resumo
We report on the role of Al(2)O(3) and K(2)O on crystallization in glasses featuring a SiO(2)/Li(2)O ratio (3.13 to 4.88) far beyond that of lithium disilicate (LD, Li(2)Si(2)O(5)) stoichiometry. Glasses in both bulk and frit form were produced by the conventional melt-quenching technique. Scanning electron microscopy analysis revealed surface nucleation as the dominant crystallization mechanism in glass-ceramics (GCs) derived from bulk glasses richer in Al(2)O(3) and K(2)O in the temperature range 800 degrees-900 degrees C and dendritic skeletal surface growth of lithium metasilicate crystalline phase (LS,Li(2)SiO(3)). The glasses with lower amounts of Al(2)O(3) and K(2)O showed an intermediate type of crystallization mechanism (simultaneous surface and volume nucleation) resulting in the preferential formation of Li(2)Si(2)O(5). The formation of LD GCs by sintering and the crystallization of glass-powder frits seems to occur via the precursor phase of LS, resulting in high-strength materials.
palavras-chave
LITHIUM DISILICATE GLASS; CRYSTAL NUCLEATION; SILICATE-GLASSES; MICROSTRUCTURE; SYSTEM; STRENGTH
categoria
Materials Science
autores
Fernandes, HR; Tulyaganov, DU; Goel, IK; Ferreira, JMF
nossos autores
Hugo Alexandre Gonçalves da Rocha Fernandes
Investigador Júnior
José Maria da Fonte Ferreira
Professor(a) Jubilado(a)Grupos
G3 - Materiais Eletroquímicos, Interfaces e Revestimentos
G5 - Materiais Biomiméticos, Biológicos e Vivos
agradecimentos
The first author is grateful for the financial support of CICECO and for the P. h. D grant from the University of Aveiro, Portugal.