Artículos de revistas
Estudo por espectroscopia micro-Raman dos mecanismos de separação de fase em vidros fosfatos de metais de transição
Micro-Raman spectroscopy studies of the phase separation mechanisms of transition-metal phosphate glasses
Registro en:
Química Nova. Sociedade Brasileira de Química, v. 32, n. 7, p. 1956-1960, 2009.
0100-4042
S0100-40422009000700045
10.1590/S0100-40422009000700045
Autor
Mazali, Italo Odone
Alves, Oswaldo Luiz
Gimenez, Iara de Fátima
Institución
Resumen
Glass-ceramics are prepared by controlled separation of crystal phases in glasses, leading to uniform and dense grain structures. On the other hand, chemical leaching of soluble crystal phases yields porous glass-ceramics with important applications. Here, glass/ceramic interfaces of niobo-, vanado- and titano-phosphate glasses were studied by micro-Raman spectroscopy, whose spatial resolution revealed the multiphase structures. Phase-separation mechanisms were also determined by this technique, revealing that interface composition remained unchanged as the crystallization front advanced for niobo- and vanadophosphate glasses (interface-controlled crystallization). For titanophosphate glasses, phase composition changed continuously with time up to the equilibrium composition, indicating a spinodal-type phase separation. 1956 1960 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)