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The Best Storage Method to Protect Against Corrosion
Board Talk
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TranscriptPhil And welcome to Board Talk with Jim Hall and Phil Zarrow, the Assembly Brothers Pick and Place. We’re here to attempt to answer your process questions regarding materials, methodology, and all of the happy stuff that makes our day go by so fast. Today, Jim, what do we have? I think we have a storage question. Jim It comes from L.N. It says which storage method will better protect against corrosion, nitrogen or super dry? Phil I would start off by saying that regardless of the methodology you use, you want to do it in compliance with IPC 1602, which covers the storage and handling of circuit boards. Also, with regard to your assemblies, you are basically treating them as a level 3 MSD. But with regard to the question, he said specifically corrosion. Correct Jim? Jim Yes. Chemically speaking, nitrogen excludes oxygen, so that would preclude any corrosion that requires oxygen in the reaction. So, from that standpoint, I have to say yes, nitrogen is more fool-proof. But the question in my mind, and I don’t know the answer, is that in super-dry, you have so little moisture; how many corrosion reactions can take place if there is absolutely no moisture available? And I don’t know the answer to that question. I suspect very few, but I don’t know for sure. Phil I believe that is the whole idea. Nitrogen is very dry, by the way also. Jim It has a lot of oxygen in the atmosphere that is not there in nitrogen. So any corrosion reaction that requires oxygen should be precluded of nitrogen but possibly could happen in super dry. Phil Well, I definitely agree with my brother on that. Make sure that regardless of your storing, if you are bare boards, if you are not putting them in the cabinet, nitrogen, or dry cabinet, they should be repackaged in a moisture barrier bag with a humidity indicator and a desiccant. Which is the way you should have received them in the first place. But again, we are talking about 1602. If we are talking about the actual assemblies, yeah. We’ll let our listeners weigh in on that as well. I suppose we will be hearing from the vendors of both super dry and nitrogen cabinets. Gee, why do I think that? I guess we know our audience. But it will be very interesting to see. My guess is that it is probably six of one, half a dozen of another to be very non-commercial about it. Jim Jim We should ask the fundamental question. What materials are on these boards or components, whatever it is you are putting in this nitrogen or super dry environment, what is on there that could cause corrosion? My feeling is that there shouldn’t be anything. Materials should be clean and free of things that can cause corrosion. Phil Yeah, I would like to think you are not storing them with flux residue on there. Not a good idea. Very, very good point, Jim. What is the worry about corrosion unless you have the moisture element that you mentioned. Jim If we were talking about oxidation on solderable surfaces, then obviously nitrogen is better. But they specifically say corrosion, so we did not mention that. Phil Hope we answered L.N.’s question and certainly opened it up for discussion. Again, you have been listening to Board Talk with Jim Hall and Phil Zarrow. Regardless of how you are storing your boards, please don’t solder like my brother. Jim And don’t solder like my brother. |
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