硫酸塩浴からのZn-Cr合金の電析過程 [in Japanese] Electrodeposition Process of Zn-Cr Alloys from Sulfate Baths [in Japanese]
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The electrodeposition of Zn-Cr alloys from sulfate baths was conducted to investigate the codeposition mechanism of Cr with Zn. Results are as follows:<br>(1) Cr was codeposited with Zn at high current densities in both polyethylene glycol (PEG)-free and PEG-containing baths. However, PEG made it possible to reduce Cr<sup>3+</sup> to metallic state and Cr existed in the form of Cr<sup>3+</sup> hydroxide in the deposits obtained in PEG-free bath.<br>(2) Partial polarization curves of Zn shifted when PEG was added to the baths.<br>(3) The pH in the cathode layer was found to rise from bulk pH 2.0 to about 4. Zn and Cr hydroxides seemed to form simultaneously in the cathode layer.<br>(4) It was estimated that alloys were electrodeposited from the composite Zn and Cr oxides formed due to the pH rise in the cathode layer and that the PEG acted as a polarizer to shift the cathode potential toward the reduction potential of Cr.
- Jitsumu Hyomen Gijutsu
Jitsumu Hyomen Gijutsu 47(10), 868-872, 1996-10
The Surface Finishing Society of Japan