Black nickel and relieve reject issues

Your parts are doing something...even when you’re not plating 

If you’re doing a plate-and-relieve antiquing process, pay close attention to the following infographic. A customer recently told us of a high scrap rate associated with the following process:

1. Steel substrate 
2. Nickel strike
3. Brass plate
4. Black nickel
5. Relieve for antique look 

We conducted a 3 part experiment focused on the black nickel step and did the following tests:

Trial 1: 3 minutes black nickel plate, rectifier on
Trial 2: 12 minutes black nickel plate, rectifier on
Trial 3: 3 minutes black nickel plate rectifier on, followed by 9 minutes immersion in black nickel black with no rectifier

As you can see, leaving the parts in the bath without a rectifier had an interesting effect and often times stripped off some of the plate that had been electrodeposited previously.