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

Crystalline powders of tungsten compounds ammonium paratungstate, ammonium metatungstate, tungsten trioxide hydrate (WO3 . H2O), and tungsten blue oxide have been studied. The complex permittivity of the pulverized materials has been measured at room temperature from 60 MHz to 9.44 GHz. Intrinsic permittivity values of the crystalline solids have been 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 plots 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 explained. (C) 1994 Academic Press, Inc.