Effect of Cu Content on Dielectric Properties of BaTiO3/Cu CompositeCeramics

The BaTiO3/Cu composite ceramics doped with Cuin the content range of 0―30 wt% were prepared by the solid―state reaction. Themicrostructure, percolation threshold and dielectric properties of ceramicswere investigated. The results show that the resistivity of BaTiO3/Cucomposite ceramic increases with Cu content decreasing and the relationshipbetween them has a non―linear downward trend at the percolation threshold ( x=25wt%), then the composite isgradually changing from insulator into conductor. The value of εr of BaTiO3/Cucomposites is raised with the increase of Cu content, and the maximal value is about9000 at 1 kHz at room temperature as Cu content of 30wt%. The dielectric lossof BaTiO3/Cu composites increases with the increasing Cu doping, butthen decreased with the increasing frequency, which is due to the reducing ofthe amount of space charge. The temperature coefficient is less than 5% in the temperaturerange from 25 to 115 , and the dielectric constant is provided with hightemperature stability.