Papers by Keyword: Energy Dispersive Spectroscopy

Abstract: New building materials must meet strict requirements on mechanical properties. Therefore structural and chemical characterization of new building materials is very important. The correlative microscopy is a new possibility of materials analysis. This method combines light microscopy (LM) and scanning electron microscopy (SEM). LM images can be then precisely extended by their morphological background and/or material distribution, e.g. with energy dispersive spectroscopy (EDS). With using correlative microscopy, the weakest places of alkali-activated concrete were found.

Abstract: The paper describes results of functional tests of photo catalytic materials directly in matrix of prefabricated vibro pressed pavement blocks. Resulting surfaces of photo catalytic concrete products were tested with respect to conversion of NOx and surface was analyzed with Scanning Electron Microscope (SEM), so called element maps were elaborated by means of Energy Dispersive Spectroscopy (EDS).

Abstract: Functionally graded WC-Co (FG WC-Co) offers superior combination of wear resistance, fracture toughness, and strength, and provides superior engineering performance over conventional homogeneous WC-Co. The cobalt gradient structure of the FG WC-Co, including the thickness of the gradient zone and the cobalt concentration distribution, have the great influence on its engineering performances. Measurement of cobalt gradient of the FG WC-Co was studied in this paper using an energy dispersive spectroscopy (EDS) technique. The result shows that the rectangular area scanning mode of EDS is suitable for evaluating the cobalt content distribution quantitatively in the FG WC-Co. Based on the cobalt content distribution curve, the thickness and the amplitude of cobalt gradient in the FG WC-Co can be measured easily.

Abstract: Resistance to wear is an important factor in design and selection of structural components in relative motion against a mating surface. The present work deals with studies on the wear behavior of metal matrix composites manufactured using powder metallurgy technique of ball milled mixing in a high energy attritor and using a blend-press-sinter methodology. Matrix of pre–mechanical alloyed Al-4.5 %wt Cu was used to which different weight percents of nano-sized TiC reinforcement were added. Microstructural characterization of the materials revealed reasonably uniform distribution of TiC reinforcement and presence of minimal porosity. Wear tests were performed using a pin on disk apparatus. The MMCs were rubbed against a carbon steel pin under loads of 10 and 20 N at a sliding velocity of 0.1 ms⁻¹; the environmental humidity lower than 30% and a track length of 1500 m. The degree of improvement in dry sliding wear resistance and hardness brought about by reinforcement is strongly dependent on the weight percent of reinforcement and the wear behavior was determined through the precise measurement of weight loss of the samples. Worn surfaces were analyzed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS).

Abstract: We have investigated the morphology and photoluminescence (PL) of Zinc Oxide (ZnO) and Zinc sulphide (ZnS) compound grown on porous silicon at room temperature. Under different excitation wavelengths (320 nm, 340nm, 370 nm), the photoluminescence (PL) spectra of PS-ZnS-ZnO composites were different, and at 550nm there is a strong photoluminescence peak. Energy dispersive spectroscopy (EDS) has been carried out to evaluate the existing of ZnO/ZnS compound. In addition, the scanning electron microscopy (SEM) observation shows that the morphology of the PS-ZnS-ZnO composites was well grown on porous silicon.

Abstract: The isothermal oxidation behavior and thermal stability of a cobalt base alloy was investigated up to a period of 312 hr in air from 1000 to 1200°C. A comparison of oxidation behavior of this alloy with a conventional nickel-base superalloy (Inconel 713C) has been conducted in detail. This experimental alloy oxidizes by forming layers of Al2O3, Cr2O3, TiO2, CoO and traces of SiO2 with WO2 oxides on the surface of the specimen in contact with air. Scanning electron microscopy (SEM) was used to study the microstructure, morphology and compositions of oxides formed after the exposure. Thermal stability of the alloy after extended periods of exposures to air at 1000, 1100 and 1200°C was studied using transmission electron microscopy (TEM).

Abstract: Bonding interface in aluminum (Al) and silicon nitride (Si3N4) clad fabricated by explosive welding has been investigated by transmission electron microscopy (TEM). The nanocrystalline region was clearly observed at the interface between Al and Si3N4. Electron diffraction pattern and energy dispersive X-ray spectroscopy (EDS) measurements across the interface revealed that this nanocrystalline region consist of the only aluminum.

Abstract: Novel catalytic systems based on PdZn alloys have been synthesized by polyol reduction over the entire compositional range [1, 2] and characterized by means of HRTEM, EDS and ICP. The expected bulk compositions were reproducible to within a 2 mol% margin and the purified particle suspensions stable for several months after preparation. The EDS results indicated the presence of considerable amounts of oxygen, especially in those samples containing high fractions of zinc. The particle size distributions were shown to be narrow and the mean sizes slightly decreased with higher molar fractions of palladium (diameter range 2.6 to 3.2 nm). In the catalytic hydrogenation of phenylacetylene, a strong dependence of the substrate conversion time on the Pd concentration was established, and selectivity towards the semihydrogenation product (styrene) was found to be close to 100 %. The selectivity dropped only shortly before the initial substrate was fully depleted.

Abstract: Experiments involving metal dusting in carbonaceous atmosphere and oxidation in air have been carried out at 593 and 704oC using T22, T91 and 800 alloy steels. The effect of Cr on these two processes can be understood because of their compositions. In general, the resistance to both metal dusting up to 1000 hours and oxidation up to 456 hours has been found to improve with increase in Cr content from 2.36 to 21.6%. However, mechanisms change from spalling to oxide scale in oxidation and from uniform metal dusting to pitting in metal dusting as the amount of Cr increases in these steels. Pitting corrosion shows higher C carbon concentration in the pits than at locations away from the pits. A detailed analysis has been performed to evaluate the scale and spalled materials in terms of oxide characterization using XRD, AES, SEM, EDS on SEM, optical microscopy and TEM.