scholarly journals Methods of the Detection and Identification of Structural Defects in Saturated Metallic Composite Castings

2017 ◽  
Vol 17 (3) ◽  
pp. 37-44 ◽  
Author(s):  
K. Gawdzińska
Keyword(s):  
Electron Microscopy ◽  
Complex Structure ◽  
Gravimetric Method ◽  
Structural Defects ◽  
X Ray ◽  
Metallic Composite ◽  
Detection And Identification ◽  
Metallic Composites ◽  
Non Destructive ◽  
Scanning Electron

Abstract Diagnostics of composite castings, due to their complex structure, requires that their characteristics are tested by an appropriate description method. Any deviation from the specific characteristic will be regarded as a material defect. The detection of defects in composite castings sometimes is not sufficient and the defects have to be identified. This study classifies defects found in the structures of saturated metallic composite castings and indicates those stages of the process where such defects are likely to be formed. Not only does the author determine the causes of structural defects, describe methods of their detection and identification, but also proposes a schematic procedure to be followed during detection and identification of structural defects of castings made from saturated reinforcement metallic composites. Alloys examination was conducted after technological process, while using destructive (macroscopic tests, light and scanning electron microscopy) and non-destructive (ultrasonic and X-ray defectoscopy, tomography, gravimetric method) methods. Research presented in this article are part of author’s work on castings quality.

Investigation of Structural Defects in 4H SiC Wafers

1994 ◽  
Vol 339 ◽  
Author(s):  
M. Tuominen ◽  
R. Yakimova ◽  
R. C. Glass ◽  
T. Tuomi ◽  
E. Janzén
Keyword(s):  
Electron Microscopy ◽  
Structural Defects ◽  
Semiconductor Materials ◽  
Power Device ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
Rocking Curve ◽  
X Ray ◽  
Device Applications ◽  
Scanning Electron

ABSTRACTFor high-power device applications SiC has better physical and electronic properties than the traditional semiconductor materials Si and GaAs. In this work, structural defects of 4H SiC wafers have been studied and partly compared with results from a previous study of 6H material. Optical microscopy, scanning electron microscopy, high-resolution X-ray diffraction and synchrotron X-ray topography were used for structural studies of 4H SiC.Optical micrographs show micropipes and larger specific defects - tubes and cracks. X-ray rocking curve peaks are broad and split revealing the mosaicity of the material. Synchrotron X-ray topographs show areas having a large number of defects, images of cracks and micropipes, and misorientated regions close to the micropipes.

scholarly journals Surface Characterization and Conductivity of Two Types of Lithium-Based Glass Ceramics after Accelerating Ageing

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5632
Author(s):  
Marko Jakovac ◽  
Teodoro Klaser ◽  
Borna Radatović ◽  
Željko Skoko ◽  
Luka Pavić ◽  
...  
Keyword(s):  
Surface Characterization ◽  
Glass Ceramics ◽  
Structural Defects ◽  
Lithium Silicate ◽  
Dental Ceramics ◽  
Ion Diffusion ◽  
X Ray ◽  
The Impact ◽  
Non Destructive ◽  
Scanning Electron

In this study, two different dental ceramics, based on zirconia-reinforced lithium-silicate (LS1) glass-ceramics (Celtra Duo, Dentsply Sirona, Bensheim, Germany) and lithium disilicate (LS2) ceramics (IPS e.max CAD, Ivoclar, Vivadent, Schaan, Liechtenstein) were examined. They were tested prior to and after the crystallization by sintering in the dental furnace. Additionally, the impact of ageing on ceramic degradability was investigated by immersing it in 4% acetic acid at 80 °C for 16 h. The degradability of the materials was monitored by Impedance Spectroscopy (IS), X-Ray Powder Diffraction (XRPD), and Field Emission Scanning Electron Microscope (FE-SEM) techniques. It was detected that LS2 (vs. LS1) samples had a lower conductivity, which can be explained by reduced portions of structural defects. XRPD analyses also showed that the ageing increased the portion of defects in ceramics, which facilitated the ion diffusion and degradation of samples. To summarize, this study suggests that the non-destructive IS technique can be employed to probe the ageing properties of the investigated LS1 and LS2 ceramics materials.

IMPEDANCE SPECTROSCOPY (IS), XRD AND SEM OF OXIDE-ADDED Si3N4

2002 ◽  
Vol 16 (14) ◽  
pp. 525-537
Author(s):  
SAADAT. A. SIDDIQI ◽  
NASIR A. KHAN ◽  
M. SABIEH ANWAR
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Impedance Spectroscopy ◽  
Ceramic Materials ◽  
Dielectric Constants ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nyquist Plots ◽  
Non Destructive ◽  
Scanning Electron

Impedance spectroscopy (IS) is a non-destructive technique used for obtaining valuable information about bulk conductivities, dielectric constants, phase composition and grain boundaries of important ceramic materials, amongst many others. We obtained Nyquist plots for four different hot-pressed Si 3 N 4 samples in two different frequency regimes: 1 Hz to 30 MHz and 1 kHz to 100 kHz. The information obtained was compared against results from scanning electron microscopy (SEM) and X-ray diffraction (XRD). The limitations of the frequency response techniques are also discussed.

scholarly journals The Effect of X-ray Energy Overlaps on the Microanalysis of Chevkinite (Ce, La, Ca, Th)4(Fe2+, Mg)2(Ti, Fe3+)3Si4O22 Using SEM EDS-WDS

Minerals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1063
Author(s):  
Alicja Lacinska ◽  
Jeremy Rushton ◽  
Simon Burgess ◽  
Eimear A. Deady ◽  
Gren Turner
Keyword(s):  
Electron Microscopy ◽  
Iterative Process ◽  
Quantitative Data ◽  
Quality Data ◽  
X Ray ◽  
Peak Fitting ◽  
Non Destructive ◽  
Good Quality Data ◽  
Scanning Electron

A light REE (LREE)-bearing mineral called chevkinite (Ce, La, Ca, Th)4(Fe2+, Mg)2(Ti, Fe3+)3Si4O22, originating from a heavy metal placer deposit Aksu Diamas in Turkey, previously assessed for potential REE extraction as a by-product of magnetite production, was studied using scanning electron microscopy with energy and wavelength-dispersive spectrometers (SEM EDS-WDS). This mineral exhibits analytical challenges associated with severe X-ray energy overlaps between the REE, titanium, and barium. Here, we present an iterative process, showing that SEM EDS-WDS is a viable technique for obtaining good quality quantitative data. SEM EDS-WDS is an in situ, non-destructive, and relatively non-expensive technique, but operator’s experience is essential to obtain good quality data. In cases where the peak fitting remains challenging, in particular, and where the constituents have large differences in abundance, an assessment of the X-ray spectrum to qualitatively assign all peaks is essential prior to quantitative analysis.

scholarly journals Microtomographic study on the anatomy of adult male eyes of two mayfly species

Zoosymposia ◽  
2016 ◽  
Vol 11 ◽  
pp. 101-120 ◽  
Author(s):  
JAVIER ALBA-TERCEDOR
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Resolution ◽  
Adult Male ◽  
Transfer Functions ◽  
X Ray ◽  
Internal Structures ◽  
Evolutionary Advantage ◽  
Non Destructive ◽  
Scanning Electron

Here I present the results obtained by scanning male adults of two mayfly (Ephemeroptera) species with a high resolution micro-tomographic scanner, allowing observation of external structures, with similar results to those obtained under scanning electron microscopy. Moreover, this non-destructive technique permits investigation of the internal structures, and to “navigate” inside them, in a way never before imagined. Moreover by using different transfer functions and in accordance with the X-ray transparency, it is possible to assign different colours to highlight different anatomical parts, and to obtain “aesthetic” images. Results are compared and discussed with previous findings. It is postulated that differences in the diameter sizes of the ommatidia, when comparing dorso-frontal and ventro-lateral parts of the compounds eyes, represent an evolutionary advantage enabling increased accuracy in movement displacement detection of competing males within the swarm.

Microstructure of Ni/Al2O3 Electrodeposited Coatings Studied with XRD and SEM Techniques

2013 ◽  
Vol 203-204 ◽  
pp. 133-136
Author(s):  
Anna Góral ◽  
Marek Nowak ◽  
Joanna Wojewoda-Budka
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Nanocomposite Coatings ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electrodeposited Coatings ◽  
Electrochemically Deposited ◽  
Steel Substrates ◽  
Non Destructive ◽  
Scanning Electron

Our interests are focused on the Ni/Al2O3 nanocomposite coatings electrochemically deposited in modified Watt’s-type baths into which α-Al2O3 nanopowder is added on steel substrates. The effect of different amounts of α-Al2O3 phase in the electrolyte baths on microstructure of electrodeposited Ni/Al2O3 coatings is investigated. In order to study the coatings the non-destructive X-ray diffraction techniques are applied. As indirect techniques, they are supported by imaging methods, especially scanning electron microscopy.

scholarly journals Scanning Electron Microscopy and X-Ray Microanalysis for Chemical and Morphological Characterisation of the Inorganic Component of Gunshot Residue: Selected Problems

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Zuzanna Brożek-Mucha
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Analytical Data ◽  
Gunshot Residue ◽  
Morphological Properties ◽  
Inorganic Component ◽  
X Ray ◽  
Detection And Identification ◽  
Spectrometry Technique ◽  
Scanning Electron

Chosen aspects of examinations of inorganic gunshot particles by means of scanning electron microscopy and energy dispersive X-ray spectrometry technique are presented. The research methodology of particles was worked out, which included a precise and repeatable procedure of the automatic detection and identification of particles as well as the representation of the obtained analytical data in the form of the frequencies of occurrence of particles of certain chemical or morphological class within the whole population of particles revealed in a specimen. On this basis, there were established relationships between the chemical and morphological properties of populations of particles and factors, such as the type of ammunition, the distance from the gun muzzle to the target, the type of a substrate the particles sediment on, and the time between shooting and collecting the specimens. Each of these aspects of examinations of particles revealed a great potential of being utilised in casework, while establishing various circumstances of shooting incidents leads to the reconstruction of the course of the studied incident.

Systematic Approach to the Detection of Explosive Residues. V. Black Powders

1977 ◽  
Vol 60 (6) ◽  
pp. 1331-1340
Author(s):  
Willard D Washington ◽  
Robert J Kopec ◽  
Charles R Midkiff
Keyword(s):  
Electron Microscopy ◽  
Systematic Approach ◽  
X Ray Diffraction ◽  
Black Powder ◽  
X Ray ◽  
Detection And Identification ◽  
Explosives Residues ◽  
Ignition Characteristics ◽  
Layer Chromatography ◽  
Scanning Electron

Abstract Part V of the series describes tests for the detection and identification of black powder explosives residues in post-blast debris. Standard and modified formulations of commercial or custom origin can be distinguished. Different tests used in characterizing black powder residues are microscopy, ignition characteristics, spot chemical tests, IR spectroscopy, thin layer chromatography, x-ray diffraction, and scanning electron microscopy with energy dispersive x-ray spectroscopy.

scholarly journals Composition of Amphiboles in the Tremolite–Ferro–Actinolite Series by Raman Spectroscopy

Minerals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 491 ◽  
Author(s):  
Bersani ◽  
Andò ◽  
Scrocco ◽  
Gentile ◽  
Salvioli-Mariani ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Raman Spectroscopy ◽  
Environmental Sciences ◽  
X Ray ◽  
Preliminary Characterization ◽  
Provenance Studies ◽  
Important Family ◽  
Non Destructive ◽  
Scanning Electron

Amphiboles are an important family of rock forming minerals, whose identification is crucial in provenance studies as well as in many other fields of geology, archaeology and environmental sciences. This study is aimed to find a quick way to characterize Ca-amphiboles in the tremolite (Ca2Mg5Si8O22(OH)2)–ferro–actinolite (Ca2Fe5Si8O22(OH)2) series. Raman spectroscopy is established as technique to perform non-destructive and quick analysis, with micrometric resolution, able to give the composition in terms of Mg/(Mg + Fe2+) ratio. To exploit the method, a preliminary characterization is performed by Scanning Electron Microscopy coupled with Energy-dispersed X-ray Spectroscopy (SEM-EDS). Two independent methods to evaluate the composition from the Raman data (aiming to an accuracy of about 5%), using the low-wavenumbers part of the spectrum and the OH stretching bands, are developed. The application of the proposed method to micro-Raman mappings and the possible use of handheld Raman spectroscopy to have compositional information on Ca-amphiboles are discussed.

Sign in / Sign up

Export Citation Format

Share Document