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 sy ntheses of numerous chemical compounds. This paper draws particular at tention to the formation of metals, viz. copper and silver, and carbid es, viz. TaC, carried out at ambient atmosphere. The monomode techniqu e is highly available; in this case, the beam was nearly focused at th e 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 pentox ide and zirconium dioxide were studied. The crystallographic structure s of these materials were systematically determined by X-ray diffracti on before and after treatment. A scanning electron micrograph is given for copper metal, and the value of the dielectric absorption paramete r is evaluated for silver oxide and sulfide. The measurement of temper ature in the case of incandescent red powders is addressed, because it leads to various controversies.