Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
Stabilizing effect of the carbon shell on phase transformation of the nanocrystalline alumina particles. / Yakovlev, Ilya V.; Volodin, Alexander M.; Zaikovskii, Vladimir I. и др.
в: Ceramics International, Том 44, № 5, 01.04.2018, стр. 4801-4806.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
}
TY - JOUR
T1 - Stabilizing effect of the carbon shell on phase transformation of the nanocrystalline alumina particles
AU - Yakovlev, Ilya V.
AU - Volodin, Alexander M.
AU - Zaikovskii, Vladimir I.
AU - Stoyanovskii, Vladimir O.
AU - Lapina, Olga B.
AU - Vedyagin, Aleksey A.
N1 - Publisher Copyright: © 2017 Elsevier Ltd and Techna Group S.r.l.
PY - 2018/4/1
Y1 - 2018/4/1
N2 - Intensive phase transformations of alumina are known to occur at temperatures above 1000 °C. In the present work, high temperature behaviour of pure Al2O3 and the carbon coated Al2O3@C sample with core-shell structure was comparatively studied using low-temperature nitrogen adsorption, transmission electron microscopy, powder X-ray diffraction (XRD) analysis and solid-state nuclear magnetic resonance (NMR). The solid-state NMR 27Al method has allowed us to identify and estimate the concentration of all phases appeared during the transformation of pseudoboehmite γ-Al2O3 into corundum α-Al2O3. The data obtained correlate well with the results of XRD analysis and low-temperature nitrogen adsorption. It is shown that the deposition of carbon coating with formation of core-shell Al2O3@C system stabilizes the size of oxide core and prevents the formation of corundum phase until the temperatures of 1350–1400 °C, which are close to the temperature of carbothermal reduction of alumina. The stabilization of the size of the oxide core nanoparticles was considered as a main factor preventing the formation of corundum phase at high temperatures. At the same time, the carbon coating does not affect the phase transformation of γ-Al2O3 to δ-Al2O3.
AB - Intensive phase transformations of alumina are known to occur at temperatures above 1000 °C. In the present work, high temperature behaviour of pure Al2O3 and the carbon coated Al2O3@C sample with core-shell structure was comparatively studied using low-temperature nitrogen adsorption, transmission electron microscopy, powder X-ray diffraction (XRD) analysis and solid-state nuclear magnetic resonance (NMR). The solid-state NMR 27Al method has allowed us to identify and estimate the concentration of all phases appeared during the transformation of pseudoboehmite γ-Al2O3 into corundum α-Al2O3. The data obtained correlate well with the results of XRD analysis and low-temperature nitrogen adsorption. It is shown that the deposition of carbon coating with formation of core-shell Al2O3@C system stabilizes the size of oxide core and prevents the formation of corundum phase until the temperatures of 1350–1400 °C, which are close to the temperature of carbothermal reduction of alumina. The stabilization of the size of the oxide core nanoparticles was considered as a main factor preventing the formation of corundum phase at high temperatures. At the same time, the carbon coating does not affect the phase transformation of γ-Al2O3 to δ-Al2O3.
KW - Alumina
KW - Carbon coating
KW - Core-shell structure
KW - Phase transformations
KW - Solid-state NMR
KW - Stabilization effect
KW - SOLID-STATE NMR
KW - SURFACE-AREA
KW - ADSORPTION
KW - GAMMA-ALUMINA
KW - CO OXIDATION
KW - METAL
KW - GAMMA-AL2O3
KW - SPECTRA
KW - C12A7
KW - CATALYSTS
UR - http://www.scopus.com/inward/record.url?scp=85039045644&partnerID=8YFLogxK
U2 - 10.1016/j.ceramint.2017.12.066
DO - 10.1016/j.ceramint.2017.12.066
M3 - Article
AN - SCOPUS:85039045644
VL - 44
SP - 4801
EP - 4806
JO - Ceramics International
JF - Ceramics International
SN - 0272-8842
IS - 5
ER -
ID: 9643010