Colloid and Surface Science 2017; 2(2): 76-80 http://www.sciencepublishinggroup.com/j/css doi: 10.11648/j.css.20170202.15 Microstructural and High Tc Dielectric Properties of Microwave Sintered Ba 0.7 Ca 0.3 TiO 3 (BCT) Ceramic Sagar M. Mane 1, 2 , Pravin M. Tirmali 1 , Snehal L. Kadam 1 , Chandrakant B. Kolekar 2 , Shrinivas B. Kulkarni 1, * 1 Department of Physics, the Institute Of Science, Mumbai, India 2 Department of Physics, Sahakar Maharshi Shankarrao Mohite Patil Mahavidyalaya, Natepute, Solapur, India Email address: sbk_physics@yahoo.com (S. B. Kulkarni) * Corresponding author To cite this article: Sagar M. Mane, Pravin M. Tirmali, Snehal L. Kadam, Chandrakant B. Kolekar, Shrinivas B. Kulkarni. Microstructural and High Tc Dielectric Properties of Microwave Sintered Ba 0.7 Ca 0.3 TiO 3 (BCT) Ceramic. Colloid and Surface Science. Vol. 2, No. 2, 2017, pp. 76-80. doi: 10.11648/j.css.20170202.15 Received: January 13, 2017; Accepted: March 11, 2017; Published: April 10, 2017 Abstract: Nanopowder of Ba 0.7 Ca 0.3 TiO 3 (BCT) lead free ferroelectric ceramic was synthesized by hydroxide co- precipitation method. As-synthesized powder is sintered using the microwave sintering technique at different temperature 1100°C and 1200°C. Sintered ceramic samples were investigated for its structural, morphological, and temperature dependent dielectric properties. Structural analysis confirms biphasic crystal structure, tetragonal phase corresponding to BaTiO 3 lattice and orthorhombic phase resulting from the CaTiO 3 lattice. Scanning electron microscope images reveals the formation of grains with higher density. Ferroelectric-Paraelectric transition (Tc) of the material shifts towards higher temperature (Tc ~ 155°C) with maximum dielectric constant and low loss tangent. Keywords: Ferroelectrics, Microwave Sintering, Dielectric Properties, Microstructure, Phase Transformation 1. Introduction BaTiO 3 (BT) is one of the most important lead-free ferroelectric material and extensively useful material for number of electronic appliances such as multilayer ceramic capacitors, actuators, lead free piezoelectric transducers, infrared detectors, voltage tunable device in microwave electronics and as a charge storage device etc. BT material is known for exhibiting interesting electrical properties like high dielectric constant, low dielectric loss, ferroelectric, piezoelectric and pyroelectric behavior and stands as one of the most useful perovskite oxide compared with other dielectric materials [1]. Addition Sr 2+ , Ca 2+ or Zr 4+ ions at A or B site of BaTiO 3 will results in formation of solid solutions like Ba 1-x Sr x TiO 3 (BST), Ba 1-x Ca x TiO 3 (BCT) and BaZr x Ti 1-x O 3 (BZT). These solid solutions has improved electrical and mechanical properties and found useful for various applications [2]. Particularly, BZT and BCT materials are used as ceramic capacitors and also founds numerous applications as an electrical material [1-2]. Replacing of Ba 2+ ions by Ca 2+ ions at A-site in BaTiO 3 lattice results in the prospective lead-free material which can applicable in electro-optic modulators and memory devices [10]. Solid solution of BCT was most used as a multilayer ceramic capacitor also this can be used in various other applications like: dielectric filter, dielectric antenna, dielectric resonator, dielectric duplexer, capacitor and phase shifter [1, 10]. Sintering at particular and desirable temperature is one most important and necessary stage in the development of the ceramic material. Though it is widely used, conventional method of ceramic processing founds drawbacks such as, need of higher sintering temperature (1400 - 1500°C) for longer duration (above 5 hrs), unusual grain growth during heating, etc. On the other hand the microwave sintering technique is superior than conventional sintering (CS) due to its unique characteristics, such as rapid heating, enhanced densification rate and improved microstructure. In the microwave process, the heat is generated internally within the material instead of originating from external sources, and hence there is an inverse heating profile as compared