DIELECTRIC-PROPERTIES OF SELECTED TUNGSTEN COMPOUNDS FROM 60 MHZ TO 9.44 GHZ

Crystalline powders of tungsten compounds ammonium paratungstate, ammo nium metatungstate, tungsten trioxide hydrate (WO3 . H2O), and tungste n blue oxide have been studied. The complex permittivity of the pulver ized materials has been measured at room temperature from 60 MHz to 9. 44 GHz. Intrinsic permittivity values of the crystalline solids have b een derived from the apparent dielectric data of the powder material. Heating rate plots of powder samples of about 30 g at 2.45 GHz and 850 W radiation have also been taken. The slopes of the heating rate plot s and the estimated dielectric loss factors of the crystalline solids are correlated. The experimentally observed microwave heating behavior and decomposition properties under microwave irradiation have been ex plained. (C) 1994 Academic Press, Inc.