Thermal evolution of porous anodic aluminas: a comparative study
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| Format: | Artículo científico |
| Language: | en |
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Sociedad Mexicana de Física A.C.
2005
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| _version_ | 1876466524536963072 |
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| author | M.E. Mata-Zamora |
| author_facet | M.E. Mata-Zamora |
| contents | Thermal evolution of porous anodic aluminas: a comparative study M.E. Mata-Zamora J.M. Saniger Física, Astronomía y Matemáticas nanostructures thermal analysis Anodic porous alumina The comparative study presented in this work concerning the thermal evolution of sulfuric, oxalic and phosphoric porous anodic aluminas,points out some differences among their physico-chemical and structural properties which were not previously reported. Empirical formulascalculated from the thermal analysis of all the anodic aluminas under study indicate that sulfuric aluminas have a significant higher contentof dopant anionic species, oxygen excess, and hydroxyl groups than the oxalic and phosphoric aluminas, indicating that porous sulfuricanodic aluminas should have a higher structural disorder and hydrophilic character than its counterparts. For all samples, transition aluminaphases are formed around 900±C and ®-alumina above 1200±C, but in these transformations sulfuric and oxalic aluminas follow a differentevolution from phosphoric alumina. In the former case, the formation of transition aluminas occurs with the almost simultaneous thermaldecomposition of sulfates and oxalates and finally a pure ®-Al2O3 phase is formed; while for the phosphoric alumina, the phosphate doesnot decompose even at 1400±C, when a ®-Al2O3phase unpurified with AlPO4 is observed. Infrared spectroscopy studies show that thecoordination modes of the sulfuric and oxalic dopant species start to change well before their thermal decomposition, while, in the case ofthe phosphoric alumina, aluminum phosphate starts to form at the same time as the transition alumina phases. 2005 artículo científico 0035-001X https://www.redalyc.org/articulo.oa?id=57064110 https://www.redalyc.org/journal/570/57064110/ https://www.redalyc.org/journal/570/57064110/html/ https://www.redalyc.org/journal/570/57064110/57064110.epub https://www.redalyc.org/journal/570/57064110/movil en http://www.redalyc.org/revista.oa?id=570 Revista Mexicana de Física application/pdf Sociedad Mexicana de Física A.C. Revista Mexicana de Física (México) Num.5 Vol.51 |
| format | Artículo científico |
| id | redalyc_57064110 |
| institution | Redalyc |
| language | en |
| publishDate | 2005 |
| publisher | Sociedad Mexicana de Física A.C. |
| spellingShingle | Thermal evolution of porous anodic aluminas: a comparative study M.E. Mata-Zamora Física, Astronomía y Matemáticas nanostructures thermal analysis Anodic porous alumina Thermal evolution of porous anodic aluminas: a comparative study M.E. Mata-Zamora J.M. Saniger Física, Astronomía y Matemáticas nanostructures thermal analysis Anodic porous alumina The comparative study presented in this work concerning the thermal evolution of sulfuric, oxalic and phosphoric porous anodic aluminas,points out some differences among their physico-chemical and structural properties which were not previously reported. Empirical formulascalculated from the thermal analysis of all the anodic aluminas under study indicate that sulfuric aluminas have a significant higher contentof dopant anionic species, oxygen excess, and hydroxyl groups than the oxalic and phosphoric aluminas, indicating that porous sulfuricanodic aluminas should have a higher structural disorder and hydrophilic character than its counterparts. For all samples, transition aluminaphases are formed around 900±C and ®-alumina above 1200±C, but in these transformations sulfuric and oxalic aluminas follow a differentevolution from phosphoric alumina. In the former case, the formation of transition aluminas occurs with the almost simultaneous thermaldecomposition of sulfates and oxalates and finally a pure ®-Al2O3 phase is formed; while for the phosphoric alumina, the phosphate doesnot decompose even at 1400±C, when a ®-Al2O3phase unpurified with AlPO4 is observed. Infrared spectroscopy studies show that thecoordination modes of the sulfuric and oxalic dopant species start to change well before their thermal decomposition, while, in the case ofthe phosphoric alumina, aluminum phosphate starts to form at the same time as the transition alumina phases. 2005 artículo científico 0035-001X https://www.redalyc.org/articulo.oa?id=57064110 https://www.redalyc.org/journal/570/57064110/ https://www.redalyc.org/journal/570/57064110/html/ https://www.redalyc.org/journal/570/57064110/57064110.epub https://www.redalyc.org/journal/570/57064110/movil en http://www.redalyc.org/revista.oa?id=570 Revista Mexicana de Física application/pdf Sociedad Mexicana de Física A.C. Revista Mexicana de Física (México) Num.5 Vol.51 |
| title | Thermal evolution of porous anodic aluminas: a comparative study |
| topic | Física, Astronomía y Matemáticas nanostructures thermal analysis Anodic porous alumina |
| url | https://www.redalyc.org/articulo.oa?id=57064110 https://www.redalyc.org/journal/570/57064110/ https://www.redalyc.org/journal/570/57064110/html/ https://www.redalyc.org/journal/570/57064110/57064110.epub https://www.redalyc.org/journal/570/57064110/movil |