Papers by Keyword: Energy Dispersive X-Ray Spectroscopy (EDS)

Abstract: Cast aluminium alloys are widely utilized in various industrial applications due to their favourable properties. A comparative analysis of fracture surfaces for EN AC 5083 cast aluminium alloy specimens processed in a single-pass by friction stir processing (FSP) and submerged friction stir processing (SFSP) has been carried out in this paper. Fracture surface evaluation involves mechanical tensile tests, microscopic investigations using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) to analyse the microstructure, fracture characteristics and elemental composition of the processed material. The findings provide valuable insights into the fracture behaviour of EN AC 5083 aluminium alloy FSP and SFSP processed, contributing to further research on optimizing friction stir processing techniques in ambient and submerged process conditions.

Abstract: In this study, we have investigated the source of the n-type conductivity in bulk ZnO. Four samples with Zn concentrations 52%, 53%, 54% and 55 % were prepared by molecular beam epitaxy (MBE). ZnO layers exhibited reamarkable increase in carrier concentration (5.0×10¹⁶ cm^-3 to 2.2×10¹⁹ cm^-3) and decrease in resistivity (14.4 Ω cm to 0.009 Ω cm) as a function of Zn contents (52% to 55%) in the layers, respectively. We observed that with increasing thickness, the microstructure of films was improved. The thick films have less Zn-interstitials defects and consequently have lower carrier concentration and higher resistivity. The shifting of Raman E₂^high mode of ZnO towards higher frequency with increasing Zn contents in the samples also confirmed the presence of excessive Zn-interstitials in the layer.

Abstract: 1¹/₄Cr¹/₂Mo³/₄Si (T11) and 2¹/₄Cr1Mo (T22) grade steels are extensively used in critical parts of sub-critical thermal power plants like superheater, reheater tubes or headers. The tubes are designed to last for a very long time in service. These tubes are exposed to hot flue gas on the outer side and consequently, the inner side heats the steam passing through the tube. The outlet temperature of the steam ranges from 500-550°C. Therefore, not only the temperature on the outer side is much higher than the steam outlet but also the environment which the tube faces is extremely corrosive thereby leading to hot corrosion/ fireside corrosion. Some parts of the tubes are also exposed to fly ash coming from the combustion of coal leading to the formation of deposits on the tubes. In the present work, the tubes are cut and taken out during overhaul shutdowns and they are characterized by X-Ray Diffraction (XRD) for the likely phases that are formed on the surface of the fireside corroded layer. The deposits/scales are also qualitatively characterized. The cross-sections of the tubes are used for characterization of fireside corroded product layers using Optical Microscopy and Field Emission Scanning Electron Microscopy (FESEM) coupled with Energy Dispersive X-Ray Spectroscopy (EDS). This work will be extended further to develop rate laws and rate mechanisms of the corrosion product layers formed on the service exposed tubes.