JPH01247555A - Hyperfine-crystal fe-base alloy excellent in corrosion resistance and its production - Google Patents

Abstract

PURPOSE:To manufacture a hyperfine-crystal Fe-base alloy excellent in corrosion resistance by forming an oxide layer of a specific thickness on the surface of a hyperfine-crystal Fe-base alloy having a specific composition and containing fine crystalline grains under specific conditions. CONSTITUTION:In a hyperfine-crystal Fe-base alloy having a composition represented by a general formula (Fe1-aMa)100-x-y-z-alpha-beta-gammaCuxSiyBzMalpha'Mbeta''Xgamma (atomic%) (where M means Co and Ni, M' means Nb, W, etc., M'' means V, Cr, etc., X means C, Ge, etc., the symbols (a), (x), (y), (z), alpha, beta and gamma stand for 0-0.5, 0.1-10, 0-30, 0-25, 0.1-30, <=10 and <=10, respectively, and y+z=5-30 is satisfied) and also having a structure in which fine crystalline grains comprise at least 50% and the average grain size measured by the maximum sizes of respective crystalline grains is regulated to <=1000Angstrom and the balance is composed of amorphous substance, an oxide layer of >=50Angstrom , preferably 50-5000Angstrom , thickness is formed on the surface. By this method, the hyperfine-crystal Fe-base alloy excellent in corrosion resistance can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides an ultrafine crystalline Fe-based alloy with excellent corrosion resistance for use in applications requiring corrosion resistance, such as magnetic heads, various transformers, etc., and a method for producing the same. This is related to the improvement of

[Conventional technology] Silicon steel, F
e-AI-8t alloy, permalloy alloy, amorphous alloy, etc. are used, and to improve corrosion resistance, CR
, r+, etc., or surface coating is performed to improve the corrosion resistance. These examples are from the Tokuko Sho 6
Publication No. 0-39160.

Special Publication No. 60-41139 and Special Publication No. 60-4114
It is described in Publication No. 1, etc. However, these alloys have advantages and disadvantages in terms of saturation magnetic flux density and soft magnetism, and their properties are not necessarily satisfactory.

By the way, we have previously reported in Japanese Patent Application No. 183876/1983 that Fe-based alloys with ultrafine grain structures have soft magnetic properties, and that by adding Cr, RU, etc., corrosion resistance is significantly improved. showed that it could be improved.

[Problems to be Solved by the Invention] However, in the ultrafine crystal Fe-based alloy, when Cr or the like is added for the purpose of improving corrosion resistance, the saturation magnetic flux density decreases, so it is difficult to maintain a high saturation magnetic flux density. It is not necessarily sufficient to improve corrosion resistance, and it has been desired to further improve corrosion resistance with the same addition amount.

An object of the present invention is to provide an Fe-based alloy having the same composition and an ultrafine grain structure with further improved corrosion resistance, and a method for producing the same.

[Means for solving the problem] As a result of intensive studies in view of the above objectives, the present inventors have determined that Fe −
Cu, Nb, W, and T are added to the alloy whose basic component is s+-8.
By adding at least one element selected from the group consisting of a, Zr, Hf, Ti, and MO in a composite manner to form an amorphous alloy and subjecting it to appropriate heat treatment, most of the structure becomes fine. It was discovered that an Fe-based alloy consisting of crystal grains and an oxide layer formed on the surface of the alloy can be obtained, and corrosion resistance is improved, and the present invention was conceived.

That is, the Fe-based alloy of the present invention has the general formula: % formula % (where M is CO and/or Ni, M' is Nb,
At least one element selected from the group consisting of W, Ta, Zr, Hf, Ti and Mo, M IIf, tV, Cr
, Mn, △1. White metal element, Sc, Y.

Rare earth elements, at least one element selected from the group consisting of Au, Zn, Sn, and Re, X is C1Gc, P, Ga
, Sb, 'In, Be, and As, at least one element selected from the group consisting of a, x, y, z, α, β,
and γ are 0≦a≦o, s, o, i≦X≦1, respectively.
0.0≦y≦30.0≦2≦25.5≦l/+Z≦3
0. 0.1≦α≦30. β≦10 and γ≦10 are satisfied. ) has the composition represented by

At least 50% of the structure consists of fine crystal grains, and an oxide layer is formed on the alloy surface.

Furthermore, the method for producing an Fe-based alloy of the present invention is characterized by comprising a step of rapidly cooling the amorphous alloy, and a heat treatment step of heating it in an atmosphere containing oxygen to form fine crystal grains. shall be.

In the Fe-based alloy of the present invention, Fe may be substituted with GO and/or Ni in a range of 0 to 0.5.

In the present invention, Cu is an essential element, and its content ×
is in the range of 0.1 to 10 at.%.

3i and B are elements particularly useful for refining the alloy structure. The Fe-based alloy of the present invention preferably contains -DanSi,
It is obtained by forming an amorphous alloy due to the effect of B addition and then forming fine crystal grains by heat treatment. 3i content m
The content 1z of y and B is preferably 30 at % or less for y, 25 at % or less for l, and 5 to 30 at % for y+z.

In the present invention, the preferred range of y is 6 to 25 at%, the preferred range of l is 2 to 25 at%, and y+
The preferred range of z is 14 to 30 atomic %. In the present invention, M- has the effect of refining the crystal grains that are precipitated by being added in combination with C0, and Nb,
At least one element selected from the group consisting of W, Ta, Zr, Hf, Ti, and MO. Nb and the like have the effect of avoiding an increase in the crystallization temperature of the alloy, but their interaction with Cu, which has the effect of forming clusters and lowering the crystallization temperature, suppresses the growth of crystal grains and makes the precipitated crystal grains finer. considered to be a thing.

The content α of M' is 0.1 to 30 at%, and if it is less than 0.1 at%, the effect of grain refinement is insufficient;
Exceeding atomic % causes a significant decrease in saturation magnetic flux density. The preferable M' content α is 1 to 10 atomic %. A more preferable range of α is 2≦α≦8, and particularly excellent soft magnetism can be obtained within this range.

Note that Nb is most preferable as M' in terms of magnetic properties. Furthermore, by adding M', the material has a high magnetic permeability equivalent to that of a CO-based high magnetic permeability material.

V, Cr, Mn, AI, platinum metal element, Sc, Y.

M'', which is at least one element selected from the group consisting of rare earth elements, Au, Zn, Sn, and Re, is used for the purpose of improving corrosion resistance, improving magnetic properties, and adjusting magnetostriction. However, the content is at most 10 atomic % or less. This is because if the content exceeds 10 atomic %, the saturation magnetic flux density will be significantly lowered, so the particularly preferable content is It is 5 atomic % or less.

Among these, t'Ru, Rh, Pd, Os, and Ir.

When at least one element selected from the group consisting of Pr, Au, Cr, AI, and V is added, corrosion resistance improves, especially when an oxide layer is formed on the surface, making it suitable as a magnetic head material. .

In the alloy of the present invention, C, Ge, P, Qa
.

3b, In, 3e, and AS.

These elements are effective for amorphization, and Si, B
By adding it together, it helps to make the alloy amorphous and is effective in adjusting the magnetostriction and Curie temperature.

In the Fe-based alloy of the present invention having the above composition, at least 50% of the structure consists of fine crystal grains.

It is thought that these crystal grains are mainly composed of α-Fe with a bcc structure, and Si, B, etc. are dissolved therein.

These crystal grains are characterized by having a significantly small crystal grain size of 1000 Å or less, and are uniformly distributed in the alloy structure. The average grain size of crystal grains is the average of the maximum dimensions of each grain. If the average particle size exceeds 1,000 particles, good soft magnetic properties cannot be obtained.

The average particle size is preferably 500 Å or less, more preferably 200 Å or less, and especially 50 to 200 particles.

The parts of the alloy composition other than the fine crystal grains are mainly amorphous. Note that the proportion of fine crystal grains may be substantially 100%.

It goes without saying that even if unavoidable impurities such as N, O, and S are contained to the extent that desired characteristics are not deteriorated, the alloy composition can be considered to be the same as the alloy composition of the present invention.

The pressure difference in the oxide layer is usually desirably in the range of 50 to 5,000, and a strong oxide layer is easily formed within this range.

Next, the method for manufacturing the Fe-based alloy of the present invention will be explained.

First, a ribbon-shaped amorphous alloy is formed from a molten metal having the above-mentioned predetermined composition by a known liquid quenching method such as a single roll method or a twin roll method. Usually, the thickness of an amorphous alloy ribbon produced by a single roll method or the like is about 5 to 100 μm.

Although this amorphous alloy may contain a crystalline phase, it is preferably amorphous in order to uniformly generate fine crystal grains during subsequent heat treatment. The liquid quenching method makes it possible to obtain the alloys of the invention without heat treatment.

The amorphous ribbon is processed into a predetermined shape by winding, punching, etching, etc. before heat treatment. This is because the ribbon has good workability in its amorphous state, but once it crystallizes, the workability deteriorates significantly.

Heat treatment is performed by holding an amorphous alloy ribbon processed into a predetermined shape in an atmosphere containing oxygen for a certain period of time.

The heat treatment temperature and time vary depending on the shape, size, composition, etc. of the magnetic core made of amorphous alloy ribbon.
A 5 minute to 24 hour type at ~700°C is preferable. When the heat treatment temperature is less than 450°C, crystallization is difficult to occur and the heat treatment takes too much time. On the other hand, if the temperature is higher than 700°C, coarse crystal grains may be formed, making it impossible to uniformly obtain fine crystal grains. In addition, if the heat treatment time is less than 5 minutes, it is difficult to bring the entire processed alloy to a uniform temperature, and the magnetic properties tend to vary.
If it is longer than that, not only will productivity deteriorate, but also excessive growth of crystal grains will likely occur. The preferable heat treatment conditions are 500~
The temperature is 650°C for 5 minutes to 6 hours.

The heat treatment atmosphere is preferably an oxidizing atmosphere such as air, but
An atmosphere containing oxygen in an inert gas may also be used. Cooling can be performed appropriately by air cooling, furnace cooling, or the like. In addition, multi-stage heat treatment can be performed depending on the case.

Heat treatment can also be carried out in a magnetic field. Magnetic anisotropy can be produced in this alloy by heat treatment in a magnetic field.

It is not necessary to apply the magnetic field throughout the heat treatment; it is sufficient to apply it at a temperature below the Curie temperature of the alloy, 11TC. In the case of heat treatment in a magnetic field, the heat treatment can also be performed in two or more stages. Moreover, heat treatment can also be performed in a rotating magnetic field.

Further, the Fe-based alloy of the present invention can also be manufactured using a thin film forming technique such as a sputtering method, and thin film magnetic heads and the like can also be manufactured. Moreover, thin wire-like products can also be produced by the rotating liquid-in-rotation method, the glass coating method, etc.

Further, it is also possible to produce a powdered material by TIJ, for example, by crushing a ribbon produced by a cuvitation method, an atomization method, or simply a roll method.

The alloy of the present invention can also be obtained by manufacturing an amorphous alloy in an oxidizing atmosphere, forming an oxide on the surface, and then heat-treating the alloy in an inert gas.

[Example 1] The present invention will be described below with reference to Examples, but the present invention is not limited thereto.

Example 1 Atomic % rsi 13.5%, 89%, N'b 3%, CO
A molten alloy having a composition consisting essentially of Fe with the remainder being 1% was rapidly cooled in Ar gas by a single roll method to a thickness of 18 μm.

An amorphous alloy ribbon with a width of 5II1 m was prepared and heated at 550 m in vacuum.
Heat treatment was carried out by holding at ℃ for 1 hour. After heat treatment, most of the structure of the alloy is ultra-fine with a grain size of about 100 mm.cc
It consisted of Fe solid solution crystal grains. Next, the surface of this alloy was analyzed using an Auger electron spectrometer.

The results obtained are shown in FIGS. 1(a) and (b). The free solidification surface side contained 46 oxygen, and the roll contact surface side contained 42 oxygen, and the oxide layer was less than 50 oxide thick.

Next, the amorphous alloy ribbon was mixed with 5% oxygen and about 95% nitrogen.
Heat treatment was carried out by holding the temperature at 550° C. for one hour in a gas atmosphere containing 50%. Most of the structure of the alloy after heat treatment has a grain size of 1.
It consisted of ultra-fine hccFa solid solution crystal grains of about 0.000. Next, the surface of this alloy was analyzed using an Auger electron spectrometer.

The obtained results are shown in FIGS. 2(a) and (b).

It was confirmed that 230 people on the free solidification surface side and 150 people on the roll contact side contained oxygen and the thickness of the oxide layer on the surface was 50 Å or more.

Next, the alloys subjected to these two heat treatments were placed in water for one day to examine their corrosion resistance. While the alloy heat-treated in vacuum developed rust, the alloy of the present invention, which was heat-treated in an atmosphere containing oxygen to form an oxide layer with a thickness of 50 Å or more on the surface, showed almost no rust and was in good condition. It showed excellent corrosion resistance.

Example 2 A molten alloy having a composition consisting of 11% CL, 10% -1'Jb, 39% [39% atomic %], and the remainder substantially Fe was rapidly cooled in He gas by a single roll method to form an amorphous material with a thickness of 15 μm and a width of 5 Ill. An alloy ribbon was produced.

Next, this alloy ribbon was held at 590° C. for 1 hour in a mixed gas of 70% nitrogen and 30% oxygen, and cooled to room temperature at a cooling rate of 5° C./win. After heat treatment, the microstructure inside the alloy consisted of approximately 50 ultrafine crystals. Next, the surface of this alloy ribbon was analyzed using an Auger electron spectrometer. The results obtained are shown in FIG.

880A on the free solidification surface side, 1380A on the roll contact surface side
It was confirmed that 0 oxygen was present up to the thickness of a human being, and a fairly thick oxide layer was formed.

This oxide is thought to be an oxide of Nb, 3i, Fe, or the like.

Next, this alloy was placed in water for 3 days to examine its corrosion resistance. The alloy heat-treated in hydrogen developed rust, whereas the alloy of the present invention, which had an oxide layer formed on its surface, showed almost no rust and exhibited good corrosion resistance.

Example 3 A molten alloy having a composition consisting of 1% Cu, 10% Nb, 89% Nb, and the remainder substantially Fe in atomic % was rapidly cooled in the atmosphere, which is an oxidizing atmosphere, by a single roll method, and was made into a molten alloy having a thickness of 15 μm and a width of 5 mm.
An amorphous alloy ribbon of I1m was produced.

Next, this alloy ribbon was heated to 590°C in an Ar gas atmosphere.
The mixture was maintained for a period of time and cooled to room temperature at a cooling rate of 5° C./min. The micro Ig texture inside the alloy after heat treatment was the same as in Example 2. Next, the surface of this alloy was analyzed using an Auger electron spectrometer. , 1q are shown in Figure 4.

Oxygen O was present up to a thickness of 285A on the free solidification surface side and 315A on the roll contact surface side, and it was confirmed that a considerably thick oxide layer was formed as in Example 2.

Next, this alloy was placed in water for 3 days to examine its corrosion resistance. The alloy of the present invention exhibited good corrosion resistance with almost no rust.

Example 4 A molten alloy having a composition consisting of CIJI%, Nb 3%, 3i 8%, 39%, and the balance substantially Fe in atomic % was rapidly cooled in an oxidizing atmosphere in the air by a single roll method, and a thickness of 15 μm was obtained.
An amorphous alloy ribbon having a m1 width of 5II11 was produced.

Next, this alloy ribbon was heated to 550°C in an Ar gas atmosphere and a mixed gas atmosphere of nitrogen gas and oxygen gas (5%).
After heat treatment for 1 hour and cooling to room temperature, surface analysis was performed using an Auger electron spectrometer.

Figure 5 shows the case of heat treatment in an Ar gas atmosphere, and Figure 6 shows the case of heat treatment in an atmosphere containing oxygen gas.1° When heat treatment was carried out in an atmosphere containing oxygen, the oxide layer became noticeably thicker. You can see that

When heat-treated in high-purity Ar gas, the oxide layer becomes 50%
When the alloy was submerged in water and its corrosion resistance was examined, rust occurred and the corrosion resistance was inferior to that of a material with a thick oxide layer.

Example 5 A ribbon of the alloy of the present invention having the composition shown in Table 1 was prepared and placed in tap water to examine its corrosion resistance. The results obtained are shown in Table 1.

(Hereinafter, blank spaces) The corrosion resistance of the alloy of the present invention is superior to that of an alloy with a thin oxide layer.

[Advantageous Effects of the Invention 1] According to the present invention, it is possible to provide an ultrafine-crystalline Fe-based alloy with excellent corrosion resistance and a method for producing the same, so the effects are remarkable.

[Brief explanation of the drawing]

FIGS. 1 and 5 are diagrams showing the analysis results in the thickness direction of the surface of an alloy with a thin oxide layer, which is shown for comparison, analyzed using an Auger electron spectrometer. FIGS. 3, 4, and 6 are diagrams showing the results of analysis of the surface of the alloy of the present invention in the thickness direction using an Auger electron spectrometer. No change in the content of the nails on the r

Claims (7)

[Claims] (1) General formula: (Fe_1_-_aM_a)_1_0_0_-_x_-
＿y＿−＿z＿−＿α＿−＿β＿−＿Cu_xSi_y
B_zM′_αM″_βX_γ (atomic %) (However, M is Co and/or Ni, M′ is Nb,
At least one element selected from the group consisting of W, Ta, Zr, Hf, Ti and Mo, M'' is V, Cr, Mn,
Al, platinum metal element, Sc, Y, rare earth element, Au, Zn
, Sn, Re, X is C, Ge, P, Ga, Sb, In, Be, A
at least one element selected from the group consisting of s, and a, x, y, z, α, β, and γ are each 0≦a≦
0.5, 0.1≦x≦10, 0≦y≦30, 0≦z≦2
5, 5≦y+z≦30, 0.1≦α≦30, β≦10, and γ≦10. ) and at least 50% of the tissue
In ultrafine crystalline Fe-based alloys that are composed of fine crystal grains and the average grain size measured at the maximum dimension of each crystal grain is 1000 Å or less, an oxide layer with a thickness of 50 Å or more is formed on the alloy surface. An ultrafine crystalline Fe-based alloy with excellent corrosion resistance. (2) The ultrafine crystalline Fe-based alloy according to claim 1, characterized in that the crystal grains have an average grain size of 500 Å or less. (3) An ultrafine-crystalline Fe-based alloy with corrosion resistance, characterized in that the remainder of the structure is amorphous in the Fe-based alloy according to claim 1 or 2. (4) In the Fe-based alloy according to claim 1 or 2, the ultrafine-crystalline Fe-based alloy has excellent corrosion resistance, characterized in that the structure consists of substantially fine crystal grains. . (5) Ultrafine crystalline Fe base with corrosion resistance according to any one of claims 1 to 4, wherein the oxide layer has a thickness of 50 to 5000 Å. alloy. (6) General formula: (Fe_1_-_aM_a)_1_0_0_-_x_-
＿y＿−＿z＿α＿−＿β＿−＿γCu_xSi_yB
＿zM′_αM″_βX_γ (atomic %) (However, M is Co and/or Ni, M′ is Nb,
At least one element selected from the group consisting of W, Ta, Zr, Hf, Ti and Mo, M'' is V, Cr, Mn,
Al, platinum metal element, Sc, Y, rare earth element, Au, Zn
, Sn, Re, X is C, Ge, P, Ga, Sb, In, Be, A
at least one element selected from the group consisting of s, and a, x, y, z, α, β, and γ are each 0≦a≦
0.5, 0.1≦x≦10, 0≦y≦30, 0≦z≦2
5, 5≦y+z≦30, 0.1≦α≦30, β≦10, and γ≦10. 1.) A method for producing an Fe-based alloy, comprising the step of heat treating an amorphous alloy having a composition represented by (7) General formula: (Fe_1_-_aM_a)_1_0_0_-_x_-
＿y＿−＿z＿−＿α＿−＿β＿−＿γCu_xSi_
yB_zM′_αM″_βX_γ (atomic %) (However, M is Co and/or Ni, M′ is Nb,
At least one element selected from the group consisting of W, Ta, Zr, Hf, Ti and Mo, M'' is V, Cr, Mn,
Al, platinum metal element, Sc, Y, rare earth element, Au, Zn
, Sn, Re, X is C, Ge, P, Ga, Sb, In, Be, A
at least one element selected from the group consisting of s, and a, x, y, z, α, β, and γ are each 0≦a≦
0.5, 0.1≦x≦10, 0≦y≦30, 0≦z≦2
5, 5≦y+z≦30, 0.1≦α≦30, β≦10, and γ≦10. ) is prepared in an oxidizing atmosphere, and after forming an oxide layer on the surface, at least 50% of the structure is
A method for producing an Fe-based alloy, comprising the step of heat treatment so that % becomes fine crystal grains.