Effect of agitation on tin-lead alloy deposition in a methane sulfonate system

摘要

Tin/lead alloy electrodeposition within methane sulfonic acid (MSA) solutions was studied. The thickness and composition of the deposit formed under static condition were investigated initially, then contrasted with the data obtained under a reflow system. It was found that when the electrolyte was stagnant, the high current area appeared on the edge region of the electrode surface where the lead deposition dominates, while the central region of the plate was the low current area that facilitated the tin deposition. Moreover, the increase of flow rate could significantly improve the distribution of Ph/Sn, although it had little effect on the composition of the deposition, which was mainly controlled by current density. Finally, the Ph/Sn alloy deposition in a MSA bath was found to be mainly controlled by the mass transfer of active ions. So the flow pattern and circulation greatly affect the current distribution of the alloy deposition. The flow pattern with a certain cell can be accurately simulated by mathematical modeling with the assistance of appropriate flow 3D software.