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Comparative study on sintering in microwave and conventional oven and the influency in the NONOHMIC properties of composite ceramic CaCu3Ti4O12 / CaTiO3 with addition SnO2

Grant number: 15/10938-1
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): August 01, 2015
Effective date (End): July 31, 2016
Field of knowledge:Engineering - Materials and Metallurgical Engineering
Principal Investigator:Miguel Ángel Ramírez Gil
Grantee:Gabriel Cotrim de Cesare Peinado
Home Institution: Faculdade de Engenharia (FEG). Universidade Estadual Paulista (UNESP). Campus de Guaratinguetá. Guaratinguetá , SP, Brazil
Associated research grant:13/07296-2 - CDMF - Center for the Development of Functional Materials, AP.CEPID

Abstract

This project intends to study the effects of SnO2 addition (1%, 2% e 5%), in the varistors properties, into the ceramic CaCu3Ti4O12/CaTiO3 (CCTO/CTO), using two sintering methods: by conventional furnace and microwave furnace. Ceramic powders will be prepared and they are going to be sintered in conventional furnace and microwave furnace. These powders will be thermally characterized by dilatometric technique to determine the sintering temperature and by thermogravimetric technique to determine the calcination temperature. To samples in powder and bulk, microstructural and structural characterization will be fulfilled with the X-ray diffraction technique (XRD) and with Scanning Electronic Microscopy - SEM - (FEG), to identify the phases and to measure the particles size in powder and the grain size in bulk. The compounds relative density will be determined through Archimedes' method and the porosity, with size and pore shape by Mercury intrusion porosimetry. Lastly, to appraise the CCTO/CTO/SnO2 non-ohmic property will be realized measurements in direct current (DC) to obtain E vs J plots and, from them, calculate some non-ohmic parameters, as nonlinear coefcient value, breakdown electrical eld and leakage current. With the technique of impedance/admittance spectroscopy (AC - alternating current) will be find these parameters: height and width of barrier voltage, donor density and surface state density.