Scanning electron microscopy sample coating

Scanning Electron Microscopy. Samples of unweathered and weathered untreated and formaldehyde-treated wools were mounted or specimen stubbs using conducting silver paint and coated with two thin layers of silver. Scanning electron micrographs of the samples were prepared and examined for changes In the fiber surface (Fig. 1). 

This technique can be applied to samples prepared for study by scanning electron microscopy (SEM). When subject to impact by electrons, atoms emit characteristic X-ray line spectra, which are almost completely independent of the physical or chemical state of the specimen (Reed, 1973). To analyse samples, they are prepared as required for SEM, that is they are mounted on an appropriate holder, sputter coated to provide an electrically conductive surface, generally using gold, and then examined under high vacuum. The electron beam is focussed to impinge upon a selected spot on the surface of the specimen and the resulting X-ray spectrum is analysed. 

Figure 4.11 Scanning electron microscopy images of bare and coated magnesium chips. Clear morphological differences are seen between the coated and uncoated samples. (Reproduced from ref. 13, with permission.)...

Scanning electron microscopy (SEM) seems to have been used only scarcely for the characterization of solid lipid-based nanoparticles [104], This method, however, is routinely applied for the morphological investigation of solid hpid microparticles (e.g., to smdy their shape and surface structure also with respect to alterations in contact with release media) [24,38,39,41,42,80,105]. For investigation, the microparticles are usually dried, and their surface has to be coated with a conductive layer, commonly by sputtering with gold. Unlike TEM, in SEM the specimen is scanned point by point with the electron beam, and secondary electrons that are emitted by the sample surface on irradiation with the electron beam are detected. In this way, a three-dimensional impression of the structures in the sample, or of their surface, respectively, is obtained. 

Scanning Electron Microscopy, An ISI model Super II (International Scientific Instruments Inc., Milpitas, CA) scanning electron microscope was used for morphology study (Labtech, Fairfield, NJ). Powder was properly loaded on specimen stub via a double stick tape. Samples were coated with 60% gold and 40% palladium for 6 min at 100 to 200 mtorr in a sputter coater. 

Microscopy. Scanning electron microscopy was run on resin samples using a AMR 1200 Scanning Electron Microscope. The samples were mounted on the stub using double stick tape and then sputter coated with gold. 

Scanning electron microscopy is an important tool when examining the mode of wear of any sample. The surface of the sample is coated with a very thin layer (only several atoms thick) of a conductive material such as gold. The surface is scanned using a beam of electrons and the image magnified and recorded. 

For scanning electron microscopy of electrically insulating materials, the surface of the specimen may be electrically isolated when bombarded with electrons. This leads to charge buildup on the specimens that makes imaging or other analysis difficult. To address this issue, special sample coating steps are often required and have been discussed in Section 9.2.3. 

Samples of microspheres were mounted on aluminum specimen mounts by means of double-faced tapes. The microspheres were fractured with razor blades to expose the internal matrix. The samples were then coated with approximately 125 of gold by pulsing the sputter coater to avoid the possibility of artifact caused by heat generation. Secondary emissive scanning electron microscopy was performed with an Amray 1600 Turbo scanning electron microscope. 

If the sample is thicker, then interaction is with the surface of the sample and the products of this interaction follow trajectories away from the surface. In scanning electron microscopy (SEM), it is usually the secondary emitted electrons that are detected, the electron beam being scanned (rastered) across the sample surface. For reflection techniques non-metallic surfaces have to be coated with a thin metal film (about... 

Fig. 2.2. Mycelium of Hebeloma crustuliniforme after colonization of a potassium feldspar surface for seven months. The sample was prepared by fixation and critical point drying followed by gold coating and analysis by scanning electron microscopy. Hyphae (H) and bacteria (B) are visible. Scale bar = 10 pm. The hyphal surface contact is mediated by a fdm of extracellular mucilage (arrow) and bacteria are seen in the mucilage.

Single small samples representative of each distinguishing feature from each object were cut and mounted for scanning electron microscopy. Each was carbon coated, and X-ray microanalysis [energy dispersive spectroscopy (EDS)]... 

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