Soft magnetics Ni alloy 1

[marcus4]

Hi. I have a problem identifying this alloy (material) . It should be soft magnetics material made in Germany (1940-1960) . Thanks

Ni-58%
Fe-26.3%
Cr-6.6%
Cu-3.7%
Mn-1.1%
Al-1.2%
Na-1%
Si-0.7%
Co-0.3%

 

[EdStainless]

This looks like a constant (wrt field strength) permeability alloy similar to Permivar or Mumetal.
It will not have a very high saturation but will be very constant.

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Plymouth Tube

 

[marcus4]

Thanks, i'm confused with 58% Ni percentage. Since the results are from X-ray flurescence spectrometry, is it possible that Lab made error or some manufacturers use smaller amount of Ni in their Mumetal mixtures ??? Sorry for dumb question.

 

[EdStainless]

The Cr, Cu and Al are added to increase electrical resistance.
There is no Na in it. Was it cleaned and freshly polished? Might be surface contamination messing with the analysis.
You are correct, the 60% Ni/25% Fe is an odd ratio.
It does make me wonder how close their reference standard was.....

But if this material was used in the 40's, it may be a design from the 20's.
The alloy may not be for maximum perm but rather for either constant perm with field strength or constant perm with temperature.
It could have been used as a tuning shunt on a magnetic circuit. Bleed off more field at room temp and less at high temp so that the working field stays more consent.

What kind of device what this used in?

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Plymouth Tube

 

[marcus4]

Thanks for answers. Well, it looks like some variation of Mumetal since it was used for output audio transformer (small signal and power), lamination 0.35mm thickness. I'm not sure about cleaning since I was not in the lab during Xray but it's possible that it's contaminated somehow. Sheet says "No sample preparation" so it must be over the years. I would really like to know history of this material and possibility or reproducing the same since it works great under the application.

 

[MagBen]

since it was used for audio transformer, most probably this is something like Perminvar (=permeability invariable) with 50%nickel, 25%cobalt, 25%iron. Is that for telecommunication? the constant permeability at low magnetic field will minimize the signal distortion, so high sound quality.
nowadays, people like to use mumetal or permalloy for audio transformer, since one of main goals is to decrease the exciting current in primary to negligible level, high permeabiltiy is obviously beneficial. Also, since harmonci distortion is inversely proportional to permeability, high permeability means low distortion.
constant permeability is beneficial either, but if you can design a transformer to operate at a low flux density such that mumetal is more in the linear portion of curve, you will obtain benefit for a constant permeability.

 

[marcus4]

As I can see there is no Co inside this alloy. Of course, this material can be substituted with similar "modern" but I was interested in exact (or few % up/down) chemical composition. Unfortunately I have no idea where to start from .

 

[MagBen]

It seems there are different version of perminvar, and no Co is possbile (see the paper publishedin 1930: Perminvar, an alloy of nickel, copper, and iron, used in proposed trans-Atlantic telephone cable, J. Chem. Educ., 1930, 7 (1), p 176).

A full wet chemistry analysis would give you an accurate composition of the alloy. But an electrical steel might be able to do a better job if you could design the transformer properly. And Si steel is cheap too.

 

[marcus4]

According to Woldman's Engineering alloys Bell Labs produce only Co Perminvar Alloys. Not sure about other manufacturers.

 

[EdStainless]

I am not in my office to check, but Perminvar was called other names by other companies.
Who knows what the Germans did.

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Plymouth Tube

 

[marcus4]

Please post when you check, I'm sure that Germans had a different name for that alloy.

 

[marcus4]

Polite bump