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 - Nonmetallic Materials
• 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 the conventional furnace and microwave furnace. Ceramic powders will be prepared and they are going to be sintered in a conventional furnace and microwave furnace. These powders will be thermally characterized by a dilatometric technique to determine the sintering temperature and by a 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 compound's 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 coefficient value, breakdown electrical eld, and leakage current. The technique of impedance/admittance spectroscopy (AC - alternating current) will find these parameters: height and width of barrier voltage, donor density, and surface state density.