TY - JOUR
T1 - Anodizing of Aluminum Coated with Zirconium Oxide by a Sol-Gel Process I. Effect of Heat Treatment on the Formation of the Anodic Oxide Film
AU - Watanabe, Keiji
AU - Sakairi, Masatoshi
AU - Takahashi, Hideaki
AU - Takahiro, Katsumi
AU - Nagata, Shinji
AU - Hirai, Shinji
N1 - Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 1999/12
Y1 - 1999/12
N2 - Aluminum specimens were covered with zirconium oxide films by sol-gel dip coating at Th, = 573 and 873 K, and then anodized galvanostatically in a neutral borate solution. The time-variation in the anode potential during anodizing was monitored, and the structure of anodic oxide films was examined by TEM, EDX, and RBS. During anodizing of specimens coated with ZrO2 at Th = 573 K, the anode potential, Ea, increased linearly with time, ta, and the slope of the Ea vs. ta curve increased with increasing the number of sol-gel coatings. An anodic oxide film, which was composed of an inner Al2O3 layer and an outer Al-Zr composite oxide layer, grew at the interface between the ZrO2 layer and metal substrate during anodizing. The thickness of the inner layer increased with ta, whereas the thickness of the outer layer showed a maximum before decreasing with ta. Specimens coated with ZrO2 at Th=873 K showed Ea -jumps between 40 and 110 V just after the commencement of anodizing, and then a slow Ea increase. An anodic oxide film composed of a single layer of A12O3, formed beneath the ZrO2 layer during anodizing. The mechanism of the formation of anodic oxide films on aluminum coated with ZrO2 films is discussed in terms of ion transport across the anodic oxide film.
AB - Aluminum specimens were covered with zirconium oxide films by sol-gel dip coating at Th, = 573 and 873 K, and then anodized galvanostatically in a neutral borate solution. The time-variation in the anode potential during anodizing was monitored, and the structure of anodic oxide films was examined by TEM, EDX, and RBS. During anodizing of specimens coated with ZrO2 at Th = 573 K, the anode potential, Ea, increased linearly with time, ta, and the slope of the Ea vs. ta curve increased with increasing the number of sol-gel coatings. An anodic oxide film, which was composed of an inner Al2O3 layer and an outer Al-Zr composite oxide layer, grew at the interface between the ZrO2 layer and metal substrate during anodizing. The thickness of the inner layer increased with ta, whereas the thickness of the outer layer showed a maximum before decreasing with ta. Specimens coated with ZrO2 at Th=873 K showed Ea -jumps between 40 and 110 V just after the commencement of anodizing, and then a slow Ea increase. An anodic oxide film composed of a single layer of A12O3, formed beneath the ZrO2 layer during anodizing. The mechanism of the formation of anodic oxide films on aluminum coated with ZrO2 films is discussed in terms of ion transport across the anodic oxide film.
KW - Anodizing of Aluminum
KW - Composite Oxide Film
KW - Sol-gel Coating
KW - Zirconium Oxide
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U2 - 10.5796/electrochemistry.67.1243
DO - 10.5796/electrochemistry.67.1243
M3 - Article
AN - SCOPUS:0004538954
VL - 67
SP - 1243
EP - 1248
JO - Electrochemistry
JF - Electrochemistry
SN - 1344-3542
IS - 12
ER -