Microwave Heating of Metals

Here's something I just read about:

http://www.e4engineering.com/story.a...d-a7bd9b6a4258


So I'm wondering if this microwave heating of metals can be used for
making of glassy metals. Glassy metals are based on rapid cooling of
molten metal, causing the glassy molecular structure. From what I've
read so far, this has entailed formulating metal alloys with very low
melt points. But why can't a glassy metal be made with a very high
melt-point, by microwaving an alloy formulation to be molten at very
high temp, and quickly chilling it below a melt-point that would
itself also be quite high?

This microwave heating of metals sounds like an efficient and
controllable way to get metals to very high temperatures very quickly.
It also seems like you could cut off that microwave heating very
quickly, to facilitate the quick-chilling necessary for glassy metal
formation.

Comments?

sanman wrote:

Here's something I just read about:

http://www.e4engineering.com/story.a...d-a7bd9b6a4258

So I'm wondering if this microwave heating of metals can be used for
making of glassy metals. Glassy metals are based on rapid cooling of
molten metal, causing the glassy molecular structure. From what I've
read so far, this has entailed formulating metal alloys with very low
melt points. But why can't a glassy metal be made with a very high
melt-point, by microwaving an alloy formulation to be molten at very
high temp, and quickly chilling it below a melt-point that would
itself also be quite high?

This microwave heating of metals sounds like an efficient and
controllable way to get metals to very high temperatures very quickly.

Google
"amorphous alloys" cooling 1780 hits

It also seems like you could cut off that microwave heating very
quickly, to facilitate the quick-chilling necessary for glassy metal
formation.

Comments?

You think slowly and type quickly.

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf

Uncle Al wrote in message ...
Google
"amorphous alloys" cooling 1780 hits

It also seems like you could cut off that microwave heating very
quickly, to facilitate the quick-chilling necessary for glassy metal
formation.

Comments?

You think slowly and type quickly.

Hi Al,

I'm afraid that after reading some Google hits, I was unable to come
up with answers. I guess it wasn't so obvious to me. Are you saying
that microwave heating is already being used for amorphous alloys
formation? Are you saying that there is something intrinsic to
amorphous alloy formation that is incompatible with microwave heating?
Or are you saying that amorphous alloy formation would not usefully
benefit from microwave heating?

I don't get it. Please let me know, thanks.

sanman wrote:

Uncle Al wrote in message ...
Google
"amorphous alloys" cooling 1780 hits

It also seems like you could cut off that microwave heating very
quickly, to facilitate the quick-chilling necessary for glassy metal
formation.

Comments?

You think slowly and type quickly.

Hi Al,

I'm afraid that after reading some Google hits, I was unable to come
up with answers. I guess it wasn't so obvious to me. Are you saying
that microwave heating is already being used for amorphous alloys
formation? Are you saying that there is something intrinsic to
amorphous alloy formation that is incompatible with microwave heating?
Or are you saying that amorphous alloy formation would not usefully
benefit from microwave heating?

I don't get it. Please let me know, thanks.

1) There is no reason to desire it in your version.
2) Microwaves don't penetrate metal (skind depth).
3) We already have several variants of induction heating. If
cleverly executed, the crucible's contents stir themselves.
4) Your cooling argument is specious.

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf

sanman wrote:
Here's something I just read about:


http://www.e4engineering.com/story.a...d-a7bd9b6a4258


So I'm wondering if this microwave heating of metals can be used for
making of glassy metals. Glassy metals are based on rapid cooling of
molten metal, causing the glassy molecular structure. From what I've
read so far, this has entailed formulating metal alloys with very low
melt points. But why can't a glassy metal be made with a very high
melt-point, by microwaving an alloy formulation to be molten at very
high temp, and quickly chilling it below a melt-point that would
itself also be quite high?

This microwave heating of metals sounds like an efficient and
controllable way to get metals to very high temperatures very
quickly.
It also seems like you could cut off that microwave heating very
quickly, to facilitate the quick-chilling necessary for glassy metal
formation.

Comments?

Read carefully, not the metal is heated directly, they create a
microwave plasma around the part to heat it. Such a system has no
benefits for rapid cooling, compaerd to an induction heater for
example. It is just a very uniform heat source without the insulation
needs of a conventiunal furnace.

if you want an amorphous alloy that works without crazy cooling rates,
read here :

http://mrsec.wisc.edu/edetc/IPSE/educators/amMetal.html

You will not be able to make it at home. Don't try to heat the stuff
outside of a vacuum or inert gas furnace or you will get a nice highly
toxic firework.

"Uncle Al" wrote in message ...
sanman wrote:
It also seems like you could cut off that microwave heating very
quickly, to facilitate the quick-chilling necessary for glassy metal
formation.
Comments?
You think slowly and type quickly.
I don't get it. Please let me know, thanks.

1) There is no reason to desire it in your version.
2) Microwaves don't penetrate metal (skind depth).
3) We already have several variants of induction heating. If
cleverly executed, the crucible's contents stir themselves.
4) Your cooling argument is specious.

What I suspect that Al is suggesting is that even if you were stuck
with a slow and hard to cut off heating technology, such as a
furnace, you could just remove your melt from the furnace and
transfer it to your quick-chilling device. Quick cooling simply
doesn't require quick cut-off of heating.

(sanman) wrote in message . com...
Here's something I just read about:

http://www.e4engineering.com/story.a...d-a7bd9b6a4258


So I'm wondering if this microwave heating of metals can be used for
making of glassy metals. Glassy metals are based on rapid cooling of
molten metal, causing the glassy molecular structure. From what I've
read so far, this has entailed formulating metal alloys with very low
melt points. But why can't a glassy metal be made with a very high
melt-point, by microwaving an alloy formulation to be molten at very
high temp, and quickly chilling it below a melt-point that would
itself also be quite high?

This microwave heating of metals sounds like an efficient and
controllable way to get metals to very high temperatures very quickly.
It also seems like you could cut off that microwave heating very
quickly, to facilitate the quick-chilling necessary for glassy metal
formation.

Comments?

Microwaves are generally reflected off of metals. I have found google
links for microwave sintering of powdered metals. I don't truely
understand how microwaves sinter powedered metals. I suspect that it
would be a very dangerous thing to attempt without an inert
atmosphere.

Now for non-metals, microwaves can facilitate ultra rapid volumetric
heating. These guys have some interesting (if not sparse) info about
using a gyrotron source for ceramic sintering
http://www.gyrotrontech.com/

If you want rapid heating of metals you need an inductance heater.
Check this out http://ameritherm.com/videoindex.html

Inductance heaters can utilize a range of operating frequencys. Lower
frequencys seem to heat from the inside out, higher frequencys seem to
heat the outer surface.

Maybe you could couple a non-conductive coolant to the metal part as
it is heated by a low frequency inductance heater.. Just a thought

It seems to me that what happens depends on the conductivity of the metal.
A metal is a lattice of ions swimming in a sea of electrons, so when you
impose a microwave (electric vector in rotary motion) the photon-electron
interactivity coefficient (frequency dependent) the electron will be put
into motion (ie, electric current). Given the resistivity (reciprocal of
the conductivity) there will be an I-squared R loss. This energy term via
the metals heat capacity would generate some temperature rise. I do not
have the numeric databases available so can't estimate the temperature
increase.

On the other hand, I once accidently put a ceramic dinner plate that had a
decorative gold rim into the microwave. The sparking was impressive and
the grub on the plate never warmed up at all. I expect the mobility of the
gold rims electrons sucked up all the microwave energy. Someone else told
me that was a good way to burn out a microwave.

Do not induction furnaces operate at much lower frequencies.

(sanman) wrote in message . com...
Here's something I just read about:

http://www.e4engineering.com/story.a...d-a7bd9b6a4258


So I'm wondering if this microwave heating of metals can be used for
making of glassy metals. Glassy metals are based on rapid cooling of
molten metal, causing the glassy molecular structure. From what I've
read so far, this has entailed formulating metal alloys with very low
melt points. But why can't a glassy metal be made with a very high
melt-point, by microwaving an alloy formulation to be molten at very
high temp, and quickly chilling it below a melt-point that would
itself also be quite high?

This microwave heating of metals sounds like an efficient and
controllable way to get metals to very high temperatures very quickly.
It also seems like you could cut off that microwave heating very
quickly, to facilitate the quick-chilling necessary for glassy metal
formation.

Comments?

Read the material more carefully.
It is the crucible that is heated, not the metal itself.
The coatings on the crucibles are designed to absorb the microwave
radiation, the metal itself does not.
Pragmatist.

(Jack Ferman) wrote in
:




On the other hand, I once accidently put a ceramic dinner plate that
had a decorative gold rim into the microwave. The sparking was
impressive and the grub on the plate never warmed up at all. I expect
the mobility of the gold rims electrons sucked up all the microwave
energy. Someone else told me that was a good way to burn out a
microwave.

A loop of metal in an RF field tends to look like a short circuit.
Try it with loosely crumpled aluminum foil. (Actually, don't!)
Food seems to be innately higher impedance, and the mass is greater
than a thin gold foil so heating is much slower, and less
spectacular. It's not nuclear physics, just basic RF electronics.

Do not induction furnaces operate at much lower frequencies.

I think so, but probably still in the RF range.

--Damon