Influence of anodizing conditions on generation of internal cracks in anodic porous tin oxide films grown in NaOH electrolyte
| Autor: | Dominika Gilek, Magdalena Dziurka, Grzegorz D. Sulka, Magdalena Gurgul, Marlena Nowak, Karolina Gawlak, Leszek Zaraska |
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| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Materials science
Anodizing Nanoporous Oxide General Physics and Astronomy 02 engineering and technology Surfaces and Interfaces General Chemistry Electrolyte equipment and supplies 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics Tin oxide 01 natural sciences 0104 chemical sciences Surfaces Coatings and Films chemistry.chemical_compound chemistry Chemical engineering 0210 nano-technology Porosity Layer (electronics) FOIL method |
| Popis: | Nanoporous tin oxide layers were synthesized via simple one-step anodic oxidation of a low-purity Sn foil (98.8%) in sodium hydroxide electrolyte. The process of pore formation at the early stage of anodization was discussed on the basis of concepts of oxygen bubble mould effect and viscous flow of oxide. The effect of anodizing conditions on the generation of internal cracks and fractures within the anodic film was investigated in detail. It was confirmed that crack-free tin oxide films can be obtained if the anodization is carried out at the potential of 4 V independently of the electrolyte concentration. On the other hand, the porous anodic film with a totally stacked internal morphology is obtained at the potential of 5 V in 0.1 M NaOH electrolyte. The generation of internal cracks and voids can be attributed to a much lower surface porosity and local trapping of O2 inside the pores of the oxide layer. However, increasing electrolyte concentration allows for obtaining less cracked porous films due to effective and uniform liberation of oxygen bubbles from the channels through completely open pore mouths. Furthermore, it was confirmed that uniformity of the anodic tin oxide layers can be significantly improved by vigorous electrolyte stirring. Finally, we observed that the addition of ethanol to the electrolyte can reduce anodic current density and the oxide growth rate. In consequence, less cracked anodic film can be formed even at the potential of 6 V. The generation of oxygen at the pore bottoms, together with the open pore mouths were found to be critical factors responsible for the anodic formation of crack-free porous tin oxide films. |
| Databáze: | OpenAIRE |
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