In the aluminum anodizing process, does the oxide layer grows indefinitely as long as current flows? Or how thick can it get?
My intention is to anodize a tube to electrically insulate it. This way I can wind Ni-Cr wires directly around it to make a mini hot air gun.
Thanks.jpsmith123 - 30-11-2007 at 09:16
Hello Tacho,
I admire your resourcefulness, but is it worth it to even fool around like that when you can get a heat gun for $10.00? (I would think in Brazil there must be something similar?)
Anyway, here's an article from the Electrochemistry Encyclopedia that might be helpful.
One concern I would have would be the difference in thermal expansion between the metal and the oxide, especially if the oxide were thick and subject
to repeated thermal cycling.12AX7 - 30-11-2007 at 10:26
Hardcoat may suffice. I know electronics professionals (good ones ) who have
been known to mount transistors on hardcoat heatsinks. It's also very thermally conductive, being aluminum oxide.
Aluminum goes up to 500V or so- think aluminum electrolytic capacitors. As the anodization grows, the voltage must be increased.
TimTacho - 3-12-2007 at 02:48
Thank you.
The link ( Electrochemistry Encyclopedia ) is the best information on anodizing I have seen so far.
My Idea is really a small scale thing and, as Tim pointed out, oxide insulation layers can be useful in many other projects. Besides, I really never
saw one of those for sale for U$10 (or equivalent). Bless China.Nixie - 17-12-2007 at 04:59
Quote:
Originally posted by 12AX7
It's also very thermally conductive, being aluminum oxide.
Bah, you can get beryllia insulators from eBay.unionised - 17-12-2007 at 13:03
You can get a fair few carcinogenic things on eBay if you look hard enough.
I don't know how thick a layer you can get but there's another neat trick you can do. You can anodise a layer of oxide onto the Al then dissolve away
the Al from the other side with I2 soln. That way you might get an Al2O3 tube without the metal.Nixie - 17-12-2007 at 14:43
Quote:
Originally posted by unionised
You can get a fair few carcinogenic things on eBay if you look hard enough.
How is it carcinogenic? Only the dust is. Cut/drill under water and it's perfectly safe (the diamond bits you need to work this hard ceramic are
intended for wet use anyways, as they overheat otherwise).
) who have
been known to mount transistors on hardcoat heatsinks. It's also very thermally conductive, being aluminum oxide.