Electrodeposition of chromium from trivalent chromium urea bath containing sulfate and chloride

来源期刊：中国有色金属学报(英文版)1999年第3期

论文作者：陈磊 蒋汉赢 龚竹青

文章页码：641 - 645

Key words：electrodeposition; chromium; polymerization

Abstract: The reduction of Cr(Ⅲ) to Cr(Ⅱ) on copper electrode in trivalent chromium urea bath containing chromium sulfate and chromium chloride as chromium source has been investigated by potentiodynamic sweep. The transfer coefficientαfor reduction of Cr(Ⅲ) to Cr(Ⅱ) on copper electrode was calculated as 0.46.The reduction is a quasi-reversible process.J—tresponses at different potential steps showed that the generation and adsorption characteristics of carboxylate bridged oligomer are relevant to cathode potential. The interface behavior between electrode and solution for Cr(Ⅲ) complex is a critical factor influencing sustained electrodeposition of chromium. The hypotheses of the electro-inducing polymerization of Cr(Ⅲ) was proposed. The potential scope in which sustained chromium deposits can be prepared is from -1.3V to-1.7V (vs SCE) in the urea bath. Bright chromium deposits with thickness of 30μm can be prepared in the bath.