MgB2 Superconductors

[MSimon]

Nice short overview of MgB Supers.

http://superconductors.org/39K.htm

General Search:

http://www.google.com/search?q=MgB+Supe ... art=0&sa=N

[pstudier]

More importantly, here is a company who has actually used magnesium diboride in a real product:
http://www.columbussuperconductors.com/ ... elease.pdf

[MSimon]

Here is an even better one doing stuff for the US Navy and Air Force among others:

http://www.hypertechresearch.com/index.html

[Keegan]

Wow the tape they have in production is remarkably complex geometry of diffrerent metals. It looks like we have got a lot of work infront of us. That was a huge machine and it only got to 0.5T

[MSimon]

You need 2X the amper turns for a coil 2X across to maintain the field strength.

[scareduck]

Why MgB2 over other superconductors? MgB2 operates below the boiling point of liquid nitrogen (39K to superconducting temperature vs. ~77K boiling point for liquid nitrogen). Is it just cost considerations?

[MSimon]

Why MgB2 over other superconductors? MgB2 operates below the boiling point of liquid nitrogen (39K to superconducting temperature vs. ~77K boiling point for liquid nitrogen). Is it just cost considerations?

There are a number of considerations.

MgB is conductive at all temperatures. It is easy to manufacture. It looks like the Tc can be raised at least another 5K.

For equivalent magnetic fields MgB vs the other high temp superconductors have to operate at about the same temperature ranges.

If only B10 was used in the mfg that would raise Tc a bit.

Then we come down to cost. MgB looks good. Plus, being a metal bending issues are not so serious. So it is easier to use. A big plus.

Update: using only Mg24 vs 25 or 26 (which total about 20% of natural Mg) would also raise Tc some.

http://en.wikipedia.org/wiki/Isotopes_of_magnesium

[MSimon]

Existing superconducting MRI systems use niobium titanium (NbTi), a metal superconductor, and require liquid helium bath cooling, which results in large, high-cost systems. The current MRI market growth is driven by three factors: 1) the requirement for having a more open structure, 2) the use of smaller and less complicated systems, and 3) the need to lower the cost of MRI diagnoses to the patient (and the insurance carrier). These factors can be satisfied by building and supplying smaller, less complicated (liquid helium free), lower cost superconducting MRI systems. This will require magnets that can operate at higher temperatures (higher than 4.2 K) and can be cooled conductively with a cryocooler cold-foot and small refrigerator instead of convectively in a large liquid helium container and an attached re-condensing refrigerator. MgB2 superconducting wire will function in the 20 to 30 K temperature range and can be supplied at an overall wire cost similar to that of NbTi wire, which operates at 4 K (or lower). Along the same lines, MgB2 can be supplied at one-tenth the cost of ceramic high-temperature superconductors (YBCO and BSCCO).

The combination of lower wire price, higher operating temperature, and lower cooling costs will enable MRI manufacturers to build systems that require no liquid helium to directly cool the magnet, offer more open access to meet market needs, and have lower initial system costs and lower operating costs.

http://www.hypertechresearch.com/page5.html