-----

Solder and Silver plating problem

2001

Q. 1. We have continuous reel to reel (strip) plating setup. The steps are degreasing - nickel strip - nickel plating - silver plating or solder plating. The speed is 1 meter per min. The adhesion of plating is tested by
a) tape test
b) cross cut test
c) bend test.

Our observation is that after plating no failure in adhesion is observed. However when the same coil goes for punching of products the solder layer peels off from nickel layer (nickel is an undercoat) which causes rejection. This peel off is intermittent and the extent is very low.

2. We use Mercaptan based proprietary passivating agent for silver plating. The barrel plated and passivated silver products do not tarnish but the plated and passivated strip after punching gets tarnished.

Please give us any suggestions.

Rajan Joshi
- Pune, Maharashtra, India

---