(1.山東礦業(yè)學(xué)院材料工程研究所 泰安 271019;
2.北京科技大 學(xué)理化系， 北京 100083)
摘 要: 通過吸光度測量和示波極譜等方法研究了不同來源的Cr3+在不同介質(zhì)中的配合離子存在形態(tài)。結(jié)果表明， 新還原得到的Cr(Ⅲ)主要以[Cr(H2O)6]3+形式存在于溶液中，而普通CrCl3·6H2O中Cr(Ⅲ)的具體形態(tài)為較難還原的[Cr(H2O)4?/FONT>Cl2]+。介質(zhì)pH值發(fā)生變化時(shí), Cr (Ⅲ)的存在形式也隨之變化，由pH<3時(shí)的[Cr(H2O)6]3+逐漸轉(zhuǎn)變?yōu)閜H>3時(shí)的[Cr(H2O)5OH]2+，還原電位隨之負(fù)移。 因此， 為了保證Cr(Ⅲ)陰極過程的順利進(jìn)行， 應(yīng)盡量保持鍍液中的Cr3+以[Cr(H2O)6]3+的形式存在。
關(guān)鍵字: 電鍍鉻 三價(jià)鉻 陰極過程 配合物
（1.Shandong Institute of Mining and Technology, Tai'an 271019, P. R. China;
2.University of Science and Technology Beijing, Beijing, 100083 P. R. China）
Abstract:The species of Cr3+ complex-ion coming from different source in different media have been investigated by means of measurement of light absorptivity and oscillographic polarography. The results showed that the freshly-reduced Cr(III) exists mainly as [Cr(H2O)6]3+ in the solution, while the species of Cr(III) in common CrCl3·6H2O is [Cr(H2O)4Cl2]+ reduced more difficultly; when pH value of the medium changes, the species of Cr(III) changes gradually from [Cr(H2O)6]3+ at pH<3 to [Cr(H2O)5OH]2+ at pH>3 and the reducing potential shifts negatively. To ensure cathodic reduction of Cr(III) to be proceeded smoothly, one should make efforts to keep Cr3+?in the bath to exist as Cr(H2O)6]3+.
Key words: chromium electroplating trivalent chromium cathodic reduction complex.
