JPH09260125A - Magnetic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a good strength and wear resistance as well as magnetic characteristics by forming a two-dimensional quasicrystal decagonal phase to produce a novel alloy revealing a controllable soft magnetic or ferromagnetic property. SOLUTION: A magnetic material has a quasi-crystal single phase composed of a decagonal Phase(D phase) or quasi-crystals composed of the D phase as a main phase, contg. Mn as a main element and at least Al, Ge and B. An alloy composed of or contg. the D phase is a magnetic material composed of Mna Alb Gec Bd (a=40-55atm.%, b=15-30atm.%, c=10-30atm.%, d=3-20atm.%, 45 atm.%<=b+c+d<=60atm.%. The quasicrystal composed of the D phase has a laminate structure having a quasi-crystal size of 50-200nm. Thus it is possible to obtain a magnetic material having a superior mechanical property.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic material composed of a substantially regular decagonal phase quasicrystal which can be applied to various applications as a ferromagnetic material.

[0002]

2. Description of the Related Art In an Al--Mn alloy, 5 times, 10
Since the discovery of a new alloy having a rotationally symmetric crystal structure, a so-called quasicrystal, a quasicrystal alloy has been extensively studied as a new material for the purpose of elucidating the range of formation, structural analysis, and basic physical properties. It was Along with that, physical properties such as hardness, brittleness, high Young's modulus, and high electric resistance have become clear as characteristics of an ideal quasicrystal (having a stoichiometric composition ratio). Although there are some proposals for application as high-strength materials, few proposals utilize physical properties due to the crystal structure of quasicrystals. Among them, as research on electromagnetic characteristics,
Al40% -Cu10% -Mn25% -Ge25% alloy (all are atomic%) (AP Tsai et al; T
pn. Appl. Phys. 27 [1988], L22
52) and an Al-Mn-Si based alloy (RA Dun.
lap et al. Phys. Rev .. B. 39 [1
989] 4808), Al-Cu- (Pd, Mn) -B.
It has been reported that a system alloy (Japanese Patent Laid-Open No. 6-53021) exhibits ferromagnetism.

[0003]

However, the magnetic properties of the above alloys need to be improved before they can be put to practical use as magnetic materials. It is an object of the present invention to provide a material useful as a magnetic material by conducting a study to bring out physical properties due to anisotropy of a quasicrystal characterized by a two-dimensional atomic arrangement.

[0004]

The first aspect of the present invention is a magnetic material which is a two-dimensional quasi-crystal D phase or an alloy containing the D phase and which has the following composition formula. .

M _a Al _b Ge _c B _d However, a: 40 to 55 atomic%, b: 15 to 30 atomic%, c: 10 to 30 atomic%, d: 3 to 20 atomic%, 45
Atom% ≦ b + c + d ≦ 60 atom%.

A second invention is that Mn of the above alloy composition is M element (one or two elements selected from Fe; Co).
It is a magnetic material characterized by being replaced in the range of 10 to 15 atomic%.

A typical structure known as a quasicrystal is an icosahedral phase (I).
Phase) and the D phase. Phase I is a three-dimensional quasicrystal,
Phase D is a two-dimensional quasicrystal. 2 times, 3 times, 5
Although it has a symmetric atomic arrangement of times, the D phase has a quasicrystalline structure in the two-dimensional a-b plane, but has a periodically stacked structure in the C-axis direction. In order to bring out the magnetic properties, it is useful to use an atomic structure arranged with strong anisotropy like the D phase.

The present invention was invented based on this concept. That is, the D phase can be obtained by rapidly solidifying the Mn-Al-Ge-B (-M) based alloy by the liquid quenching method. The reason why the composition range is limited to the above is that if it deviates from the range, quasicrystals are not formed or desired magnetic characteristics cannot be obtained.

Mn, Al, and Ge are essential components for forming the D phase, and B having a small atomic radius forms a solid solution in the quasicrystal to reduce the lattice constant of the quasicrystal, thereby reducing magnetic properties such as magnetization. It strengthens the interaction of the factors Mn-B and Mn-Mn pairs. M (Fe or / and Co) forms an M-B pair by forming a solid solution in the alloy, and contributes to an increase in coercive force and the like. The quasi-crystal of the present alloy is a metastable phase and changes to a crystal phase such as an intermetallic compound by heating, but its magnetic characteristics are reduced by crystallization.

[0010] In the general formula Mn _a Al _b Ge _{c B d} alloy, the size of the quasi-crystals consisting of D phase 50nm~200n
It is preferably m, the general formula Mn _a Al _b Ge _c
It is preferred B _d M _e alloy whose magnitude is 5 nm to 20 nm.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The material of the present invention can be manufactured by a liquid quenching device such as a conventionally known melt spinning device. However, the conventionally known gas atomizing method, sputtering or the like 10 ² K is used. It can also be manufactured by another manufacturing method having a quenching effect of about / sec or more. The present invention can also be produced by crystallization or decomposition treatment such as heating an amorphous phase or a supersaturated solid solution obtained by rapid solidification.

Since the quasicrystal of the present invention has no deformation zone such as slip, it has high strength, high Young's modulus and high hardness.
It has strong resistance to deformation and abrasion, and has excellent properties and utility as a structural material. That is, not only a new substance called a magnetic material is provided, but also a composite functional material excellent in mechanical properties is provided at the same time.

[0013]

The present invention will be specifically described below with reference to examples.

Example 1 99.999 wt% pure Al, Mn and Ge, 9
A predetermined amount of a B raw material having a purity of 9.9 wt% was sampled, and a uniform master alloy was melted in an arc melting furnace in an argon atmosphere.
This master alloy was made to have a thickness of 0.
The ribbon was 02 mm in width and 1 mm in width. At that time, a copper roll having a diameter of 200 m was used as the quenching roll, and the rotation speed of the roll was 2000 rpm. The crystal structure of the as-quenched and solidified sample and the sample heat-treated at various temperatures were investigated by X-ray diffraction and a transmission electron microscope. Magnetic characteristic is 1
It was measured by a vibrating magnetometer (VSM) in a temperature range of 4.2 to 950 K in a magnetic field of 8 kOe.

In FIG. 1, Mn is fixed at 45 atom%, Al,
The result of having investigated the histological structure by changing the composition of Ge and B is shown. As a result, Al is 22 to 28 atomic%, G
e in the range of 12 to 24 atomic% and B in the range of 7 to 17 atomic% D
It can be seen that they form a phase. If deviating from the composition range of the D phase, an orthorhombic crystal phase appears on the Al-rich side and a B ₂ type crystal phase appears on the Al poor side.

FIG. 2 shows the range of D phase formation when Mn is fixed at 50 atomic%. In this case, it is understood that the D phase is formed in the range of 18 to 28 atomic% of Al, 18 to 23 atomic% of Ge, and 5 to 15 atomic% of B. Comparing these two cases, the composition range of B was reduced when Mn was increased from 44.5 atomic% to 50 atomic%.
This seems to indicate that the atomic sites occupied by n and B are almost the same. Mn ₄₅ Al ₂₅ Ge ₁₅ B ₁₅ alloy and M
The measurement result of the X-ray diffraction of the n ₅₀ Al ₂₀ Ge _22.5 B _7.5 alloy is illustrated in FIG. As a result, any diffraction peak can be determined to be the D phase. It is considered that the peak of the latter alloy becomes weaker, and an increase of Mn from 45 atom% to 50 atom% tends to reduce the formation of D phase. When observed with a transmission electron microscope to confirm the presence of the second phase, the second phase was not present, and instead, a streak in which the diffraction spot extended twice in the rotation axis direction (010010) was observed, and C
It was confirmed to be a D phase (two-dimensional quasicrystal) having a periodic structure of 1.2 nm in the axial direction. At that time, the size of the D phase on the ab two-dimensional plane was 50 to 200 nm. This D
The phase changed to a crystalline phase by heating for 60 seconds at a temperature of 950K.

Mn ₄₅ Al ₂₅ Ge ₁₅ B ₁₅ alloy and Mn ₅₀ Al
The measurement result of the magnetization curve (JH curve) of the ₂₀ Ge _22.5 B _7.5 alloy is shown in FIG. The magnetization, remanent magnetization and coercive force of a magnetic field of 18 kOe are 2 Mn ₄₅ Al ₂₅ Ge ₁₅ B ₁₅ alloy, respectively.
6 emu / g, 8 emu / g and 300 Oe, Mn ₅₀
Al ₂₀ Ge _22.5 B _7.5 alloy with 7 emu / g, 3 emu / g
g and 350 Oe. The coercive force was slightly increased by the increase of 5 atom% of Mn, but the magnetization and the residual magnetization were sharply decreased. This is considered to be due to the decrease of Mn-B atom pairs, which is considered to be the origin of ferromagnetism, due to the decrease of B due to the increase of Mn.

FIG. 5 was carried out to examine the Curie temperature (Tc). The heating magnetic characteristic curve of this alloy in the magnetic field of 10 Oe is shown. In the figure, what is described as D phase is a sample which was heat-treated at 950 K for 60 seconds while being rapidly solidified. The magnetization of the crystal phase is slightly reduced as compared with the magnetization of the D phase. The Tc of the D phase and the crystalline phase obtained from the relationship between (magnetization) ² and temperature is 570K and 530K for the alloy of 45 atomic% Mn and 558K and 530 for the alloy of 50 atomic% Mn.
It was K. The magnetization behavior does not depend on the alloy composition, and Mn-
It appears to be due to the B atom pair, and its strength seems to indicate that it varies depending on the number of Mn-B.

Example 2 An alloy in which a part of Mn of the Mn-Al-Ge-B system alloy was replaced with a transition metal (Cr, Fe, Co or Ni, where Cr and Ni are for reference) was the same as in Example 1. It was created by the method. Composition range _{Mn 45-x Al 25 Ge 15} B 15 Fe x (x:
5, 10, 15). The effect of these transition metals on the coercive force is shown in FIG. As shown in the figure, Cr and Ni have the effect of reducing the coercive force and increasing Fe and Co, and the effect of Fe is particularly remarkable, showing an increase of 11.1 kA / m for every 1 atomic% increase in Fe.

FIG. 7 shows the difference in the amount of Fe in the Mn _45-x Al ₂₅ Ge ₁₅ B ₁₅ Fe _x alloy (however, x: 0, 5, 10, 1
5 shows the result of X-ray diffraction according to 25, 35) as a reference. As shown in the figure, the Fe phase is a single phase up to 15 atomic%, and as the Fe content further increases, the mixed phase structure of the D phase and the crystalline phase (2
5 atomic%) and the crystal phase (35 atomic%). As a result of observation by a transmission electron microscope, the alloy having 15 atomic% Fe does not have the second phase, and has a grain size of 5 to 20 nm in the ab plane and a D phase having a periodicity of 1.2 nm in the C-axis direction. Be a
It was found that a -P plane defect was included in the -b plane ((100000) direction). This internal defect is considered to be due to a large amount of Fe being forced to form a solid solution and the strain being frozen inside during rapid solidification.

8 and 9 show the JH curves for these alloys. It is apparent that the coercive force (Hc) and the remanent magnetization (Br) increase while the magnetization slightly decreases as the substitution amount of Fe increases. The magnetization in a magnetic field of 18 kOe was 25 emu / g (3.14 × 10 to ⁵ Wbm / k) with 0 atomic% of Fe.
g) up to 10 atomic% 27 emu / g (3.39 × 10
~ ⁵ Wbm / kg), almost constant, 23 emu at 15 atom%
/G(2.89×10~ ⁵ Wbm / kg) and decreased slightly. On the other hand, the remanent magnetization (Br), the coercive force (Hc), and the energy product ((BH) _max ) are each 7 e at 0 atomic% Fe.
mu / g (0.87 × 10 ~ ⁵ Wbm / kg), 329O
e (26.3 kA / m) and 0.16 kJ / m ³ , Fe
10 emu / g (1.25 × 10 ~ ⁵ Wbm at 15 atom%
/ Kg), 1425 Oe (114 kA / m), 1.44
It was kJ / m ³ .

The Curie temperature Tc is 0 atomic% of Fe.
It increased to 570K at 570K and 620K at 15 atom%.

From these facts, it is understood that the substitution of Fe for Mn reduces the saturation magnetization by reducing the number of Mn-B atom pairs and Mn-Mn atom pairs. Further, the miniaturization of the D phase and the increase of internal defects due to Fe substitution increase Hc and BHmax. As is well known, Hc is sensitive to the microstructure and increases with the increase of crystal grain boundaries and internal defects. Correspond to what you do.

From the above examples, Mn-Al-Ge-B
The system alloy and the Mn-Al-Ge-B-Fe system alloy form a two-dimensional quasi-crystalline D phase, and the Mn-Mn atom pair and Mn-B are formed.
It can be seen that it is a novel alloy that exhibits ferromagnetic or soft magnetic magnetic properties by the interaction of atomic pairs.

[0025]

As described above, the alloy of the present invention is a novel alloy which exhibits soft magnetism or ferromagnetism by forming a two-dimensional quasicrystalline regular decagonal phase and can control them. . Further, the quasicrystal is originally a composite functional material having excellent mechanical properties and having magnetic properties, strength, and wear resistance.

[Brief description of drawings]

FIG. 1 is a graph showing the microstructure of Mn ₄₅ Al _55-XY Ge _{X BY} .

FIG. 2 is a graph showing a D-phase formation range when Mn is fixed at 50 atom%.

FIG. 3 is an X-ray diffraction diagram of a representative two-type alloy.

FIG. 4 is a graph showing the measurement results of the magnetization curves of typical two type alloys.

FIG. 5 shows a heating magnetic characteristic curve of a representative two-type alloy in a magnetic field.

FIG. 6 is a graph showing the effect of the transition metal on the magnetic force in the present invention.

FIG. 7 shows an X-ray diffraction diagram due to a difference in Fe content in an alloy of Mn _45-x Al ₂₅ Ge ₁₅ B ₁₅ Fe _x .

FIG. 8 shows a magnetization curve of the above alloy.

FIG. 9 shows a magnetization curve of the above alloy.

Front Page Continuation (72) Inventor Yoshihiko Yokoyama 2-31-504, Nagamachi, Taichiro-ku, Sendai-shi, Miyagi Prefecture (12) Inventor Junichi Ei-dong 11-12-12, General Manager, Izumi-ku, Sendai-shi, Miyagi Prefecture

Claims (6)

[Claims] 1. Mn as a main element and at least Al and G
A regular decagonal phase containing e and B (decagonal ph)
and a quasi-crystal single phase composed of D phase) or a quasi-crystal composed of D phase as a main phase. 2. The magnetic material according to claim 1, wherein the alloy composed of the D phase or containing the D phase has the following composition formula. Mn _a Al _b Ge _{c B d} where a: 40 to 55 atomic%, b: 15 to 30 atomic%, c: 10 to 30 atomic%, d: 3 to 20 atomic%, however, 45 atomic% ≦ b + c + d ≦ 60 atom%. 3. The magnetic material according to claim 1, wherein the quasicrystal composed of the D phase has a laminated structure having a quasicrystal grain size of 50 to 200 nm. 4. Mn as a main element and at least Al and G
A regular decagonal phase containing e, B and Fe or / and Co (de
A magnetic material characterized by having a quasi-crystal single phase composed of a cationic phase (D phase) or a quasi-crystal composed of a D phase as a main phase. 5. The magnetic material according to claim 4, wherein the alloy composed of the D phase or containing the D phase has the following composition formula. _{Mn a'Al b Ge c B d} M e (M: Fe, 1 kind or two elements selected from Co) however, a': 30-45 atomic%, b: 15 to 30 atomic%, c: 10 -30 atom%, d: 3-20 atom%, e:
10 to 15 atomic%, but 55 atomic% ≦ b + c + d +
e ≦ 75 atom% 6. The magnetic material according to claim 4, wherein the quasicrystal composed of the D phase has a laminated structure in which the size of quasicrystal grains is 5 to 20 nm.