日本金属学会誌

J. Japan Inst. Met. Mater, Vol. 80, No. 2 (2016),
pp. 151-156

Electrodeposition of Zn-Zr Oxide Composite from Dispersed Particles-Free Solution

Hiroaki Nakano1, Yosuke Hara2, Satoshi Oue1 and Shigeo Kobayashi3

1Department of Materials Science and Engineering, Kyushu University, Fukuoka 819-0395
2Department of Materials Process Engineering, Kyushu University, Fukuoka 819-0395
3Department of Applied Chemistry and Biochemistry, Kyushu Sangyo University, Fukuoka 813-8503

Abstract:

Electrodeposition of Zn-Zr oxide composite was examined from an unagitated sulfate solution containing Zn2+ and Zr ions at pH 1 to 2 and 313 K under galvanostatic conditions. Zr content in deposits was higher in pH 2 than that in pH 1, and decreased for the moment with increasing current density, but the further increase in current density brought about the increase in Zr content in deposits. This increase in Zr content in deposits is attributed to the acceleration of the hydrolysis of Zr ions by means of an increase in hydrogen evolution in the cathode layer. In solution containing Zr ions, Zn deposition was significantly polarized due to the film resistance of Zr oxide formed by the hydrolysis of Zr ions. The pH in the vicinity of the cathode, as measured by an Sb microelectrode, was approximately 2.2, which is close to the critical pH for the formation of ZrO2. SEM and EDX point analysis of deposits revealed that the granular Zr oxide deposited at the surface of Zn platelet crystals and at the void between the Zn platelet crystals. It was found from the polarization curves in 3 mass% NaCl solution that the corrosion potential of deposited Zn-1.1 mass% Zr oxide films was more noble than that of pure Zn, and the corrosion current density of Zn-1.1 mass% Zr oxide films was lower than that of pure Zn.

[doi:10.2320/jinstmet.J2015038]


(Received 2015/6/8)

Keywords:

electrodeposition, zinc, zirconium oxide, polarization curve, corrosion potential, corrosion current density, antimony microelectrode, oxide composite, hydrolysis


PDF(Free)PDF (Free)     Table of ContentsTable of Contents

Please do not copy without permission.