Electrical Properties and Infrared Studies of Heated Mica Sheets

Dielectric constant (έ), dielectric loss (ε") and (tan δ) have been
measured for heated Mica sheets at different temperatures (200-900oC) for 2
hours in the frequency range (0.1-100KHZ). It has been found that the dielectric
constant and dielectric loss are nearly stable till 600ºC but showing an increase
at 800 and 900oC. The dielectric loss and tan δ show maximum 800 and 900oC.
The activation energy values of dielectric relaxation have been calculated for
mica sheets for the latter temperatures. It was observed that the activation
energy values go on increasing with increasing heating temperature from 800ºC
to 900ºC. The resistivity of mica sheets was studied also as a function of
temperature in the range (30–70ºC) for the samples heated at 800ºC and 900ºC
over frequency range [0.1–100 KHz]. It was found that the resistivity increases
with temperature and decreases with frequency. The resistivity at 900ºC is
higher than 800ºC overall the range used. Infrared spectra were studied to link
the influence of the structure of heated mica with their thermal behavior.