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Thermistor formation using BaTiO3 powders synthesised by the Pechini method
Conformación de termistores utilizando polvos de BaTiO3 sintetizados por el método pechini
Keywords:
BaTiO3, electrical characterisation, Pechini, synthesis, thermistor (en)BaTiO3, caracterización eléctrica, Pechini, síntesis, termistor (es)
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Barium titanate (BaTiO3) is a compound of interest in the field of electroceramics which is widely used in the manufacture of capacitors, piezoelectric transducers and resistive devices having a positive temperature coefficient (PTCR) and in manufacturing pyroelectric and optoelectronic devices. Most of these devices are obtained by consolidating high purity, suitable sized particle ceramic powders; structured synthesis methods are required to ensure such requirements. BaTiO3 powders were synthesised by a polymeric precursor method (Pechini) in this work. Very pure, small particle sized, raw material was obtained. These powders were characterised using thermogravimetric and differential thermal analysis (TGDT), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The results indicated that samples treated at 650°C presented cubic BaTiO3 as unique crystalline phase. If a sample were treated at 1,100°C, the tetragonal phase having a c/a < 1.007 relationship was the main crystalline phase. Samples treated at 1,100°C showed ferroelectric-paraelectric transition at T ≈ 123°C. BaTiO3 tetragonal ceramic powders were uniaxially pressed and then synthesised at 1,200°C for 2 hours. These samples were electrically characterised. These samples' curves of electrical resistance versus temperature (R-T) showed their PTCR thermistor behaviour. Current-voltage (IV) variation was also measured at different temperatures.
El titanato de bario, BaTiO3, es un compuesto de gran interés en el ámbito de la electrocerámica, ya que se utiliza en la fabricación de condensadores, transductores piezoeléctricos y dispositivos resistivos con coeficiente positivo de temperatura (PTCR), así como en la manufactura de piroeléctricos y dispositivos optoelectrónicos, entre otros dispositivos. La mayoría de estos componentes son conformados con polvos cerámicos de elevada pureza y tamaño de partícula adecuado. Esto exige estructurar métodos de síntesis que garanticen estos requerimientos. En este trabajo se sintetizaron polvos cerámicos de BaTiO3 por el método de precursor polimérico (Pechini), obteniéndose una materia prima muy pura y con pequeño tamaño de partícula. Los polvos obtenidos se caracterizaron utilizando análisis térmico (ATD/TG), difracción de rayos X (DRX) y calorimetría diferencial de barrido (DSC). Los resultados indican que en las muestras tratadas a 650 °C la única fase cristalina presente es el BaTiO3 cúbico y a 1.100 °C la tetragonal, con una relación c/a < 1.007. Las muestras tratadas a 1.100 °C presentaron una transición ferroeléctrica a paraeléctrica a una temperatura de T ≈ 123 °C. Los polvos cerámicos de BaTiO3 tetragonal fueron prensados uniaxialmente y posteriormente sinterizados a 1.200 °C durante 2 horas. Estas muestras se caracterizaron eléctricamente, obteniéndose curvas de resistencia eléctrica en función de la temperatura (R-T), evidenciándose en ellas su comportamiento termistor tipo PTCR. Además, se midió la variación de la corriente-voltaje (I-V) a diferentes temperaturas.
References
Caballero, A. C., Fernández, J. F., Duran, P., Moure, C., Titanato de bario Cerámico., Boletín de la Sociedad española de cerámica y vidrio, Vol. 33, No.1, 1994, pp.5-21.
Cahn, R. W., Nanostructured materials., Nature, Vol. 348, No. 6300, Nov. 1990, pp. 389–390.
Duran, P., Capel, F., Tartaj, J., Gutierrez, D., Moure, C., Heating-rate effect on the BaTiO3 formation by thermal decomposition of metal citrate polymeric precursors, solid state ionics, Vol. 141-142, May. 2001, pp. 529–539.
Frey, M. H., Payne, D. A., Grain size effect on structure and phase transformations for barium titanate., Physics Review B, Vol. 54, No. 5, Aug.1996, pp. 3158– 3168.
Fernández, C. P., Rivera, E. F., Rodríguez-Páez, J. E., Conformación de Dispositivos Termistores con Coeficiente Positivo de Temperatura (PTCR)., tesis presentada a la Universidad del Cauca, para optar por el título de Ingeniero Físico, 2009.
Habib, A., Haubner, R., Stelzer, N., Effect of temperature, time and particle size of Ti precursor on hydrothermal synthesis of barium titanate., Materials Science and Engineering B, Vol.152, No. 1-3, Aug. 2008, pp. 60–65.
Ohara, S., Kondo, A., Shimoda, H., Sato, K., Abe, H., Naito, M., Rapid Mechanochemical synthesis of fine barium titanate nanoparticles., Materials Letters, Vol. 62, No. 17-18, Jun. 2008, pp. 2957-2959.
Shih, W.Y., Shih, W.-H., Aksay, I.A., Size dependence of the ferroelectric transition of small BaTiO3 particles: effect of depolarization., Physics Review B, Vol. 50, No. 21, Dec. 1994, pp. 15575–15585.
Vinothini, V., Paramanand, S., Balasubramanian, M., Synthesis of barium titanate nanopowder using polymeric precursor method., Ceramics International, Vol. 32, No. 2, Mar. 2005, pp. 99–103.
Wang, X., Lee, B.I., Hu, M., Payzant, E.A., Blom, D.A., Nanocrystalline BaTiO3 powder via a sol process ambient conditions., Journal of the European Ceramic Society, Vol. 26, No. 12, May. 2006, pp. 2319–2326.
Wegmanna, M., Brönnimann, R., Clemens, F., Graule, T., Barium titanate-based PTCR thermistor fibers: Processing and properties., Sensors and Actuators A, Vol. 135, No. 2, Apr., 2007, pp. 394–404.
Wegmann, M., Clemens, F., Hendry, A., Graule, T., Dispersion of lanthanoid-coated barium titanate in a paraffin-based extrusion binder system., Ceramics International, Vol. 32, No. 2, May. 2005, pp. 147-156.
Zhou, D., Chen, Y., Zhang, D., Liu, H., Hu, Y., Gong, S., Fabrication and characterization of the multilayered PTCR ceramic thermistors by slip casting., Sensors and Actuators A, Vol. 116, No. 3, Oct., 2004, pp. 450–454.
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