resumo
This present article addresses the reactive behaviour of barium titanate (BaTiO3, hereafter referred to as BT) with water either in powder form or as bulk ceramics. Chemisorbing a suitable phosphate-based protective agent at the surface of BT particles prevented hydrolysis reactions and made aqueous processing of BT a safe and viable route. Highly concentrated (50 vol.%) fluid and long term stable suspensions could be easily prepared from surface treated BT particles, contrasting with the poor stability and high viscosity of slurries derived from the as received powders. For aqueous suspensions, the course of hydrolysis reactions was monitored through changes in pH and concentrations of leached ionic species along ageing time. For bulk ceramics, the extent of hydrolysis reactions was assessed through the microstructural changes occurred at polished surfaces without and with surface treatment, which have been kept in contact with water for a certain time period. (C) 2015 Elsevier Ltd. All rights reserved.
palavras-chave
BARIUM-TITANATE POWDERS; POLYMERIC STABILIZATION; AMMONIUM-SALT; SUSPENSIONS; DISPERSION; MEDIA; ACID; PH
categoria
Materials Science
autores
Olhero, SM; Kaushal, A; Ferreira, JMF
nossos autores
Ajay Kaushal
Bolseiro de pós-Doutoramento
José Maria da Fonte Ferreira
Professor(a) Jubilado(a)
Susana Maria Henriques Olhero
Professor AuxiliarProjectos
Development of microelectromechanical systems by gelcasting - GELMEMS (PTDC/CTM/099489/2008)
agradecimentos
The authors SM Olhero and Ajay Kaushal are thankful to the Foundation for Science and Technology of Portugal (FCT) for the postdoc fellowship grants SFRH/BPD/87486/2012 and SFRH/BPD/77598/2011, respectively. The financial support from FCT under the project PTDC/CTM/099489/2008, and the facilities from CICECO are also gratefully acknowledged.