Lilac Flowers Close-up
Lilac flowers are generally better known for their unique pleasant violet colors and aromatic fragrances throughout the spring season. It might be wonderful to grab a fresh large bouquet of lilacs flowers and saturate your nose directly into flower petals to whiff the fragrance, but once you see these SEM (Scanning Electron Microscope) photographs you may want to change your mind. Inside the microscopic world a lot of these flowers may look somewhat creepy.
These photographs had been captured on a Hitachi S-3400N Scanning Electron Microscope, without covering the sample in gold or carbon to make it conductive. It is a bit more difficult to acquire a great picture, due to the organic nature of the sample, however by not coating the sample the actual surface area is revealed. The challenge is to not burn the sample to a crisp or damage the sample with an excessive amount of vacuum.
The first color image in the gallery below shows the stigma of a Lilac flower, or the female part of the flower that’s generally coated in a sticky substance to collect pollen from passing insects. Numerous grub like tentacles reach out to passing bugs in hopes of gathering precious plant pollen for the purpose of reproduction. I was initially surprised at the appearance of the Stigma, it reminded me of tentacles from a horror show, and so I decided to color lilac flower stigma.
In high vacuum mode, the SEM caused some of the lilac petals to wilt or lose its water, making the flower petals resemble weird alien egg sacks. Perhaps in the future I’ll have to add some color to one of the petal images. In environmental mode which has a lesser vacuum pressure, the last few images show the lilac pollen which resemble rice krispies if you ask me.
After examining the lilac flower in the SEM There’s no doubt that I learned a lot about the parts of a flower. My primary goal was to see if I was able to successfully capture organic and natural images in a SEM, and try taking some interesting pictures. Hopefully most of these photographs do not scare you away from smelling any kind of flowers in the future. I think my next project will be to analyze a rose flower, I’m absolutely sure everybody would like to see. Feel free to leave a comment or get in touch with me for any questions.
Ductile Fracture or Final Fracture
If you were to break something metallic or plastic, and then examined the fracture in a SEM (Scanning Electron Microscope) you would most likely see a ductile fracture. A ductile fracture is a crucial concept in fractograpy to describe a type of fracture mode. You would not be able to see it with the human eye, to get a good look at the dimpled cup and cone fracture appearance you would have to observe it at around 1000x with in a SEM. A ductile fracture is a tear or rupture in the material typically found in the final stage of a fracture.
During the final stage of fracturing, the material undergoes a plastic deformation prior to breaking apart. Usually, the more the material stretches and faster it breaks, the better the fracture appearance. The typical appearance of a ductile fracture is a cup and cone structure when observed in a SEM. The fracture may also look like dimples, micro voids, or taffy like appearance after being pulled apart.
These kind of key features on the fracture surface are very important to metallurgists and engineers in identifying fracture mode of materials along with mechanical failures. Metallurgist can easily determine how a material failed by simply looking at the surface, to most metallurgist this known as final fracture. Sometimes if the fracture has ductile shearing it can often help point to the initiation or source of a failure.
Almost every fracture will have the ductile appearance in the final fracture area of the material. Unless the material is really hard, then you may get a brittle fracture or sometimes even both. A brittle fracture looks like a leaf in some ways, with cleavage planes fanning out along the surface of the grain. If you interested in images of a brittle fractures follow my link.
These images were captured on aHitachiS-3400N Scanning Electron Microscope. Below is a showcase of different ductile fractures images on a variety of different materials that I have observed. Some of these images come from tensile tests. During a tensile test, a bar of metal is pulled from both ends of the bar, and the material usually stretches like taffy, until it breaks in half. Ductile fractures usually come out pretty nice under a SEM, because it is usually the final stage of fracture, free of contamination or rust.
Lead and Tin Balls
This is SEM (Scanning Electron Microscope) photograph of powdered lead and tin used for sintering in powder metallurgy technology. Sintering allows the metallurgist to create complex objects at below the melting point often by cold pressing it together, and then slightly heating it to about half the melting point to form a strong bond. Typical objects made from sintering are gears, and moldings for ceramic or glass.
The image was captured using a backscatter collector on the SEM. Backscatter allows us to see the elemental bonds between the Pb (lead) and SN (tin) showing us pattered effect. The light patterned areas in the photograph are made of lead and the darker patterned areas in the photo are made of tin.
A Diatom From A Pond Sample.
This is a SEM (Scanning Electron Microscope) image captured in environmental mode of a Diatom about 50 microns in size. Environmental mode protects the sample from getting fried by the electrons, and I don’t have to coat the sample with gold or carbon which results in a natural image of the sample. I found this Diatom in a pond sample I collected before coming to work. A Diatom is a common type of algae or phytoplankton that grows in all parts of the world. I did an EDS (Energy Dispersive Spectroscopy) on the outer shell to determine the elemental compounds. This outer shell is made up of mostly silicon or silica (hydrated silicon dioxide) called a frustules. SEM images are typically black and white, so I recolored this in Photoshop to give it a lively appearance. Also I looked up the species identification online and found this Diatom species name is Navicula Lanceolata. Now I can go tell my friends what I found.
Image Captured by Don Svederus on a Hitachi S-3400N, and EDS results were from Oxford/Inca collector.
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