Anodes for a trivalent chromium electroplating bath

• Main Authors: Olga I. Kasian, Yulia A. Velichenko, Tatiana V. Luk’yanenko, Alexander B. Velichenko
• Format: Article
• Language: English
• Published: Oles Honchar Dnipropetrovsk National University 2014-12-01
• Series: Vìsnik Dnìpropetrovsʹkogo Unìversitetu: Serìâ Hìmìâ
• Subjects: Cr electroplating; semiconductor; anode materials; electrocatalytic activity
• Online Access: http://chemistry.dnu.dp.ua/article/view/22055
• ISSN: 2306-871X; 2313-4984

Electrochemical behavior of different anode materials in electrolytes containing trivalent chromium salts was investigated. Some of electrodes (Ti/MnO₂, platinized titanium, materials based on Ebonex^®) were shown to be n-type semiconductors. Semiconducting properties of electrodes affects their electrochemical behavior.It was shown that choice of an appropriate anode for a trivalent chromium electroplating bath should be based on compromise between its selectivity and service life. It was found that current efficiency of Сr(VI)-species strongly depends on the nature of anode material. Dimensionally stable anode based on mixture of titanium oxides and ruthenium oxides, PbO₂, Ti/MnO₂ anodes are characterized by low rates of Cr(VI)-species generation. Nevertheless these materials are not stable in the electrolyte media that limits their application for hard chromium electrodeposition. Composite materials based on platinized titanium or platinized Ebonex^®are recommend as anodes for carbamide-containing electrolytes since they characterized by good service life and admissible values of current efficiency of Сr(VI)-species.