abstract
This study reports on the fabrication of BST (Ba0.6Sr0.4TiO3)-based 3D microcomponents through an aqueous colloidal approach. The BST powder was synthesized by solid-state reaction assisted by thermal analysis and XRD diffraction. Well crystalline cubic BST single phase was obtained upon heat-treating the precursor powder mixture at 1200 degrees C-1250 degrees C. The reactivity of the BST powder toward water was evaluated by the changes in pH and concentration of leached ionic species along aging time. Hydrolysis reactions were suppressed by chemisorbing a suitable phosphate-based protective agent and enabled an excellent dispersion ability to be achieved. Aqueous suspensions with solids loadings as high as 50vol% that are stable against hydrolysis for several days could easily be prepared from the surface-treated BST powder in aqueous solutions of an epoxy resin. After adding a suitable hardener, the colloidal suspensions could easily be cast into soft silicon rubber molds to obtain homogeneous and high dense green BST bodies.
keywords
SOLID-SOLUTIONS; POLYMERIC STABILIZATION; MICROWAVE APPLICATIONS; DIELECTRIC-PROPERTIES; AMMONIUM-SALT; SPINEL POWDER; BATIO3; DISPERSION; MEDIA; DEPENDENCE
subject category
Materials Science
authors
Olhero, SM; Kaushal, A; Ferreira, JMF
our authors
Ajay Kaushal
Post-Doc Fellowship
José Maria da Fonte Ferreira
Retired Professor
Susana Maria Henriques Olhero
Assistant ProfessorProjects
Development of microelectromechanical systems by gelcasting - GELMEMS (PTDC/CTM/099489/2008)
acknowledgements
The authors are thankful to the Foundation for Science and Technology of Portugal (FCT) for the financial support under the project PTDC/CTM/099489/2008, and the post-doc grants of S.M. Olhero SFRH/BPD/87486/2012 and A. Kaushal (SFRH/BPD/77598/2011). The support from CICECO, University of Aveiro is also acknowledged. The support from Professor Tim Button/University of Birmingham as molds supplier is also gratefully acknowledged.