JPS59143037A - Alloy having high magnetic permeability and its production - Google Patents

Abstract

PURPOSE:To produce easily an alloy having high magnetic permeability with a high initial magnetic permeability in a low temp. region by subjecting the alloy having the specific compsn. consisting of Ni, Mo, Cu, Mn, Si and Fe to a high- temp. treatment at the m.p. or below then cooling the alloy at a specific cooling rate. CONSTITUTION:An alloy consisting of 70-84wt% Ni, 0.5-5.5% Mo, 0.5-6.5% Cu, <=2% Mn, <=1% Si, and the balance Fe and a small amt. of impurities is subjected to a heating treatment for 10min-100hr at a temp. of >=1,000 deg.C and the m.p. or below in a non-oxidative atmosphere or vacuum in order to avoid oxidation and to prevent deformation and is cooled to an ordinary temp. at a rate of 1,000-0.1 deg.C/min, thereby the alloy having high magnetic permeability with >=20,000 initial magnetic permeability in a low temp. region of a room temp. or below is obtd. The alloy having high magnetic permeability similar to the above-mentioned alloy is also obtainable by cooling the alloy once to an ordinary temp. after the high-temp. heating treatment and further subjecting the same to a low-temp. heating treatment for 10min-100hr at 300-700 deg.C then cooling the alloy down to the ordinary temp. at a rate of 1,000-0.1 deg.C/min.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high magnetic permeability alloy having an initial magnetic permeability of 20,000 or more in a low temperature region below room temperature, and a method for producing the same.

Recently, the first fly ronics using superconductors.

In particular, applied research on No-Josefson elements that operate in liquid helium (below 4.2 degrees) is being actively conducted.
Some of them have even been put into practical use.

In general, superconductors are completely antiferromagnetic (completely antiferromagnetic) that completely exclude magnetic flux in a weak magnetic field below the critical magnetic field specific to the material.
Meissner effect). However, in reality, the magnetic flux remains pinned (trapped) in various physical and chemical defects scattered throughout A', A, V, and V. On the other hand, the Noyosefson element operates by inputting a minute magnetic field.

Therefore, in order to operate the Josephson element without malfunction, it is necessary to completely shield the external magnetic field (residual magnetic field of 1 μG or less).

Two methods of magnetic shielding are considered: shielding the Noyosefson element itself, and shielding the cryostat by inserting the Josephson element into the cryostat. In the latter case, in order to surround the cryostat as completely as possible with a ferromagnetic material and to construct a magnetic circuit with high permeability to external magnetic fields, a cylinder of high permeability material (e.g., Gumalloy) is used. case.

It must be installed on the outer periphery of the cryostat.

Furthermore, the latter method is not practical because a large-scale case with a multilayer structure (with gaps between layers) is required to carry out sufficient 7-fold heating. On the other hand, the former is for loading the Noyosefson element shielded with Nosomalloy etc. into the cryostat.

The former is structurally more advantageous than the latter. but,
The temperature in the cryostat is 4. ．． 2', the permeability decreases as shown by curve a in Figure 1, and the initial permeability is less than 0,000, and sufficient magnetic flux is not expected. .

Guma I carp, which has high magnetic permeability in frozen liquid helium (having the characteristics shown by the curve in Figure 1), has been put into practical use to some extent, but this permalloy has the following drawbacks. /child.

1) The temperature range in which high magnetic permeability can be obtained is narrow, i.e., it has high magnetic permeability at 42°, but the initial magnetic permeability at room temperature is 1.00.
00 or less. If a shield case is made and put into practical use at this monthly rate.

Even after the temperature is lowered to below 42 degrees, the residual magnetic field inside the 7-cold case at room temperature remains as it is, so that sufficient magnetic shielding is not performed.

2) Heat treatment to obtain high magnetic permeability is difficult. In other words, in this conventional permalloy, the temperature at which the initial magnetic permeability reaches a maximum is 42 degrees.
Two-stage heat treatment is applied to adjust the temperature close to .
If this two-stage treatment temperature changes by ±5° C. or more from the predetermined temperature, the extreme temperature of the initial magnetic permeability will change significantly, which is industrially disadvantageous.

Therefore, the object of this invention is to provide a high magnetic permeability alloy that is easy to heat-treat and has an initial magnetic permeability of 20,000 or more in a low temperature region below room temperature. ~84%, Mo0.5
~5.5%, CuO, 5-6.5%, Mn 2% or less, S
It is a high magnetic permeability alloy consisting of i1% or less, the balance Fe and a small amount of impurities, and has an initial magnetic permeability of 20,000 in the low temperature range below room temperature. This high magnetic permeability alloy is obtained by preparing an alloy having the above composition, heating the alloy 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 or less to fully recrystallize it. ,1
Cool to room temperature at a rate of 000°C/min to 0.1°C/min, or further cool to room temperature at a temperature of 300 to 700°C.
O obtained by heating for 0 minutes to 100 hours and then cooling to room temperature at a rate of 1000°C/min to 01°C/min I will explain.

This is because outside the range of N170 to 84%, the magnetic permeability decreases not only near room temperature but also in a low temperature region below room temperature.

When Mo and Cu are less than about 10%, it has high magnetic permeability near room temperature, but below 2 room temperature, especially below 100°, the initial permeability becomes small, less than 20,000, and high magnetic permeability occurs in the low temperature region below room temperature. M who can't get it.

The upper limit for Cu is 5.5%, and the upper limit for Cu is 65%. The lower limit of Mo and Cu is set at 05% because if it is less than this, the initial magnetic permeability will not reach 20,000 or more in a low temperature region below room temperature.

Mn and Si are added to improve workability, and a sufficient improvement can be achieved with Mn of 142% or less + S+ of 1% or less.

Furthermore, in the method for producing the alloy of the present invention, the high temperature heat treatment
This is carried out to remove solution heat treatment and processing strain, and the reason why the heating temperature is 1000°C or higher and lower than the melting point is because the recrystallization temperature (
Recrystallization will start if the heating temperature is higher than 1000°C, especially 1100°C, but recrystallization will be insufficient.
More preferably, the temperature is 1200° C. or higher because it is suitable for sufficiently recrystallizing and obtaining high magnetic permeability. Note that the upper limit of the heating temperature is set below the melting point (approximately 1500° C.) because this heat treatment is performed after molding and cannot be heated above the melting point. The atmosphere during the heat treatment of the shredder must be a non-oxidizing atmosphere or a vacuum in order to avoid the formation of oxides on the surface of the material.

The reason why the heating time in this case is set to 10 minutes or more and 100 hours or less is that the heating time is related to the temperature.

At 1400° C. or higher, recrystallization can be sufficiently performed in a short time of about 10 minutes, but if the heating temperature is lower than 1000° C., 100 hours or more is required, which is industrially laborious. Note that the relationship between heating temperature and heating time needs to be determined depending on the alloy composition.

The rate of cooling from the above recrystallization completion state to room temperature is 10
00 'c/e ~ 0.1 The speed of the job was chosen.

At temperatures above 1o o Or/';', thermal distortion occurs due to cooling.

It lowers the magnetic permeability and is 0.1 'C/', + J
-), high magnetic permeability can be obtained near room temperature, but the initial magnetic permeability becomes 20,000 or less in the temperature range below room temperature (particularly below 1,000 degrees Celsius). Note that an appropriate cooling rate may be determined within this range depending on the alloy composition.

Furthermore, when performing low-temperature heat treatment following the above-mentioned high-temperature heat treatment, a heating temperature of 75g at 300 to 700°C is appropriate; outside this temperature range, the initial magnetic permeability is 200 in the low temperature range below room temperature.
00 or less. In addition, the force 1 heat time and cooling rate at this time are 10 minutes to 100 hours and 10 minutes to 100 hours, respectively.
The reason why the speed is set at 00° C. 2 minutes to 01 minutes is because an initial magnetic permeability of 20,000 or more near room temperature can be obtained even outside this range, but it becomes 20,000 or less in the temperature range of 2 degrees Fahrenheit below room temperature.

In addition, the initial magnetic permeability is 20,000 or more in the low temperature range below room temperature, and the shielding effect when making a shield case with two alloys is due to the dimensions of the shield case.

This is because, although it is related to the shape, a practically sufficient shielding effect can be obtained if the initial magnetic permeability is 20,600 or more, preferably 4,000 or more.

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

Below margin <Example-1> 77%Ni -2.4% Mo = 4.7%Cu -
Q, 6% MnO, 3% Si-Fe alloy.

Using raw materials with a nominal purity of 99 or higher, a total weight of 3 kg mixed to have the above composition was placed in an alumina crucible and melted in a high frequency induction furnace in a vacuum to form C1Ca2Mg, At.
A small amount (1% or less) of a deoxidizing agent and a desulfurizing agent were added, and the molten metal was poured into a casting pot of an appropriate shape to obtain a sound ingot. Further, this ingot was hot-forged at 1100°C and hot-rolled into a plate with a thickness of 4 mm, which was then cold-rolled to a thickness of 15 mm. Next, the material was heated at 900° C. to soften it, and then cold-rolled to a thickness of 1 mm, and a ring-shaped sample with an outer diameter of 10 mm and an inner diameter of 6 mm was punched out. This sample was subjected to various heat treatments in hydrogen as shown in Table 1, and the properties shown in Table 1 were obtained. The measurement temperature is liquid helium (4
2°K) liquid nitrogen (77°K), room temperature (293°K), and for some samples dry ice + acetone (
196°K) was also measured. The relationship between the measured temperature and the initial magnetic permeability of the sample treated under the heat treatment condition (a) in Table 1 is shown by curve 1 in FIG.

Table 1 <Example-2> 76%Ni-2,O%Mo-4,3%Cu-0.4%Al-〇,2%Si-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. The relationship between the measured temperature and the initial magnetic permeability of the sample treated under the heat treatment condition (a) in Table 2 is shown by curve 2 in FIG.

It can be seen that in Examples 1 and 2, an initial magnetic permeability of 40,000 or more was obtained in a low temperature region below room temperature.

Table 2 <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.
-Mn-Si alloy at a high temperature above 1000℃ and below the melting point in a non-oxidizing atmosphere or in vacuum for at least 10
Heating for at least 100 hours at 1000℃h~0.1
Cool to room temperature 1 at a rate of 1°C/min, 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 0.1°C/min. By doing so, a high magnetic permeability alloy can be obtained which is easy to heat-treat and has an initial magnetic permeability of 20,000 or more at a low temperature below room temperature.

Several of these alloys exhibit good shielding effects when used in shield cases used below room temperature.

[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 different embodiments of the present invention.

Claims (1)

[Claims] 1. Ni 70-84%, Mo 0.5-84% by weight
5.5%, Cu 0.5-6.5%, Mn 2%
Below, Si is 1% or less. A high magnetic permeability alloy comprising the balance Fe and a small amount of impurities, and having an initial magnetic permeability of 20,000 or more in a low temperature range below room temperature. 2. Ni 70-84% by weight, Mo 0.5-5.
5%, Cu 0.5-6.5%, Mn 2% or less,
Si 1% or less. An alloy consisting of the remainder Fe and a small amount of impurities is obtained, and 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 a vacuum for 10 minutes or more and 100 hours or less, and then heated for 10.00 minutes to 100 hours. A method for producing a high magnetic permeability alloy having an initial magnetic permeability of 20,000 or more in a low temperature region below room temperature, characterized by cooling to room temperature at a rate of 0.1° C./min. 3. Ni70-84%, Mo0.5-55 in weight%
%, ' Cu 0.5--6.5%, Mn 2% or less, S
An alloy consisting of i1% or less with the balance Fe and a small amount of impurities is obtained.8 The alloy is heated in a suitable temperature suitable for the composition in a non-oxidizing atmosphere or in vacuum at a temperature of 1000°C or higher and lower than the melting point for at least 10 minutes and 100 hours. After heating for an hour,
Cool to room temperature and further heat at 300°C to 700°C in a non-oxidizing atmosphere or in vacuum for 10 minutes to 100 hours, and then heat to 1000'C/e.
~0. A method for producing a high magnetic permeability alloy having an initial magnetic permeability of 20,000 or more in a low temperature region below room temperature, characterized by cooling to room temperature at a rate of IV minutes.