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X-ray Diffraction (XRD)
Structure of materials
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X-ray diffraction method is an effective method for determining the crystal
structure of materials
Material
Crystalline
Single crystal
Polycrystalline
Amorphous
Crystal
Composed of atoms arranged in a r
ULTRAVIOLET AND VISIBLE ABSORPTION SPECTROSCOPY
ELECTROMAGNETIC RADIATION
Electromagnetic radiation may be considered as a simple harmonic wave propagating
from a source
Electromagnetic radiation, traveling at a constant speed of light, varies in waveleng
Fracture Toughness
Critical stress for crack propagation (c) is related to the crack length (a) as,
Kc Y c a
Kc is fracture toughness, which is a measure of a materials resistance to brittle fracture,
when a crack is present
The unit of Kc is MPam
Y i
Thermal Analysis
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Thermal events
Heating of solid in inert atmospheres lead to various changes
Glass transition
Glass : non crystalline solid
Do not melt at sharp defined temperature but soften over a
temperature interval . This transition from rigid g
Chemisorption Technique
Metal atoms deposited on surface
In catalysts and adsorbents metals are deposited on surface of support
( e.g Pt/Al2O3, Pt/C, Ni/Al2O3)
These metals act as active sites ( many times in zero valence state)
Most commonly these metals
