Estudo da compatibilidade eletromagnética em placa de circuito impresso de centrais telefônicas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise de integridade de sinal e crosstalk em placa de circuito impresso

Pós-graduação em Engenharia Elétrica - FEIS

Desenvolvimento experimental e simulação numérica de uma réplica térmica de placa de circuito impresso

Pós-graduação em Engenharia Mecânica - FEIS

A qualidade de placas de circuito impresso confeccionadas a partir de poliestireno reciclado

Pós-graduação em Engenharia Mecânica - FEG

Fabrication and structural characterization of bismuth niobate thin films grown by chemical solution deposition

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Electrical properties of screen printed BaTiO3 thick films

The deposition of thick film pastes by screen-printing is a relatively simple and convenient method to produce thicker layers with thickness up to 100 mum. In the present work, the barium titanate thick films were prepared from mechanically activated powders based on BaC03 and TiO2. After mixing, the powders were calcined at low temperature by slow heating and cooling rates. The thick films were deposited on to Al2O3 substrates through hybrid technology. The obtained films were fired at 850 degreesC together with electrode material (silver/palladium). The electrical properties of thick films: dielectric permittivity, dielectric losses, Curie temperature, hysteresis loop were reported. The obtained BT thick films can be applied in as multilayer capacitors or in gas sensor application. (C) 2003 Elsevier Ltd. All rights reserved.

Barium titanate screen-printed thick films

Barium titanate (BT) thick films were prepared from mechanically activated powders based on BaCO(3) and TiO(2). After homogenization and milling in a high-energy vibro mill, the powders were calcined at 700 degreesC for 2 h by slow heating and cooling rates. A thick film paste was prepared by mixing BT fine powders with small amount of low temperature sintering aid and organic binder. The thick films were screen-printed on alumina substrates electroded with Ag-Pd. The BT films were sintered at 850 degreesC for 1 h. The thickness was 25-75 mum depending of number of layers. The microstructure of thick films and the compatibility between BT layers and substrate were investigated by SEM Results of dielectric property measurements are also reported. (C) 2002 Elsevier B.V. Ltd and Techna S.r.l. All rights reserved.