DIYbanter - View Single Post - C4 Racing from Newbury

Basil Jet[_2_]

On 2011\02\15 16:58, greenaum wrote:
On Mon, 14 Feb 2011 15:03:04 +0000 (UTC),
(Andrew Gabriel) sprachen:

Aluminium oxide is both an excellent insulator, and very hard.

The tiny thin layer of it on aluminium is. But you can still conduct
current easily through aluminium foil, or metal. The oxide layer in
practice is too thin to insulate electrically.

The layer of oxide forms in just a few seconds on pure aluminium. I've
seen it happen on TV, it forms before one's very eyes. Same as when
you slice through Sodium.

It's too thin to make a difference. I imagine in your MOSFET case,
either one of them wasn't making proper contact or, more likely, the
FETs were tougher than you thought. Electronics, and power electronics
particularly, can take a lot more than they're rated for, before they
actually blow.

The current rails in third rail railway systems are nowadays made of
aluminium, so the insulating effect of the oxide layer is not important.