Effect of cerium chloride on electric crystallization behavior and grain refinement of electrodeposited copper.

Rare earth additives have an important influence on the quality of the deposited layer and the electric crystallization behavior during metal electrodeposition. In this paper, linear scanning voltammetry (LSV), cyclic voltammetry (CV), and chronoamperometry (CA) were used to investigate the effects of different concentrations (0 –1.0 g·L−1) of cerium chloride additives on the electric crystallization behavior of copper electrodeposited by industrial electrolytes. The microscopic morphology, grain size, and preferred orientation of copper deposition layers obtained from Harlem tank experiments were analyzed by scanning electron microscopy and X-ray diffraction to investigate the effect of cerium chloride on the grain refinement and crystal growth orientation of copper deposition layers in industrial electrolysis. The results show that: When cerium chloride was added into industrial electrolyte, the copper deposition potential shifted negatively, the cathode polarization increased, the nucleation relaxation time decreased, the nucleation rate of copper increased, and the grain was refined. However, the addition of cerium chloride did not change the nucleation/growth mechanism of copper, which is still three-dimensional instantaneous nucleation. When the concentration of cerium chloride is 0.4 g·L−1, the cathodic polarization was the largest, the nucleation relaxation time was the shortest, and the deposited layer grains were the smallest. Moreover, the preferred orientation of the deposited layer is changed from (220) to (220) and (222) to double preferred, thus suppressing grain growth and uniform grain distribution of the deposited layer. Therefore, 0.4 g·L−1 is the optimum concentration of cerium chloride to be added. [ABSTRACT FROM AUTHOR]