Synthesis, consolidation and dielectric properties of BLT ceramics processed by M-PVA gel ignition technique

Abstract

Abstract

Polycrystalline samples of lanthanum modified bismuth titanate ceramics with composition Bi_3·25La_0·75Ti₃O₁₂ (BLT) were prepared at three different sintering temperatures (1050, 1100 and 1150°C) using M-PVA gel ignition technique. The samples were characterised for structural and electrical properties. A significant amount of as burnt BLT powder was found to be crystalline in nature having a yellowish colour. Very fine BLT nanoparticles were characterised by TEM analysis. Single phase with orthorhombic crystal structure was observed for all the samples, confirmed by X-ray analysis. Dielectric properties were studied as a function of frequency and temperature. More than 95% relative density was observed for all the three sintered samples. The sample sintered at 1100°C showed highest dielectric constant and relative density and lowest loss.

Keywords:

• Ceramics
• Sintering
• Electron microscopy
• Dielectric properties

Authors gratefully acknowledge Dr G. Malakondaiah, Director, Defence Metallurgical Research Laboratory, Hyderabad, for giving permission to publish the work. Authors also sincerely acknowledge Dr Y. Srinivasa Rao, International Advanced Research Centre for Powder Metallurgy and New Materials, Hyderabad, for TGA/DSC measurements. They would like to thank Mr Vajinder Singh for SEM measurements.