After incorporation of Pr6O11 into the primer matrix, XRD analysis determined that Pr(OH)3, Pr6O11 and PrO2 were in as-deposited coatings (Fig. This was compared with a similar as-deposited panel that had not been subjected to ASTM B117 exposure. Goldstein, J. While commercial peak-identification software is improving all the time, it is not yet 100% accurate. The solvent-based primer formulation contains both Pr2O3 and gypsum. FIGURE 8. Comparison of SEM images showed that Pr-hydroxide/hydroxycarbonate species were more concentrated on the surfaces of primers containing Pr2O3 coatings (Fig. Our Energy Dispersive X-ray (EDX) or Energy Dispersive Spectroscopy (EDS) system consists of a iXRF Systems silicon drift (SDD) light element x-ray detector of 30 mm 2 sensor area and 133 eV resolution mounted on our Topcon ABT-32 SEM. Scanning electron micrographs of the two stents after prolonged indwelling. EDS can be used to find the chemical composition of materials down to a spot size of a few microns, and to create element composition maps over a much broader raster area. Primers formulated with only gypsum or talc did not undergo a phase or morphological change during ASTM B117 testing. 3, p. 213-217. For example, iron commonly shows strong Kα and Kβ peaks. 6.10. Figure 14.22. Dot map of a failed component used in oil and gas exploration component showing patchy salt on surface and corresponding Na and Cl distribution. Selected panels were removed after 500 hour increments for subsequent materials and electrochemical analysis, up to 3000 hours of salt spray exposure. Per the law of conservation of energy, a 6.9(a), (c), and (e)). These peaks are generally related to organic material, which can be either polyurethane or bacteria biofilm. Automatic sample drift correction is usually employed when gathering the data. This means that changes in composition and electronic structure can be studied on the atomic scale including catalyst particles and their active sites. It may be noted that in an EDX spectrum the X-ray intensities can be seen on the vertical axis and the X-ray energies on the horizontal axis. Here, we explain the EDS and EELS analyses which have been widely used since the 1970s as the most basic compositional analysis of AEM. For example a 256 by 256 pixel image with a spectrum acquired at each pixel have a dwell time of 0.1 seconds would take 24 minutes not including the time taken for each drift correction. The elemental composition at a point, along a line, or in a defined area, can be easily determined to a high degree of precision. It relies on the investigation of an interaction of some source of X-ray excitation and a sample. 6.12(a). Also, the presence of gypsum in the solvent-based primer series seems to suppress the rapid re-precipitation of Pr3+ species. In the spectral zone from 1200 to 600 cm−1, vibrations of chains of single bonds are found: the bands in this range are typical of a polymer chain, in this case of polyurethane and heparin. Example failure analysis applications include: materials verification based on elemental analysis; nondestructive alloy verifications, small-area elemental analyses such as those revealed by cross-section samples. CRC Press (electronic resource), Petroglyph--An atlas of images using electron microscope, backscattered electron images, element maps, energy dispersive x-ray spectra, and petrographic microscope-- Eric Chrisensen, Brigham Young University. However this probe does not have sufficient brightness to allow Energy Dispersive Spectroscopy (EDS) spectrum profiling and imaging. Short URL: https://serc.carleton.edu/18414. Therefore, spectrum overlapping occurs and attention will be needed in interpretation. After removal, the heparin-coated stents were morphologically, compositionally and qualitatively analyzed. 6.11. Figure 6.10 shows representative images of selected shiny and darkened/salted scribe areas. The EDS technique detects x-rays emitted from the sample during bombardment by an electron beam to characterize the elemental composition of the analyzed volume. 6.7. The best way to ensure good analysis is to run standards of the elemental mixes to see how the EDX spectra vary with the compositional ratios. (e) Diagram indicating where cross-section of PTS coating was removed for analysis. The application of all these methods in combination along with other bulk methods such as XRD creates a very powerful set of tools to analyze structure and phase transitions in catalyst particles over time. It is important to stress that only elemental information is provided and many times false assumptions as to the identity of unknown materials result. (Chapter 7) Cerium counts measured using Rutherford Backscattering Spectroscopy for coatings developed on AA2024-T3 as a function of temperature and time. Selected current profiles for map b (c) and maps e, f and g (d) (Zheludkevich et al., 2011). (c) LEI SEM image of cross-sectioned and polished PTS coating showing pulse deposited layers and level of porosity. From elemental data alone this is a guess, many times a good one, but examples of inorganic carbon are numerous including carbonate corrosion products. During exposure to a salt spray environment, Pr3+ actively transported within the coating, reacted with atmospheric H2O and CO2, and re-precipitated in the form of a mixed Pr-hydroxide/hydroxycarbonate on the surface of the coating. J.A. The results indicated that the Pr2O3 that was formulated into the primer converted to Pr(OH)3 at some point before beginning the analysis. EDS systems are typically integrated into either an SEM or EPMA instrument. Following 3000 hours of salt spray exposure, the 02GN084 primer has no visible white corrosion product in the scribe while visual darkening of the scribe occurred. The amount of Pr(OH)3 and CaSO4•2H2O detected in the coating was normalized against TiO2, which was assumed to be inert and not changing in composition during salt spray exposure. At these energies, only M-line X-rays are generated and many of these overlap with the substrate Si-K X-rays, like Ta-M and W-M. up to 1500 hours). The detection limit in EDS depends on sample surface conditions, smoother the surface the lower the detection limit. The depth profiles of these films after the hydrogen recovery treatment at 663 K 48 h, followed by treatment at 773 K 24 h, show very low sulfur content (~3%), in agreement with the hydrogen flux recovery observed through the films. From: Corrosion and Conservation of Cultural Heritage Metallic Artefacts, 2013, Seifollah Nasrazadani, Shokrollah Hassani, in Handbook of Materials Failure Analysis with Case Studies from the Oil and Gas Industry, 2016. Features or phases as small as 1 µm or less can be analyzed. An EDS spectrum of the mineral Ilmenite is shown on the left. Yoshiyasu Harada, Yuichi Ikuhara, in Handbook of Advanced Ceramics (Second Edition), 2013. 6.2. There are two kinds of EDS detectors which are used with AEM. In the UTW/EDS analysis, peaks of Ti–Kα (4.51 keV) and Ba–Lα (4.47 keV), Ti–Kβ (4.93 keV) and Ba–Lβ (4.83 keV), and O–Kα (0.53 keV) and Ti–Lα (0.45 keV) overlapped, and identification of Ti and Ba was not possible. The talc primer provided no corrosion protection because no active inhibitors were present in the primer matrix. Primers containing either gypsum or Pr2O3 showed significant corrosion protection on its own. is a well-established and accepted protocol. In the present case, the increase of—CH3 and—CH2 stretching vibrations from spectrum (a) to spectrum (c) is related to the deposition of an organic film on to the polyurethane stent surface, thus forming the biofilm. Also an element of interest may be present below the detection limit of EDS (typically about 0.2-0.5%). The calculated values were based on tests conducted on amorphous MSR of various Al-Co-Ce alloys in 0.6 M NaCl solution deaerated, at neutral pH (Scully et al., 2008). EDS is used extensively for examination of metallic and ceramic specimens, and their associated weathering crusts or corrosion products. 6.5. Based on these results, Pr2O3 is the more favorable starting Pr-phase for enhanced corrosion protection and gypsum by itself can also provide some corrosion protection for moderate testing times (i.e. At longer times, limited salting was observed in the scribes. (Chapter 8) SEM image of the alloy surface (a) and corresponding EDS maps of aluminum (b), oxygen (c) and Ce (d) elements acquired on the coated AA2024 after 1 day immersion in 0.05M NaCl (Lisenkov et al., 2010). However, there are methods to overcome this limitation. WDS is less well known but is a related technique that is typically an addition to an existing EDS system. Neither of the coated stents showed any kind of encrustation or degradation of the heparin surface. Electrochemical testing was conducted by precisely machining circular holes on 02GN098 Pr-based primers that were on chromate conversion coated Al 2024-T3 substrates. Advantages of EDS include: a relatively quick elemental analysis technique (in most cases); elemental coverage for all but the lightest elements (carbon and above are detectable, boron is problematic); quantitative elemental data; the ability to scan areas (raster scanning) and single spots; a large spatial range from about 1 mm2 to submicron2; elemental spectra are linked to image data generated by electron microscope; elemental maps, “dot maps,” can be generated from the data; depth information is possible using variable excitation voltages and modeling packages such as Monte Carlo simulations; generated data are from only the top couple of microns of the material under investigation (surface sensitive); while many consider this a destructive technique, particularly in the case of electronic components, it is in fact not in many cases (e.g., in most cases electronic components are not damaged by the electron beam). 6.7(b)). Quantitative analysis of Ca, S and Pr in the corrosion product found in the scribe of solvent-based 02GN084 primers on chromate conversion coatings following 500 hours of salt spray exposure was done by using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) to further understand which species in the primer matrix transport and migrate during attack. The x-ray absorption thus converts the energy of individual x-rays into electrical voltages of proportional size; the electrical pulses correspond to the characteristic x-rays of the element. Following salt spray exposure of the primer containing Pr2O3, Pr6O11 and the solvent-based primer, Pr-rich species were found to have precipitated on the surface of the coating. During SEM EDS Analysis, an electron beam is scanned across a sample’s surface and the electrons strike and stimulate the sample. 6.8(a)) and solvent-based (Fig. In the spray-applied talc primer, the primary components of talc (Mg, Si and O) were detected by SEM-EDS. EDS can be used to (1) determine the chemical composition of the aerogel materials, (2) detect the presence of any residual starting materials or unwanted byproducts, and (3) show the distribution of elements in the aerogel structure. (f) X-ray tomography image/slice of the PTS coating and section 1 (top section) of 3D porosity image for a standard, as-deposited PTS coating (Tailleart et al., 2012). In the 02GN084 primer coatings, Pr(OH)3 and gypsum were present and identified by XRD (not shown). Such extraneous contributions may cause errors by masking elements present in the specimen, by producing unwanted peaks in the spectrum, and by production of excess continuum, which causes problems in quantification. 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