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SALT SPRAY RESULTS?

 

I'M A ELECTROLESS NI PLATER THAT RECENTLY WAS LEFT IN CHARGE OF A WHOLE PLATING SHOP, BECAUSE MY SUPERVISOR QUIT. I RUN A MID PHOS. ELECTROLESS NI BATH. I WOULD LIKE SOME HELP ON MY TEST PANELS. I'm TESTING FOR 96 HRS AT .5 MIL THICKNESS IN SALT SPRAY. DON'T KNOW WHAT TO LOOK FOR , WHAT'S PASSIBLE AND WHAT'S FAILING.WHAT SIGNS OF CORROSION SHOULD I LOOK FOR? THE ONES I HAVE TESTED ALL HAVE BLISTERS AND WHITE SPOTS ON THEM, IS IT MY PRETREATMENT? OR MY THICKNESS? PLEASE HELP.

THANKS....

Pedro Galvez
- Paso Robles, CALIFORNIA

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Half a mil should last 96 hours, and more if the metal is well prepared. So I think it's the pretreatment rather than the thickness. You didn't mention what the substrate is so it's hard to say what might be wrong.

As for what to look for as signs of failure, you're doing fine :-)

No need to look any harder, because what you've described are failures.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
 

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What Ted told you is correct. How to conduct a salt spray test is spelled out inASTM B117, but this specification does not touch interpretation of results with a 10-foot pole. This criteria is usually based on what a typical sample of the particular plating lasts on average. The pass/fail criteria is also often established between the customer and supplier beforehand.

PS - Please do not write in all capital letters. It's bad internet manners to do so.

Tim Neveau
Rochester Hills, Michigan