ok, so i open up an old Palm III which was shelved for like months. Batteries inside. The batteries by now have all leaked some strange looking white substance all over the Palm’s pants.
So i remove the batteries, clean up the mess and put in new batteries. The Palm III remains lifeless. So i open it up and see that the battery contact springs are rusted and therefore might not be conducting. So i connect the batteries directly to the contact point on the pcb/board. The Palm III wakes up and talks to me about near death experiences and all the light it saw and all.
So, does rust conduct ? Why not ? How do i remove the rust to make the contact springs conduct again ?
Any solution ? pun intended.
Aside, what effect do leaking batteries have on electronic gadgets ? And why do shelved batteries behave this way ?
You know those abrasive erasers for erasing pen marks, the kind that scratches away the surface of the paper? I’ve always found those to work best for removing corrosion.
The stuff on your contacts isn’t rust which is iron oxide. It’s corrosion due to
whatever chemical cocktail is in your batteries. You should check the batteries for a
guarantee – a lot of
manufacturers will replace (so they claim) equipment that’s damaged by leaky batteries).
Metal oxides are used to manufacture resistors. The more oxide thats evaporated on the substrate the lower the resistance.
The spring that provides the negative connection is damaged. Better to send the equipment in to have it repaired.
I just contacted Energizer about a flashlite I have that was damaged by their batteries. They want their customer service to look at it. Thats fair I think.As soon as I find a statement of the cost I’ll send it to them.
In all fairness to Energizer this doesn’t happen often.
I think it’s important to remember that conductivity is measured on a continuous scale, not a pigeonhole of “is/isn’t.” While many oxides are by composition poor conductors, a little corrosion that would open a 1.2V AA circuit might not inhibit, say, a 9V battery.
As to your question of removing the deposits, you did not mention what type of battery was involved. However, you might find good results by swabbing the anodic contacts with vinegar, and the cathodic ones with a baking soda & water solution. Or I have them reversed in my overtired mind, in which case you’ll figure out the difference pretty quickly.
Buy a tiny wire brush from a hobby store or get a pair of wire clippers and clip out a narrow head on a disposable emery board small enough to get between the spring wires and sand off the rust. I would hesitate to use fluids and solvents unless they were applied with q tip.
Actually metal film is evaporated onto the substrate in a vacuum which removes free oxygen so its metal film molecules that are evaporated onto the target not metal oxide.
You guys are slipplng. I really thought you’d catch me on that one.
Why not? Well, conductivity depends on the number of electrons that are free to move within the material. It would take a dissertation on the solid state physics (about which I know practically nothing) of iron oxide to answer this question.
As another poster said, metal oxides range all the way from fair conductors to insulators to semiconductors. A MOS FET, for example, is a Metal Oxide Semiconductor Field-Effect Transistor. Examples of insulators include aluminum oxide which is a ceramic. If you need good electrical contact between aluminum sheets, for example to shield against radio frequency interference, it is necessary to treat the surface so as to remove the oxide and prevent it from returning.
One thing about rust is that it crumbles and flakes off so under a lot of pressure a rusty contact might conduct because the rust has been forced out by high pressure and some metal to metal contact is achieved. But it would be a relatively high resistance contact.
Remove the rust with abrasive paper. Since any plating is probably also gone you will get more rust in time.
Batteries leak. Don’t leave dry cells in unused electrical equipment for long periods. Don’t ask me how long is long. But, I would err on the safe side and make it not over a month or two.
For inexpensive and easily replaced equipment, the bother of taking the cells out and putting them back in might make risking ruining the item a good bet.
To re-emphasize what has been said here (kinda): rust is iron oxide, a ceramic material. Formed in the proper manner, and mixed with other chemicals, and you can cast some cool stuff out of iron oxide. Most people think of rust as a metal because it is found on iron and steel, and the part typically has a good bit of metal in it. Pure rust is all oxidized, and like most ceramics is a poor conductor of heat and electricity due to its electron configuration and bonds.
i was using 2 Duracell Alkaline AAA 1.5v batteries.
i shall try out the solutions offered here… starting with sandpaper and/or eraser… initially i thought i’d have to get some new springs and solder it to the board… but now i have hope…
