Alumina

[Prune]

Where do I get alumina? I'm trying to find a bit of thin (0.2 to 0.5 mm) alumina ceramic, but all sources I found on the net do only wholesale.

[jneutron]

Originally posted by Prune
Where do I get alumina? I'm trying to find a bit of thin (0.2 to 0.5 mm) alumina ceramic, but all sources I found on the net do only wholesale.

I used Coors ceramic back in 85.

What width and length?

Is the app thermal, or voltage, or both?

John

[Prune]

Both. The thickness must be in the range 0.2-0.5 mm.

[jneutron]

hmmm...

I had some stock 3 by 3's laser perfed to 100 mil squares, some were 10 mil thick, others were 25 and 40. Those were the stock sheet sizes that were kept on hand at the vendor. But, I think it may have been the laser house that stocked the sheets for rapid turnaround..it was a while back..they say memory is the second thing to go, I forgot what the first was..

Try coors, ntk, even brush wellman (they are BeO people, but may know of a few laser houses.)

What thermal conductivity are you looking for. Will a filled epoxy work?

Cheers, John

[Prune]

I don't care about thermal conductivity. It needs to be able to withstand high heat and voltage. I need it for a microhollow cathode discharge. Most researchers using the device have used alumina. The MHCD can be used as a cathode itself to generate large volumes of stable air plasma (glow discharge) without it degenerating into an arc. I've gotten an arc to reproduce music, but it's noisty, makes way more ozone and NOx, shines tons of UV, and melts everything. I'm going to try a Hill-type tweeter, but using air instead of helium, which is possible with recent techniques. Much better than all the corona discharge ionic tweeters (Acapella etc.)