Dielectric properties of Bismuth Titanate densified by Spark Plasma Sintering and Pressureless Sintering

► Dielectric constant for Bismuth Titanate (BiT) is very sensitive to Pressureless Sintering (PLS) temperature because PLS can be accompanied with grain growth and a texture formation. ► For BiT processed by Spark Plasma Sintering (SPS), it is reported that the sintering temperature has small influence on the dielectric constant because SPS produces similar structures for all the processing temperatures. ► Higher values for dielectric constant and loss tangent are obtained for SPS. ► The behavior of the loss tangent is similar for SPS and PLS. Bismuth Titanate powder Bi4Ti3O12 of 175nm mean particle size has been synthesized through chemical precipitation and calcination of chemical precursors at 700°C. Ceramic pellets were sintered by conventional Pressureless Sintering (PLS) and Spark Plasma Sintering (SPS) techniques. SPS is shown to be effective in inhibiting grain growth and allowing the formation of a homogeneous microstructure. The optimum SPS temperature is 800°C in less than 5min. PLS specimens seem to be more sensible to temperature rise and sintering time, undergoing grain grow and plates-like morphology. This fact leads formation of a given crystallographic texture. Dielectric properties of SPS specimens are found dependent of the electric signal frequency and less sensitive to sintering temperature than PLS counterparts.