DE2244925C3 - Use of a cobalt-nickel-iron alloy as a semi-hard magnetic material - Google Patents

Description

35

The invention relates to the use of an alloy as a semi-hard magnetic material.

In general, magnetic materials used in switching elements or semi-permanent magnetic Storage devices are used that have the following properties:

1. Both the saturation magnetic flux density (Bs) and the remanent magnetic flux density (Br) are large.

2. The square hysteresis loop has a high square ratio (BrjBs) and a large "fill factor". The expression "fill factor" jo is represented by the formula

\ (BH) _n JBr Hc

where (BH) _{wax is} the product of the maximum magnetic energy and Hc is the coercive force.

3. The coercive force (Hc) is in the range between 10 and 50 Oe. In particular, the magnetic materials used in switching elements such as reed switches should also have the following properties.

4. Even if the magnetic materials are diffused or melted down in the glass are exposed to a high temperature, this high temperature will cause the desired magnetic remanence properties are not impaired.

5. The coefficient of thermal expansion of the magnetic Materials is essentially the same as that of the glass material to choose between these two Materials to ensure a good seal.

6. The plastic deformability is excellent, that is, the materials can easily be molded into the desired shape or size, such as τ. B. a thin wire rod with a diameter of the size of a millimeter can be deformed.

Several cobalt-iron alloys have already become known as semi-hard magnetic materials. One of these materials, which consists of an alloy of 48% iron, 48% cobalt, 3.5% vanadium and 0.5% manganese, is described in the journal "Bell Laboratories Record", p. 257, June 1965. In the journal "Journal of Applied Physics", p. 1268, February, Vol. 39, 1968. a permanent magnet alloy with low magnetostriction is described, which consists of 82% cobalt, 12% iron and 6% gold. So far, however, no semi-hard magnetic materials have become known which meet all of the requirements listed above.

By the German Auslegesohrift 1 239 107 is an iron-nickel-cobalt-based alloy has become known that contains small amounts of titanium. niobium and contains tantalum individually or together, but either niobium or tantalum must be present This alloy is characterized in the hardened state by one of the temperature essentially independent modulus of elasticity and serves as a material for objects such as springs and vibration elements, where the thermoelastic coefficient should remain constant over a wide range.

When looking for a semi-hard magnetic material that has the properties listed above fulfilled and in particular an excellent squareness ratio as well as an excellent cure ven fill factor, it was found that au the basis of the known alloy with corresponding! Composition and treatment of the desired " can win semi-hard magnetic material.

The invention is characterized by the use of an alloy consisting of (a) cobalt (b) iron, (c) nickel and (d,) niobium or (d ₂ ) niobium and at least one metal from the group of tantalum titanium. Vanadium. Zirconium. Molybdenum. Chromium tungsten, with the proviso that the weight ratio of (a) cobalt to (b) iron in the range from 3: 2 to 1: 2 and the weight ratio of (c) nicke to (b) iron in the range of 1: 1 up to 1: 3 and the proportion of ld,) or (d ₂ ) is 1 to 5 percent by weight of the entire alloy, which has been age-hardened at 600 to 9 (X) C and then cold-worked by at least 75%, as semi-hard magnetic Material.

The alloy materials listed above may contain a trace of impurities that will last You can also use deoxidizers or ent Sulphurizing agents such as manganese, magnesium. Calcium, aluminum or silicon, in which to fulfill contain the amount required for their purpose. In general, the proportion of the deoxidation initiation is or the desulfurizing agent below I weight percent.

The presence of niobium in the alloy material has a great effect on an increase in the coercive force of the alloy, the proportion exceeds but 5 percent by weight of niobium, then the magnetic flux density, i.e. H. the magnetic induction, of the alloy obtained, and the workability of the alloy is significantly deteriorated. On the other hand, if the niobium content is less than 1 percent by weight, then the effect is the coercive force to enlarge, too small to be of any practical use.

Part of the niobium contained in the alloy material can be replaced by one or more other metals that perform a similar function. These metals are e.g. B. tantalum, titanium, vanadium, zirconium. Molybdenum, chromium, tungsten and the like. The amount of these metals used in addition to niobium is preferably chosen so that the weight ratio of these metals to niobium is below 30:70. If the weight ratio is not less than 30 to 70, then the coercive force of the le _c ation is not increased as much as is the case when only niobium is used.

The amount of cobalt is chosen so that the weight ratio of cobalt to iron is in the range from 3: 2 to 1: 2, preferably between 3: 2 and 2: 3, but most preferably approximately 1: 1. If the weight ratio is within this range, the alloy material is superior in magnetic properties, particularly magnetic flux density (B ₁₀₀ ).

The nickel content is chosen so that the weight ratio of nickel to iron is in the range between 1: 1 and 1: 3. If the weight ratio of nickel to iron is below 1: 3, it is difficult to carry out the desired cold working. On the other hand, if the weight ratio is greater than 1: 1. then the saturation magnetization (a _s ) of the alloy material is too small. The weight ratio of nickel to iron is preferably between 2: 3 and 1: 3 in view of the desired coefficient of thermal expansion of the alloy material.

The semi-hard magnetic properties of the alloy material, especially the squareness ratio (BrIB ₁₀₀ ) and the curve fill factor

(S [BH) _n JBr-Hc)

must be trained so by appropriate procedural steps will. In order to be suitable for use according to the application, the alloy material must have a Annealing treatment at a temperature between 600 and 900 "C and cold working with a May be subjected to a reduction in area of not less than 75%. In general, cold working is used carried out gradually until the reduction in cross-section has reached 75% or more, one or more annealing treatments at a temperature between the deformation steps of not less than 600 "C at suitable intervals inserted.

If the reduction in cross-section is below 75%, then both the coercive force (Hc) and the magnetic induction (β, ₀₀ ) of the alloy material obtained are acceptable. Furthermore, if the annealing treatment is carried out at a temperature below 600 ° C., the plastic workability of the alloy material is not improved and it is difficult to achieve the desired reduction in area during cold working. Optimal results are achieved when the annealing process is carried out at a temperature between 600 and 900 C. The verifiability of the rights and the curve fill factor are noticeably improved as a result.

The thus treated alloy material is preferably subjected to a final heat treatment or a thermal aftertreatment at a temperature below 800 ° C, the temperature exceeding 800 ⁰ C, then the coercive force is below 10 Oe.

The invention is illustrated in more detail by means of examples.

example 1

Mixtures of cobalt, iron, nickel and niobium in the ratio given in Table I with traces of silicon ^; to consist of the five metal materials cobalt, electrolytic iron, nickel. Ferroniobium and silicon produced. Each of the mixtures was in a crucible in a vacuum Ge- "chmolzen. The melt was then formed into a billet. The billet was machined by means of a forging press at a temperature of 110o ⁰ C. Thereafter, the ingot by means of a forging press, a draw bench and one was. Wire drawing machine cold drawn to form a wire rod with a diameter of 0.6 mm. During the cross-section reduction, annealing treatments were ^{inserted at suitable time intervals at temperatures between 1000 and 1100 °} C. The final cross-section was 92%. The expression "final cross-section" (in%) ) is by the formula

[((*? - d \)! D \\ - 100

defined, where d and d ₂ mean the diameter of the rod before the cold deformation and of the rod after the cold deformation, respectively.

Table I.
Composition of the alloy in percent by weight

Sample no. Co F ^; e Ni Nb SH-OOI (control) .... 46 46 5 3 SH-002 (control) .... 44 43 10 3 SH-003 (invention) 47 35 15th 3 SH-004 (invention) .... 39 38 20th 3

Of the four alloy materials listed in Table I, the two alloys SH- (X) I and SH-002 could not be processed into a wire rod because of their hardening during forging.
The two rods SH-003 and 3H-004 were

fto finally a final annealing treatment, d. H. subjected to hardening at different temperatures, FIG. 1 shows the dependence of the magnetic Properties of the alloys SH-003 and SH-004 on the temperature of the aging treatment shown. In Fig. 1, the abscissa is the temperature of the final incandescent treatment in Degrees Celsius and the magnetic induction on the ordinate, ™) in kiloaus for a Mannet field

of 100 Oe, the specific saturation magnetization (fr,) in electromagnetic units and the coercive force (Hc) plotted in Oe.

As from Fig. 1, the saturation magnetization (a _s ) is only slightly or not dependent on the curing temperature, ie it remains almost constant over the entire temperature range. The coercive force (Wc) varies up to almost 700 ⁰ C only slightly in function of the temperature. The magnetic inductions (B _m ) are large in to a temperature range above about 60FC.

Example 2

Using appropriate men- ■ j genes of cobalt, electrolytic iron, nickel and ferroniobium as well as a trace amount of silicon in in the same way as described for Example 1. Lead wires with a diameter of 0.6 mm mil the one in Table I! specified composition.

before the aging treatment. This goes from the Figs. 5 and 6 emerge.

F i g. 7 shows the dependency of the thermal expansion coefficient («) on the niobium content. As can be seen from this figure, the thermal expansion coefficient of the pipe bar before hardening decreases sharply with increasing niobium content. In contrast to this, the thermal expansion coefficient (n) of the wire rod has an almost constant value after the aging treatment at a temperature of 700 "C with a niobium content in the range between a very small percentage up to approximately 5%, ie almost the value 100 · IO ~ ⁷ on.

In this example only the alloy materials are included with a weight ratio of cobalt to iron of approximately 1: 1. It was found however, that similarly good results are obtained when the weight ratio is in the range between 3: 2 to I: 2 is varied.

Example 3

Tables
Composition of the alloy in percent by weight

Sample No. Co Fe Ni Nb

SH-005 (control) .... 40 40 20 0

SH-006 (invention) 40 39 20 I.

SH-007 (invention) .... 38 39 20 3

SH-008 (invention) .... 38 38 20 4

SH-009 (invention) .... 38 37 20 5

The F i g. 2 to 6, the dependence represent the magnetic properties of the niobium content in weight percent in the alloys door represents the case. That the conduit rods were subjected to vacuum to an aging treatment at temperatures of 600'C (curve 1) and 700 ⁰ C (curve 2) for 1 hour . In these figures, the curves labeled AD illustrate the data on the lead rods before the aging treatment. .

The following facts can be gleaned from these figures:

The coercive force (Hc) increases, as shown in FIG. 4 shows, with an increase in niobium content. The specific saturation magnetization ^) takes, as F i g. 2 shows, with an increase in the niobium content. The magnetic induction (B ₁₀₀ ) of the conduction rods subjected to the final annealing treatment at temperatures between 600 and 700 ^° C. is remarkably high compared to that of the conduction rods before the final annealing, as can be seen from FIG. 3 emerges. Both the _{squareness ratio} (Br / B xoo) and the curve fill factor A metal mixture consisting of 39 weight percent iron, 38 weight percent cobalt, 20 weight percent nickel and 3 weight percent niobium was produced from electrolytic iron, cobalt, nickel and ferroniobium. The mixture was melted in vacuo and then shaped into an ingot. The ingot was made by means of a forge

V) press thermoformed at a temperature of HOO ^{1 C.} The ingot was then cold-formed into seven wire rods, each 0.6 mm in diameter, using a forging press, a draw bench and a wire drawing machine. During the reduction in cross-section, annealing treatments at temperatures of 1000 to 1100 ^° C. were inserted at suitable time intervals. The final annealing treatment, ie the annealing immediately before the last cold drawing, was carried out at a temperature of 1100 ° C

executed. The final draft of the seven wire rods is given in Table III.

Table IH

Hc)

are high with a niobium content ranging from a very small percentage to approximately 5%, and the squareness ratio and the curve fill factor of the wire rods subjected to the aging treatment at temperatures between 600 and 700 ^° C. are higher than those of the wire rods

Sample no. 50
SH-010 Final
Reduction in cross-section
in% SH-Ol 1 0 SH-012 30th SH-013 51 SH-014 64 SH-OI5 75 SH-016 92 97

Finally, the cold drawn wire rods were cured at the various temperatures given in Tables IV and V. The dependence of the coercive force (Hc) in Oe and the

Magnetic induction (B ₁₀₀ ) of the conductor rods produced in this way from the final cross-sectional reduction in percent and the aging temperature is illustrated in Tables IV and V, respectively.

Table IV

Coercive force (lic) in Oe Temperature of the final annealing treatment: 110O ⁰ C

Enduring

tcmperalur

in C

AD
400
600
700
800
900

0.5
0.5
0.5
0.5
0.5
0.5

30th

11th

15th

15th

Il 4.3 0.5

Final reduction in cross-section in%

51

19 23 21 18

0.5

64 75 92 97 24 27 31 28 30th 34 41 39 25th 29 31 29 23.5 25th 26th 24.5 9.5 10 12th 10.5 0.8 I. 3 1.5

Table V

Magnetic induction (B _WQ ) in kilogauss. Temperature of the final annealing treatment: 1100 ° C

Curing
lemperalur
in C η AD 16.5
16.5 400 16.5 600 16.5 700 16.5
16.5 800 900

Final reduction in cross-section in%

.in 51 64 7.2 6.6 6.2 6.8 6.2 6.7 7.4 7.6 8.4 10.0 10.5 11.4 15.0 14.4 14.4 15.0 15.9 16.0

75 92 97 7.2 9.0 10.0 7.4 11.6 12.1 10.0 14.5 16.1 12.6 15.0 15.6 14.6 15.3 15.4 16.0 16.0 16.0

The F i g. 8 and 9 graphically represent the data of Tables IV and V. In these figures, the curves marked with the reference numerals 1, 2, 3.4 and 5 give the data of the temperatures 400, 600, 700, 800 and 900 " C. In Figures 8 and 9 and Tables IV and V, AD denotes data of a wire rod manufactured in the same manner as the other wire rods but not subjected to curing.

From the tables and figures it is apparent that both the magnetic induction (ß _IO o) and the coercive force [Hc) of the subject at a temperature of 1100 ⁰ C final annealing lead rods with an increase of the final cross-sectional reduction in Bereic of not less increase than 75%.

Example 4

The process according to Example 3 was repeated, the final annealing treatment being carried out at temperatures between 700 and 900 ° C. and the final cross-sectional reduction being varied while maintaining the other conditions as indicated in Tables VI to IX. Di <coercive force [Hc) and the magnetic _{inductor (B 100} ) of the conductive rods produced in this way are given in Tables VI to IX.

Table VI

Coercive force [Hc) in Oe. Temperature of the final annealing treatment: 700 ° C

Final . 400 Hardening temperature in ° C 500 600 700 800 900 Cross-sectional 47 37 28 20th 10 ² ^; =, diminishing 46 38 29 22nd 9 3 ■ ■ in % AD 41 34 33 21 11th 3 ^; · ■■■ · 75 55 92 44 97 36

10

(Jiiaschnitlv-
vcrminderiini!
in % AD 75 8.8 92 10.0 97 11.0

Table VII

Magnetic induction (B _m) in kilogauss temperature of the final annealing: 700 C

Aiisliiirtiingstcmpcriiuir in C

4 (X)

12.4
12.0
13.6

5 (X)

14.0
14.3
14.5

WX)

15.0
15.5
17.2

7 (K)

15.5
15.7
17.0

K (X)

15.2 15.4 15.8

¹ J (X)

16.0 15.4 16.1

Table VIII

Coercive force (Hc) in Oe Temperature of the final annealing treatment: 900 ° C

Kndgülligc AD 40 (1 Aiismirlunpslempcraiur 5 (X) WX) in C 7 (X) 8 (X) •) IK) (Juerschnills- 37 46 42 31 26th 6th 2.5 reduction 39 51 41 31 24 9 2.5 in "ή 34 44 54 26th 22nd 10 2.5 75 92 97

Table IX

Magnetic induction (B _10n ) ' ⁿ kilogauss temperature of the final annealing treatment: 900''C

Final .-ID 400 Curing temperature in C 500 600 700 800 900 Cross-sectional 7.5 8.2 8.8 11.2 14.1 15.3 15.5 reduction 9.2 12.0 14.0 14.8 14.4 15.6 15.5 in % 10.1 12.4 13.4 16.5 15.4 15.4 15.4 75 92 97

Table X
Hysteresis loop

55

From Tables VI and VIII it can be seen that the most essential values corresponding to the hysteresis loops are the coercive force (Hc) at a curing temperature. door reaches a maximum of approximately 400 ⁰ C and then decreases with increasing aging temperature. At a curing ^{temperature above 800 °} C., the coercive force (Hc) is below about 50 10 Oe. The magnetic induction (B ₁₀₀ ) generally increases with an increase in the final cross-sectional area and the hardening temperature.

Example 5

The process according to Example 3 was repeated, the final annealing treatment being carried out at 700, 900 and 1100 ¹ C and the hardening treatment at 60O ⁰ C. The final reduction in area was 92%. All other conditions remained unchanged.

10 shows the hysteresis loops of the conductor rods produced in this way. In this figure the curves marked with the reference numerals 1, 2 and 3 indicate the data of the lead wires at temperatures 700,900 and 1100 ° C in the final Annealing treatment. In Table X are the

Temperature of
final
Annealing treatment
in C "100
in kilogauss Br
in kilogauss Hc
in Oe 700
900
1 100 16.2
15.0
14.5 16.0
14.5
12.5 29
31
31

As shown in Fig. 10, both the rectangle ratio and the curve fill factor are the same greater, the lower the temperature of the final annealing treatment '

In the case of the alloys, an X-ray

diffraction is carried out and the following is determined. The alloy exposed to the final annealing treatment at a temperature of 700 ^° C. had a mixed phase of an α-phase with a spatial

centered cubic lattice structure and a; ■ phase with a face-centered cubic (coil structure. In contrast, the ^{alloy subjected to a final annealing treatment at a temperature above 9 (M) 1} C showed a single phase, namely a j-phase that the alloy having the mixed phase is superior in plastic workability, squareness ratio and curve filling factor, and therefore is excellent as a semi-hard magnetic material.

Example 6

The process according to Example 5 was repeated, the hardening treatment being carried out at the various temperatures given in Table XI. The coercive force (Hc) of the alloy so treated is in Table XI and in F i \\. 11 illustrates. In FIG. 11, the curves provided with the diff. 1, 2 and 3 indicate the data of the alloys which were subjected to the final annealing treatment at 700.900 and 1100 ° C., respectively.

Table XI
Coercive force (Wc) in Oe

Tempera ι ur AD 100 from the 44 45.5 closing 39 47 Oliih- 31 37 behanillunt: in C 700 900 1100

Aiishärliingslempemtiir in C

4 (X)

46
51
41

WX)

29
31
31

700

22nd
24
26th

800

12th

WX)

3.5 2.5 3

As can be seen from Table XI and FIG. II, the coercive force (Hc) reaches ^{a maximum at a curing temperature of approximately 400 °} C. and then falls as the curing temperature increases. If the curing temperature is higher than 800 ° C, the coercive force (Hc) is below about 10 Oe. The curing should therefore preferably be carried out at a temperature not above 800.degree.

In addition 5 sheets of drawings

Claims (3)

Sponsorship claims: 1. Using an alloy consisting of (a) cobalt, (b) iron (c) nickel and (d,) niobium or (d ₂ ) niobium and at least one metal from the group of tantalum, titanium, vanadium, zirconium, molybdenum, chromium and tungsten, with the proviso, that the weight ratio of (a) cobalt to (b) iron in the range from 3: 2 to 1: 2 and the weight ratio of (c) nickel to (b) iron in the range from 1: 1 to 1: 3 and the proportion of (d,) or (d ₂ ) I to 5 percent by weight of the entire alloy, as well as the usual production-related impurities, which have been cured at 600 to 900 ° C ι S and then cold-worked with intermediate annealing at temperatures of at least 600 ° C by at least 75%, as a semi-hard magnetic material. 2. Use of an alloy of the composition according to claim 1 and treated after Claim 1, which has been re-annealed after cold working at a maximum of 800 "C, for the Purpose according to claim 1. 3. Use of an alloy of the composition according to claim 1 and treated according to claim 1 or 2, in which the component (d ₂ ) consists of less than 30% of one or more of the metals tantalum, t'tan. Vanadium, zirconium, molybdenum, chromium and / or tungsten and the remainder is niobium, door the purpose according to claim 1.