Formation and crystallization of zinc borosilicate glasses: Influence of the ZnO/B2O3 ratio
| Autor: | J. P B Veiga, Regina da Conceição Corredeira Monteiro, A. T G Kullberg, Maria Margarida Rolim Augusto Lima, Andreia A. S. Lopes |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Materials science
Willemite Analytical chemistry chemistry.chemical_element Mineralogy 02 engineering and technology Zinc engineering.material Porous glass 01 natural sciences law.invention chemistry.chemical_compound law Differential thermal analysis 0103 physical sciences Materials Chemistry Crystallization 010302 applied physics Zinc borate Borosilicate glass 021001 nanoscience & nanotechnology Condensed Matter Physics Electronic Optical and Magnetic Materials chemistry Ceramics and Composites engineering 0210 nano-technology Glass transition |
| Zdroj: | Journal of Non-Crystalline Solids. 441:79-85 |
| ISSN: | 0022-3093 |
| Popis: | Different glasses based on the ZnO–B 2 O 3 –SiO 2 system, with a ZnO content ≥ 60 mol% and a fixed SiO 2 content (20 mol%), were synthesised using a melt-quenching method. Glass samples with zinc oxide concentrations as high as 65 mol% were prepared successfully without deteriorating the glass-forming ability. The glass samples were submitted to controlled heat-treatments, and the effect of the ZnO/B 2 O 3 molar ratio on the formation of crystalline phases within the glass matrix was investigated by means of differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). DTA results indicated that the glass transition and the onset crystallization temperatures of the studied glasses tended to increase with the increment on the ZnO/B 2 O 3 ratio. XRD data showed that the zinc binary crystalline phases, willemite (Zn 2 SiO 4 ), a zinc orthosilicate, and zinc borate (Zn 3 B 2 O 6 ) could be present in the crystallized glasses, depending on the heat-treatment conditions. The formation of willemite was promoted by an increasing ZnO/B 2 O 3 ratio. Microstructural observations performed by SEM indicated that under controlled experimental parameters (glass composition, heat-treatment temperature and time) the precipitation of nanocrystals within the glass matrix can be achieved, resulting in transparent and translucent willemite glass-ceramics. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect