著者

津留 壽昭 木村 哲二 乾 忠孝

出版者

The Surface Finishing Society of Japan

雑誌

金属表面技術 (ISSN:00260614)

巻号頁・発行日

vol.27, no.3, pp.130-134, 1976

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A study was made on electrodeposition of cobalt from cobalt ethylenediamine chelate solution for the purpose of investigating the stability of chelate on pH and the optimum condition in electrolysis. The results obtained were as follows: 1) Ethylenediamine (en) and cobalt ion (II) formed stable chelate compound of (Coen₃)²⁺ in a pH range 8.0-10. 2) Bright cobalt platings were obtained from chelate solutions of pH 3.0-5.0 by the addition of two addition agents, and cathodic current efficiency was found to be decreased. The optimum bath composition for bright cobalt plating was as follows: CoCl₂⋅6H₂O (CoSO₄⋅7H₂O) 0.05-0.20mol/<i>l</i> (0.1-0.3mol/<i>l</i>), en 0.15-0.60mol/<i>l</i> (0.3-0.9mol/<i>l</i>), HOCH₂C: CCH₂OH 0.05g/<i>l</i>, C₁₀H₆ (SO₃Na)₂⋅2H₂O 0.03g/<i>l</i>, pH 3.0-5.0, Temperature Room temperature, Cathodic current density 0.8-1.5A/dm². The cathodic current efficiency under the above condition was about 70-80%. 3) The cobalt deposits obtained from Co-en baths were of small grains in crystal structure, and the brightness apparently increased with increasing electrolysis time.

著者

津留 壽昭 木村 哲二 乾 忠孝

出版者

The Surface Finishing Society of Japan

雑誌

金属表面技術 (ISSN:00260614)

巻号頁・発行日

vol.27, no.2, pp.80-84, 1976

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The stability of electrolyte containing cadmium-ethylenediamine (en) chelate in various pH ranges has been investigated to determine the optimum condition for electrodeposition of cadmium. Cathodic polarization measurement was made in the above bath, and the cadmium deposits obtained under various conditions were examined by X-ray diffraction. The results obtained were as follows: 1) Cadmium (II) ions seemed to react with en to form a stable complex, and bright and smooth cadmium deposits on copper plates were obtained over the range of pH 9-12. 2) Complex ions were greatly affected by anion. Cadmium was not deposited from acidic baths containing a small amount of chloride ions and various precipitates such as Cd(en)_mCl₂(<i>m</i>=1-3), but was deposited from neutral and weak acidic baths. Cadmium-en complex was not formed, when pH-value was in acidic or strong alkaline ranges. In this case, en seemed to act merely as an addition agent upon electrolysis. 3) By the addition of gelatine in to the cadmium-en bath, adherent cadmium deposits having a fine grain (270-290Å) structure were obtained. It was shown by X-ray diffraction analysis that the orientation of the cadmium deposits was strong in (101), but weak in (102) and (103). 4) The optimum composition and operation condition of the bath were found to be Cd (CH₃COO)₂⋅2H₂O: 0.3-0.5mol/<i>l</i>, en: 1.2-2.0mol/<i>l</i>, gelatine: 0.5-1.0g/<i>l</i>, pH: 9-11, temperature: 20-50°C, current density: 1.0-2.5A/dm²; current efficiency was above 90%.

著者

津留 壽昭 木村 哲二 小林 繁夫 乾 忠孝

出版者

The Surface Finishing Society of Japan

雑誌

金属表面技術 (ISSN:00260614)

巻号頁・発行日

vol.27, no.5, pp.230-234, 1976

被引用文献数

3

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By using N, N-dimethylformamide(DMF), an aprotic polar solvent, the electrodeposition of lead from PbCl₂-DMF and Pb(NO₃)₂-DMF solutions was studied. The deposits of lead gave rise to the welldefined dendrites, when the electrolysis was carried out in higher concentration bath and at higher current densities, while at lower current densities (-3mA/cm²), the deposits became dark-gray and smooth. The dendrites of lead were of 2D [110], 3D [110] and 2D [100] types. The deposits from PbCl₂-DMF solutions were the isolated nuclei of the layer growth (hexagonal, tetragonal and trigonal deposits), when temperature was higher than 40°C. The deposits from Pb(NO₃)₂-DMF solutions were white powder when temperature was higher than 50°C, while at 100°C the dendrites were not observed. The X-ray analysis of the deposits of crystalline lead had well-defined diffraction patterns. By the addition of thiourea and 2-butyne-1, 4 diol to Pb(NO₃)₂-H₃BO₃-DMF baths, semi-bright and smooth lead deposits were obtained. They had fine grains in crystal structure and were found to have the strong preferred orientation of (220). The grain size of the deposit was 150-350Å. From these results the optimum condition for the electrolysis was as follows: Pb(NO₃)₂: 100g/<i>l</i>, H₃BO₃: 10g/<i>l</i>, (NH₂)₂CS: 4g/<i>l</i>, HOCH₂C≡CCH₂OH: 3g/<i>l</i>, temperature:room temperature, current density:0.5-1.0mA/cm², plating time: 60min, current efficiency: ca 50%.

著者

乾 忠孝

出版者

一般社団法人 表面技術協会

雑誌

金属表面技術 (ISSN:00260614)

巻号頁・発行日

vol.8, no.7, pp.224-228, 1957-11-30 (Released:2009-10-30)

参考文献数

1

被引用文献数

1

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The mechanism of tungsten plating was investigated and the following results were obtained.1) The decomposition potential of tungsten in Na2WO4 solution is more negative than that of hydrogen, and its accurate decomposition potential could not be obtained from its current density potential curves. Of course, its decomposition potential differs according to the kind of cathodic metals.2) In the constant current density electrolysis, the cathodic potential is elevated with the progress of the electrolysis.3) In the constant potential electrolysis (e.g. 0.124V for Pt-W poles), a beautiful deposition of whitish grey metalic luster is obtained, with a little higher potential (e.g. 0.184V for Pt-W poles) a reddish brown metalic luster, and with a much higher potential black and spongy. With the lower potential, nothing is obtained but the generation of hydrogen.4) By the electron diffraction analysis, it is found that the whitish grey metalic deposition is chiefly composed of W-oxide (not WO2 or WO3) with a little metalic tungsten.5) When the Na2WO4 solution is electrolised, the tungsten becomes special cation of its oxide. When the solution is electrolysed with constant cathodic potential, the tungsten is regularly obtained as metalic deposition on the cathode. This deposition is chiefly composed of lower oxide tungsten (such as WO) containing a little tungsten. So, the resistance increases and the potential is elevated with the progress of electrolysis.As the potential is gradually elevated, the deposition grows rich in higher oxide and finally becomes to be spongy.After all, it might be concluded that, in order to obtain thick deposition from Na2WO4 solution, the amount of metallic ions in the solution is to be restricted and hydrogen ions increased, or some other reducing regents more powerful than hydrogen are to be used, or the alloy-plating is to be applyed.