University:
York University
Course:
CHEM 1100 | Chemistry and Materials Science for Engineers
Academic year:

2021
Views:

318

Pages:

2
Author:

Nick T.

Title: Bulk or volume Defects Defects: Pores, cracks, foreign inclusion Under pressure or thermal treatment Through pores, you allow solid materials to give space for gas diffusion. Atomic vibrations: Consider atomic vibrations as defects. The temperature of a solid is just the measure of vibration activity of its atoms and molecules. If vibration is beyond the band energy, bonds will break leading to types of defects rising. Grain boundaries: Grain boundaries are planes, don't have volume, volume needs depth. Dimensions of structural features (m): Subatomic particles: 10^-14 Atom/ion diameters: 10^-10 Unit cell edge lengths: 10^-10 Dislocations (width): 10^-8 Second phase particles: 10^-8 Grains: 10^-6 Macostructural features (porosity, voids, cracks): 10^-3 to 10^0 Sizes of Several Structures in Materials: Visual size of atoms: 10^-10 Optical microscope: Conventional microscope, use optical light SEM & TEM: Use electrons to heat the sample Penetrate material more and give more information about the sample BIC (backscattered electrons) are highly energetic Title: Microscopies Diagram: A chart showing the range of useful resolution for different types of microscopes, from scanning probe microscopes to the naked eye. Diagram: A cross-section of a sample with a beam of electrons interacting with it. Labels: X-rays EDX (Energy-dispersive X-ray spectroscopy) Microscopic analysis Photons Secondary electrons Auger electrons Backscattered electrons Diffracted electrons Text: "Characteristic of Sample (how photos are formed)" "Polished and etched surface" "Different surfaces" "When its rough, different angle of deflection" "Diff. features of sample interact with beam in different way & send it back in a diff angle" "4 smooth surface, almost all energy is deflected back" "Microscopes heat sample with incoming beam of e-" "Collect reflected e-" "SEM: Scanning electron microscopy, how many e- you can magnify at a point" "TEM: Transmission electron microscopy, X1,000,000"