Study on the Effect of Additives in the Electrodeposition of Sn-Ag-Cu Ternary Alloy Solder

Abstract

Sn-Ag-Cu ternary alloy is the most ideal substitute for Sn-Pb alloy at present, and can be prepared by electrodeposition with high production efficiency, simple equipment, easy maintenance and excellent coating performance. The coordination system of the electroplating solution was investigated through the Hull cell experiment. The type of brighteners used in the plating solution and the ratio of the two brighteners were determined through the microscopic morphologic characterization, electrochemical corrosion test and cathodic polarization curve test. In addition, the dispersant and stabilizer were studied by observing the microscopic morphology and measuring the concentration change of Sn²⁺ ions in the plating solution, respectively. The results showed that when ammonium citrate and thiourea were used as the complexing agents, benzylidene acetone and polyethylene glycol as the brighteners, poly propylene glycol as the dispersing agent, and ascorbic acid as the stabilizer, the wide current density range of the plating solution and excellent stability were obtained. Furthermore, the resulted coating was dense and smooth with high corrosion resistance.

Keywords

ternary alloy / electrodeposition / additive / Sn-Ag-Cu

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