RESUMO As soluções sólidas de titanato de zirconato de chumbo, Pb(Zr1-xTix)O3 – PZT, são amplamente reconhecidas por representar um grupo especial de materiais ferroelétricos com várias aplicações potenciais em eletro-cerâmica e (micro) dispositivos eletrônicos. A cerâmica PZT é produzida por reação em estado sólido (via convencional) e temperaturas frequentemente acima de 1200 °C. Como conseqüência, o custo do produto cerâmico é caro. Apresentamos aqui as condições de síntese e processamento da cerâmica PZT 52/48 (x = 0,48), na qual foi possível reduzir a temperatura de sinterização para cerca de 900 ° C. Aplicamos uma rota para a obtenção de cerâmica ferroelétrica PZT52/48 através da sinterização de pós nanométricos preparados pelo método de síntese de precursores poliméricos (método de Pechini modificado). A sinterização foi realizada a uma temperatura de 900ºC por 2 horas e as amostras obtiveram 96% de sua densidade teórica e tamanho médio de grão de 1,3 µm. A permissividade elétrica das cerâmicas, estudada por espectroscopia de impedância, apresentou temperatura de Curie em torno de 390 ºC. As curvas da histerese ferroelétrica revelaram que a polarização remanescente é de 3,2 μC/cm2 e o campo coercitivo é de 10 kV/cm a 60 Hz. Todos os resultados e caracterizações mostraram que as amostras de PZT obtidas com a via polimérica são eficientes como as preparadas no protocolo SSR convencional.

ABSTRACT Lead zirconatetitanate solid solutions, Pb(Zr1-xTix)O3 – PZT, are widely recognized for representing a special group of ferroelectric materials with various potential applications in electroceramics and (micro)electronic devices. The PZT ceramics is produced by solid state reaction (conventional route) and temperatures frequently above 1200 °C. As a consequence, the cost of ceramic product is expensive. Herein, we present the synthesis and processing conditions of PZT52/48 (x = 0.48) ceramics in which it was possible to lower the sintering temperature down to around 900°C. We have applied a route for PZT52/48 obtaining ferroelectric ceramics through sintering of nanometric powders prepared by the polymeric precursor synthesis method (modified Pechini’s method). The sintering was achieved with a temperature of 900ºC for 2 hours and the samples got 96% of their theoretical density and 1.3 mm mean grain size. The electrical permittivity of the ceramic plates, studied by impedance spectroscopy, presented Curie temperature around 390 ºC. Ferroelectric hysteresis measurements revealed that the remnant polarization is 3.2 μC/cm2 and coercive field is 10 kV/cm at 60 Hz. All results and characterizations have shown that the PZT samples obtained with the polymeric route are efficient as the ones prepared in the conventional SSR protocol.

The scientific community has shown a growing interest in relating to the ferroelectric materials and it has made an effort to develop them. Among these several ferroelectric materials, we proposed to investigated Pb(ZrTi)O3 doped with distinct Er+3 concentrations. Our aim was to investigate how the erbium affects the PZT electrical properties. To determine the ideal sintering temperature of our ceramic samples, the dilatometry tests were performed. These results have showed that the erbium caused a change in sample densities (91.9% < ρ < 99.0%) as compared to undoped PZT sample. Furthermore, the X-ray diffraction results indicated that all samples are monophasic and peaks are indexed to tetragonal crystalline structure. According to these also results, there was an increment of the parameter a and a reduction of parameter c as compared to undoped PZT sample. On the other hand, the average grain size have decreased with the increment of erbium content. The electrical characterization of ours ceramics showed a peculiar ferrelectric-paraeletric phase transition around 390 ºC. Finally, the ferroelectric hysteresis measurements for doped samples in site A have revealed that remnant polarization and coercive field values depend on content. Whereas, doped samples in site B, the corresponding values are similar.