Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
Annealing induced structural and phase transitions in anodic aluminum oxide prepared in oxalic acid electrolyte. / Roslyakov, I. V.; Kolesnik, I. V.; Levin, E. E. и др.
в: Surface and Coatings Technology, Том 381, 125159, 15.01.2020.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
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TY - JOUR
T1 - Annealing induced structural and phase transitions in anodic aluminum oxide prepared in oxalic acid electrolyte
AU - Roslyakov, I. V.
AU - Kolesnik, I. V.
AU - Levin, E. E.
AU - Katorova, N. S.
AU - Pestrikov, P. P.
AU - Kardash, T. Yu
AU - Solovyov, L. A.
AU - Napolskii, K. S.
PY - 2020/1/15
Y1 - 2020/1/15
N2 - Anodic aluminum oxide (AAO) films with uniform cylindrical pores are widely used as templates and membranes. The annealing of initially amorphous AAO enhances its chemical stability, but simultaneously changes its morphology and phase composition. Here we study the effect of annealing in the temperature range up to 1150 °C on structural and phase transitions in porous AAO films prepared by Al anodization in oxalic acid. Full-profile analysis of high-resolution X-ray diffraction patterns using the Rietveld method reveals the sequence of phase transformations (amorphous alumina → a mixture of γ-Al2O3 and θ-Al2O3 → a mixture of γ-Al2O3, δ-Al2O3, and θ-Al2O3 → α-Al2O3) and is used for quantitative phase analysis. Decomposition of oxalate-impurities, induced by the AAO crystallization, is studied using combined Fourier-transform infrared spectroscopy and thermogravimetry analysis. The removal of impurities results in the formation of mesopores in the AAO cell walls with a consequence increase in the specific surface area up to 80 m2·g− 1. The apparent activation energies of the removal of water (~35 kJ·mol− 1) and of the decomposition of carbon-containing impurities (~350 kJ·mol− 1) are calculated. Morphology-dependent kinetics of the impurities removal is described in the framework of the limited mass-transport of oxalate decomposition products through the cell walls.
AB - Anodic aluminum oxide (AAO) films with uniform cylindrical pores are widely used as templates and membranes. The annealing of initially amorphous AAO enhances its chemical stability, but simultaneously changes its morphology and phase composition. Here we study the effect of annealing in the temperature range up to 1150 °C on structural and phase transitions in porous AAO films prepared by Al anodization in oxalic acid. Full-profile analysis of high-resolution X-ray diffraction patterns using the Rietveld method reveals the sequence of phase transformations (amorphous alumina → a mixture of γ-Al2O3 and θ-Al2O3 → a mixture of γ-Al2O3, δ-Al2O3, and θ-Al2O3 → α-Al2O3) and is used for quantitative phase analysis. Decomposition of oxalate-impurities, induced by the AAO crystallization, is studied using combined Fourier-transform infrared spectroscopy and thermogravimetry analysis. The removal of impurities results in the formation of mesopores in the AAO cell walls with a consequence increase in the specific surface area up to 80 m2·g− 1. The apparent activation energies of the removal of water (~35 kJ·mol− 1) and of the decomposition of carbon-containing impurities (~350 kJ·mol− 1) are calculated. Morphology-dependent kinetics of the impurities removal is described in the framework of the limited mass-transport of oxalate decomposition products through the cell walls.
KW - Annealing
KW - Anodic aluminum oxide
KW - Kinetic analysis
KW - Quantitative phase composition
KW - Rietveld method
KW - Specific surface area
KW - GAMMA
KW - MEMBRANES
KW - THERMAL-DECOMPOSITION
KW - DESORPTION
KW - ANODIZATION
KW - TEMPERATURE
KW - CATALYTIC-PROPERTIES
KW - KINETICS
KW - PROFILE REFINEMENT
KW - FABRICATION
UR - http://www.scopus.com/inward/record.url?scp=85075858100&partnerID=8YFLogxK
U2 - 10.1016/j.surfcoat.2019.125159
DO - 10.1016/j.surfcoat.2019.125159
M3 - Article
AN - SCOPUS:85075858100
VL - 381
JO - Surface and Coatings Technology
JF - Surface and Coatings Technology
SN - 0257-8972
M1 - 125159
ER -
ID: 22600442