On Wed, Oct 15, 2014 at 7:49 AM, Robert Dorr <rod...@comcast.net> wrote:
I've been thinking of tungsten for a while now. Do they make an alloy with > tungsten that operates at high temps in an oxygen atmosphere. I ask > because, although the tungsten that is embedded in the reactor would be > protected from oxygen by the aluminum oxide coating, you have to connect it > to power somewhere outside the reactor that would be exposed to air and the > wire, if pure tungsten, would decompose rapidly. > In the case of some metals, oxygen will react with the surface of the metal thereby forming a protective layer against further corrosion. I take it this would not be possible with tungsten or another refractory? Does this imply that heating elements operating above ~ 1400 C must be used in a low-oxygen environment? I note that kanthal super, referred to by Bob Higgins elsewhere, appears to be used in some cases under a normal atmosphere: http://www.kanthal.com/scaled/11551/headtest-width960height320.jpg http://www.keithcompany.com/images/gallery/2-zone%20super%20kanthal%20heating%20elements.jpg Eric
