Microwave-monomode energy transfer: Chemical syntheses, crystallographic and thermal properties of mineral powders

The high energy transfer produced by means of the electromagnetic beam of microwave apparatus is used more and more to carry out chemical syntheses of numerous chemical compounds. This paper draws particular attention to the formation of metals, viz. copper and silver, and carbides, viz. TaC, carried out at ambient atmosphere. The monomode technique is highly available; in this case, the beam was nearly focused at the center of the test tube containing the powder. The compounds copper hemioxide, copper hemisulfide, tantalum pentoxide, titanium dioxides (anatase and rutile), palladium black powder, and mixed vanadium pentoxide and zirconium dioxide were studied. The crystallographic structures of these materials were systematically determined by X-ray diffraction before and after treatment. A scanning electron micrograph is given for copper metal, and the value of the dielectric absorption parameter is evaluated for silver oxide and sulfide. The measurement of temperature in the case of incandescent red powders is addressed, because it leads to various controversies.