Effect of Syntesis and Frequency on Electrical Properties on Dielectric Ceramics MgCO<sub>3</sub>-TiO<sub>2</sub>

Abstract

Magnesium titanate based dielectric materials are used for producing type-I capacitors. A common way of obtaining this material is a solid-state reaction. The process of sintering can be enhanced if mechanical activation preceedes. In this work starting powders of magnesium carbonate (MgCO3) and titanium dioxide (TiO2) with a rutile crystal modification were weighed to attain a 1:1 molar MgCO3:TiO2. Mechanical activation of the starting mixture was performed by high energy ball milling using ZrO balls and vessels with ball to powder mass ratio 40:1. The observed grinding times were 15, 30, 60 and 120 minutes. The isothermal sintering of compacted powders was conducted at 1100°C during 30, 60 and 180 minutes. For specimens synthesized in such a manner, microwave dielectric properties were measured, quality factor Q and the dielectric constant (εr) in function of frequency. The measurements of electrical resistivity, capacitance and loss tangent of samples were measured in the frequency range from 500 Hz to 5 MHz frequencies with a HIOKI 3532-50 LCR HiTESTER device at a constant voltage mode (amplitude 0.5 V of sinusoidal signal applied to the specimens).