Sciencemadness Discussion Board

Help needed re: metals or compounds that glow

Papa Smoke - 16-6-2012 at 05:14

I have recently come across a problem I wish to solve. I am trying to find a metal, mineral, or compound that will glow very brightly when flame is applied but will NOT vaporize rapidly. It must be able to be formed into various shapes or rods. It must be stable, safe, and non-toxic before, during, and after the application of flame/heat.

In which forum subsection would I best be served asking about this?

Thanks for your help. I will check back later but for now, I will go back to doing what I do best. Griping at my college students!

[Edited on 16-6-2012 by Papa Smoke]

plante1999 - 16-6-2012 at 05:28

Calcium oxide with a glassing on top?

Wizzard - 16-6-2012 at 06:09

SiC fibers COULD be used, like whiskers, but you'd need to protect them from any physical contact- They are VERY thin!

Zan Divine - 16-6-2012 at 07:00

Molybdenum disilicide?

There are many commercial suppliers of formed "Moly DiSi"
heating elements. Therefore fabrication problems have already been addressed. These operate @ 1700 C in furnaces and are resistant to oxidation. They are costly, however.

Since the criteria you specify are grossly similar to those of the heating element industry (ability to form into thin cross-sectional forms and ability to operate in a region where blackbody radiation means things glow), this is a good area to mine.

As to metal options, you can purchase platinum coated tungsten wire commercially. It resists oxidation very well and tolerates very high temps. If your needs are not that demanding, there are any number of cheaper resistance heating formulations.

[Edited on 16-6-2012 by Zan Divine]

chornedsnorkack - 17-6-2012 at 03:23

Among metals, the highest temperature tolerance in air or oxidizing flame is iridium - the only metal that endures over 2000 Celsius. All transition metals from tantalum to osmium form volatile oxides, and platinum melts at 1750 Celsius.

Among oxides, high melting point is possessed by, e. g. thoria, zirconia, ceria, magnesia, quicklime. These are generally brittle, though, so they may be vulnerable to crumbling away.

dann2 - 17-6-2012 at 05:39

Plant1999 Suggested using the 'lime light' as it was called when used way back in the day for stage shows.
Sounds like a good solution.

phlogiston - 17-6-2012 at 15:01

Zinc oxide and cerium oxide also exhibit 'candoluminesence', like CaO.

Thorium oxide is well known for its use in gass mantles, but it also radioactive and therefore doesn't match your requirements.

Papa Smoke - 17-6-2012 at 16:23

Thanks all! Wow! I have LOTS of experimenting to do (some of it quite expensive!!)

I am trying to find the wire, etc. that glows the brightest and is destroyed the slowest by fire.

Should be great fun!!!;)

Neil - 18-6-2012 at 04:43

Yitrium oxide and MgO from heated MgSO4 work well.

A wire? Platinum.

RadioTrefoil - 18-7-2012 at 00:26

Platinum wire! Heat it up and then dangle it over a flask with ammonia solution in the bottom, it will glow bright red hot for ages and will not be damaged AT ALL because it is acting as a catalyst for oxidation of the ammonia gas. It will only stop glowing when there is no more ammonia or oxygen left.

barley81 - 18-7-2012 at 04:21

The mineral fluorite (CaF<sub>2</sub>;) is thermoluminescent and glows when heated. It is safe, non-toxic, and stable; however, it cannot easily be formed into shapes. A jeweler may be able to take large crystals and grind them down to the shape you want.

EDIT: this happens if the fluorite has been exposed to ionizing radiation. The energy is released when the fluorite is heated.

[Edited on 18-7-2012 by barley81]


polymerizer87 - 18-7-2012 at 08:34

Look up "luciferin" the compound in fireflies that makes them glow. Not sure how you would synthesize this considering it's an enzymatic process.