JPH01195261A - Highly rust-resisting amorphous alloy - Google Patents

Abstract

PURPOSE:To obtain a highly rust-resisting amorphous alloy having superior rust resistance while maintaining excellent magnetic properties by specifying a composition consisting of Fe, Co, Cr, B, and Si. CONSTITUTION:This highly rust-resisting amorphous alloy has a composition represented by a general formula FevCowCrxBySiz (where the symbols (v), (w), (x), (y), and (z) stand for 60-78% by atom, 3-15%, 4-,12%, 8-20%, and 0-10%, respectively, and v+w+x+y+z=100% is satisfied) and this alloy maintains the superior magnetic properties of amorphous alloy. This amorphous alloy can be obtained by blending respective powders of the above metals, mixing them, melting the resulting mixture, and then subjecting the above molten alloy to super rapid cooling at >=about 10<4> deg.C/sec cooling rate. The above highly rust-resisting amorphous alloy can be suitably used as a material for various sensors for use in high-humidity places, etc.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a highly rust-resistant amorphous alloy, and in particular, to the excellent magnetic properties (magnetostriction, magnetic permeability, Δ
The present invention relates to a highly rust-resistant amorphous alloy that maintains excellent rust resistance (e.g., E effect, etc.) and also has excellent rust resistance.

[Conventional technology]

Amorphous alloys are non-crystalline materials obtained by solidifying metals from a molten state without undergoing crystallization, and due to their special properties, they are being developed for practical use in various fields. In particular, iron-based amorphous alloys have higher magnetostriction and magnetic permeability than other alloys, so they have high conversion efficiency between mechanical signals and electrical signals, and are expected to be used as various sensors.

An example of this is its use as a frost sensor (for example,
7-35744), use as a torque sensor (
For example, the Institute of Electrical Engineers of Japan magnetics research material MAG-81
-72), use as a fluid pressure sensor (Japanese Unexamined Patent Publication No. 61-732), impact detection sensor (Unexamined Japanese Patent Application No. 57-163827)
) as a position sensor (Japanese Unexamined Patent Publication No. 6O-13581
9) has already been proposed.

[Problem that the invention seeks to solve]

However, although known amorphous alloys have good magnetic properties, they have the disadvantage of being susceptible to rust.
The problem is that it is difficult to use as a material for use in harsh environments such as in humid places or outdoors.

Therefore, although amorphous alloys have been proposed for various uses including sensors, the current situation is that they have not yet been effectively utilized.

The present invention has been made in view of the problems of the prior art described above, and provides a highly rust-resistant amorphous alloy that maintains the excellent magnetic properties of amorphous alloys and also has good rust resistance. The purpose is to

The present inventors conducted intensive research in line with the above objectives, and first
Cr, which is highly effective in improving the corrosion resistance of iron, was added as a fourth component to a -B-8i iron-based amorphous alloy, and its effect was investigated. As a result, it was found that although the corrosion resistance was certainly improved when C was introduced, the magnetostriction and magnetic permeability were significantly lowered, and although various composition ratios were investigated, this problem could not be improved.

Therefore, as a result of studying various metal elements as the fifth component, we found that adding a certain amount of Go in addition to Cr increases magnetostriction, and the combination significantly improves magnetic permeability, and also provides excellent rust resistance. It was discovered that an amorphous alloy can be obtained, and the present invention was achieved.

[Failure to solve the problem]

That is, the amorphous alloy for highly rust-resistant sensors of the present invention has the general formula % (in the above formula, V + x + y + z ~ 10 (la
t,% (atomic %), and ■ is 60 to 78 at
, %, W is 3 to 15 at%, %, X is 4 to 12 at%, y
is 8 to 20at, %, and 2 is 0=lOat,%).

[Effect]

In the present invention, high rust resistance can be obtained by the above composition.

The highly rust-resistant amorphous alloy for sensors of the present invention has a conventionally known Fe-B-Si iron-based amorphous alloy as its base alloy, and the content of Fe1B and Si is such that Fe is 60%. ~78 at, %, B is 8~20a
t, %, and Si is O~1 Oat, %. If the content of these elements is outside the above range, good magnetic properties as an iron-based amorphous alloy cannot be obtained.

In the present invention, by adding a predetermined amount of CO and a predetermined amount of Cr to the Fe-B-8t-based iron-based amorphous alloy, the rust resistance is improved without impairing the magnetic properties.

In particular, Cr is contained in order to improve rust resistance, and is contained in the alloy in an amount of 4 to 12 at%. Its content is 4at,
If it is less than 5, the effect of improving rust resistance is small, and if it is less than 12 a
If it exceeds t,%, the high magnetostriction necessary for the sensor alloy cannot be obtained, and at the same time, there will be problems in manufacturing since the melting point and viscosity will be higher.

As mentioned above, co is contained in order to prevent deterioration of magnetic properties due to the addition of Cr, and contains 3 to 15 at
,% contained. If the content is less than 3 at, the magnetic properties such as magnetostriction and magnetic permeability will be insufficient;
If it exceeds t,%, the magnetic permeability deteriorates significantly and the magnetic properties required as a sensor alloy cannot be obtained.

The highly rust-resistant amorphous alloy for sensors of the present invention is prepared by melting a mixed metal powder obtained by mixing powders of the above metals with the above composition, and rapidly cooling and solidifying the molten state without undergoing crystallization. can be obtained. For example, by ultra-quenching and solidifying at a cooling rate of 10'C/sec or more, usually 104 to 1011C/SeC, an amorphous alloy can be obtained. When super-quenching a molten alloy, the molten alloy is injected from a nozzle and various known methods such as a twin-roll method, a single-roll method, and a centrifugal quenching method are employed. When such ultra-high-speed cooling and solidification is performed, an amorphous alloy is usually obtained in the form of a ribbon, thin wire, or fine powder of 20 to 30 μm.

In addition, the above composition can be modified using various sputtering methods (high frequency, plasma,
It is also possible to obtain an amorphous thin film by laminating it on a specific substrate using a magnetron, etc.).

The amorphous alloy of the present invention obtained as described above is preferably used as a material for various sensors used in harsh environments such as places with high humidity and outdoors. For example, it can be suitably applied to sensor units such as frost sensors, position sensors, torque sensors, and fluid pressure sensors.

The frost sensor here refers to the property that an elastic wave is generated in a magnetostrictive ribbon made of an amorphous alloy, and when frost adheres to the magnetostrictive ribbon, the propagation loss of the elastic wave increases rapidly. A sensor that detects frost.

Furthermore, the position sensor referred to here refers to a coil wound around an amorphous magnetostrictive ribbon, which is applied with a pulse voltage to a predetermined position (
When a bias magnetic field (by a permanent magnet) is applied to the coil (on the coil), an induced voltage due to magnetostrictive vibration waves is generated from that position, so by detecting the timing, the specified position can be accurately determined.

The torque sensor referred to herein is one in which an amorphous magnetostrictive ribbon is fixed to the surface of a rotating shaft that transmits torque, and the strain generated on the shaft surface due to torque is detected as a change in the magnetic permeability of the ribbon.

Furthermore, a liquid pressure sensor uses an amorphous magnetostrictive ribbon as a diaphragm, and detects the fluid pressure applied thereto as a change in magnetic permeability of the ribbon.

Similarly, an impact detection sensor detects an impact stress applied from the outside to an amorphous magnetostrictive ribbon as a change in magnetic permeability of the ribbon.

Note that the amorphous alloy of the present invention is useful not only for these various sensors but also as an amorphous alloy for use in areas where rust resistance is required.

〔Example〕

Examples of the present invention will be described below while comparing them with comparative examples.

<Examples t to 3 and Comparative Examples 1 to 4> Amorphous alloys of the set 75-X7x14 consisting of FeCoCrBSi4 were produced by a single roll liquid quenching method.

Note that X is O (Comparative Example 1), l (Comparative Example 2), 3 (Comparative Example 3), 5 (Example 1), 6 (Example 2), 7 (Example 3), 8. (Example 4).

In order to investigate the rust resistance and magnetic properties of the obtained amorphous alloy, the following rust development test and saturation magnetostriction test were conducted.

(Rust test) In the rust test, the test piece is immersed in distilled water at room temperature.
The state of rusting was visually observed, and the rusting ability was evaluated based on the time it took for rust to occur. The results are shown in FIG.

As is clear from FIG. 1, the rust resistance improves as the Cr content increases, and increases markedly from about 4 at.%.

(Saturation magnetostriction test) The saturation magnetostriction test was conducted as follows.

A semiconductor strain gauge was attached to the surface of the sample using instant gauge adhesive. Next, a magnetic field was applied from the outside until the magnetization of the sample was saturated, and the expansion and contraction of the sample was measured by the change in resistance of a semiconductor strain gauge. The applied force direction of the magnetic field is set to the ribbon longitudinal direction (λ
X), and in the middle direction (λy), and was calculated using the following formula.

The results are shown in FIG.

As is clear from FIG. 2, the saturation magnetostriction decreases as the Cr content increases.

<Examples 5-6 and Comparative Examples 4-6> Amorphous alloys having the composition 75-x X 7 14 consisting of Fe Co Cr B Si4 were obtained by a single roll liquid quenching method.

In addition, X is O (comparative example 4), 7 (example 5), 15 (
Example 6), 22 (Comparative Example 5), and 30 (Comparative Example 6).

In order to examine the magnetic properties of the obtained original amorphous alloy, the saturation magnetostriction test described above and the magnetic permeability test described below were conducted. Figure 3 shows the results of the saturation magnetostriction test.

As is clear from FIG. 3, the saturation magnetostriction increases as the CO content increases, and from about 3 at.%, the saturation magnetostriction is preferred as a sensor alloy.

(Magnetic permeability test) The magnetic permeability test was conducted as follows.

Y HP LF Impedance Analyzer 4192
A, it was calculated from the inductance value L[H] when 50KIIz and 5 moe were applied using the following formula.

Mi= Ldx 10'/4 S N' where d is the average diameter of the sample core, S is the effective cross-sectional area [cn+], and N is the number of coil turns.

The results are shown in FIG.

The approximate efficiency of the sensor alloy performance can be determined by the electromechanical coupling coefficient K in the following equation. From this equation, it can be seen that a sensor alloy needs to have a large magnetostriction change and high magnetic permeability.

(B: Magnetic flux density, H: Magnetic field, E: Young's modulus, μ: Magnetic permeability) As is clear from Figure 4, the magnetic permeability reaches its maximum when the Co content is about 10 at.%, and if more than that is contained. Therefore, the co content is 3 to 15 at.

It turns out that % is suitable.

In other words, the conventional knowledge is that adding CO to l;'esiB reduces the magnetic permeability, but as is clear from this example, by combining it with a predetermined amount of Or, the permeability decreases.
The permeability increases significantly between ~15 at,%. This results in a high-performance, highly rust-resistant sensor alloy with high magnetic permeability and reasonable magnetostriction.

<Comparison Example 7> Fe78B1, a conventionally known iron-based amorphous alloy
3Si19 was subjected to the above saturation magnetostriction test, the above magnetic permeability test, and the rust development test, and compared with the above Experimental Example 2.

In addition, in the rusting test, the test piece was kept at 40℃ and humidity 95℃.
% or more, the state of rusting was visually observed, and the rusting property was evaluated based on the time it took for rust to develop. The results are shown in Table 1.

Table 1 [Effects of the Invention] As explained above, the present invention provides a highly rust-resistant amorphous alloy that maintains the excellent magnetic properties of an amorphous alloy and also has good rust prevention properties. be able to.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the results of the rust development test in Examples and Comparative Examples, Figures 2 and 3 are diagrams showing the results of the saturation magnetostriction test, and Figure 4 is a diagram showing the results of the magnetic permeability test. . Patent issuer Mitsui Petrochemical Industries Co., Ltd. JC Figure 1 Cr warehouse t X (at, %) Figure 2 Cr famous quantity X (at, %)

Claims (1)

[Claims] (1) General formula Fe_vCo_wCr_xB_ySi_z (in the above formula, v+w+x+y+z=100 at.%, and v is 60 to 78 at.% and w is 3 to 15 at.
．． %, x is 4 to 12 at. %, y is 8 to 20 at. %,
z is 0 to 10 at. A highly rust-resistant amorphous alloy characterized by having a composition shown in (%).