摘要
测定了卤素-铬酸-硫酸体系中铬的电沉积效率及阴极极化曲线;XPS、AES测定了该体系中形成的阴极膜的组成。结果表明,硫酸能有效地催化光亮铬的形成,F^-、Cl^-能显著地提高铬沉积的电流效率;除Br^-外,F^-、Cl^-均参加成膜;膜的深度剖析曲线表明,卤素分布在膜的深层,SO_4^(2-)集中在膜的表面。由此可推测,F^-、Cl^-在金属表面和铬酸的还原产物重铬酸铬形成易发生电子转移反应的表面过渡态配合物,[Cr~Ⅲ-X-Cr~Ⅲ]~≠。
The current efficiency of chromium deposition and cathodic polarlization curves were determined in halogen-chromic acid-sulphuric acid systems. The results show that sulphate is an effective catalyst for the deposition of bright chromium and the current efficiency of the chromium deposition is remarkably increased when F- and Cl- were added to chromic acid. The composition of the cathodic film formed in the systems was determined by XPS and AES. The results show that, except Br-, F- and CF participated in the formation films. The depth profile curves of the film illustrate that halogen is distributed in inner layer of the film, and SO42- in surface layer. It is deduced that F- and Cl- have entered into on the surface of the cathod and formed a bridged complex with reduced chromium dichromate, [CrIII-X--CrIII], in which electron transition was easily carried out.
出处
《无机化学学报》
SCIE
CAS
CSCD
北大核心
1992年第3期266-271,共6页
Chinese Journal of Inorganic Chemistry
