JPS588566B2 - Temperature sensing element material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic material having a Curie temperature below room temperature, and particularly to an amorphous alloy suitable for use as a temperature-sensitive element material.

2. Description of the Related Art Conventionally, ferromagnetic materials have been used as temperature-sensitive element materials by taking advantage of the fact that their magnetic permeability changes greatly with temperature changes around the Curie temperature.

Ferromagnetic materials used as such temperature-sensitive element materials include Fe--Ni--Cr magnetic alloys and ferrite magnetic oxides.

Due to its nature, Fe-Ni-Cr magnetic alloys do not have a large AC magnetic permeability at temperatures below room temperature, and are mainly used as temperature-sensitive element materials at temperatures above 100°C.

On the other hand, this alloy requires molding and heat treatment in hydrogen at high temperatures (above 1000°C), making the manufacturing process not only complicated, but also expensive in terms of fuel and electricity, making it difficult to use. It is expensive compared to the cost of raw materials.

Ferrite magnetic oxides are conveniently used as temperature-sensitive element materials because materials having a desired Curie temperature over a wide temperature range can be easily produced.

Mainly, Mn--Cu type, Ni--Zn type, and Mn--Zn type ferrites are used, and among them, Mn--Zn type ferrite is used in large quantities because it can obtain a relatively high AC permeability.

However, ferrite has the disadvantage of poor thermal conductivity and therefore poor thermal response, and is also porous, so when used in devices that operate at low temperatures, such as refrigerators and freezers, it is difficult for ferrite to absorb moisture in the pores. There is a risk of destruction due to freezing, which is disadvantageous when used at low temperatures.

In view of the above, an object of the present invention is to provide a magnetic alloy suitable for sensing low temperatures below room temperature.

The main object of the present invention is to provide an amorphous alloy for temperature-sensitive elements that has a Curie temperature below room temperature, excellent corrosion resistance, high hardness, and no temperature change.

Furthermore, it is an object of the present invention to provide an amorphous alloy for a temperature-sensitive element as described above, which has a large AC magnetic permeability at room temperature or below and has a large change in magnetic permeability due to a temperature change near the Curie temperature. It is.

The temperature-sensitive element material according to the present invention contains 3 to 16 at. % of iron, 20 to 66 at.
A non-quality alloy consisting of 0 atomic % and 5 to 25 atomic % boron, with a total of 18 to 32 atomic % silicon and boron, and has a Curie temperature below room temperature.

This non-quality alloy has a significantly high AC permeability by heat treatment at a temperature below its crystallization temperature.

Since the temperature-sensitive element material according to the present invention is a non-quality alloy,
There are no grain boundaries, so there is no intergranular corrosion, and since it contains Ni, it has excellent corrosion resistance, and has a Vickers hardness of 7.
It exhibits a hardness of 00 to 900, and has features such as being extremely hard and resistant to deterioration of characteristics due to strain.

The crystallization temperature of this amorphous alloy is approximately 420 to 550°C.
in the range of ℃.

Normally, metals are in a crystalline state in the solid state, but under certain special conditions, for example, when a special alloy composition is cooled and solidified from a molten state at high speed, even in the solid state, metals have an atomic structure similar to that of a liquid (i.e., they do not have a crystalline structure). are obtained, and such metals or alloys are called non-quality alloys or amorphous metals.

This type of high-speed cooling required for quality deterioration will be referred to as super-quenching or rapid cooling.

This inferior alloy changes to a crystalline alloy at a certain degree depending on its component composition, and loses its properties as an amorphous alloy.

This temperature is called the crystallization temperature (Tx).

Hereinafter, the present invention will be described in detail with reference to examples.

Table 1 shows the composition and properties before and after heat treatment of the non-quality alloy for temperature sensitive elements according to the present invention.

For comparison, the characteristics of Fe-Ni-Cr alloy and Mn-Zn ferrite, which are conventionally used temperature-sensitive element materials, are also shown.

Note that the heat treatment was performed on alloy No. Nos. 1 to 11 were heated in the air at 450°C for 20 minutes and then air cooled.
Sample No. 12 was heated in the atmosphere at 400° C. for 60 minutes and then cooled in air.

In either case, no crystal structure appeared after heat treatment, and the material remained amorphous.

The shapes of the amorphous alloys used in the measurements were ribbons each having a thickness of about 25 μm, a width of about 1.5 mm, and a length of about 5 to 10 m.

This ribbon was cut to a length of 80 cm, and the AC permeability and Curie temperature of the alloy were measured.

The alternating current magnetic permeability (μac) was measured using a Maxwell Bridge with a ribbon wound around a ring-shaped porcelain having a diameter of 15 mm to form a toroidal core at a frequency of 1 kHz and a measurement magnetic field of 16 mOe.

The Curie temperature (Tc) of the alloy is μa measured under the above conditions.
Draw the temperature characteristics of c, the maximum value is 80% at the falling part of μac
The point where the extension line connecting the μac point and the 20% point intersects the μac=1 line was found, and that temperature was defined as the Curie temperature.

As can be seen from Table 1, the material according to the invention, despite its non-quality characteristics, has a Curie temperature below room temperature and a significantly high hardness (almost unchanged before and after heat treatment).

) It is clear that this material is excellent as a temperature-sensitive element material for low temperatures.

In particular, the heat-treated material has a slightly higher Curie point, but it has a Curie point below room temperature, and its AC permeability is significantly increased, making it particularly excellent as a temperature-sensitive magnetic material for low temperatures.

Figure 1 shows alloy No. 1 in Table 1. AC magnetic permeability at each heat treatment temperature when a ring-shaped sample was made by wrapping the thin ribbon in the quenched state of 4 around porcelain and heating it in the air at various temperatures up to 450°C for 20 minutes and then cooling it in air. (μac)
The results of measurement of Curie temperature (Tc) are shown in a graph, and changes in μac and Tc with respect to heat treatment temperature are shown.

FIG. 2 similarly shows alloy No. 4 as quenched, and heat treated at 400°C for 20 minutes (400°C x 2
0 minutes), heat treated at 300℃ for 20 minutes (300℃
20 minutes) is a graph showing changes in AC permeability with temperature.

As shown in Figure 1, the μac of the alloy is at a heat treatment temperature of 200
It increases gradually from ℃ and increases rapidly from 300℃.

It can be seen that at a heat treatment temperature of 400°C, μac=33000, which is difficult to obtain with conventional temperature sensing elements.

On the other hand, the Curie temperature changes by applying heat treatment as shown in the figure.

That is, although the heat treatment temperature increases rapidly from 200°C,
It can be seen that it becomes almost flat and stabilized at a processing temperature of ℃ or higher.

As shown in FIG. 2, it can be seen that the μac of the non-quality alloy improved by the heat treatment effect shows a rapid drop due to temperature changes near the Curie temperature.

Note that the heat treatment temperature needs to be lower than the crystallization temperature because it will no longer be amorphous.

From the above, it will be understood that the non-quality alloy according to the present invention is excellent as a temperature-sensitive element material.

Next, the reason for limiting the content of each component in the non-quality alloy for temperature-sensitive elements of the present invention will be explained.

Si is an element that promotes deterioration of the alloy structure, but 2
If it is less than 20 atomic %, it is difficult to make it amorphous even if the molten metal is ultra-quenched, while if it is more than 20 atomic %, the alloy becomes brittle, so it is necessary to keep it within the range of 2 to 20 atomic %. .

Like Si, B is an element that promotes deterioration of quality, but if it is less than 5 at%, it is difficult to make it amorphous even if it is ultra-quenched, while if it is more than 25 at%, it embrittles the alloy. Therefore, it is necessary to keep it within the range of 5 to 25 at.%.

Furthermore, if the sum of Si and B is less than 18 atomic percent, even if the alloy is ultra-quenched, it is difficult to produce a non-quality alloy, and the crystallization temperature of the alloy decreases, resulting in a loss of thermal stability.

On the other hand, if the sum of Si and B exceeds 32 atomic %, the alloy becomes brittle, so the sum of Si and B needs to be within the range of 18 to 32 atomic %.

When Fe is less than 3 atomic % or more than 16 atomic %, the AC permeability decreases, making it difficult to use Mn-Zn ferrite and Fe-Ni, which have been conventionally used for thermosensing elements.
- Since it loses its superiority compared to Cr alloy, 3 to 1
It is necessary to keep it within the range of 6 atomic %.

Figure 3 is a diagram used to explain the reason for limiting the Ni component content, (FeaCobNic)74Si10B1
6 (FeaCobNic)72Si10B18 and (
Figure 2 shows isocurves of the Curie temperature (Tc) before heat treatment of a non-quality alloy having a component composition of FeaCobNio)70Si10B20.

However, a, b, and c are symbols indicating the atomic ratio, and a+c=1.

Also, Fig. 4 shows (Fe0.1Co0.5Ni0.4)xS
FIG. 3 is a diagram showing isovalue curves of the Curie temperature (Tc) of a non-quality alloy having a component composition of iyBz when the ratio of transition metal elements is kept constant and the values of x, y, and 2 are changed.

However, x, y, and z are symbols indicating atomic %, and x + y + z = 100 atomic %.

As is clear from FIGS. 3 and 4, the Curie temperature of the amorphous alloy of the present invention depends not only on the Ni component content, but also on the
It is also possible to vary widely depending on the amount of semimetal elements Si and B.

Therefore, Ni is an element that increases corrosion resistance, increases AC permeability, and lowers the Curie temperature of the alloy.
At 0 atomic % or less, it is difficult to obtain an amorphous alloy with a Curie temperature below room temperature even if the metalloid elements Si and B are added in amounts that do not embrittle the amorphous alloy, and at 66 atomic % or higher, The content must be within the range of 20 to 66 atom % because it becomes an amorphous alloy with a significantly low Curie temperature and loses its practicality as a temperature-sensitive element material for devices such as refrigerators and refrigeration equipment.

By heat-treating a non-quality alloy having the above component composition at a temperature below the crystallization temperature of the alloy, preferably in a temperature range of 250°C or above and below the crystallization temperature, the Curie temperature is below room temperature and the AC It is possible to obtain an amorphous alloy for a temperature-sensitive element that has high magnetic permeability and exhibits a large drop in magnetic permeability due to temperature changes near the Curie temperature.

In this case, the holding time required for the heat treatment is within the range of approximately 1 minute to 480 hours.

Next, a method for manufacturing a non-quality alloy having the above-mentioned composition will be explained.

FIG. 5 is a schematic diagram showing an example of an apparatus for manufacturing the non-quality alloy.

In this figure, reference numeral 1 is a quartz tube having a nozzle 2 at its lower end, into which raw metal 3 mixed to have a predetermined composition is charged and melted.

4 is a heating furnace for melting raw metal.

5 is a high speed using a rotating machine such as a motor, for example 1500
~5500r. p. m. This is a rotary cooling member (diameter 20φcm) that is rotated by.

The material of this cooling member may be any material as long as it can remove heat from the molten material at a cooling rate that solidifies the molten material in the form of a thin strip on the outer circumferential surface portion 6, such as copper, iron, aluminum alloy, etc. A material having a high thermal conductivity is suitable.

8 is an air piston for supporting the quartz tube 1 and moving it up and down.

The raw metal is first charged through the inlet 1a of the quartz tube 1 by fluid conveyance, heated and melted in the heating furnace 4, and then heated by the air piston 8 so that the nozzle 2 faces the outer peripheral surface 6 of the cooling member. Almost at the same time as the quartz tube 1 is lowered to the position shown in the figure, gas pressure is applied to the molten metal 3, causing the molten metal to jet toward the outer peripheral surface 6 of the cooling member.

In order to prevent oxidation of the metal 3, an inert gas such as argon gas 9 is constantly fed into the quartz tube to create an inert atmosphere.

The jetted molten metal contacts the outer circumferential surface of the cooling member rotating at high speed, and at the same time is subjected to ultra-rapid cooling (cooling rate of 104°C/sec or more) and instantly solidifies, forming a ribbon-shaped non-quality alloy 10. Become.

Next, examples of alloys according to the present invention will be explained.

Example 1 Fe7.0Co28.5Ni38.5Si10B16(
Alloy No. 1), Fe7.0Co27.0Ni40Si
10B16 (alloy No. 2), Fe7.0Co25.5
Ni41.5Si10B16 (alloy No. 3), Fe
11.1Co14.8Ni48.1Si10B16 (alloy No. 7) and Fe7・OCo22.6Ni44・
A thin ribbon of an alloy having a composition of 4Si10B16 (alloy No. 10) having a thickness of about 25 μm, a width of about 1.5 mm, and a length of several meters was produced by the above manufacturing method.

No crystal structure was detected in these ribbon-shaped samples by X-ray diffraction or electron beam diffraction, and it was confirmed that they were amorphous alloys.

Next, these ribbon-shaped samples were cut to appropriate lengths and wound around circular porcelain to form a toroidal core.The temperature characteristics of AC magnetic permeability and the Curie temperature were measured using the method described above, and the following results were obtained.

First, FIG. 6 shows the temperature characteristics of AC magnetic permeability (μac) of each sample measured in the rapidly cooled state (before heat treatment).

In the figure, the number of the curve is the number of each alloy (No.
．． ) is shown.

As shown in this figure, the AC magnetic permeability of these samples shows a rapid drop with temperature changes near the Curie temperature, indicating that they can be used as temperature-sensitive element materials.

FIG. 7 shows the temperature characteristics of AC magnetic permeability obtained by heating a non-quality alloy sample having the above-mentioned composition in the atmosphere at 450° C. for 20 minutes, cooling it in air, and then measuring it.

As is clear from the comparison with Figure 6, the AC magnetic permeability of each alloy sample was significantly improved by applying the above heat treatment compared to the one in the quenched state, and it was found that It is possible to obtain a high AC magnetic permeability that is difficult to obtain with other materials, and the permeability shows a rapid drop due to temperature changes near the Curie temperature, which indicates that it is suitable as a temperature-sensitive element material.

Example 2 Figure 8 shows the Fe7.0Co25.5Ni4 used in Example 1.
An amorphous alloy sample having a composition of 1.5Si10B16 (No. 3) was heated in the air at various temperatures up to 450°C.
2 is a graph showing the measured values of AC magnetic permeability (μac) and Curie temperature (Tc) at each heat treatment temperature when heated for 0 minutes and air cooled.

From this figure, the μac of the alloy sample gradually increases from the heat treatment temperature of 200°C, and rapidly increases at 300°C.

It can be seen that at a heat treatment temperature of 450° C., μac=430 00, which is difficult to obtain with conventionally used temperature-sensitive element materials.

On the other hand, the Curie temperature of the alloy sample changes by applying heat treatment, as shown in the figure.

That is, Tc increases rapidly from the heat treatment temperature of 200°C, and
It can be seen that the temperature becomes almost flat and stable from the processing temperature of 00°C.

Figure 9 shows the temperature characteristics of AC magnetic permeability measured after heating a sample of alloy grade 3 at 450°C for 20 minutes and cooling it in air.The arrow in Figure A indicates the direction of the measurement temperature of μac. , The right direction indicates that the temperature was changed sequentially from low temperature to high temperature, and the left direction indicates that the temperature was changed from high temperature to low temperature.

As shown in this figure, the temperature characteristics of AC magnetic permeability in the vicinity of the Curie temperature show almost reversible changes, which indicates that the Curie temperature of the alloy has good reproducibility and is thermally stable.

As described above, the non-quality alloy of the present invention has a high AC permeability that is difficult to obtain with temperature-sensitive element materials such as conventionally used Fe-Ni-Cr alloys and ferrite, and has a high AC permeability near the Curie temperature. It is found that it is suitable as a temperature-sensitive element material because it shows a rapid drop in magnetic permeability due to temperature changes, and has a Curie temperature that is thermally stable and has excellent reproducibility.

[Brief explanation of the drawing]

Figure 1 shows Fe7.0Co24.1Ni42.9Si10
A diagram showing changes in AC permeability (μac) and Curie temperature (Tc) depending on heat treatment temperature of a non-quality alloy having a component composition of B16. Figure 2 is an amorphous alloy having the component composition used in Figure 1. Figure 3 shows the temperature characteristics of AC magnetic permeability of (Fe
aCobNic)4Si10B16, (FeaCobN
iC)72Si10B18 and (FeaCobNi
c) A diagram showing an isovalue curve of the Curie temperature (Tc) of an amorphous alloy having a component composition of 70Si10B20, Figure 4 is (Feo.ICoo.5NiO.4)xSi B
With the component composition of x, y, keeping the ratio of transition metal elements constant
, z is a diagram showing isovalue curves of the Curie temperature of non-quality alloys when the atomic percent amount of Fe7. 0 Co28.
5Ni38・5Si10B16 (No.1) Fe7
・0Co27.0Ni40Si10Bl6 (No.2)
,Fe7・OC025・5Ni41・5Si10B16
(No. 3), Fe11.1Co14.8Ni48
．． 1Si10B16 (No.7) and Fe7.0Co
22.6Ni44.4Si10B16 (No. 10) A diagram showing the temperature characteristics of AC magnetic permeability in the quenched state of a non-quality alloy having the component composition of 22.6Ni44.4Si10B16 (No. 10). Figure 8 shows the temperature characteristics of AC magnetic permeability of each alloy sample when heat treated at 450°C for 20 minutes in the atmosphere.
FIG. 3 is a diagram showing changes in AC permeability (μac) and Curie temperature (Tc) depending on each heat treatment temperature of a non-quality alloy having a component composition of 5Si10B16. Figure 9 shows Fe7. OCo25.5Ni41.5Si10
After heat treatment of an amorphous alloy having a composition of B16 (45
FIG. 3 is a diagram showing the temperature characteristics of AC magnetic permeability at 0° C. x 20 minutes. In FIG. 5, each reference symbol is as follows. 1...Quartz tube, 2...Nozzle, 3...
... Raw metal, 4 ... Heating furnace, 5 ...
...Rotating cooling member, 6...Outer peripheral surface portion, 8...
...Air piston, 9...Argon gas,
10...Amorphous alloy.

Claims (1)

[Claims] 1 3 to 16 at% iron, 20 to 66 at% nickel, cobalt, but the total of iron, nickel and cobalt is 6
8-82 atom%, silicon 2-20 atom% and boron 5-82 atom%
A temperature-sensitive element material which is a non-quality alloy consisting of 25 atomic % of silicon and boron in a total of 18 to 32 atomic %, and has a Curie temperature below room temperature.