Observe particles by using Scanning Electron Microscope (SEM), Energy Essay

Observe particles by using Scanning Electron Microscope (SEM), Energy Dispersive X-ray SEM and Transmission Electron Microscopy - Essay Example Analysis shows that even though the particle size range is from 10 ?m to 160 ?m; however most of the particles are confined in three size ranges: 10 - 20 ?m, 50 – 70 ?m and 110 – 120 ?m. SEM-EDS analysis shows that the bright particle in the silica sample are yttrium oxide. TEM images show two kinds of shape – spherical and cylindrical for TiO2 and faceted equiaxed morphology for Fe2O3 particles. The detailed results and analysis is presented in this report. Introduction Powders play very important role in materials science and industry so much so that one stream of metallurgy is known as powder metallurgy. Besides, ceramics engineering revolved around powders. Consolidation of many materials becomes possible only through powder metallurgy route, which involves filling, compaction and sintering of powders. All these processes depend heavily on powder characteristics like shape, size, size distribution etc. to name a few. Experimental determination of these attrib utes of powder is very important. Some of these attributes like size and size distribution can be determined by indirect methods like laser particle size analysis. However, only a direct method like microscopy gives the confidence in the result. Beside, many attributes like shape and chemistry can be determined only by advance electron microscopy. Electron microscopy involves obtaining high magnification images of the samples using focused beam of accelerated electrons as probe and then forming images by collecting the different signals like backscattered electrons, secondary electrons, transmitted electrons etc [1]. As wavelength of accelerated electrons is much smaller as compared to light; therefore, it can be focused to much finer spots and much higher resolution and magnification is possible in case of electron microscopes as compared to the same in case of optical microscopes. Besides, many signals generated by electron – matter interaction like auger electron, characte ristic X-rays etc. contain information about chemistry of the matter and these signals can be used to determine chemistry of the sample using different detectors like Wavelength Dispersive Spectrometer (WDS), Energy Dispersive Spectrometer etc. Accordingly there are different instruments like Scanning Electron Microscope (SEM), SEM-EDS, Electron Probe Microanalyser (EPMA), Transmission Electron Microscope (TEM), High Resolution Transmission Electron Microscope (HRTEM) etc. A basic description of SEM, SEM-EDS and TEM which were used in these experiments is provided in the subsequent sections. Scanning Electron Microscope (SEM) [2]: As suggested by the name, in this microscope a focused beam of electron is scanned over the sample in a raster using scanning coils. This leads to generation of signals like secondary electrons and backscattered electrons; which are used for image formation on a CRT screen. The image is formed in a pixel by pixel manner and therefore, the raster size corre sponds to the CRT screen size magnification is arrived by dividing the CRT length by the raster length. The magnification can thus be increased gradually by reducing the rater size on the sample as the CRT size is fixed. An SEM consists of an electron source or an electron gun, apertures to block unwanted beam, electromagnetic lenses to focus the beam, different detectors like secondary electron detector and backscattered electron detector for image formati