Hello, all!
A while back, I made some extremely thin niobium ribbon for some jewelry. Sadly, I could'nt get it to affix to the silver.
However, I was wondering if anyone else could use some if I were to make more. I can likely get access to a roller for pressing out the niobium into a thin foil; getting it straight would be a bit trickier.
Niobium has a few interesting properties, the most notable of which being that it is a very inert metal, and won't oxidize under almost any circumstances. It is, however, somewhat brittle.
I've got a few bits of niobium wire left; could anyone use these for ribbon drivers?
A while back, I made some extremely thin niobium ribbon for some jewelry. Sadly, I could'nt get it to affix to the silver.
However, I was wondering if anyone else could use some if I were to make more. I can likely get access to a roller for pressing out the niobium into a thin foil; getting it straight would be a bit trickier.
Niobium has a few interesting properties, the most notable of which being that it is a very inert metal, and won't oxidize under almost any circumstances. It is, however, somewhat brittle.
I've got a few bits of niobium wire left; could anyone use these for ribbon drivers?
Well not sure if you can use it in a ribbon should be interesting. My dad did some research with Niobium for a high temperature heat exchanger for a nuclear reacter, apparently the metal is very expensive and very hard and they had trouble cutting it their tools. Should be interesting if anyone cooks something up not sure about any other properties of Niobium.
Niobium foil - can anyone use it?
Hi,
I use Niobium where I work - we make very sensitive measuring instruments which depend on the properties of this rather unusual metal.
We use it to wind electro-magnet coils, but when they are cooled down to the temperature of liquid Helium, the Niobium becomes a superconductor, so all the resistance disappears.
We make the coils into a closed loop by welding the ends of the wire together, and by some clever stuff I won't describe, we can trap a current into the coil and make a permanent but adjustable magnet. ( as long as it stays cold )
As far as using the stuff at room temperature is concerned, all I know is that it's a pig to machine, you can't solder to it, and it work-hardens, so if you think it's brittle now, you aint seen nuthin yet... Don't use it for any application where it will see repeated stress - it WILL crack through.
Electrically it's not a lot of use - about 10 times worse a conductor than Copper - unless you have some way to cool it below 9 degrees Kelvin...
It forms an insulating skin when exposed to the Oxygen in air, like Aluminium does, but faster, so it's like anodising for free, and once it's formed, the Oxide coating can be dyed in the same way.
It's too heavy for things like surgical implants - Titanium is better for hip-joints, etc., but as the oxide makes it non-allergenic, it's OK for jewelry, and lighter than stainless steel.
Hope this helps
grahamprie
Hi,
I use Niobium where I work - we make very sensitive measuring instruments which depend on the properties of this rather unusual metal.
We use it to wind electro-magnet coils, but when they are cooled down to the temperature of liquid Helium, the Niobium becomes a superconductor, so all the resistance disappears.
We make the coils into a closed loop by welding the ends of the wire together, and by some clever stuff I won't describe, we can trap a current into the coil and make a permanent but adjustable magnet. ( as long as it stays cold )
As far as using the stuff at room temperature is concerned, all I know is that it's a pig to machine, you can't solder to it, and it work-hardens, so if you think it's brittle now, you aint seen nuthin yet... Don't use it for any application where it will see repeated stress - it WILL crack through.
Electrically it's not a lot of use - about 10 times worse a conductor than Copper - unless you have some way to cool it below 9 degrees Kelvin...
It forms an insulating skin when exposed to the Oxygen in air, like Aluminium does, but faster, so it's like anodising for free, and once it's formed, the Oxide coating can be dyed in the same way.
It's too heavy for things like surgical implants - Titanium is better for hip-joints, etc., but as the oxide makes it non-allergenic, it's OK for jewelry, and lighter than stainless steel.
Hope this helps
grahamprie
can't use it but it's cool...
http://en.wikipedia.org/wiki/Niobium
can't your company resell the stuff?
http://en.wikipedia.org/wiki/Niobium
can't your company resell the stuff?
Re: Niobium foil - can anyone use it?
Awww, your no fun.
What's so special about persistance switches, anyway?
Cheers, John
grahamprie said:
Awww, your no fun.
What's so special about persistance switches, anyway?
Cheers, John
poobah said:
Rocket boy?? who, me??😉
Ya make a coil using supers.
Ya take da ends, and ya connects em togetha.
Den ya puts da heater on it.
And ya's solder some more leads to the coil leads...
When ya's wanna put current in da coil, ya heats da connection, makin it a resistor. Puts in current to da coilz, coupla hunnert or tousands of amperesands.. When ya'z done, ya toins off da heater. The joint, itsa gonna cool down. When it gets colda again, poof...ya gots ya persistant currents..
Easy..right??
For super magnets, helium is a big cost issue. The leads that come out to room temperature consume a lot, as they have to be very good conductors of current, but that also comes with good heat conduction. Ice forms at the exit points, and it costs a lot of helium.
So, one solution is to short the magnet inside the helium with another piece of superconductor. That way, once there is current in the magnet, it will continue (persist) even with the supply off. Because the shorting piece is superconducting, it has to be made non-superconducting for the time you wish to charge the magnet.. That is done by heating it a bit. Once that is done, a voltage can be put across it, and the magnet will begin to charge..one volt across one henry, one ampere per second..
Once the magnet current is at the desired point, the heater for the shorting piece is turned off. When it becomes a superconductor, you can turn the supply off, and the current will continue to circulate.
Then, you have a mechanical widget that disconnects the leads to the outside world, and now there is no thermal conduction to boil off helium.
There are a several other charging techniques, but this switch is simple, reliable, and is used all over the place. By welding the niobium titanium filaments without the copper cladding, you can even eliminate the small ir drop that happens through the copper cladding. While solder joints can be made that drop into the nano-ohm regime, it is still better to have super to super contact. That way, the field remains constant for a long time, a prerequisite for MRI machines.
Cheers, John
persistence switches
for instance, a strap of superconductor across the magnet terminals... run above Tc by heating to develop a voltage, then the heater is turned off to allow it to superconduct and complete the persistent mode circuit.
auplater
for instance, a strap of superconductor across the magnet terminals... run above Tc by heating to develop a voltage, then the heater is turned off to allow it to superconduct and complete the persistent mode circuit.
auplater
Superconducting magnets, etc.
Hi everyone,
I'm glad I'm surrounded by experts...
We wind the superconducting wire round an 1/8 watt resistor and when we pass a small current which warms the resistor a short length of the wire goes 'normal' and we can inject a current across the small resistance ( 10 milliohms ) it puts into the loop.
Just to give you an idea of the scale - we use 0.1mm diameter Niobium wire and we can store 15 Amps in it. Any more and the flux density in the wire takes it out of the superconducting state and the current is lost.
We also use another surprising effect - transformers will pass DC if they're wound with superconductors - so we can use coupled circuits to link sections of the system together. This is useful to us because we use SQUIDs as detectors, and we want a level frequency response down to DC.
We also have a partial answer to the heat input down the wiring issue - we use Phosphor-Bronze wire which is about 8 times the electrical resistance of Copper, but 100 times the thermal resistance. This means we have to use thicker leads than we would need with Copper, but we still save on the heat input.
We have 168 thin wires to drive the resistive switches, 112 more thin wires for the SQUIDS, and a couple of thick ones for the setup currents, and we currently boil off about 3 litres of liquid Helium an hour from the 80 litre reservoir. This means we can run the system with just a daily refill, and get at least 16 hours of work out of it.
Anyone got any idea what we make?
Bye...
Hi everyone,
I'm glad I'm surrounded by experts...
We wind the superconducting wire round an 1/8 watt resistor and when we pass a small current which warms the resistor a short length of the wire goes 'normal' and we can inject a current across the small resistance ( 10 milliohms ) it puts into the loop.
Just to give you an idea of the scale - we use 0.1mm diameter Niobium wire and we can store 15 Amps in it. Any more and the flux density in the wire takes it out of the superconducting state and the current is lost.
We also use another surprising effect - transformers will pass DC if they're wound with superconductors - so we can use coupled circuits to link sections of the system together. This is useful to us because we use SQUIDs as detectors, and we want a level frequency response down to DC.
We also have a partial answer to the heat input down the wiring issue - we use Phosphor-Bronze wire which is about 8 times the electrical resistance of Copper, but 100 times the thermal resistance. This means we have to use thicker leads than we would need with Copper, but we still save on the heat input.
We have 168 thin wires to drive the resistive switches, 112 more thin wires for the SQUIDS, and a couple of thick ones for the setup currents, and we currently boil off about 3 litres of liquid Helium an hour from the 80 litre reservoir. This means we can run the system with just a daily refill, and get at least 16 hours of work out of it.
Anyone got any idea what we make?
Bye...
Re: Superconducting magnets, etc.
Ummmm, let me guess....hmmmm, squids...
Ok, I got it....you make fishtank calibration units...
no, no...ummm, airbag deployment detectors...
No, no..that can't be it...liquid helium....I know..special effects for Lethal Weapon movies...wait, wait..that was liquid nitrogen, wasn't it??
15 amps to self quench?? Holy mackeral.. I'm sorry, I don't have experience with supers that small. The smallest I have is 13 mil Niobium Ti, short sample over 200 amps.
.1mm. whats that, 40 awg? I hate that small stuff, my arms are too short to see it...I'm havin trouble with the 13 mil as it is..
Your "transformer passing dc" is interesting. I take it you mean that a super loop which intercepts flux, circulates current..we have that problem with the dipoles, as the recirculating currents cause sextupole harmonics.
Strange beast, this supercon stuff, ain't it?
My current headache is testing a six layer sextupole in superfluid without a lambda plate. What a pita..we're down to 11 mm pressure, the leads keep quenching..
On your phosphor bronze, you using formvar insulation, or a polyimide? My apps require ground isolation for ramp and quench protection, and I find the formvar sucks big time..I use 50% overlap kapton covered by tefzel heatshrink.. I need at least 2 to 3 kilovolt ground isolation to dump the energy outside the cryostat. Fingerprints wipe that out with formvar.
Even the quad twist from lakeshore is insufficient for my needs.
Cheers, John.
grahamprie said:
Ummmm, let me guess....hmmmm, squids...
Ok, I got it....you make fishtank calibration units...
no, no...ummm, airbag deployment detectors...
No, no..that can't be it...liquid helium....I know..special effects for Lethal Weapon movies...wait, wait..that was liquid nitrogen, wasn't it??
15 amps to self quench?? Holy mackeral.. I'm sorry, I don't have experience with supers that small. The smallest I have is 13 mil Niobium Ti, short sample over 200 amps.
.1mm. whats that, 40 awg? I hate that small stuff, my arms are too short to see it...I'm havin trouble with the 13 mil as it is..
Your "transformer passing dc" is interesting. I take it you mean that a super loop which intercepts flux, circulates current..we have that problem with the dipoles, as the recirculating currents cause sextupole harmonics.
Strange beast, this supercon stuff, ain't it?
My current headache is testing a six layer sextupole in superfluid without a lambda plate. What a pita..we're down to 11 mm pressure, the leads keep quenching..
On your phosphor bronze, you using formvar insulation, or a polyimide? My apps require ground isolation for ramp and quench protection, and I find the formvar sucks big time..I use 50% overlap kapton covered by tefzel heatshrink.. I need at least 2 to 3 kilovolt ground isolation to dump the energy outside the cryostat. Fingerprints wipe that out with formvar.
Even the quad twist from lakeshore is insufficient for my needs.
Cheers, John.
squids and such
well... ~30 years or so ago we were building josephson bridges with niobium metallization on quartz substrates for radio astronomy detectors...
soo... maybe you're looking for extremely small rf signals...
Is this a test? 😉
auplater
well... ~30 years or so ago we were building josephson bridges with niobium metallization on quartz substrates for radio astronomy detectors...
soo... maybe you're looking for extremely small rf signals...
Is this a test? 😉
auplater
Re: squids and such
Of course it's a test..
It is a well known fact that some ichthyosaur vomit (alleged vomit, of course) was discovered in a quarry in Peterborough in the UK in 2002, and it supposedly contained partially digested squid remains..
So, obviously, he is involved in quality control for ichthyosaur vomit bags..
(isn't google soooo coool?)
Cheers, John
auplater said:
Of course it's a test..
It is a well known fact that some ichthyosaur vomit (alleged vomit, of course) was discovered in a quarry in Peterborough in the UK in 2002, and it supposedly contained partially digested squid remains..
So, obviously, he is involved in quality control for ichthyosaur vomit bags..
(isn't google soooo coool?)
Cheers, John
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