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The surface condition effect of Cu2O flower/grass-like nanoarchitectures grown on Cu foil and Cu film.

Hu L, Ju Y, Hosoi A, Tang Y - Nanoscale Res Lett (2013)

Bottom Line: The FGLNAs are approximately 3.5 to 12 μm in size, and their petals are approximately 50 to 950 nm in width.The high compressive stress caused by a large oxide volume in the Cu2O layer on the specimen surface played an important role in the growth of FGLNAs.PACS: 81.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Mechanical Science and Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan. ju@mech.Nagoya-u.ac.jp.

ABSTRACT
Cu2O flower/grass-like nanoarchitectures (FGLNAs) were fabricated directly on two category specimens of Cu foils and Cu film using thermal oxidation method. The FGLNAs are approximately 3.5 to 12 μm in size, and their petals are approximately 50 to 950 nm in width. The high compressive stress caused by a large oxide volume in the Cu2O layer on the specimen surface played an important role in the growth of FGLNAs. The effects of surface conditions, such as the surface stresses, grain size, and surface roughness of Cu foil and Cu film specimens, on the FGLNA growth were discussed in detail. PACS: 81. Materials science; 81.07.-b Nanoscale materials and structures: fabrication and characterization; 81.16.Hc Catalytic methods.

No MeSH data available.


Related in: MedlinePlus

Illustration of stress generation mechanism due to the volume expansion of oxide layer.
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Figure 5: Illustration of stress generation mechanism due to the volume expansion of oxide layer.

Mentions: When the specimens were heated in air, a Cu2O oxide layer formed on the surface of the specimens. As shown in Figure 5, compressive stress occurred in the oxide layer due to the oxide volume expansion. Meanwhile, as a reactive force, tensile stress occurred in the Cu substrate at the interface of Cu2O/Cu, which leads to the generation of vertical gradient stress (VGS) in the thickness direction of the specimen. Therefore, Cu atoms diffuse from the center of the Cu substrate to the interface between the oxide layer and the substrate due to the VGS. In the initial stage, since the temperature is relatively low (120°C and 240°C), the surface oxidation of the Cu foil/film is carried out under a low speed. The Cu2O layer that formed on the Cu foil/film is very thin, and the VGS is not large enough. Therefore, the diffused Cu atoms cannot penetrate the oxidation layer. However, with the participation of a catalyst and humidity, sufficient bivalent oxygen ions with two chemical bonds (BOICBs) were generated from the water vapors during the process of hydrogen absorption of the nickel catalyst, as indicated in Equation 1.


The surface condition effect of Cu2O flower/grass-like nanoarchitectures grown on Cu foil and Cu film.

Hu L, Ju Y, Hosoi A, Tang Y - Nanoscale Res Lett (2013)

Illustration of stress generation mechanism due to the volume expansion of oxide layer.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4231356&req=5

Figure 5: Illustration of stress generation mechanism due to the volume expansion of oxide layer.
Mentions: When the specimens were heated in air, a Cu2O oxide layer formed on the surface of the specimens. As shown in Figure 5, compressive stress occurred in the oxide layer due to the oxide volume expansion. Meanwhile, as a reactive force, tensile stress occurred in the Cu substrate at the interface of Cu2O/Cu, which leads to the generation of vertical gradient stress (VGS) in the thickness direction of the specimen. Therefore, Cu atoms diffuse from the center of the Cu substrate to the interface between the oxide layer and the substrate due to the VGS. In the initial stage, since the temperature is relatively low (120°C and 240°C), the surface oxidation of the Cu foil/film is carried out under a low speed. The Cu2O layer that formed on the Cu foil/film is very thin, and the VGS is not large enough. Therefore, the diffused Cu atoms cannot penetrate the oxidation layer. However, with the participation of a catalyst and humidity, sufficient bivalent oxygen ions with two chemical bonds (BOICBs) were generated from the water vapors during the process of hydrogen absorption of the nickel catalyst, as indicated in Equation 1.

Bottom Line: The FGLNAs are approximately 3.5 to 12 μm in size, and their petals are approximately 50 to 950 nm in width.The high compressive stress caused by a large oxide volume in the Cu2O layer on the specimen surface played an important role in the growth of FGLNAs.PACS: 81.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Mechanical Science and Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan. ju@mech.Nagoya-u.ac.jp.

ABSTRACT
Cu2O flower/grass-like nanoarchitectures (FGLNAs) were fabricated directly on two category specimens of Cu foils and Cu film using thermal oxidation method. The FGLNAs are approximately 3.5 to 12 μm in size, and their petals are approximately 50 to 950 nm in width. The high compressive stress caused by a large oxide volume in the Cu2O layer on the specimen surface played an important role in the growth of FGLNAs. The effects of surface conditions, such as the surface stresses, grain size, and surface roughness of Cu foil and Cu film specimens, on the FGLNA growth were discussed in detail. PACS: 81. Materials science; 81.07.-b Nanoscale materials and structures: fabrication and characterization; 81.16.Hc Catalytic methods.

No MeSH data available.


Related in: MedlinePlus