed by scanning electron microscopy and energy dispersive x-ray spectrometry using a universal testing machine and magnified 35 times. No structural changes were detected on morphological surface characterization, only substrate accumulation. As for composition, there were concentration differences in the titanium, oxygen, and carbon elements. Implants with surface acid treatment undergo greater superficial changes in chemical composition than machined implants, that is, the greater the contact area of the implant with the substrate, the greater the oxide layer change. In addition, prior manipulation can alter the chemical composition of implants, typically to a greater degree in surface-treated implants.

scholarly journals Characterization of mixing state of tropospheric aerosols by using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS)

2019 ◽  
Vol 1 (1) ◽  
pp. 21-22
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Chemical Composition ◽  
Energy Dispersive Spectroscopy ◽  
Nano Particles ◽  
Energy Dispersive ◽  
Quality Monitoring ◽  
Air Filters ◽  
Imaging Science ◽  
Scanning Electron

With the aim of understanding the role of aerosols and clouds in the global climate scenario as single components and/or as a system, the related recent studies are realized taking advantage of the space borne missions, of enormous advances in measurement technologies based on active/passive sensors and finally of analytical microscopy, spectroscopy and imaging science [1]. Referring to the necessity of the nanoscale imaging & spectroscopy, the recently scientific reports state that the atmospheric aerosols are a heterogeneous mixture of various particle types and its climate effects can only be fully understood through detailed knowledge of the physical and chemical properties of individual particles. As instance, the changes of particle shapes and mixing states through condensation, coagulation, and cloud processing influence how nano-sphere soot (ns-soot) particles mix with others [1, 2]. In this paper, air filters [air particle deposition from an aerosol spectrometer] are used to retain dangerous macro, micro and nano particles also different gaseous that can affect human health. The filter is made of micro and nano fibers of polytetrafluoroethylene (PTFE). The main applications of the filter are as quality monitoring systems and air filters fields [2, 3]. Filter was taken from an air quality monitoring from a thermal power station. Scanning electron microscopy (SEM) was performed using VegaTescan LMH II equipment with SE detector at 30 kV voltage of electron gun scan rate 5 and working distance 15.5 mm. Emission was 75 µA, heat at 49% and stigmator at 1.1 and 0.9. The filter was analyzed as in use without metallization process using a double-sided copper band and images are presented in figure 1. Chemical composition determinations (qualitative and quantitative) were realized using an energy-dispersive spectroscopy (EDS) detector from Quantax Bruker (XFlash silicon drift detector, Esprit software). Beside chemical composition determinations (after 5 area analyzed were identified next elements: Pb, Ca, Zn, Cu, Fe, Ti, Ni, Mn and C) mapping of the elements was performed, figure 2, on a selected area. The results present nano and micro particles retained in the air filter.

scholarly journals ANALYSES OF WASTE PRODUCTS OBTAINED BY LASER CUTTING OF AW-3103 ALUMINIUM ALLOY

2020 ◽  
Vol 60 (6) ◽  
Author(s):  
Jan Loskot ◽  
Maciej Zubko ◽  
Zbigniew Janikowski
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Composition ◽  
Aluminium Alloy ◽  
Energy Dispersive ◽  
Pure Aluminium ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

In the presented research, the methods of scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction and transmission electron microscopy were applied to analyse the powder waste obtained by cutting of AW-3103 aluminium alloy using a fibre laser. The scanning electron microscopy allows to analyse the morphology of the waste microparticles, the energy-dispersive X-ray spectroscopy revealed their chemical composition, which was compared with the composition of the original cut material. In the waste powder, mainly plate-like particles were observed that contain almost pure aluminium. X-ray powder diffraction measurements confirmed that the waste powder is composed of aluminium phase with only a slight presence of other phases (magnetite, austenite and graphite) and the transmission electron microscopy revealed the presence of nanoscale particles in this waste powder. Furthermore, it was found that the average size of the microparticles depends on the thickness of the cut material: particles obtained from a thicker workpiece were substantially bigger than those obtained from the thinner material. On the contrary, the dimensions of the workpiece have only a little impact on the particles’ shape and no significant influence on their chemical composition. The results also suggest that the microparticles could be used as an input material for powder metallurgy. But there is also a certain health risk connected with inhalation of such tiny particles, especially the nanoparticles, which can penetrate deep into the human pulmonary system.

Plasma Electrolytic Carbonitriding of 20CrMnTi Steel

2010 ◽  
Vol 154-155 ◽  
pp. 1393-1396 ◽  
Author(s):  
Xin Min Fan ◽  
Jie Wen Huang ◽  
Qun Yang ◽  
Jun Jie Gan
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Chemical Composition ◽  
Phase Structure ◽  
Energy Dispersive ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plasma Electrolytic ◽  
Scanning Electron ◽  
Microhardness Tester

A carbontirided layer was produced on 20CrMnTi steel by plasma electrolytic carbonitriding (PEC/N). Scanning electron microscopy with an energy dispersive X-ray analysis was employed to study the morphology and chemical composition of the carbonitrided layer. Hardness of the layer was measured using a microhardness tester, and the phase structure was determined by X-ray diffraction. The results show that a compact carbonitrided layer can be obtained on the surface of 20CrMnTi steel. The thickness of the layer increases with carbontriding time. When the sample was treated at 120V for 20min, the thickness is 45μm and the highest microhardness is 766HV0.05. The carbontrided layers are composed of Fe3C, Fe5C2, ε-Fe3N and α-Fe.

scholarly journals Texture and chemical composition analyses on the Hg0.66Pb0.33Ba2Ca2Cu3Oy superconductor using the sealed quartz tube technique

1996 ◽  
Vol 11 (6) ◽  
pp. 1367-1372 ◽  
Author(s):  
J.C.L. Chow ◽  
P.C.W. Fung ◽  
H.M. Shao ◽  
C.C. Lam
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Composition ◽  
Energy Dispersive ◽  
Quartz Tube ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Pb-substituted Hg-based superconductor of Hg0.66Pb0.33Ba2Ca2Cu3Oy has been fabricated using the sealed quartz tube technique. R- and x-ray diffraction pattern (XDP) measurements show that the specimen has a Tc of 135 K and contains mainly the Hg-1223 phase. Scanning electron microscopy/energy dispersive x-ray analysis (SEM/EDX) and transmission electron microscopy/energy dispersive x-ray analysis (TEM/EDX) were employed to study the texture and chemical composition of the specimen. It is found that the specimen contains round-shaped grains with a mixture of Hg-1223, BaCuO2, and Ca0.85CuO2 phases, square-shaped grains with a formula of PbBa2O3, small single crystals with single Hg-1223 phase, and crystal-like layers with a mixture of Hg-1223 and BaCuO2 phase. We consider that though the doping of Pb can benefit the stabilization of the Hg-1223 phase, it introduces other impurity phases and textures in the specimen at the same time.

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