Why does water “destroy” electronics and how does waterproofing work to stop this
In: Technology
Rainwater and tapwater have a small amount of sodium, magnesium and calcium in them. Not enough to make the water very conductive, but enough to make it an “electrolytic solution”.
An electrolytic solution is a chemical where, if you put two different metals in it at different voltages, ions will start exchanging between the two metals, causing them to chemically change.
Electronic circuits use a lot of copper and iron. When you get electronics wet, that can corrode the copper and iron. When you get them wet *and* you have them powered on, the corrosion happens much more quickly because the water is an electrolytic solution.
As things corrode, the water may leech some rust or other corrosion products across the circuit board, short-circuiting things and causing strong enough electrical currents to burn something out. Or, a connection might corrode badly enough that it stops conducting electricity and so it no longer works.
There are a handful of ways that this can be avoided in a product that is expected to get wet:
* Waterproofing, like we do with cell phones: The body of the device is well sealed so that water can’t get in to the circuits.
* Dielectric grease: If there’s only a few minor places where water ever gets in and it doesn’t get in too badly, just smearing some grease on the component or connector can keep water off of it well enough.
* Conformal coating: The circuit board can be sprayed or painted or dipped in a chemical that’s kind of like a clear paint intended to be an impenetrable shield against water.
* Potting: A block of plastic resin can be cast around the circuit.
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