六弗化チタン酸アンモニウム水溶液からのチタンの電解析出機構について

抄録

Cathodic potential measurements on Pt, Cu, Ti, Zn, and Al electrodes were carried out at various current densities in aqueous solution of (NH₄)₂TiF₆. The solution contains the cations Ti⁴⁺, NH₄⁺ and H⁺, and the anions TiF₆⁻⁻, F⁻ and OH⁻ according to the following equations:
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Though Ti⁴⁺ ions begin to be reduced at about −0.8 V (vs. S.C.E.), the potential where the titanium deposition becomes visible is less noble than −1.1∼−1.2 V. The mechanism of the electrodeposition of titanium is either the direct discharge of Ti⁴⁺ ions or the reduction of titanium ions of lower valency such as Ti³⁺ or Ti²⁺ to metallic titanium by active hydrogen, but since a simultaneous evolution of hydrogen with the deposition of titanium was observed, the mechanism could not be identified in the present experiments.