| Texto completo | |
| Autor(es): |
Rodrigues, Lorena Raphael
;
dos Santos, Gisele Guimaraes
;
Acosta, Maria Helena Ramirez
;
Koike, Akio
;
Akiba, Shusaku
;
Sawamura, Shigeki
;
Yoshida, Satoshi
;
Mastelaro, Valmor Roberto
;
Nascimento, Otaciro Rangel
;
Zanotto, Edgar Dutra
Número total de Autores: 10
|
| Tipo de documento: | Artigo Científico |
| Fonte: | Crystal Growth & Design; v. N/A, p. 11-pg., 2024-11-20. |
| Resumo | |
Transparent and hard ZnO-Al2O3-SiO2 (ZAS) glass-ceramics (GCs) are desirable for various applications. However, TiO2, an effective nucleating agent for this system, can introduce an unwanted yellow coloration. This study explores the effect of partially replacing TiO2 with ZrO2 on the crystallization pathways, color, transparency, and hardness of ZAS glasses and corresponding GCs, by evaluating compositions containing a constant content (4.5 mol %) of the referred nucleating agents. Optical transmittance showed that all glasses and GCs prepared were transparent in the visible range. However, they presented a yellowish hue that faded as the ZrO2/TiO2 ratio increased, as indicated by the CIELab analyses. One possible source of such coloration is the presence of iron ions in different oxidation states such as Fe2+ and Fe3+, this last detected by Electron Paramagnetic Resonance measurements in all the glasses. The samples' color is also likely affected by the Ti4+-O2- charge transfer mechanism. Concerning the mechanical performance, all GCs present similar hardness, which is a consequence of the slight variation in the crystallization kinetics with the varying ZrO2/TiO2 ratio. Therefore, the partial replacement of TiO2 with ZrO2 enables the preparation of glasses and GCs with a lighter coloration, without impairing their hardness. (AU) | |
| Processo FAPESP: | 13/07793-6 - CEPIV - Centro de Ensino, Pesquisa e Inovação em Vidros |
| Beneficiário: | Edgar Dutra Zanotto |
| Modalidade de apoio: | Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs |