New super conductor

If LK-99 can be mass produced, it would be a world changer.

The key point is that the material does not require massive pressures to be applied, unlike previous room temperature superconductors.

LK-99 is the first room temperature superconductor to work at ambient pressure.
 
With the moving mass of the diaphragm/voice coil exercising the static B field of a field coil, I think the effort will be not worth the trouble--i.e., persistent induced eddy currents in the field coil. Also, the requirement for an extremely slow rate of energization of the field coil to minimize induced eddy currents, as well as likely quenching episodes due to magnet training if high field strengths are designed, etc. will also make the use of superconducting materials for static magnetic fields (in audio) unlikely.

Room temperature superconductors would be nice to have for DC power transmission use for microgrids, etc., but only if the price of the superconducting material itself drops to near copper prices.

Chris
 
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Let's hope they can make a better sample that actually levitates.

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Extraordinary claims require extraordinary evidence, as the saying goes. So far there is no replication neither strong evidence towards this substance being a superconductor.
First, actual resistivity as shown in the research data is larger than resistivity of copper:
Secong, "semi-levitation" is replicated using ordinary diamagnetic, a piece of pyrolytic graphite:

Is there any indication that you can even bend this stuff and still have it work?
This stuff so far exists only as vapor deposed film, so while a copper substrate can definitely be bend, I'm not sure the coating itself will retain its properties.

If someone wish to take a deeper dive, here is open acess paper:
https://www.kci.go.kr/kciportal/landing/article.kci?arti_id=ART002955269
(click "Download PDF" button on the right)
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""This stuff so far exists only as vapor deposed film, so while a copper substrate can definitely be bend, I'm not sure the coating itself will retain its properties.""
A manu process consistent with HTS tapes. To get around the bending issue, the HTS film is deposited on a hastalloy tape, and a second hastalloy tape is bonded to the film. That way, the film is in the neutral plane when the tape is bent, the edges are soldered together. No conductor strain in the neutral plane (I should copyright that phrase).

Using that design change, we can now do 50mm radius bends without damaging the properties. I believe they are getting better with that recently. But I've not seen production quantities yet. Everything we've used is of limited length, we need kilometers of it for production of magnets. At this point in time, fusion is getting the big quantities. The meter size fusion devices require 12 to 20 tesla fields, HTS is the only candidate for that due to critical current/field capabilities, and easier cooling requirements.

If it is real, wire production is way into the future. I believe a CORC construction would be best for transmission cables.

The real problem is what happens if it quenches? Our LTS conductors need to have the quench detected in low milliseconds (Niobium titanium), and 10 microseconds for Niobium Tin (with energy extraction and distributed quench dispersion heaters). HTS has a slower quench profile, not sure what this possible RT material would do.

How to do this with a transmission line with time varying loads and load transients is a huge technical challenge. The transmission lines would need to be at least a factor of 10 or 20 times the current being carried to absolutely avoid quenches.

It is possible to make the cable coaxial with a center copper wire, that being used to detect any IR drop in the superconductor, with the core wire being impervious to the currents of the outer super. That has the detection speed limited by the coax prop speed. For HV cables, that would mean roughly 5-10 nSec per foot capability, or a 10 microseconds per 1000 feet. But the quench detection electronics would have to float off ground, again not an easy task (but doable).

Ah, forgot to mention... If this stuff were used in house wiring and a quench occurred in the wall, the house burns. Production of millions of reliable quench detectors that will be reliable for the masses, well lets just say I'm not holding my breath. We are very good at doing that, and it ain't ready for prime time.

As a field coil construct, the limiting factor would be the iron used for the magnetic circuit. At 1.5 tesla gap field, we are already into saturation in spots in the structure, but the wind is in the good direction for any tape.

For VC's, the wind is more challenging. Also, the strength needed for hoop forces is an issue. In this case, weight would be the best advantage, as a 20-40 amp super could be as small as 20 mils diameter. Lots of turns in a very small space, and due to small size, little in the way of eddy losses, especially in the bass to midrange frequencies. But VC's are the best place for advantage if the RT super is real.
John
 
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The level of noise caused by a quench depends on the energy stored,the support structure integrity, and what is within the field that can move or react to the quick drop of magnetic field (eddies). The LHC for example, vaporized 2000 gallons of helium 3, resulting in an event picked up by seismographs in neighboring coutries. Others, like the ALPHA antimatter confinement bottle, are lower energy and make no noise. None of my direct wind magnets make noise when quenched. MRI's, I have no idea.

John
 
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