摘要
The preparation process of the Cr（III） bath was studied based on a perspective of accelerating the formation of active Cr（III） complexes. The results of ultraviolet-visible absorption spectroscopy （UV-Vis） and electrodeposition showed that active Cr（III） complexes in the bath prepared at room temperature in several days were rare for depositing chromium. The increase of heating temperature, time, and pH value during the bath preparation promoted the formation of active Cr（III） complexes. The chromium deposition rate increased with the concentration of active Cr（III） complexes increasing. Increasing the heating temperature from 60 to 96℃, the chromium deposition rate increased from 0.40 to 0.71μm/min. When the concentration of active Cr（III） complexes increased, the grain size of Cr coatings increased, and the carbon content of the coating decreased. It is deduced that Cr（H20）4（OH）L2＋ （L is an organic ligand, and its valence is omitted） is a primary active Cr（III） complex.
The preparation process of the Cr（III） bath was studied based on a perspective of accelerating the formation of active Cr（III） complexes. The results of ultraviolet-visible absorption spectroscopy （UV-Vis） and electrodeposition showed that active Cr（III） complexes in the bath prepared at room temperature in several days were rare for depositing chromium. The increase of heating temperature, time, and pH value during the bath preparation promoted the formation of active Cr（III） complexes. The chromium deposition rate increased with the concentration of active Cr（III） complexes increasing. Increasing the heating temperature from 60 to 96℃, the chromium deposition rate increased from 0.40 to 0.71μm/min. When the concentration of active Cr（III） complexes increased, the grain size of Cr coatings increased, and the carbon content of the coating decreased. It is deduced that Cr（H20）4（OH）L2＋ （L is an organic ligand, and its valence is omitted） is a primary active Cr（III） complex.
基金
financially supported by the National Basic Research and Development Program of China(No.2013CB632606)
the National Natural Science Foundation of China(No.51274180)
