The Effects of Frequency and Temperature on the Dielectric Constant of X%Al2O3 Powder Extracted From Iraqi Kaolin


Samples of X%Al2O3 ( X = 17.85, 28.05, 87.98 and 95.63 ) were prepared from Iraqi kaolin, after calcinations process, by the method of evaporation. From the temperature dependence of capacitance, the temperature dependence of dielectric constant are studied for the samplesof annealed powders of various Al2O3 contents in the frequency range 1KHz – 1MHz. The frequency dependent values of dielectric constant for the powder content 87.98% Al2O3 and 95.63%Al2O3 are found to be varies between 9.21 – 12.29 and 6.99 – 12.063, respectively. While for the others percentage of 17.85%Al2O3 and 28.05%Al2O3 powder content samples, it changes between 22.195 – 151 and 13.015 – 21.09 , respectively. These dependence are analyzed and discussed in details. The annealing temperature effect on the dielectric constant are given for the frequency investigation of 10KHz. However, the annealing temperature transforms the structure and that consequently affects the dielectric constant. The dielectric constant found to be decreases with increasing the temperature for all the investigated samples from 17.85%Al2O3 to the 95.63%Al2O3.