Letter 39068

Help - need info on AMS 2433B spec  

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I have a callout for AMS 2433B Type 2 electroless nickel. I don't have the spec. Can someone help me? I need to know what the type 2 refers to - thickness, phos content, heat treatment?

Thanks

Stephen Rohrbacher
plating co., - Lowell, Massachusetts

My suggestion is NO QUOTE! AMS2433 [link is to spec at TechStreet] is NOT electroless nickel as most platers know it. It calls specifically for nickel-boron-THALLIUM which is a far cry from the conventional nickel phosphorus electroless nickels as called out in AMS2404 [link is to spec at TechStreet] and AMS-2405 [link is to spec at TechStreet]. Straight nickel-boron is covered by AMS 2399. Most companies won't touch thallium bearing solutions - check out the health concerns associated.... From one websource: "Exposure to high levels of thallium can result in harmful health effects. Studies in people who ingested large amounts of thallium over a short time have reported vomiting, diarrhea, temporary hair loss, and effects on the nervous system, lungs, heart, liver, and kidneys. It has caused death. A study on workers exposed on the job over several years reported nervous system effects, such as numbness of fingers and toes, from breathing thallium."

Milt Stevenson, Jr. Anoplate Corp Syracuse, NY, USA

Another letter here, 34681, says that although Type 1 contains thallium, Type 2 doesn't, Milt. We should all work from actual copies of the spec, but I don't have one and am not going to buy one for a theoretical discussion. Maybe someone who is looking at it can advise us on that.

Ted Mooney, P.E.  finishing.com Brick, New Jersey

Hello Stephen!

AMS 2433C is the current revision, and it says Type 1 is Nickel Thallium Boron, while Type 2 is Nickel Boron. N-T-B has 2.5 to 5.0% Boron with 2.5 to 6.0% Thallium. The Nickel Boron is 2.5 to 8.5% Boron.

There isn't a change bar next to these paragraphs, so I believe that the B revision says the same thing.

Lee Gearhart metallurgist East Aurora, NY

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