Nicad leakage

Maybe vinegar? The electrolyte is lye (either KOH or NaOH) so a mild acid should neutralize it. But, it is darn corrosive stuff, so it will eat many materials pretty quickly.

Jon

The KOH electrolyte is at about 30% concentration for a pH of about

1. Strong stuff, but not really dangerous. Any acid will wash off the KOH but may leave salts behind. (That's what's left when the KOH attacks aluminum, tin, brass, bronze, lead, zinc, etc).

For KOH cleanup, the MSDS sheet recommends dilute acetic acid (vinegar). For cleaning up the salts, I use baking soda, 409 cleaner, or whatever household cleaner I have handy that evaporates and doesn't leave a mess.

Note that cadmium is a hazardous waste. Dead NiCd batteries should be properly disposed of, not mixed with the household trash.

More:

Incidentally, the KOH does not enter into the chemical reactions inside the battery and just acts as a conduit for the ion exchange. The KOH concentration is the same for a brand new charged NiCd battery, as it is for an old dead battery.

John :-#)#

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"David Lesher"

The spill needs to be simply removed - so use tissue and/or clean rags to get up the worst of it, then use the same dipped in methylated spirits to get the surfaces clean as possible. Slight surface corrosion can be treated with WD40.

Any spillage that has become trapped in crevices or small holes must be washed out ( use a toothbrush ) and the item dried with hot air.

Pouring acid onto alkali inside some piece of equipment is BARKING MAD !!

.... Phil

Ok. I had to look up methylated spirits. Sometimes I just use tap water, but on good stuff I then use those methylated stuff. Then wd-40 or crc

Greg

Well, actually, using a mild acid to neutralize the mild alkali that leaked is the only way to be sure you have removed the corrosion risk.

Simply washing with pure water isn't quite enough - a 50/50 solution of water and white vinegar will often bubble even after you have washed the area. So, scrub some of the 50/50 mixture into the leakage area, then wash with lots of water.

Look for possible alkali leakage under conformal coatings over the PCB copper traces as they can be a bit of a time bomb if not the coating is not scrapped back a bit, then neutralized as well.

Lift/remove connectors - you'd be surprised how little alkali it takes to eat under these!

Once finished protect with a spray conformal coating.

Not sure how many ni-cad leakage logic boards you have dealt with, but I'd repaired hundreds.

John :-#)#

To change the subject a bit... The origin of the word "alcohol" is fascinating, among the most-interesting I've ever come across. Would you believe that it's related to mascara?

Ethyl alcohol is distilled from water/alcohol solutions, hence it is "the fine part of" the solution ("fine" as in small, not good).

Jeff Liebermann frembragte:

Yeah. I once made a dumpster dive, when I discovered the boss had dumped several boxes of used NiCd's in the regular trash. Don't ever do that again, I told him...

Leif