resumo
Crystalline (Ba (x) Sr(1-x) TiO(3)) (x = 0, 0.5 0.8 and 1) nanosized powders is synthesized by an ambient pressure and low temperature sol process. The influence of Ba/Sr ratio, temperature, pH and reflux time on the phase formation and morphology of (Ba (x) Sr(1-x) TiO(3)) powders is assessed. Amorphous powders are obtained at temperatures lower than 90 A degrees C and crystalline, stoichiometric and monophasic Ba (x) Sr(1-x) TiO(3) (x = 0, 0.5, 0.8 and 1), powders are synthesized at 95 A degrees C. Under identical preparation conditions, the powder particle size depends on the Ba/Sr ratio. High values of pH decrease the particle size. For reflux times lower than 2 h the particle size decreases with increasing of reflux time, reflecting the dominant role of the nucleation step. For reflux times higher than 2 h the growth step becomes dominant and the particle size increases with the increase of reflux time.
palavras-chave
LARGE-SCALE SYNTHESIS; HYDROTHERMAL SYNTHESIS; PARTICLE-SIZE; DIELECTRIC-PROPERTIES; BATIO3; PHASE; MORPHOLOGY; SRTIO3
categoria
Chemistry; Science & Technology - Other Topics; Materials Science
autores
Wu, AY; Vilarinho, PM; Gonzalez, M
nossos autores
Paula Maria Lousada Silveirinha Vilarinho
Vice-DiretorProjectos
Novos filmes dielEctricos de BST para memorias dinamicas de acesso aleatoriode elevada densidade (POCTI/CTM/47285/2002)
Functionalised Advanced Materials and Engineering of Hybrids and Ceramics - FAME (FAME)
agradecimentos
Financial support from FCT (POCTI/CTM/47285/2002), FEDER and the European Network of Excellence, FAME under the contract FP6-500159-1 is acknowledged.