Effect of Ultrasound on the Performance of Nickel Hydrazine Electroless Plating Baths

This article addresses the relationship between morphology of metallic skin layer and process parameters of hydrazine-based electroless plating baths during the fabrication of nickel-ceramic microfiltration membranes. While process performance was evaluated in terms of overall conversion and metal plating efficiency, the film morphology was characterized in terms of average metal film thickness, pore size, and percent pore densification. Sonication was considered as an additional degree of freedom to the conventional electroless plating process. Process parameters varied include initial nickel solution concentration (0.04-0.16 mol/L), loading ratio (196 and 393 cm(2)/L), and relevant mass transfer coupling (sonication). It was observed that sonication assisted electroless plating provided the best combination of both process as well as performance characteristics in comparison with the base case and membrane stirred cases. Ultrasound was found to enhance the selective conversion by more than 50% compared to the other cases. About 50-100% excess nickel plating rate was evaluated for the sonication assisted case due to which the membranes with pore size as low as 11nm were achieved.