On Fri, Oct 7, 2016 at 1:08 PM, andy pugh <[email protected]> wrote:
> On 7 October 2016 at 17:09, Dave Cole <[email protected]> wrote: > > > > Does this give me a clue? > > https://www.researchgate.net/post/What_is_aluminium_and_ > its_oxide_electrical_properties2 > > It seems to be lots of people saying "Aluminium is non-conducting" > without doing the simple test with a multimeter to check their theory. > Aluminum metal is of course conductive, because it is, well, a metal with free charge carriers and all. Al2O3 (aka ALUMINA) layer on the surface is not conductive, except that when it is naturally formed, it's just 5-10nm thick. If you apply 1V across it, the field strength is in the megavolts per centimetre, which happens to be near the dielectric breakdown field for alumina, so under normal conditions you get conductivity. If the alumina layer is thickened (e.g. by anodization), the aluminum objects will be isolated; this is sometimes used for heatsinks and such, except that the isolation is fragile because alumina is hard, and the underlying aluminum metal is soft. ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
