Crystallization Kinetics and Structure Refinement of CaTiO3 Glass-Ceramics Produced by Melt-Quenching Technique

• Autor(a) principal: Silveira,Wagner da
• Data de Publicação: 2021
• Outros Autores: Macedo,Wagner Costa, Santos,Gleyson Tadeu de Almeida, Santos,Luis Fernando dos, Fernandes,José Diego, Rocha,Kleper de Oliveira, Teixeira,Silvio Rainho
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Materials research (São Carlos. Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392021000700213
• topic: Glass-ceramics; Melt-quenching Technique; CaTiO3; Rietveld Method; Kissinger Method

Glass-ceramic materials were obtained by heat treatment (960 ºC for 2, 4, and 6 hs) of glasses with CaCO3 47.50 wt%-TiO2 23.75 wt%-SiO2 23.75-Al2O3 5.00 wt% formulation produced by the melt-quenching technique (melting at 1650 ºC and subsequent annealing at 650 ºC). The materials’ structural characterization and crystallization kinetics (Kissinger method) indicate the presence of CaTiO3, CaSiO3, and CaTiSiO5 crystalline phases with activation energies 217, 281, and 446 kJ/mol, respectively. The structure refinement (Rietveld method) suggests metastability for the CaSiO3 and CaTiSiO5 phases as a function of the heat treatment time. The increase in time favors CaTiO3 crystallization, from 62.97 wt%, in the 2 hs treated sample, to 79.21 wt%, in the 6 hs treated sample. EDS and microstructure analyses confirm the glass-ceramic production and indicate segregation of the CaTiO3 phase for longer heat treatment times.