Papers by Keyword: Scanning Electron Microscope (SEM)

Abstract: Materials performance plays a pivotal role to the smooth operation of present and future nuclear energy systems operating in severe irradiation environment in reactors. Therefore selection of structural materials with the desired properties is vital for this field of applications. The present work reports the effect of milling time during mechanical alloying of a novel Oxide Dispersed metal matrix composite consisting of multi-component AlCrFeMnNi high entropy alloy system with minor addition of Partially Stabilized Zirconia (PSZ) (1 wt.%). The main focus of this work is to understand the phase stability behaviour during mechanical alloying. High Entropy Alloy AlCrFeMnNi with Partially Stabilized Zirconia (PSZ) as Dispersoid phase was prepared by mechanical alloying. For study of phases, milled powder was investigated through X-Ray diffraction technique followed by Scanning Electron Microscopy for microstructural morphology. The study reveals that PSZ Dispersed AlCrFeMnNi alloy mainly consists of BCC (Fe Type) and FCC (Ni Type) mixed structure. At the end of 30 h lattice strain and crystallite size were measured to be 0.738 % and 13 nm respectively.

Abstract: Many of the excavated pottery artifacts are suffering from different deterioration aspects. The pressure of burial environment is considered the most deteriorative agent for pottery in soil, which leads to damage of the artifact. Therefore, it is necessary to join these damaged parts to be suitable for museum display. The adhesive materials play a significant role in the joining processes of these artifacts. In this study, Paraloid B-72 in its traditional and nano form was prepared (50% in acetone) as adhesive for pottery artifacts. Twelve pottery tiles (14 ×4×1 cm) were prepared and then were adhered together with the adhesive in traditional and nano forms. The pottery samples were exposed to artificial aging as follows; accelerated heat-humid aging (temperature 100°C and 60% relative humidity) and light aging by U.V lamp for 100 hours. Visual assessment and several analytical techniques were used for the evaluation of the selected adhesive. The analytical techniques are transmission electron microscope (TEM), scanning electron microscope (SEM), color change and tensile strength. The results obtained from transmission electron microscope showed that grain size of nano paraloid was ranging from 33 to 51 nm where the particle size of the traditional paraloid was in the range between 103 to 150 nm. Visual assessment proved that nano paraloid had some simple changes in appearance. Scanning electron microscope revealed that the nano paraloid was more resistance for aging than traditional form. Color change revealed that nano paraloid gave the lowest level of total color differences (ΔE) after light, heat-humid and light-heat aging with 2.31, 3.26 and 4.60 respectively. The tensile strength revealed that nano paraloid gave highest tensile strength (81.3 N/mm²). According to these results, we recommend the use of nano paraloid in joining of archaeological pottery artifacts.

Abstract: The study presents the results of the investigation on the effect of soaking time on the, Crystalline structure and morphological properties of annealed EN-47 Spring Steel. The EN-47 Spring Steel samples were heated at 860 °C for soaking times of 60, 120, 240, 480 minutes. SEM analysis and XRD analysis were carried out to determine the morphology and crystalline phase of the material with increasing soaking time. Interatomic Distances also decreased with increased in soaking time. The sample with the Soaking time of 480 minutes exhibits a higher Interatomic Distance because of Formation of bigger grains. Through X-ray Diffraction transformation of the crystalline structure were analyzed, in that it is observed that Iron did not undergo any crystalline structure transformation with respect to soaking time whereas other elements changed their structure. Keywords: EN-47, Annealing, XRD, Crystalline Structure, SEM.

Abstract: This BC Soil are expansive in nature and are problematic because of low shear strength and high compressibility. Review of literatures have proven that addition of lime imparts high strength with a corresponding reduction in swell of BC soils. In addition, Bio-enzymes have also been found to play a key role as activators in improving the characteristics of clayey soils such as BC soil. Development and use of non-traditional ground improvement techniques such as bio-enzymes in combination with lime for soil stabilization helps to reduce the cost and the detrimental effects on the soil environment. In the present study lime and bio-enzymes were used as soil stabilizing agents. Compaction test results on BC soil admixed with different percent of lime indicated that 3% addition lime gives higher maximum dry density of 17kN/m3 with OMC of 21% compare to other addition of lime percentages. Keeping 3% of lime as optimum lime content(OLC), BC Soil was admixed with different dosages of Bio-enzymes 25ml/m3, 50ml/m3, 100 ml/m3,150ml/m3, and 200ml/m3 along with OLC was tested for compaction and unconfined compressive strength(UCC). Further UCC test was carried out for different curing period of 0, 7, 15, 30, and 60 Days to analyse the long term effect of BC soil admixed with bio-enzymes with and without lime content. Morphological and chemical analysis was done by using XRD and SEM analysis, from all the test results it was found that 3%OLC + 75ml/m3 of bio-enzymes for 7 day of curing gives higher UCC of 450 kPa. From the SEM it was found that better bond between particles found to develop in bio-enzyme+ lime admixed BC soil in comparison with lime alone admixed BC soil. XRD studies indicated morphological changes in crystallinity and structure of stabilized BC soil in comparison to BC soil alone.

Abstract: Advanced continuous polymer matrix composite materials provide considerable increase in flexural property values as compared with their bulk and monolithic counter parts. In this research work the effect of fiber orientation on the flexural strength of epoxy matrix composite materials reinforced with glass fiber was studied. Filament winding technique was employed for fabrication of composite with various fiber orientations. The flexural strength value of the glass fiber reinforced composite was comprehensively studied by means of three point bending flexural test and analysed by scanning electron microscopy. Experiments were conducted as per ASTM standards and it was concluded that reinforcement with 0^o orientation of glass fibers shown improved flexural strength as compared to 45^o and 90^o orientation of fibers.

Abstract: Cadmium sulphide nanocrystallites have been synthesized using precipitation method. The average sizes of the prepared samples is determined by XRD (x-ray diffraction) method. Morphological studies are carried out by SEM (scanning electron microscopy) measurement. Necesssary elements present in prepared samples, are confirmed by EDAX (energy dispersive analysis of x-ray spectroscopy) method. By Ultraviolet visible spectroscopy measurement, the value of absorption wavelength, band gap values are calculated in optical method. The electrical properties are analysed using impedance analyser measurement for the Nanocrystallites.

Abstract: Composite materials are extensively used in various applications like space, aircraft, and automobile sector because of superior physical and mechanical properties even though they are costly. In recent technological innovations, using Montmorillonite (Nanoclay) to reinforce polymer-based composites has raised attention to academic and industrial sectors since small addition could enhance Mechanical properties thereby decreasing failures like delaminations. In present research work, the effect of AWJ machining parameters on delaminations of glass fibre reinforced epoxy composite is investigated. The Main objective is determining delamination factor and reduce delaminations which is major failure in laminates. This paper investigates on effects of impregnated Nanoclay epoxy in Bi-directional GFRP where previous research has been made only in changing the parameters for reduction of delaminations. The samples were machined using AWJ, delamination factors are measured using image-J software and SEM analysis for comparing micrographs. Finally with increase in nano clay weight fraction, delaminations are checked.

Abstract: Glass substrates are used to deposit thin films utilizing basic and value effective chemical bath deposition (CBD) technique. The films were prepared from the mixture as solutions of manganous acetate tetrahydrate [C₄H₆MnO₄4H₂O] as a manganese source, thiourea [(H₂ N) ₂ CS] as a sulfur source and triethanolamine (TEA) [(HOC₂H₄)₃N] as a complexing agent.In the present paper the deposition was successfully done at 60 °C temperature. The absorption properties and band gap energy were determined employing double beam spectrophotometer. The optical band gap value calculated from absorption spectra of MnS thin film is found to be about 3.1eV.The MnS thin film was structurally characterized by X-ray Diffraction (XRD). The MnS thin film was morphologically characterized by Scanning Electron Microscopy (SEM) and elemental analysis was performed using EDS to confirm the formation of MnS.

Abstract: In this paper, the effect of size variation of cadmium sulphide nanocrystallites which have been prepared by precipitation method is analyzed. These prepared samples were studied using X-ray diffraction (XRD), Scanning electron microscopy (SEM), and Energy dispersive analysis of spectroscopy (EDAX) techniques. SEM analysis represents the morphological nature of prepared samples and EDAX indicates the confirmation of elements present in the sample. XRD analysis determines the size of the samples and identifies the structure using miller indices (h k l values) of the nanocrystallies matches with JCPDS. From the XRD analysis, the size variation which depends on dopant, capping agent are discussed and corresponding results are reported in this paper.

Abstract: The effective modeling methodology of 4H-SiC trench gate MOSFETs is presented. The potential barrier lowering at the MOS channel region suggested by I-V measurements is implemented to commercial TCAD tool as the net-doping reduction. The proposed model is validated by comparison of TCAD simulations with I-V measurements and SEM image observations.