Where the world gathers for
plating, anodizing, & finishing Q&As since 1989




-----

Suitable sodium nitrite levels to inhibit corrosion

May 13, 2009

Q. I have a history in the metal finishing business and have forgotten an old solution make up that we used for a short term, indoor rust preventive. I remember that it was a heated solution and that the parts had to be dried after immersion so that they wouldn't corrode. This treatment was used after a stripping process, to keep the parts from rusting and essentially "plating line ready" for a few days to a week. No oils were needed and the solution was made up in house. This offered a good short term RP for us and I would like to use the solution again.
Can anybody help? The material used was sodium nitrite and water, and if I remember it was used at 160 °F, with a minute to two minute soak time. The parts were then pulled and dried prior to packing for plating in the next few days.
I cannot remember the make up - any help?

Terry Miller
plating manager - York, Pennsylvania, USA

---

2005

Q. I work at an factory that sends aerosol cans through a water bath with sodium nitrite among other things to inhibit corrosion. Does anybody know what is the recommended concentration of sodium nitrite in ppm to use as a rust inhibitor. Couldn't find anything in print to include in my training manual.
Thank so much in advance.

Jim W [last name deleted for privacy by Editor]
quality assurance - Viburnum, Missouri