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High-temperature annealing of porous anodic aluminium oxide prepared in selenic acid electrolyteстатья Исследовательская статья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 8 апреля 2022 г.
- Авторы: Roslyakov I.V., Shirin N.A., Evdokimov P.V., Berekchiian M.V., Simonenko N.P., Lyskov N.V., Napolskii K.S.
- Журнал: Surface and Coatings Technology
- Том: 433
- Год издания: 2022
- Издательство: Elsevier BV
- Местоположение издательства: Netherlands
- Номер статьи: 128080
- DOI: 10.1016/j.surfcoat.2022.128080
- Аннотация: Selenic acid is a new inorganic electrolyte that provides porous anodic aluminium oxide (AAO) films with low porosity and high optical transparency. Here, the high-temperature behaviour of AAO obtained in a selenic acid electrolyte is reported for the first time. The crystallization of as-prepared amorphous AAO at about 800 °C is accompanied by the elimination of electrolyte impurities, an increase in pore diameter from 15 to 21 nm, and an increase in specific surface area to 55 m2·g−1 due to the mesopore formation inside the cell walls. The second crystallization stage at about 1150 °C results in the formation of coarse-grained corundum (α-Al2O3) films with a mean grain size of about 11 μm. Each of the grains consists of regularly arranged 27-nm-diameter pores, which are stable up to 1300 °C. AAO physicochemical properties depend on the annealing temperature. In particular, chemical stability is up to three orders of magnitude higher after two-step crystallization. Optical properties and thermal expansion of selenic-acid-made porous AAO films with different phase composition are quantified. The crystallization of as-prepared AAO to low-temperature Al2O3 polymorphs has a minor influence on optical transmittance and effective refractive index of porous alumina, whereas the coarse-grained structure of corundum causes an order of magnitude decrease in average transmittance in the visible region. The coefficient of thermal expansion increases by 25% to 8.5 × 10−6 K−1 for α-Al2O3 porous films compared to as-prepared AAO.
- Добавил в систему: Ширин Никита Александрович