Crystallization, mechanical, and optical properties of transparent, nanocrystalline gahnite glass-ceramics
| Autor: | Alisson Mendes Rodrigues, Ricardo Felipe Lancelotti, Andrea S. S. de Camargo, Mohammad Reza Dousti, Shiv Prakash Singh, Claudio José Magon, I. D. A. Silva, Atiar Rahaman Molla, Edgar Dutra Zanotto, Ana Candida Martins Rodrigues |
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| Rok vydání: | 2017 |
| Předmět: |
010302 applied physics
Materials science Absorption spectroscopy Precipitation (chemistry) Spinel Infrared spectroscopy 02 engineering and technology engineering.material 021001 nanoscience & nanotechnology MATERIAIS ÓPTICOS 01 natural sciences Nanocrystalline material law.invention Chemical engineering law Phase (matter) visual_art 0103 physical sciences Materials Chemistry Ceramics and Composites visual_art.visual_art_medium engineering Ceramic Crystallization 0210 nano-technology |
| Zdroj: | Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) Universidade de São Paulo (USP) instacron:USP |
| Popis: | This paper describes the preparation of a transparent glass-ceramic from the SiO2-K2O-ZnO-Al2O3-TiO2 system containing a single crystalline phase, gahnite (ZnAl2O4). TiO2 was used as a nucleating agent for the heat-induced precipitation of gahnite crystals of 5-10 nm. The evolution of the ZnAl2O4 spinel structure through the gradual formation of Al-O bonds was examined by infrared spectroscopy. The dark brown color of the transparent precursor glass and glass-ceramic was eliminated using CeO2. The increase in transparency of the CeO2-doped glass and glass-ceramics was demonstrated by UV-visible absorption spectroscopy. EPR measurements confirmed the presence of Ce3+ ions, indicating that CeO2 was effective in eliminating the brown color introduced by Ti3+ ions via oxidation to Ti+4. The hardness of the glass-ceramic was 30% higher than that of the as-prepared glasses. This work offers key guidelines to produce hard, transparent glass-ceramics which may be potential candidates for a variety of technological applications, such as armor and display panels. |
| Databáze: | OpenAIRE |
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