| Search our quarter-million Q&As |
Home of the finishing HOTLINE since 1989
-----Phosphate Buffered Saline Solution Corrosion Problems
I have been testing an electroless nickel phosphorus (360 Brass Substrate) plating for use in our chemically harsh environment. I tested a 6-8% Nickel and a 10% Nickel combination and after two days in an agitated bath my test parts turned a bronze color. Our solution is a phosphate buffered saline which includes a NaCl, KH2PO4, Na2HPO4,and KCL in a 1000 ml of deionized H2O. Can anyone suggest a plating that will not oxidize in this environment. We have previously been using a 316 SST that has worked, but we are looking for plating possibilities.
David Willford- Richland, Washington
2002
Dave,
Only precious metals and some exotic intermetallic or PVD compounds will not oxidize. Other protective metals such as EN, chrome, plain Ni, Tin-Ni, even SS will passivate which is a form of oxidation (some change in color, some do not). About ceramics, they also will not oxidize because they are already oxides (well, many of them).
Monterrey, NL, Mexico
2002
A high phosphorus (10% or more) will not turn color if the plating solution is free from divalent sulfur, cadmium, or other reactive trace materials commonly used as stabilizers. Select a proprietary product that will pass the "nitric acid test" that is will not blacken in 30 seconds exposure to 50% by vol nitric acid. Ask your supplier.
Don Baudrand
Consultant - Poulsbo, Washington
(Don is co-author of "Plating on Plastics"
and "Plating ABS Plastics" eBay or AbeBooks affil links])
2002
Sorry! Finishing.com is temporarily Read-Only.
Ted Mooney is retiring but I have several offers to take it over.
We're working hard to make sure we find it the best new home.