GB2023653A

GB2023653A - Zero Magnetostriction Amorphous Alloys

Info

Publication number: GB2023653A
Application number: GB7908118A
Authority: GB
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1978-04-20
Filing date: 1979-03-07
Publication date: 1980-01-03
Also published as: FR2423548A1; DE2915765A1; JPS54148121A

Abstract

Amorphous metal alloys having essentially zero magnetostriction consist of iron, silicon and another glass former in proportions of 70- 90, 5-20 and 5-20 atom percent, respectively. The glass forming elements may be B, C, Al and P and mixtures thereof; and the alloys may be produced as ribbons.

Description

SPECIFICATION Amorphous Metal Alloys Having Zero Magnetostriction and Ribbons Thereof The present invention relates generally to the metal alloy art and is more particularly concerned with novel amorphous metal alloys having zero magnetostriction and with ribbons and other useful articles made therefrom.

It has been recognized by those skilled in the art that amorphous metals having little or no magnetostriction could have possibly important uses in magnetic devices. They have also been aware that in crystalline alloys zero magnetostriction compositions occur at approximately 80Ni--20Fe and 95Co-5Fe. The addition of glass formers to the 80Ni--20Fe composition results in amorphous alloys which - are not magnetic at room temperature. The 95Co-5Fe alloy can be made amorphous but it makes use of the expensive and scarce cobalt.

Consequently, there has not heretofore been an amorphous metal with essentially zero magnetostriction with high Fe contents to the best of my knowledge.

This invention, based upon a new concept to be described, provides a new class of amorphous metals having essential zero magnetostriction. In general terms, these are iron-silicon alloys which contain another glass former which may be boron, carbon, aluminum or phosphorus or any mixture thereof. The proportions of the constituents of these alloys expressed in atom percent are 70 90 iron, 5-20 silicon and 5-20 second glass former (G). While other elements may be included in these new alloys of this invention without detrimental effect upon magnetostriction or other desired property, the foregoing essential constituents will be present in the ranges of proportions to each other stated above.

Further, these new alloys can be used to produce amorphous metal ribbons likewise having essentially zero magnetostriction and consequently having special utility in the construction and operation of magnetic devices.

Moreover, these new ribbons can be produced by methods and means used in the production of ribbons or amorphous metals of the prior art.

This invention is predicated upon the observation that certain iron-silicon alloys which are crystalline exhibit zero magnetostriction in the vicinity of 1 2 atom percent silicon, and is further based on the concept of adding one or more glass formers other than silicon to such alloy compositions to produce amorphous alloys while retaining the zero magnetostriction characteristic.

In developing that concept have concluded that it is important to maintain the constituents of these new compositions within the ratio ranges stated above. Thus, if less than 70 atom percent iron is present, the magnetic property of the ultimate alloy ribbon product will be too low for most useful purposes and it will preclude the possibility of producing an amorphous metal ribbon.

Similarly, the presence of more than 90 atom percent iron will preclude the possibility of producing an amorphous metal ribbon, as will the presence of less than five atom percent of the other or non-silicon glass former; and the presence of less than five atom percent silicon will result in substantial magnetostriction in the ribbon product.

In practicing this invention, novel alloys are prepared suitably by mixing together the alloy constituents in the required proportions in the form of powders and then melting the mixture to provide molten alloy for casting to ribbon of the desired dimensions.

Cooling is carried out in the casting operation at a rate sufficient to produce amorphous material.

While variations in melting point temperatures between alloys of this invention may impose requirements which vary with respect to alloy melting and casting operations, the preparation and processing of these alloys can be carried out with uniformly satisfactory results by following the above procedure and using the described equipment. In other words, the results of this invention are reproducible in a substantially routine manner so long as the compositional limitations stated above and in the appended claims are strictly observed in the preparation of the alloys.

Those skilled in the art will gain a further and better understanding of this invention from the following illustrative, but not limiting, examples of the practice of the invention as it may be carried out to gain the new results and advantages.

Example I A ribbon approximately 0.0025 cm thick by 0.13 cm wide of Fe80SiBg can be made by directing a stream of the alloy onto the surface of a rapidly revolving chill roll or drum.

The amorphous nature of the resulting ribbon can be confronted by X-ray diffraction, differential scanning calorimetry, or by magnetic and physical property measurements. The fact that the ribbon exhibits little or no magnetostrictive property can be confirmed by direct measurement or by applying tension to the test specimen while observing hysteresis loop behavior.

Example II A ribbon of Fe80SiaOB7AI3 can be prepared and tested as described in Example I with the same results.

Example Ill Still another amorphous metal alloy ribbon of composition Fe84Si6B8C2 can be prepared and tested as described in Example I, again with the same essential results.

Example IV A ribbon of Fe85SiaOPs can be prepared and tested as stated in Example I with basically the same results.

Example V A ribbon of Fe7sSi,5B,O can be prepared and tested as described in Example I with the results described in Example

Claims

1. An iron-silicon amorphous metal alloy having essentially zero magnetostriction consisting essentially of 70 to 90 atom percent iron, from 5 to 20 atom percent silicon and from 5 to 20 atom percent of a glass forming element (G) selected from boron, carbon, aluminium and phosphorus and mixtures thereof.

2. An alloy as claimed in claim 1 having the formula Fe80SiGg.

3. An alloy as claimed in claim 1 having the formula Fe80Si,OB7G3.

4. An alloy as claimed in claim 1 having the formula Fe84Si6B8G2

5. An alloy as claimed in claim 1 having the formula Fe85Si,OG5.

6. An alloy as claimed in claim 1 having the formula Fe75Si,5G,O.

7. An alloy as claimed in claim 1 substantially as hereinbefore described in any one of the Examples.

8. An article of manufacture, a ribbon of amorphous metal alloy as claimed in any one of claims 1 to 7.