Lecture 10

chichi's version from 2018-02-27 08:13

Section 1

Question Answer
Benefits of microwavecost savings (time and energy, reduced floor space), rapid heating of thermal insulators (most ceramics and polymers), synthesis of new materials
Wavelength range of microwavesa meter down to a few millimeters
frequency range of microwaves1 x 10^6 Hz - 1 x 10^11 Hz
Photon energy range of microwaves6.6 x 10^-26 J - 6.6 x 10^-23 J
Typical frequencies for material processing are:915 MHz, 2.45 GHz, 5.8 and 24.12 GHz

Section 2

Question Answer
Microwave processing synthesis(pyrolysis, combustion, decompositin, catalysis)
Microwave processing removal of phases(drying, solvent evaporation, binder burnout)
Microwave processing fabrication(joining, CVI, coatings)
Microwave processing consolidation(drying, sintering, melting, curing)
Microwave processing post-fabrication treatments (annealing, surface modification, nucleation crystallization, sealing, drying)

Section 3

Question Answer
Category one of materials interaction with microwavemicrowave reflectors, typified by bulk metals and alloys, such as steel, copper, brass which are therefore used in making microwaves guides
Category two of materials interaction with materialsmicrowave transmitters which are transparent to microwaves, such as fused quartz, ziron, several glasses, and cermics (not containing any transition element), teflon, polypropylene etc.; they are therefore employed for maing cookware and containers for carrying out chemical reactions in microwaves
Category three of materials interaction with microwavemicrowave absorbers which constitute themost important class of materials for microwave synthesis; they take up the energy from the microwave field and get heated up very rapidly

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