What can cause corrosion of RAM?

This company seems to be in Australia, and seemed I'd read some years back about floods in certain areas there. I considered searching back to see if there was flooding where they have their manufacturing done, or near a warehouse. I can see someone drying off motherboards and then bench testing to see if they can make it out the door OK and not fail within a year's warranty period. I guess it would depend on the company, their particular insurance coverage, their honesty, how big a loss they were or not willing to take.

I know it's not good to buy a used car in the year following flooding and even outside those areas the cars can show up, being moved since everyone in the flood area is aware of the local problem and on the watch for such in the following years.

Just clean water on a motherboard can dry up and not cause problems later on, but flood water has salts in it which can lodge in tight areas, like you'd find in RAM and card slots, might not clean out as well, then corrode things later on.

Thanks, I didn't think of that possibility, it wouldn't surprise me if either the RAM or motherboard were stored and handled in less than ideal conditions. I will be definitely taking it back down for full diagnostics and getting all the parts checked thoroughly.

I agree with James above in that I wouldn't give this place a third go at screwing things up unless there are laws similar to here, where if after a "reasonable" number (usually defined as 3) of repair attempts, they're obliged to replace the entire unit.

Take it to a third party for an independent evaluation and potentially repair.

You might want to put some subtle markings on the new RAM so that if for some odd reason this happens again you'd be able to look for your markings if the repair shop showed them to you. As for corrosion, here's where I'd love to see this myself under magnification and I'd also ask why just the RAM and nothing else. I'd want to know if it was deterioration of metal they were talking about. I have worked on lots of equipment that has had failures due to corrosion but these were devices that had liquids being pumped through them. For this reason, the quality of all material used had to be top notch. Corrosion is the result of many factors. Poor quality, unsuitable environment, heat, lack of proper air flow, etc. RAM can get quite hot and needs proper cooling. I don't know how many installations I've seen where air flow to RAM was obstructed due to the way cables were dressed. I'd want to see how yours was put together and if there was proper air flow in that area. I'd want to see if it was the gold contacts that were going bad. That layer is very thin and can be cut through by sharp edges in the socket maybe. This can expose the copper or whatever is being used these days on the boards. Copper develops a protective layer when exposed and that layer doesn't conduct as well. Heating and cooling cycles that take place in the sockets cause expansion and contraction that can wear away at materials not bonded. I suppose that could be what's happening...but why just the RAM? I've seen corrosion on the surface of circuit boards that creates bridging as well. The bridge connections don't need to be very solid. Rapidly changing voltage levels can induce current into anything that will carry it and this can result in all kinds of noise in sensitive circuitry.

In any event, it would be good if someone knowledgeable could inspect your corroded parts, how they were installed and offer a second opinion. I've had RAM fail testing in a box where pulling and reseating it has caused it to pass so it wouldn't be possible to know if your RAM was completely unusable when you took it in or whether a cleaning/reseating would have saved it for a time.