Study and characterization of composite ceramics of BaTi1-xZrxO3

• Grant number: 12/16845-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): October 01, 2012
• Effective date (End): March 31, 2014
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Nonmetallic Materials
• Principal Investigator: Eduardo Antonelli
• Grantee: Larissa Rodrigues Mendes
• Host Institution: Instituto de Ciência e Tecnologia (ICT). Universidade Federal de São Paulo (UNIFESP). Campus São José dos Campos. São José dos Campos , SP, Brazil
• Associated research grant: 11/08497-6 - Processing of ferroelectric ceramics with coupled phase transitions, AP.JP

Abstract

The Zr4+ substitution in the BaTiO3 (BT) has an important effect on the phase transitions. This substitution shift the Curie temperature to lower temperatures, while the other two transitions moving to higher temperatures. Thus, it is possible to tune the transitions temperatures, and consequently the observed peaks in the dielectric permittivity curve. However, since these higher permittivity values are observed over a narrow temperature range the application of pure BT in electronic devices is susceptible to temperature fluctuations. Among several possibilities proposed to improve the properties of BT, the production of materials with different ferroelectric phases has attracted great attention. In this project we propose to prepare materials where some ferroelectric phases of the system Ba(ZrxTi1-x)O3 (BZT) can coexist. The samples will be prepared with functional graded composition ranging from one to the other side of the sample. With these samples, we will study the ferroelectric, dielectric and piezoelectric materials properties, mainly by exploiting the characteristics of coupled phase transitions. Furthermore, we can also verify and discuss the interfaces influence on the materials. The production of new materials with improved properties is expected. Thus, this proposal is innovative in the production of lead-free materials for several applications. (AU)