JPS59157248A - High permeability alloy and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a high permeability alloy easy to heat-treat and having >=4,000 initial permeability in a low temp. region belot room temp. by restricting the amount of 2Mo+Fe+Cu in an alloy having a specified composition consisting of Ni, Mo, Cu and Fe. CONSTITUTION:This alloy consists of, by weight, 74-80% Ni, 0.5-4.5% Mo, 0.5-6.5% Cu and the balance Fe and satisfies 23%<=2Mo+Fe+Cu<=27%. The alloy is heated at about 1,000 deg.C- the m.p. in a nonoxidizing atmosphere or vacuum for about 10min-100hr, and it is cooled to ordinary temp. at 1,000- 0.1 deg.C/min cooling rate. Before carrying out the cooling, the alloy may be cooled to ordinary temp. and further heated at about 300-700 deg.C in a nonoxidizing atmosphere or vacuum for 10min-100hr. The alloy shows a significant effect as the material of a shielding case used at a temp. below room temp.

Description

Detailed Description of the Invention This invention has an initial magnetic permeability of 4 in a low temperature region below room temperature.
．． The present invention relates to a high magnetic permeability alloy having OOO0 or more and a method for producing the same.

Cryotronics using superconductors has recently been developed.

Among them, applied research on noyosephnon elements that operate in liquid helium (below 42 degrees) is being actively conducted, and some of them have even been put into practical use.

Generally, a superconductor is a completely antiferromagnetic material (Meissner effect) that completely excludes magnetic flux in a weak magnetic field below the critical magnetic field specific to the material. However, in reality, magnetic flux is pinned to various physical and chemical defects scattered throughout the material. On the other hand, a Josephson device using a superconductor operates by inputting a minute magnetic field. Therefore, in order to operate the Noyosefnon element without malfunction, it is necessary to completely shield the external magnetic field (residual magnetic field is desired to be 1 μG or less). Two methods of magnetic shielding have been considered: shielding the Noyosephnon element itself in liquid helium, and shielding the entire Taliostat by inserting the Noyosephnon element into the cryostat. In the latter case, the cryostat is surrounded as completely as possible with ferromagnetic material to form a magnetic circuit with high permeability to external magnetic fields.
Is it necessary to install a cylindrical case made of high magnetic permeability alloy (e.g. permalloy) around the outer periphery of the cryostat?

Furthermore, when performing sufficient shielding, a large-scale case with a multilayer structure (with one layer of air between the layers) is required, so the latter method is not practical in terms of operation or structure. On the other hand, in the former case, the structure of the former is more advantageous than the latter, since a shielded element shielded by a case such as Malloy is inserted into the cryostat. However, since the shield case itself is immersed in liquid helium, if ordinary 2-Ya-Malloy is used as the case material, the song &I shown in Figure 1.
As shown by a, the decrease in magnetic permeability is significant and the initial magnetic permeability is less than 10,000, and a sufficient magnetic shielding effect cannot be expected. Also, some permalloys having high magnetic permeability in liquid helium (having the characteristics shown by the curve in FIG. 1) have been put into practical use, but this permalloy has the following drawbacks.

1) The temperature range in which high magnetic permeability can be obtained is narrow, 4.2
Although it has a high magnetic permeability in the vicinity of 100°C, its initial magnetic permeability at room temperature is less than 10,000. When a shield case is made of this material and put into practical use, the residual magnetic field inside the shield case at room temperature remains as it is even after the temperature drops below 4.2 degrees, so this residual magnetic field causes magnetic flux in the superconductor. This may cause malfunction.

2) Heat treatment to obtain high magnetic permeability is difficult.

In other words, this permalloy is subjected to two-stage heat treatment in order to adjust the temperature at which the initial magnetic permeability reaches its maximum to around 4.2°, but this two-stage heat treatment temperature is ±5°C higher than the predetermined LL degree. If the temperature changes, the temperature (initial magnetic permeability) will change greatly, so it is unskillful from an industrial perspective.

Therefore, an object of the present invention is to provide a high magnetic permeability alloy that is easy to heat-treat and has an initial magnetic permeability of 4.0000 or more in a low temperature range below room temperature.

That is, in this invention, Ni74 to 80% r
Mo 0.5-4.5%, CuO, 5-6.5%,
The remainder consists of FC and a small amount of impurities, and the coefficient 23≦2Mo
+Fe+Cu is in charge 27. It is a high magnetic permeability alloy with an initial magnetic permeability of 40,000 mm in the low temperature range below room temperature.

This high permeability alloy is made by adjusting the alloy with the above composition.

The alloy is heated at a high temperature of 1000°C or more and below the melting point in a non-oxidizing atmosphere or in a vacuum for 10 minutes or more and 100 hours to fully recrystallize it, and then recrystallized at a rate of 1000°C/min to 0.1°C/min. Always! After cooling to A or heating it at a temperature of 300 to 700°C for 10 minutes to 100 hours, it is deactivated at a constant rate of 1000°C/min to 100°C/min. You can get good results.

The reason for limiting the composition of each component of this invention alloy as described above will be described below.

High magnetic permeability can be obtained near room temperature even outside the range of N174 to 80, but the magnetic permeability significantly decreases below room temperature.

Initial magnetic permeability of 40,000 or more in the low temperature range below room temperature υ
In order to do so, it is necessary to set it to N174-80.

Mo and Cu each have high magnetic permeability near room temperature even when the maximum coefficient is less than about 10, but below room temperature, especially below 100, the initial permeability becomes less than 20,000. Mo amount is 0.5 to 4.5
%, Cu amount is 0.5 to 6.5% and 23%≦
It is necessary to satisfy 2Mo + Fe + Cu < 27%.

Mn+Si+Ca+AA1Mg as a deoxidizing and desulfurizing agent
etc. may be added in a total amount of 2% or less.

Furthermore, in the manufacturing method of the alloy of the present invention, the high-temperature heat treatment is carried out for the purpose of solution treatment and removal of processing strain, and the reason why the heating temperature is set to 1000'C or higher and below the melting point is due to the recrystallization temperature (approximately 500'C or higher). If the heating temperature is higher than 9°C), recrystallization will start, but the recrystallization will be insufficient.
℃ or higher, especially 1100℃ or higher, preferably 1200℃ or higher.''
This is because it is suitable for sufficiently recrystallizing and obtaining high magnetic permeability. The atmosphere during the heat treatment must be outside a non-oxidizing atmosphere or in a vacuum to avoid the formation of oxides on the material surface. The reason why the heating time in this case was set to 10 minutes or more and 100 hours or less is because the heating time is related to the temperature! I
I) If the heating temperature is 14.00°C or higher, recrystallization can be achieved even with a heating time of about 10 minutes, but if the heating temperature is lower than 1000°C, more than 100 hours are required, which is not industrially practical. Note that the relationship between heating temperature and heating time must be determined depending on the alloy composition. The cooling rate from the above recrystallized state to room temperature was set at 1000°C/min to 01°C/min.
If it exceeds 01°C/min, the magnetic permeability will decrease due to thermal strain caused by cooling, and if it is less than 01°C/min, high magnetic permeability will be obtained near room temperature, or in the low temperature region below room temperature (especially at 100°). below) and the initial permeability is 4. This is because it goes down OOOOJ. In addition, what is the appropriate removal speed?

It may be determined depending on the two alloy compositions.

Furthermore, when performing low-temperature heat treatment following the above-mentioned high-temperature treatment, a heating temperature of 300 to 700°C is appropriate; outside this temperature range, the initial magnetic permeability is 40,000 in the low temperature range below room temperature.
The following is true. In addition, the heating time and cooling rate at this time should be set to 10 minutes or more and 100 hours or less, and 1000 hours or less, respectively.
The reason why the speed was set to 0.degree. C./min to 0.01 DEG C./min is that an initial magnetic permeability of 40,000 or more can be obtained near room temperature even outside this range.

This is because it is 4.0000 or less in a low temperature region below room temperature.

In addition, the initial magnetic permeability of 40,000 or more in the low temperature region below room temperature was obtained when the shield case was made of a single alloy.
−The shielding effect is the dimensions of the shielding case.

Although the shape and structure of VC are also related, the initial magnetic permeability is 4. OO0
This is because if it is 0 or more, a sufficient shielding effect can be obtained.

Next, embodiments of this invention will be described. Note that this example does not limit the present invention.

<Example-1> 767%N] -2,3%Mo -4,5% Cu -0
, 5% Mn+16 Fe alloy.

Using raw materials with a nominal purity of 99 or higher, a total weight of N 3 kg mixed to have the above composition was placed in an alumina crucible,
Melting in a vacuum (/ζ) in a high frequency melting furnace 71!g L, C
.

Add a small amount of deoxidizing agent and desulfurizing agent such as Car Mg + AZ, and pour the bath water into a mold of an appropriate shape to obtain a healthy ink. This ink was hot-forged and hot-rolled at 1100C. Temporarily cover with a thickness of mm,
Subsequently, it was made into a thickness of 1.5 by cold rolling. then 90
After softening and annealing at 0°C, by cold rolling, j; l 1 tnm
A ring-shaped sample with an outer diameter of 10+ nm and an inner diameter of 6 holes was punched out from the thick sample. This sample was heat-treated in hydrogen for the steps shown in Table 2, and the properties shown in Table 2 were obtained. The measurement temperature was liquid helium (4.2°K), liquid nitrogen (
77°K) and room temperature (293°K), and some samples were also measured at 196°K (dry ice + acetone). Curve 1 in FIG. 2 shows the relationship between the measured temperature and initial permeability when the sample was heated at 1200° C. for 1 hour and then cooled to room temperature at a rate of 10° C./min ((a) in Table 1).

Below margin <Example-2> 772%Ni -2,5%Mo -4,6% Cu
-0.5% Mn-152 Fe alloy.

This alloy sample was manufactured in the same manner as in <Example-1>.
Various heat treatments as shown in Table 2 were performed, and the properties shown in Table 2 were obtained. 10℃/after heating at 1200'C for 1 hour
When cooled at a rate of 1 min ((a) in Table 2)
) is shown by curve 2 in Fig. 2.

As shown in Examples 1 and 2 below, an initial magnetic permeability of 60,000 or more was obtained in the low temperature range below room temperature by high-temperature heat treatment alone.
Further, even when two-stage heat treatment is performed, an initial magnetic permeability of 40.000 or more is obtained at 460 to 540°C, which indicates that the low temperature treatment temperature range is wide.

<Example-3> Alloys having the compositions shown in Table-3 were produced and evaluated in the same manner as in <Example-1>. The results are shown in Table-3.

For comparison, 2Mo + Fe + Cu = 27.2
%, as mentioned in the paper, high magnetic permeability is obtained near room temperature, but below 100° the initial permeability is 4. It is below OOOO.

As mentioned above, N1-Mo-Cu-Fe alloy (
23%≦2Mo+Fe+Cu<27%)
Heated at a high temperature above 1000°C and below the melting point in a non-oxidizing atmosphere or in vacuum for a period of at least 10 minutes but not more than 100 hours, at a temperature of 1000°C/min to 0.
Cool to room temperature at a rate of C/9, or further heat at a temperature of 300 to 700°C for 10 minutes to 100 hours, and then cool to room temperature at a rate of 1000°C/min to 01°C/min. By removing the heat treatment, a high magnetic permeability alloy can be obtained which is easy to heat treat and has an initial magnetic permeability of 4.0000 or more in a low temperature range below room temperature.

Several of these alloys exhibit good shielding effects when used in shield cases used below room temperature. It's a place.

Room 7'? Since it has a sufficiently high magnetic permeability even near A, a shield case using a single alloy can be used not only below room temperature but also near room temperature, which is industrially useful.

Margin below

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the initial magnetic permeability and temperature of a conventional permalloy, and FIG. 2 is a graph showing the relationship between the initial magnetic permeability and temperature of two different embodiments of the present invention. 1...Characteristics of the alloy treated under the conditions (,) of Example 1. 2...Characteristics of the alloy treated under the condition (b) of Actual Example 2. Temperature (°K)

Claims (1)

[Claims] 1 N174-80%, Mo, 0.5-80% by weight
4.5%. Cu0.5-65%, balance Fe and small amount of impurities, and 23%<2 Mo' + Fe + Cu
<27%. Initial magnetic permeability in the low temperature range below room temperature 4. A high magnetic permeability alloy characterized by having OOO0 or more. 2. N174-80 split, Moo, 5-45% by weight
. CuO, 5-6.5%, balance Fe and a small amount of impurities, and 23% < 2 Mo + Fe + Cu
<27%, and after heating the alloy at a temperature of 1000°C or higher and lower than the melting point in a non-oxidizing atmosphere or in vacuum for 10 minutes or more and 100 hours or less. The initial magnetic permeability is 4.0 in the low temperature range below room temperature, which is characterized by cooling down to room temperature at a rate of 1000°C/min to 01°C/min.
A method for manufacturing a high magnetic permeability alloy having OOO0 or more. 3. N174-80% by weight, Mo 0.5-4
．． 5%. Cu0.5~65%゛, the balance consists of Fe and a small amount of impurities, and 23%≦2Mo+Fe+Cu<2
7%, the alloy is heated at a temperature of 1000°C or higher and lower than the melting point in a non-oxidizing atmosphere or in vacuum for at least 10 minutes and 100 hours or less for an appropriate time corresponding to the composition (C), and then cooled to room temperature 1. , this is further 300
After heating for up to 100 hours at a temperature of ~700°C for 10 minutes in a non-oxidizing atmosphere or in vacuum,
, a method for producing a high magnetic permeability alloy having an initial magnetic permeability of 40,000 or more in a low temperature region below room temperature, characterized by cooling to room temperature at a rate of 1000° C./min to 01° C./min.