Topic: Cloudy Ni Sulfamate Deposit With Pitting
This is from a new bath make-up, to boot. All constituents are to spec and re-checked after treatments (Ni, H3BO3, wetter (SNAP A/M), anode corroding agent, and grain refiner). The in-lab hull cell looks a lot better than the in- bath panel run at 10 ASF (in-bath bright along the borders, cloudy in the center, with what appears to be large, deep, gas pitting throughout. Minimal in number, but unacceptable). Persistent dummying and peroxide/carbon treatment (s) have produced no improvements. We use two pumps with poly filtration (a 1 micron poly-string and a 10 micron poly-spun) and good agitation. I now suspect...
1) The contamination is occurring in real-time and,
2) The contamination is organic in nature
At 1st, I suspected starch from poorly leached anode bags, but the peroxide treatment should have resolved this. Today, I saw that one of our pumps was making contact with one of the anodes (a Lab Series 650- CPVC and poly-pro body). I removed it and am carbon treating /dummying one final time before throwing in the towel. Could the pump and/or poly-spun filter making contact with the anode have been the issue? It's dubious, to be sure, but I'm all out of ideas. Before you get any other ideas, we have a duplicate, and very old, sulfamate bath has has none of these issues (without the Lab Series pump, though).
All suggestions are welcome!