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CHARACTERIZATION OF NANOMATERIALS, image, HARINI V 1961008 - Coggle…
CHARACTERIZATION OF
NANOMATERIALS
ATOMIC FORCE
MICROSCOPE
PRINCIPLE
The AFM tip is usually made of silicon or silicon nitride and is integrated near the free end of a flexible AFM cantilever. A piezoelectric ceramic scanner controls the lateral and the vertical position of the AFM probe relative to the surface. As the AFM tip moves over features of different height the deflection of the AFM cantilever changes.
This deflection is tracked by a laser beam reflected from the back side of the AFM cantilever and directed into a position sensitive photodetector. A feedback loop controls the vertical extension of the scanner in order to maintain near-constant AFM cantilever deflection and hence a constant interaction force. The coordinates that the AFM tip tracks during the scan are combined to generate a three-dimensional topographic image of the surface.
MODES OF AFM
OPERATION
NON CONTACT
MODE
TAPPING MODE
CONTACT MODE
SCANNING ELECTRON
MICROSCOPE
Electrons are produced at the top of the column, accelerated down, and passed through a combination of lenses and apertures to produce a focused beam of electrons which then strikes the surface of the sample. The sample itself is mounted on a stage in the chamber area and (unless the microscope is designed to operate at low vacuums) both the column and the chamber are evacuated by a combination of pumps. The level of the vacuum will depend on the design of the microscope.
The position of the electron beam on the sample is controlled by scan coils situated above the objective lens. These coils allow the beam to be scanned over the surface of the sample. This beam rastering or scanning enables information about a defined area on the sample to be collected. As a result of the electron-sample interaction, a number of signals are produced. These signals are then detected by appropriate detectors.
FATIGUE FRACTURE FOR FeCu Graphite
TRANSMISSION ELECTRON MICROSCOPE
PRINCIPLE
An electron source at the top of the microscope emits electrons that travel through a vacuum in the column of the microscope. Electromagnetic lenses are used to focus the electrons into a very thin beam and this is then directed through the specimen of interest.
PARTS :
Electron gun
Image producing system
Image recording system
APPLICATION
1.It is used to detect and identify fractures, damaged microparticles which further enable repair mechanisms of the particles.
2.Its also used in nanotechnology to study nanoparticles such as ZnO nanoparticles
ADVANTAGES
very efficient, high-quality images with high clarity.
magnification of about 2 million times that of the Light microscope.
NANO GOLD
FIELD ION
MICROSCOPE
Under the influence of the very strong electric field helium atoms that are incident on the tip are ionized. The positive ions thus created are repelled radially from the surface and accelerated onto the fluorescent screen, where a greatly magnified image of the crystal tip is displayed.
Field ion microscope image of the end of a sharp platinum needle. Each bright spot is a platinum atom
NANO INDENTATION
Nanoindentation is a method for measuring the hardness, plasticity, and elasticity index of minute quantities of materials.
PROCEDURE :
Nanoindentation is an effective approach in which a defined indenter tip is forced into a specified spot in the test sample, increasing force is applied, and gradual unloading is conducted until the required depth is achieved. Before unloading, the resting section is provided, which enables the material to relax.
The operation is done repeatedly, and the divergence transformer is used to track the location of the indenter tip and the surface.
HARINI V
1961008
