EDX Line Scan Research Articles

Study on the Technology of Explosive Welding Incoloy800-SS304

In this article, Incoloy800 and SS304 (304 stainless steel) were cladded by explosive welding. Accordingly, micro-hardness, tensile strength, shearing strength, bending properties, and SEM microstructure of cladding plate were examined in detail. The bonding interface of the plate showed a wavy morphology. Whereas, a different colorful area was observed at the wave ridge of the base layer either in optical or SEM pictures. Magnetic inspection showed that the colorful area was austenitic steel. Thus, the occurrence of the colorful areas seemed to be the result from the high deformation/cold working of the grains. EDX spectrum analysis and line scanning indicated that the diffusion through the bonding interface was not observed under the EDX and line scanning detection limitation. Micro-hardness, tensile, shearing, and bending testing results showed that the bonding strength was acceptable according to ASTM specification.

Novel non-alloy Ru/Pd composite membrane fabricated by electroless plating for hydrogen separation

This study presents a new non-alloy Ru/Pd composite membrane fabricated by electroless plating for hydrogen separation. It shows that palladium and ruthenium can be deposited on an aluminum-oxide-modified porous Hastalloy by using our new EDTA-free plating bath at room temperature and 358 K, respectively. A 6.8 μm thick non-alloy Ru/Pd membrane film could be plated and helium leak test confirmed that the membrane was free of defects. Hydrogen permeation test showed that the membrane had a hydrogen permeation flux of 4.5 × 10−1 mol m−2 s−1 at a temperature of 773 K and a pressure difference of 100 kPa. The hydrogen permeability normalized value with thickness of the membrane was 1.4 times higher than our pure Pd membrane having similar structure. The EDX profiles of the front and back side membrane, cross-sectional EDX line scanning and XRD profile show that there was no alloying progress between the palladium and ruthenium layer after hydrogen permeation test at 773 K.

Investigation of Mn/Co coated T441 alloy as SOFC interconnect by on-cell tests

T441 has been identified as the candidate for SOFC interconnect material because it is assumed that with the addition of Nb, Ti in T441, the formation of continuous silica sub-layer could be avoided or delayed due to Nb and Si rich secondary phase formation stabilizing silicon migration. Previously, electrodeposition Mn/Co alloys followed by oxidation has been proved as a simple and cost effective method to fabricate (Mn, Co) 3O 4 coatings. In this work, Mn/Co coated T441 interconnects were tested as the cathode current collector of solid oxide fuel cells. For comparison, uncoated and 500 h pre-oxidized T441 interconnects were tested as well. The cell with coated interconnect shows stable performance during total 850 h test, even after severe thermal cycles (heating rate 26.7 °C/min). The coating shows good adhesion with substrate and it can prevent Cr poisoning on SOFC cathode. While the cell with uncoated and pre-oxidized T441 interconnects degrade rapidly. XRD results show the coating peaks shifted from mainly Co 3O 4 with some little Mn before test to MnCo 2O 4 after test due to Mn diffusion from substrate. No Cr penetrated to the coating layer, as further proved by EDX linescan. The effect of laves phase on the Cr 2O 3 sub-layer formation and coating thickness was further discussed.

Effect of pulsed DC CFUBM sputtered TiN coating on performance of nickel electroplated monolayer cBN wheel in grinding steel

The present research involves the deposition of pulsed DC CFUBM sputtered TiN on nickel plated steel discs and electroplated monolayer cBN wheels at seven different target frequencies and ten different bias voltages separately. The coating microstructures and the interaction between TiN and nickel were studied using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and electron probe micro analysis (EPMA). Phase detection was carried out using grazing incidence X-ray diffraction (GIXRD) technique. The cohesive and adhesive strengths of nickel layer were assessed by scratch test. After grinding of low carbon steel (AISI 1020) and hardened bearing steel (AISI 52100), the conditions of the uncoated and coated cBN wheels were observed under Stereo Zoom Microscope and SEM. Average column size of TiN was found to decrease with increase in both target frequency and negative bias voltage. The structure of the coating gradually transformed from porous and open columnar (at 0 V bias) to very compact, dense and featureless (at − 80 V bias). EDX line scan and EPMA confirmed the cross-diffusion between TiN and nickel and GIXRD indicated the formation of nickel–titanium intermetallic phases at their interface. The cohesive strength of nickel layer was not effectively enhanced with increase in target frequency, whereas the same was significantly improved with increase in negative bias voltage. Seemingly, TiN coated wheel could not perform better than the uncoated wheel in grinding AISI 1020 steel due to high wheel loading. However, the uncoated wheel was found to undergo fracture wear, which was remarkably absent in the coated wheels. On the other hand, many fractured grits and some grit pull-out were observed in the uncoated wheel when grinding AISI 52100 steel, whereas almost no pull-out along with much less fractured grits were observed in the wheels coated at bias voltages like − 60 V and − 90 V.

The Investigation of Thin Protecting Layers on Roughened Galvanized Steel Surfaces Produced by Different Coating Methods

Protective, chromate substitute thin layers on roughened galvanized surfaces produced at OCAS (Arcelor, Belgium) were characterized and compared using Scanning Electron Microscopy (SEM+EDS), Atomic Force Microscopy (AFM), Nanoindentation and X-ray Photoemission Spectroscopy (XPS). EDX maps, line scans and point analyses obtained at various places of the surfaces have shown differences between the CVD and silane nanolayers in the matter of thickness distribution and composition. At cross-section specimens the thickness of the layers could be shown. The hardness differences caused by layer thickness variations are hard to follow by nanoindentation as the penetration depth of the indenter is much larger than the thickness of the coatings. XPS measurements can distinguish between the chemical states of silicon in CVD and silane coatings.

Comparative Qualitative and Quantitative Assessment of Biomineralization of Tooth Development in Man and Zebrafish (Danio rerio)

It was the aim of this study to investigate the distribution of Ca, P, and C in predentin, mineralizing dentin, and mature dentin of human tooth buds and compare these results with those of zebrafish (Danio rerio) teeth using energy dispersive X-ray analysis (EDX) element analysis. The mandible of a 16-week-old human fetus containing 6 mineralizing tooth buds and three complete heads of zebrafish were fixed in formaldehyde and embedded in Technovit 9100. Serial sections of 80-microm thickness were cut in frontal-dorsal direction, and from these sections, polarized light micrographs were taken. The sections with tooth buds were then investigated with scanning electron microscopy, and EDX element analysis was performed with a Philips XL 30 FEG scanning microscope and an EDAX energy-dispersive X-ray system using spot measurements, EDX line-scans and element mapping. Quantitative measurements were made in predentin, mineralizing dentin adjacent to predentin, and mature dentin. The Ca and P content increased rapidly from outer predentin toward mineralizing dentin in human tooth buds and in zebrafish teeth. The Ca/P ratio was different for predentin and dentin areas, reflecting different calcium phosphate compositions in predentin and fully mineralized dentin. Because of the similarities between human tooth buds and zebrafish teeth, it can be concluded that the zebrafish tooth development may be an excellent model for studying biomineralization processes during odontogenesis.

Electrical Performance of Calcium doped Lanthanum Ferrite for use in Single-Step Co-fired Solid Oxide Fuel Cells (SOFCs)

AbstractIn the single-step SOFC co-firing process YSZ electrolytes with sintering aid densify at a temperature of ˜1300°C. Electrodes employed in the single-step co-fired SOFC must therefore sinter with the right microstructure at ˜1300°C. Calcium-doped lanthanum ferrite, La0.8Ca0.2FeO3±δ (LCF-20) was identified in earlier studies as a possible stable cathode material for the single-step co-fired SOFC. LCF-20 is also expected to be a more stable cathode material than LSCF (strontium and cobalt doped lanthanum ferrite). Four-probe conductivity tests yielded ˜93 S/cm at 800°C and showed an increase in conductivity as pO2 increases, characteristic of p-type conduction. LCF has a higher electrical conductivity compared to LSCF and LCM+YSZ cathode materials. Oxygen ion conductivity of LCF-20 obtained from permeability measurements is higher than that of YSZ and LSF-20. Therefore LCF has excellent mixed conducting properties to serve as a catalytically active cathode material for co-fired solid oxide fuel cells operating at intermediate temperatures. Electrochemical Impedance Spectroscopy (EIS) measurements were made on symmetrical cells fabricated with YSZ electrolyte and the electrode materials. A gadolium doped ceria (GDC) barrier layer was employed to prevent LCF/YSZ reaction. Comparison of LCF/GDC/YSZ/GDC/LCF EIS data to LCM+YSZ/YSZ/LCM+YSZ EIS data gathered using identical test conditions and electrode microstructures shows that LCF has a measured polarization resistance (Rp) of approximately half that seen in LCM+YSZ. Variations in cathode thickness and porosity show the best performance with a cathode of a critical thickness and finer porosity. Slight stoichiometric deviations in LCF result in the formation of a Ca-Fe-O liquid phase during electrode sintering at around 1220 C. The liquid phase migrates into and through the GDC layer. EDX line scans show the second phase to be rich in Ca and Fe. Thicker GDC layers seem to prevent the liquid phase from reaching the electrolyte/GDC interface. Structural analysis with TEM will be performed. The properties and the effect of the Ca-Fe-O phase on the cathodic performance of the cell are being investigated; however, preliminary results indicate that minor amounts of the Ca-Fe-O phase will not interfere with the electrochemical performance of the LCF cathode. The high temperature instability in LCF has been observed in other studies, but has not been studied specifically in the literature.

Chemical Analysis of Tungsten Tips by EDX Line Scan Tomography

Extended abstract of a paper presented at MC 2007, 33rd DGE Conference in Saarbrücken, Germany, September 2 – September 7, 2007

Characterization of U/Pu particles originating from the nuclear weapon accidents at Palomares, Spain, 1966 and Thule, Greenland, 1968

Following the USAF B-52 bomber accidents at Palomares, Spain in 1966 and at Thule, Greenland in 1968, radioactive particles containing uranium (U) and plutonium (Pu) were dispersed into the environment. To improve long-term environmental impact assessments for the contaminated ecosystems, particles from the two sites have been isolated and characterized with respect to properties influencing particle weathering rates. Low (239)Pu/(235)U (0.62-0.78) and (240)Pu/(239)Pu (0.055-0.061) atom ratios in individual particles from both sites obtained by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) show that the particles contain highly enriched U and weapon-grade Pu. Furthermore, results from electron microscopy with Energy Dispersive X-ray analysis (EDX) and synchrotron radiation (SR) based micrometer-scale X-ray fluorescence (micro-XRF) 2D mapping demonstrated that U and Pu coexist throughout the 1-50 microm sized particles, while surface heterogeneities were observed in EDX line scans. SR-based micrometer-scale X-ray Absorption Near Edge Structure Spectroscopy (micro-XANES) showed that the particles consisted of an oxide mixture of U (predominately UO(2) with the presence of U(3)O(8)) and Pu ((III)/(IV), (IV)/(V) or (III), (IV) and (V)). Neither metallic U or Pu nor uranyl or Pu(VI) could be observed. Characteristics such as elemental distributions, morphology and oxidation states are remarkably similar for the Palomares and Thule particles, reflecting that they originate from similar source and release scenarios. Thus, these particle characteristics are more dependent on the original material from which the particles are derived (source) and the formation of particles (release scenario) than the environmental conditions to which the particles have been exposed since the late 1960s.

Quantitative analysis of the calcium and phosphorus content of developing and permanent human teeth

It was the aim of this study to investigate the distribution of Ca, P and C in predentin, dentin and enamel in human tooth buds and permanent teeth by EDX element analysis. The mandible of a 16-week-old human fetus containing eight mineralizing tooth buds and three human permanent molars were fixed in formaldehyde and embedded in Technovit 9100. Serial sections of 80 microm thickness of the mandible were cut in the frontal-dorsal direction, and polarized light micrographs were taken of these sections. The permanent teeth were cut in mesio-distal direction. The sections were investigated with scanning electron microscopy and EDX element analysis with a Philips XL 30 FEG scanning microscope and an EDAX energy-dispersive X-ray system using spot measurements, EDX line-scans and element mapping. Quantitative measurements were made in predentin, mineralizing dentin adjacent to predentin, mature dentin, mineralizing enamel and young enamel of developing teeth and mature enamel of permanent teeth. In developing teeth the Ca and P content increased rapidly from outer predentin towards mineralizing dentin. In enamel prisms of developing teeth the Ca and P content increased linearly from the surface towards the enamel-dentin junction. In permanent teeth only a small layer of predentin was found. The Ca and P content in enamel and circumpulpal dentin of permanent teeth was higher than in developing teeth. The Ca/P ratio differed between predentin and dentin areas reflecting different calcium phosphate compositions, but it was the same in mineralizing and young enamel. The differences in the distribution of Ca and P reflect different mineralizing patterns of the enamel and dentin matrices.

Investigation of electroless cobalt-phosphorous layer and its diffusion barrier properties of Pb-Sn solder

The capability of a cobalt-phosphorous [Co(P)] layer, which was grown via the electroless plating process, to serve as the diffusion barrier of lead-tin (PbSn) solder was investigated in this work. The Auger electron spectroscopy (AES) and energy dispersive spectrometry (EDX) indicated that the phosphorous contents in Co(P) films decrease with increasing film thickness and that the average contents are no less than 8.7 at.% for the specimens prepared in this work. X-ray diffraction in conjunction with composition analyses revealed that the electroless Co(P) layer was a mixture of amorphous and nanocrystalline structures; however, the AES depth profile and subsequent analyses indicated that the first-formed Co(P) layer should be amorphous because it contains as much as 18 at.% P. This implied a good barrier capability for electroless Co(P) because, as revealed by EDX line scan, the Sn and Cu atoms could not penetrate the Co(P) layer after the PbSn/Cu/Co(P)/Cu/Ti/Si sample was subjected to annealing at 250°C in a forming gas ambient for 24 h. The fact that Sn and Cu underlayers could not penetrate the Co layer after such a liquid-state annealing step was evidence that the Co(P) layer may simultaneously serve as a diffusion-barrier interlayer dielectric and as an under-bump metallization for flip-chip copper (Cu) ICs.

Effect of fretting amplitude and frequency on the fretting corrosion behaviour of tin plated contacts

The fretting corrosion behaviour of tin plated copper alloy contacts at 3, 10 and 20 Hz and at two different track lengths (fretting amplitude) of ±5 and ±25 μm is studied. The change in contact resistance as a function of fretting cycles, surface profile of the contact zone, extent of fretting damage, extent of oxidation and elemental distribution across the contact zone were used to assess the fretting corrosion behaviour. The time to reach a threshold value of contact resistance of 0.1 Ω is found to be early for the track length of ±5 μm compared to that of ±25 μm, at all the three frequencies. For a given track length, this threshold value reaches early at 20 Hz. The roughness and the nature of surface profile suggest considerable amount of oxidation have occurred at the track length of ±25 μm compared to that of ±5 μm. The surface morphology of the fretted zone reveals severe damage of the contact zone for samples with a track length of ±25 μm at all the three frequencies. A pictorial model is proposed to describe the evolution of change in area of the contact zone. Based on the length and width of the contact zone, the fretted area is calculated. The change is fretted area as a function fretting frequency and track length is analyzed. Delamination wear is found to be operative at both track lengths and at all three frequencies. EDX line scanning also indicates higher levels of oxidation at the track length of ±25 μm compared to that of ±5 μm. The variation in the atomic ratios of tin, copper and oxygen of the oxide debris present at the centre and edges of the fretted zone is plotted as an area plot as a function of experimental conditions. The debris is predominantly oxides of copper for the track length of ±25 μm whereas they are mostly oxides of tin for the track length of ±5 μm at all the three frequencies. The narrow and deep surface profile, lower Ra values, overlapping of the tin and copper lines in the EDX line scan and the predominance of oxides of tin support the view that the chances of accumulation of wear debris at the contact zone is very high at the track length of ±5 μm. The study concludes that tin plated contacts could encounter an early failure even at shorter track lengths of ±5 μm, if there is sufficient accumulation of the wear debris at the contact zone.

Bioactivity and mechanical properties of Na 2O·CaO·SiO 2·P 2O 5 modified glasses

The purpose of this work was to study the influence of B 2O 3 and Al 2O 3 additions on the bioactivity and mechanical properties (modulus of rupture; MOR) of eight glasses in the Na 2O·CaO·SiO 2·P 2O 5 system, so that a bioactive glass with the good mechanical properties compares to others is obtained. For investigating their bioactive capacity these glasses were soaked in a simulated body fluid (SBF) at different time intervals. The changes in surface structure were examined by scanning electron microscopy (SEM) and EDX line scan and X-ray microanalysis to determine the compositional profiles through the substrate up to the surface. In some glasses the presence of a rich calcium and phosphorous layer was observed that, according to other studies, correspond to the apatite layer growing in all glasses with B 2O 3/Al 2O 3 ratio between 0.5 and 0.55. For MOR determination of these glasses, the three point loading test was used.

Fundamental understanding of nano-sized zeolite distribution in the formation of the mixed matrix single- and dual-layer asymmetric hollow fiber membranes

We have revealed, for the first time, the evolution of nano-particle distribution and the mechanisms of nano-particle movement during the formation of single-layer and dual- membranes. Both single-layer and dual-layer mixed matrix hollow fibers have been fabricated using nano-size zeolite beta. It is found that three factors play important roles in determining the nano-particle distribution in the resultant fibers. They are (1) shear within the spinneret, (2) die swell when exiting from the annulus spinneret and (3) elongation drawing in the air gap region. The shear stress induced within the spinneret determines the initial particle distribution. As a result, the particle distributions in both wet-spun single-layer and dual-layer hollow fibers follow the parabolic shape of dope's axial velocity profile in the spinneret. Die swell flattens and levels off the particle distribution, while elongation stretch redistributes the particles to the outer surface with the aid of (1) moving outer surface inward and (2) the outflow of solvents during the phase inversion process. The particle redistribution phenomenon is significantly magnified and enhanced during the co-extrusion of dual-layer hollow fiber membranes with an outer layer made of mixed matrix materials. The proposed causes and mechanisms for particle distribution have been verified by the EDX line scanning spectra of silicon and SEM pictures. Preliminary gas separation data indicate that the outer mixed matrix layer of the as-spun hollow fiber membrane has a defective skin for Knudsen diffusion. Further post-treatment is needed to eliminate defects for gas separation.

Ultra thin CVD TiN layers as diffusion barrier films on porous low-k materials

In this work CVD TiN diffusion barriers were investigated for integration with porous ultra low-k (ULK) dielectrics. Sheet resistance measurements of thin CVD TiN films on capped porous ULK and a SiO2 reference were compared. The impact of different ULK material pore size (3 and 7 nm) on TiN diffusion barrier integrity was investigated for patterned structures by etch dip test and analytical methods. In addition a SiO2 CVD liner was used for pore sealing. It was detected that a smaller pore size facilitates a better CVD liner and TiN barrier formation which results in a better barrier integrity. Evaluation of barrier continuity by HF dip test showed no effect of the CVD liner for the ULK material with higher pore size. A remarkably decrease of the number of defects was observed compared to non-patterned samples. Also a reduced TiN penetration into the ULK compared to non-patterned samples was detected by EDX line scan. It is assumed, that a partial pore sealing during ULK etching using a photoresist mask occurred by formation of a passivation layer at the sidewall. Furthermore for lower pore size material the CVD liner improved the barrier performance.

Analytical Electron Microscopy of a Magnesium Alloy Containing Neodymium

Microstructure and phase composition studies of QE-22 magnesium based alloy with 2–3% Ag, 1.8–2.5% Nd and min. 0.4% Zr, before and after full heat treatment have been carried out using various electron microscopy techniques like EDX mapping, line scans and TEM with SAED. An extrapolation technique enabled to eliminate the influence of Mg-matrix on the quantitative analysis results and allowed to estimate the composition of the second phase which was mostly (Mg, Ag)12Nd type in the as cast alloy and (Mg, Ag)12Nd and Mg12Nd2Ag equilibrium precipitates after the precipitation process.

Investigation on hot-dip aluminised and subsequent HIP'ped steel sheets

Tritium permeation can be reduced significantly by a suitable coating on the structural material. Since alumina has the capability of tritium permeation reduction the development of such coatings on ferritic martensitic steels by hot-dip aluminising of F82H-mod. steel sheets was already performed successfully. An improvement of these coatings were achieved by subsequent HIP'ping at 1040 °C for 0.5 h at 250, 500 and 750 bar and subsequently tempered at 750 °C for 1 h at 1 bar. All samples were investigated by means of metallographical examination, EDX line scan analysis and Vickers micro hardness measurements. The high pressure produced two observed changes: firstly, with increasing pressure the thickness of the FeAl phase increases and the thickness of the α-Fe(Al) phase decreases, and secondly the formation of pores could be suppressed successfully. The Vickers micro hardness of the base material F82H-mod. is not influenced by the heat-treatment under pressure and is about 215 HV.

Microstructure of Oxidised 304L Steel and the Effects of Surface Roughness on Oxidation Behaviour

This report deals with the microstructure of the oxide formed on 304L steel exposed to dry oxygen at 600°C. The specimen surfaces were pre-treated by either mechanical grinding or polishing and oxidised for 24, 168 or 672 hours. It is observed using SEM and TEM that the oxide is composed of two types of oxide species, i.e. the sub-micron spinel particles on the outer regions and the finer corundum-type base oxide grains that are formed first on the steel surfaces. The spinel particles contain roughly 40 cation % Mn, 45 cation % Cr, 8 cation % Cu and 7 cation% Fe. Such a result shows a significant Mn, Cr and Cu enrichment compared to the composition of the steel. Individual particles are homogeneous while the composition varies substantially from one particle to another. Also, more spinel particles form on specimens with ground surfaces. The base oxide grains, measuring ≃ 10 nm, are of the corundum-type oxides (Cr,Fe) 2 O 3 with varying Cr/Fe ratios. EDX line scans results from the specimen cross-section indicate that the oxide closest to the steel is most often Cr-rich and that Cr and Mn are depleted from the steel immediately below the oxide.

The study of Ti doped ZSM-5 particles and cavities inside them

The TEM study of titanium–containing ZSM-5 zeolite before and after hydrothermal treatment was performed. The use of different TEM techniques, such as conventional TEM, HRTEM and EDX-line scans provides important information about the microscopic structure of the zeolite catalyst consisting from several phases. The hydrothermal treatment of zeolite powder leads to strong changes in the morphology of the constituting particles. They are characterized by a homogeneous structure before hydrothermal treatment while the occurrence of holes after thermal treatment was observed. These changes lead to the enrichment of zeolite with titanium which obviously enhance its catalytic activity. Some of the titanium surplus precipitates as TiO 2 anatase nanoparticles within the holes.

Constitution and crystallization behaviour of ultrathin physical vapor deposited (PVD) Al 2 O 3 /SiO 2 laminates

Abstract Ultrathin Al 2 O 3 /SiO 2 multilayers were produced by physical vapor deposition (PVD) using a double source jumping beam PVD-coater. Al 2 O 3 /SiO 2 multilayer formation is controlled by the electron beam jumping frequency yielding double-layer thicknesses of about 2, 5, 9, and 30 nm. The as-deposited Al 2 O 3 /SiO 2 laminates are non-crystalline and display periodical contrast modulations in TEM cross-sections as long as the nominal thickness of the Al 2 O 3 /SiO 2 double-layer is >5 nm. EDX line scans and 29 Si–MAS–NMR spectroscopy provide evidence of nanosized pure SiO 2 and pure Al 2 O 3 layers. XRD analyses show that films consisting of 30 nm thick Al 2 O 3 and SiO 2 layers at 1000°C form transition alumina only. Transition alumina plus minor amounts of mullite appear at 1000°C in alumino silicate coatings with intermediate Al 2 O 3 and SiO 2 layer thickness (5 and 9 nm), while only mullite occurs in samples with 2 nm thick compositional modulations. The crystallization of PVD-produced alumino silicate films with double layer thicknesses >5 nm behaves similar to diphasic (type II) mullite precursors, while Al 2 O 3 /SiO 2 double-layers 2 nm thick behave like single phase mullite precursors (type I). The latter is surprising because of the diphasic character of the double layers. Obviously, two conditions are required for mullite formation at 1000°C: Interdiffusion-produced chemical homogeneization between Al 2 O 3 and SiO 2 layers, and formation of homogeneization zones large enough for mullite nucleation (about 2 to 5 nm in size).