At CRETA-CNRS Grenoble, France, we dispose of Oxford type cryomagnets able to deliver 10 T or more with an internal bore of ~120 mm diameter. In the bore we have installed furnace (able to heat up to 1000°C even more and working under vacuum or different type gases... ..These are the best conditions to relase your treatment.

In my opinion the ribbon must be annealled parallel to the magnetic field accounting for the demagnetizing field that can operate after treatment.. But it depend also what you like to do with the material

Can you see how to dispose of such equipement not so far from you Institute, otherwise take contact with us to realise the treatment.

Best regards

Daniel

Correction read "These are the best conditions to realize your treatment."

I'm not sure how Metglas does their annealing. It looks like they are recommending a longitudinal field, and that will most likely make a difference in the easy axis of magnetization. Their heat treatments are for 1) stress annealing and 2) domain poling. The stress anneal won't need the magnetic field, but the poling will. It most likely won't change your saturation magnetization, but will probably affect a difference in permeability and coercivity. I'm not sure about the magnetostriction.

The 2605 looks to be recommended for transformer cores, so it's most likely a high cobalt alloy. However, there is probably a significant Fe concentration as well, and that would probably not do well in an ambient anneal. I would tend to recommend inert atmosphere (Ar or N2 - probably don't need H2).

Keeping the H field uniform in the furnace is probably difficult. First, the resistance of the magnet wire will change with the elevated temperature, so monitor the current during ramp up (and make sure your insulation is rated up to 320 - that's fairly toasty for some insulators). But, more tricky, the electromagnet would need to be significantly larger than the sample, in order to ensure local uniformity.

To sum up. Align the magnetic field with the preferred easy access of the ribbon to maintain permeability in that direction. An inert atmosphere is probably required. Monitor your current flow to the field generator during the ramp and soak. Make sure your field is as uniform as possible.

Keep us posted on how you manage it.

the magnetic field must be in plane, but placing an EM in a furnace is quite difficult. The best thing to do is to place a long staight ribbon in a solenoid made from fiber-glass insulated copper wire. Alternatively you can roll the ribbon in ring or frame shape and wind it. If the ring is small, just to supply a strong DC current though a copper bar passing in the hole.

I agree with D. Fruchart .

¿Can you sending technical data of equipment for heat treatment ?

¿What ribbon length can be treated ?

Yes, keep the H field uniform in the furnace is probably difficult. !

This depends a lot on the size of your sample. Is this a bit of tape, a small core, or a larger batch of cores?

To Marcelo and to all.

The field in the furnace is particularly well stabilised (~ 10-3). There is a region large enough (a few cm) whre the field can be considered as constant, apart there is a field gradient.

So it could be possible to design a easy system to move ong ribbons between two bobbins

Dear D. Fruchat : ¿ Can you send me technical data, or link of cryomagnets type? or type of colaboratión posible for futures works. I am interested in this process.

http://www.lanacion.com.ar/1409354-la-actividad-nanotecnologica-en-alza

Marcello, tody but much later.. I will answer

Marcello,

Please contact me directly by

[email protected].

I had discussed with people who have interest to discuss your questions and problems.

We can try doing something with you and your group.

Best regards

Daniel

http://creta.grenoble.cnrs.fr/

@David Gray, it is actually a Fe-Si-B alloy and thank you for the suggestion

@F. Mazaleyrat, It is a small ribbon only 0.001 in. thick. Have you tried the solenoid method on such a sample?

@Stan Zurek, It is a thin ribbon by itself that I was intending to heat treat. Would you suggest laminating a few layers together before heat treatment? If so, how would you hold the laminations together

Well, there are process as well as equipment questions. The first one is the equipment. Ultimately the volume of the material you want to process in a single run defines how big your equipment must be. For instance, you you need to anneal just a short piece of tape (e.g. to be used for a sensor) then your furnace and electromagnet can be quite small (=inexpensive). But if you need to do a large core or a reel of tape then the chamber has to have large dimensions, which means expensive equipment and quite a lot of electric power to drive it.

To attain 0.3T in thin air is not that easy over a large volume (as the annealing chamber would be).

We wrote a paper on such an electromagnet, see attached.

Yes I used the solenoid method, it was quite common in the 80's to anneal amorphous ribons that way. For this kind of ribbons; if the lenght is 10 cm or more, few 1000 A/m is more than necessary. If you need to improve the temperature homogeneity, just put the ribbon on a copper bar. The longitudinal field annealing will give you a sqaure loop, but if you need to make it flat, transversal annealing is more complicated beacause of stronger demagnetisation.