JPS63200316A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium which has high economic efficiency and cracks and peels less even if the underlying film thereof is thin by forming a composite film of a nonmagnetic or weakly magnetic alloy film and Cr film specified in compsn. as the underlying film on a nonmagnetic substrate. CONSTITUTION:The composite film composed of the nonmagnetic or weakly magnetic alloy film consisting of 37-60atom.% Cr and the balance Fe and inevitable impurities and the Cr film is deposited as the underlying film on the tempered glass substrate by using a flat plate magnetron RF sputtering device. Fe-40Cr, etc., are used as the ferromagnetic alloy film. The degree of vacuum of the sputtering device is set at 1-2X10<-6>Torr, the atmosphere at 99.99% Ar, the pressure at 6mTorr and the substrate temp. at 100 deg.C at the time of forming said film. The underlying film obtd. in such a manner is the substantially nonmagnetic film having <=1.0emu magnetization value. The magnetic film, therefore, exhibits the similar effect as compared with the underlying film consisting of Cr alone with an increase in coercive force. Such recording medium has the high economic efficiency and does not crack and peel.

Description

[Detailed Description of the Invention] Field of Application This invention is applicable to magnetic disks, etc., in which a magnetic thin film is provided on a non-metallic non-magnetic substrate such as a non-magnetic metal plate, ceramics or glass via a base film to be formed. In order to improve the magnetic recording media used, the underlayer is made of non-magnetic or weakly magnetic Fe.
The present invention relates to a magnetic recording medium formed of a -Cr alloy film or a composite film of a Fe-Cr alloy film and a Cr film, which is excellent in economic efficiency, and which has few cracks and peeling even with a thick base film.

BACKGROUND ART Magnetic disk drives are frequently used as storage devices in information processing systems such as computers. Nowadays,
In order to increase information processing ability, it is desired that magnetic disk devices have higher density and larger capacity, and metal thin films produced by sputtering, ion blating, etc. are being put into practical use as magnetic recording layers of magnetic disks.

As such a magnetic recording medium, a configuration is known in which a Cr film is formed on a nonmagnetic substrate, and then a Co film is formed on the Cr film by sputtering or vapor deposition.

This magnetic recording medium has a high coercive force in the in-plane direction and is used in an in-plane recording type magnetic disk.

Furthermore, magnetic recording media are known in which a Co--Ni film or a Co--Ni--Cr film is used as a magnetic film instead of the above-mentioned Co film.

On the other hand, regardless of the composition of the magnetic film described above, a Cr film is used as the base film in order to promote in-plane orientation of the Co-based magnetic film and increase coercive force.

However, in order to increase the coercive force of such a Cr underlayer, compared to the magnetic film thickness of 500A to 800A,
It is necessary to deposit the film to a much thicker film thickness of 2,000 to 6,000 Å.

Therefore, a large amount of expensive Cr is consumed, which increases the manufacturing cost.Also, Cr is inherently prone to embrittlement, and if the film is relatively thick, there may be a difference in the coefficient of thermal expansion with the substrate or during film formation. Since it tends to cause fine racks due to internal stress, etc., it has a problem that it lacks toughness and strength as a base film for magnetic recording media.

Purpose of the Invention The present invention solves the problems of conventional Cr underlayers in magnetic recording media used in magnetic disks, etc. in which a magnetic film is provided on a non-magnetic substrate via an underlayer, and is similar to Cr underlayers. The object of the present invention is to provide a magnetic recording medium having a novel underlayer that has the effect of increasing the coercive force of a magnetic film, is more economical than a Cr underlayer, and is free from cracking and peeling problems.

Structure and Effects of the Invention As a result of various studies aimed at creating a magnetic recording medium with a novel underlayer that can solve the problems of conventional Cr underlayers, the present invention has developed a magnetic recording medium with an equilibrium phase instead of the conventional pure Cr underlayer. Nonmagnetic or weakly magnetic F that is thought to have a different crystal structure
Using an e-Cr binary alloy film (hereinafter the Fe-Cr binary alloy film is simply referred to as Fe-Cr alloy film) or a composite film of a Fe-Cr alloy film containing an element other than Fe and Cr and a Cr film. The present invention was completed based on the finding that a magnetic recording medium with fewer problems of conventional Cr underlayer peeling could be obtained.

That is, the present invention provides a magnetic recording medium in which a base film and a magnetic film are laminated and coated on a non-magnetic substrate, wherein the base film contains Cr 37 at% to
60 at%, the balance being Fe and unavoidable impurities, or a composite film of a nonmagnetic or weakly magnetic alloy film represented by the following composition formula and a Cr film. It is a magnetic recording medium.

FexCryMz, where M is AI, 5i1Ti, VSMn, Co, Ni,
Cu, Zr5Nb, Mo, Tc, Ru, Rh,
Pd, Y, Hf, T! is at least one selected from a, W, xzytz represents at% of each element, and satisfies the following conditions.

x-1-y-1-z: 100. 35≦y-f-z≦60゜Qn<H (a) When M is at least one selected from AI and Si, 2≦25 (0) M is Ti, Nb, Mo, Tc, Ru, Rh , Pd
, in the case of at least one kind selected from W, 2≦15 (/') In the case of at least one kind selected from V and Mn, 2≦20 (d) M is selected from Zr, Y, Ta, Hf In the case of at least one type, 2≦10 (e) M is at least one selected from Co, Ni, and Cu.
In the case of seeds, 2≦8.To be more specific, in general, the base film of a magnetic recording medium is provided for the purpose of promoting in-plane orientation of the magnetic film and imparting a large coercive force to the magnetic film. If it is ferromagnetic, due to Z magnetic interaction, for example, if the coercive force of the underlying film is low, from several Oe to several tens of Oe, the coercive force of the magnetic film will also be 100
It is known that this decreases to about 0e to 2000e and deteriorates the characteristics of the magnetic film.

By the way, the known Fe-Cr alloy is Or gold-containing 70a
It is known that it exhibits ferromagnetism at room temperature up to about t%, and as is clear from the above description, it was conventionally thought that it could not be used as an underlayer for magnetic recording media.

However, as a result of various experiments, the inventors found that Cr 37at
% to 60 at%, the balance being Fe and inevitable impurities, and 20 at% or more Or, and AI
, Si, Ti, V, Mn, Co, Ni, C
u, Zr%Nb, Mo, Tc.

Ru, Rh, P<i, Y, Hf, Ta, W
35at% in total with at least one species selected from
Above, Fe containing 60 at% or less and the balance consisting of Fe
- When a Cr-based alloy film is formed on a substrate by a vapor deposition method under the required conditions, it can be used as an underlying film for a magnetic recording medium as a substantially non-magnetic film with superior properties compared to a Cr film. Furthermore, we found that Fe-Cr alloy film or Fe-C
By forming a composite film of an r-based alloy film and a Cr film, Cr
This invention was completed based on the discovery that an underlayer film for magnetic recording media having superior properties compared to other films can be obtained.

In this invention, non-magnetism or weak magnetism refers to substantially non-magnetic property, that is, practical non-magnetic property that does not significantly impair the magnetic properties of the magnetic film or affect the reproduction signal of the magnetic head. Or it means weak magnetism.

Therefore, even if the base film is composed of a mixed phase of a non-magnetic phase and some ferromagnetic phase, it is considered that there is no practical problem as long as the base film has a magnetization of about several emu/g as a whole.

Reasons for limiting the composition The Fe-Cr base film or Fe-0r base film, which is a feature of the magnetic recording medium of the present invention, has various compositions depending on the material of the substrate, the composition of the magnetic layer deposited on the base film, etc. The Cr content and the type and content of added elements can be appropriately selected and used.

In the case of a Fe-Cr base film, if the Cr content is less than 37 at%, the film formed by the normal film forming method becomes ferromagnetic and O
If r exceeds 60 at%, it is not preferable because the toughness and strength of the film decrease. Preferably, CrCr39at
% to 55at%, more preferably 40at% to 50a
t% is good.

In the Fe-Cr alloy base film, when Cr is less than 20 at%, Cr and additive element M (M is AI, St, Ti, V, Mn, Co, Ni, Zr, Nb
, Mo, Tc, Ru, Rh, Pd, Y, Hf.

If the total of at least one element selected from Ta and W) and Cr is less than 35 at%, the formed film becomes ferromagnetic with the normal film forming method, and the total of Cr and the additive element M is less than 60 at%.
If it exceeds at %, the toughness and strength of the film will decrease, which is not preferable. The desirable range is 37 at% to 50 at%, more preferably 39 at%.
~45at% is good. Moreover, Or is preferably 25 atom % or more, more preferably 30 atom % or more.

Depending on the type of additive element M, the Fe-Cr alloy of the base film has
Their characteristics are different.

(a) When the additive element M is at least one selected from AI and Si, it is effective to prevent the underlayer from having a non-equilibrium structure and make it more completely non-magnetic; however, if it is added in an amount exceeding 25 at.%, On the contrary, the magnetization increases and the mechanical strength decreases, so the content needs to be 25 atomic % or less, and preferably 15 atomic % or less.

(b) The additive element M is Ti, Nb, Mo, Tc, Ru, R
When at least one element selected from H, Pd, and W is added, it has the effect of making the base film more completely non-magnetic and improving corrosion resistance, but if it is added in an amount exceeding 15 at%, the base film cannot be formed using normal film forming methods. The amount of addition is set at 15 at % or less because the underlying film tends to take on an amorphous structure, making it difficult to achieve the purpose of improving the coercive force of the magnetic film formed on this film. Preferably, it is added in an amount of 10 at% or less.

(c) The additive element M is at least one selected from V and Mn.
In the case of seeds, the base film tends to take a non-equilibrium structure and has the effect of making it more completely non-magnetic.However, if it is added in an amount exceeding 20 at%, it becomes magnetic, so it should be added in an amount of 20 at% or less. Preferably, it is added in an amount of 10 at% or less.

(d) When the additive element M is at least one selected from Zr, Y, Ta, and Hf, the underlayer has the effect of eliminating the nonequilibrium structure and making it more completely nonmagnetic;
If more than 20% is added, the base film formed using normal film forming methods tends to take on an amorphous structure, making it difficult to achieve the purpose of improving the coercive force of the magnetic film formed on this film. Addition should be 10 at% or less. Preferably 5at%
The following additions are recommended.

(E) When the additive element M is at least one selected from Co, Ni, and Cu, it has the effect of improving the mechanical strength of the base film, but if it is added in an amount exceeding 8 at%, the formed film Since it becomes ferromagnetic, it should be added in an amount of 8 atomic % or less. Preferably 5 at% or less, more preferably 2 at%
The following additions are recommended.

In this invention, it is a more preferable embodiment to add two or more selected groups from the above-mentioned selected groups (a) to (e) in accordance with the required characteristics.

In addition, the alloy target used to coat the Fe-Cr alloy base film or Fe-Cr alloy base film may contain trace amounts of added elements or unavoidable impurity elements for purposes such as deoxidation during manufacturing. However, the properties of the composite membrane of the present invention will not be impaired.

Furthermore, it is thought that containing oxygen in an amount of several tens of ppm to several hundreds of ppm has the effect of making the base film more completely nonmagnetic.

Further, the Cr film may be any commonly used Cr film, and even if it contains unavoidable impurities, the object of the present invention can be achieved.

Preferred Embodiment of the Invention The substrate of the magnetic recording medium in this invention may be made of any material as long as it is a non-magnetic substrate. For example, in addition to an aluminum substrate coated with N1-P plating, alumite treatment, or glass coating, alumina, In addition to various ceramics such as silicon carbide, titanium carbide, zirconia, silicon nitride, and alumina-silicon oxide, non-metallic substrates such as tempered glass and crystallized glass can be used.Furthermore, ceramic substrates such as alumina can be used. In this invention, an Fe-Cr alloy film and a l or F
The composite form of the composite base film of the e-Cr alloy film and the Cr film can be applied to any combination of film types and stacking order from the substrate to the outer surface depending on the purpose.

By combining Fe-Cr alloy film and Cr film, Fe-Cr
If an alloy film, a Cr film, and a magnetic film are coated in this order, a magnetic recording medium with equivalent magnetic properties and superior mechanical properties can be produced compared to a conventional film consisting of only a Cr film and a magnetic film. Economically obtainable.

Furthermore, the coating order of the Cr film, Fe-Cr alloy film, and magnetic film is optimal for the N1-P plated AI substrate.

In addition, among the Fe-Cr alloy films, Mo, Cu, AI,
An alloy film containing Si, Ni, etc. has better corrosion resistance against alkali ions than Cr, so in particular, when using a reinforced glass substrate, an Fe-Cr alloy film, a C
The coating order of the r film and the magnetic film is preferable.

Furthermore, the coating order of the Cr film, Fe-Cr alloy film, and magnetic film is optimal for the N1-P plated AI substrate.

Further, in the present invention, a composite film of a Cr film, a Fe-Cr alloy film, and a Fe-Cr alloy film can also be used.

In addition, the thickness of the composite base film according to the present invention generally has the effect of increasing the coercive force of the magnetic film, and is preferably at least 500 A and 10,000 λ or less, more preferably 2
000 people to about 5000A is good.

In the total thickness of the composite base film, the thickness of each layer of the Fe-Cr alloy film or the Fe-Cr alloy film and the Cr film may be appropriately selected depending on the combination of film types and the order of lamination. As shown in Figure 1, Cr is deposited on the Fe-Cr alloy film.
When forming a film, the effect of the present invention can be exhibited if the Cr film has a thickness of about 100 Å or more, preferably 200 Å or more, and more preferably 500 Å or more. However, 2
If more than 1,000 Cr films are provided, the effect of the composite film of the present invention will be diminished, so the thickness is preferably 2,000 λ or less, more preferably 1,000 Å or less.

The same applies to the case where a Cr film is formed on an Fe-Cr alloy film or a Fe-Cr alloy film, and when a Cr film is used as the first layer, the thickness is preferably at least 200 Å or more.

Further, between the non-metallic substrate and the composite base film according to the present invention, Ti, Zr, Hf, Cr, Nb, Ta, M
A single oxide layer of a metal containing at least one element among o, W, and V, or an intermediate layer formed by sequentially laminating the oxide layer and a metal or alloy layer constituting the oxide, Alternatively, the intermediate layer may be made of a metal oxide layer containing the above-mentioned element and having a characteristic that the oxygen concentration in the thickness direction of the intermediate layer decreases continuously or stepwise in the direction of the metal base layer, and a metal or an alloy constituting the oxide. It is also good to interpose an intermediate layer in which layers are sequentially laminated.

That is, by having the above structure, the Fe-Cr alloy or Fe-Cr based alloy base layer is firmly bonded to the non-metallic substrate through the oxide layer alone or the intermediate layer consisting of the oxide layer and the metal layer. It is stable in terms of strength, does not cause peeling, and exhibits excellent durability during C8S of the magnetic head over a long period of time.

In addition, by giving the intermediate oxide layer a property in which the oxygen concentration in the thickness direction decreases continuously or stepwise toward the Fe-Cr alloy or Fe-Cr alloy base layer, the adhesion strength is increased. In addition, since strain caused by the difference in thermal expansion coefficient between the nonmetallic substrate and the metal underlayer can be alleviated, peel resistance is improved, and heating and cooling during manufacturing are facilitated.

In addition, the total amount of the specific metal is 10a out of all the elements in the intermediate layer.
t% or more is required, and the metal constituting the intermediate oxide layer needs to be at least 30 at% of the elements, preferably 50 at% or more.

The thickness of the intermediate layer made of a metal oxide containing at least one of the above specific metals is preferably 1/100 to 5 times the thickness of the metal base layer deposited thereon.

Further, the preferable relationship between the layer thicknesses of the intermediate oxide layer and the metal layer is that the metal layer thickness is 'Aτ111 with respect to the oxide layer thickness.
0 to 10 (in order of 181 degrees, the magnetic film is C01C
Any hard magnetic film having an hcp structure such as o-Ni, Co-Ni-Cr, or Co-Cr alloy and having in-plane magnetic anisotropy can be formed. Further, in order to improve the epitaxial properties of the magnetic film with respect to the base film, adding various additive elements is an effective means for improving the magnetic properties. The thickness of the magnetic film may also be appropriately selected from several hundred to 2,000 people, similar to the thin film media conventionally used.

In addition, if necessary, various known protective films may be applied on the magnetic film.
It is effective to extend the life of the medium by appropriately selecting and providing one hundred to several hundred layers (for example, carbon film, 5i02 film, other ceramic films, etc.).Furthermore, a lubricating film may be applied.

As a method for forming the base film of the present invention, any known vapor phase film forming method may be appropriately selected, but sputtering, ion beam sputtering, ion blating, etc. are particularly effective.

In addition, the conditions for the sputtering method for forming the base film are that the sputtering gas pressure is 1 to 100 mTorr, and the substrate temperature is room temperature to 4 mTorr.
00°C or less is desirable.

In addition to the sputtering method, the magnetic film and the protective film can be manufactured by appropriately selecting a known film forming method such as a vapor deposition method, an ion blating method, or a plasma CVD method.

Example Failure" 2 Two types of Fe-Cr alloy targets having the compositions shown in Table 1 and a Cr target were applied to a 25 mm x 25 mm x 1.2 mm thick tempered glass substrate using a flat plate magnetron RF sputtering device under the following conditions. A composite base film (base film No. 1 to 2) consisting of an Fe-Cr alloy film and a Cr film laminated thereon was deposited on the surface of the glass substrate.

Table 1 shows the composition and magnetization value of the Fe--Cr alloy base film coated on the above substrate.

Ultimate vacuum: 1 to 2X10-'I'orr Atmosphere during sputtering: 99.99% Ar 6 mTorr Input power: 300 W Pole spacing: 70 mm Substrate temperature: 100°C The analysis was performed using an X-ray microanalyzer for the alloy film and an X-ray microanalyzer for the target. used a plasma emission spectrometer and a gas analyzer.

In the table, for the alloy film, elements other than Fe, Cr, and additive elements were below the detection limit. In addition, other elements in the target were Ni, Mg, AI, P, etc., all of which were 0.04 at% or less. In addition, a vibrating sample magnetometer was used to measure the magnetic properties.

As is clear from the results in Table 1, Fe
-Cr-based alloy base film is mostly 1. It can be seen that the magnetization value is less than Oemu/g, and it is a substantially nonmagnetic film that is essential as an underlayer. In addition, 1. The reason why it is displayed as Oemu/g or less is due to the measurement limit.

Two types of F having the compositions shown in Table 1 were applied to a tempered glass substrate with a size of 25mm x 25mm x 1.0mm thick under the same conditions as in Example 1 using a flat plate magnetron RF sputtering device.
Chips of additive elements (10 mm x 10 mm x 1 mm) are added to the e-Cr alloy target and the Fe-Cr alloy target.
t) and a Cr target, a composite base film (base film No.
, 3 to 16) were applied.

Table 1 shows the composition and magnetization value of the Fe--Cr alloy base film coated on the substrate.

In the table, for the alloy film, elements other than Fe, Cr, and additive elements were below the detection limit. Further, the other elements in the target were Ni, Mg, ALP, etc., and all of them were 0.06 at% or less. In addition, a vibrating sample magnetometer was used to measure the magnetic properties.

As is clear from the results in Table 1, Fe
It can be seen that all of the -Cr-based alloy base films exhibit magnetization values of several emu/g or less, and are essentially nonmagnetic films essential as base films. In addition, 1. The reason why it is displayed as Oemu/g or less is due to the measurement limit.

Table 1 (components at%) Base film No. 1.2 in Table 1, Fe-40Cr, F
The first thin film X-ray diffraction results of the e-50Cr binary alloy base film
As shown in the figure.

For comparison, the X-ray diffraction results of Fe-40Cr alloy target powder are also shown.

As evident in the X-ray diffraction results, Fe-4 for comparison
The 00r alloy target powder has a bee structure, but the Fe-Cr alloy and F
It can be seen that in the case of e-Cr alloys, the crystal structure is different from that of the target.

Fe-0r alloy and Fe-Cr of the base film according to the present invention
The reason why the system alloy becomes substantially non-magnetic despite its composition which is considered to be inherently ferromagnetic is thought to be because it has a crystal structure different from the known equilibrium phase.

Example 4 A flat plate magnetron RF sputtering device was used on a tempered glass substrate with an outer diameter of 95 mm, an inner diameter of 25 mm, and a thickness of 1.2 plates.
Under the same conditions as Examples 1 and 2, the base film No. shown in Table 1,
After depositing a Fe-Cr alloy film to a thickness of 200 OA on the surface of the substrate glass so that the composition of Co-3ONi-7,5
A magnetic film was deposited to a thickness of 800 mm using an 0r alloy target.

For comparison, Co-3ONi-7,5Cr films were deposited with various thicknesses using the same substrate, equipment, and conditions.
A magnetic film was deposited to a thickness of 800 mm using an alloy target.

In order to make a fair comparison between the present invention and the comparative example, the interval between the formation of the base film and the magnetic film was set to 1 minute.

The various underlying films and magnetic films obtained were evaluated using FIG. 2, which shows the relationship between Cr film thickness and coercive force.

As is clear from Figure 2, the Cr film alone has a
A coercive force of 5000e or more is obtained with a Cr film thickness of 3000 Å or more, and a coercive force of 6000e or more is obtained with a Cr film thickness of 3000 Å or more.

On the other hand, in the case of the composite film of the present invention, a coercive force of 5200e is obtained when the Cr film thickness is only 200 mm, and a coercive force of 6000 e is obtained when the Cr film thickness is 500 mm.
It can be seen that the r alloy film has the same effect of improving magnetic properties as the Cr film.

Example 5 Al with an outer diameter of 130 mm, an inner diameter of 40 mm, and a thickness of 1.2 mm
A 20pm thick glass glaze is applied to the 2O3 substrate.
After polishing the surface, a FeFe-0r-alloy film was deposited on the glass glaze surface of the substrate using a flat plate magnetron RF sputtering device under the following conditions and target.
Coat a Cr film with a thickness of 200mm, then coat a magnetic film with a thickness of 800AJ*, and then apply a carbon film with a thickness of 3mm.
The film was coated to a thickness of 0.00 mm.

Ultimate vacuum: 1 to 2 x 10-6 Torr Atmosphere during sputtering: 99.99% Ar 10 mTorr Input power: 300 W Pole spacing: 70 mm Substrate temperature: 150°C Base film target: Fe-35Cr-10V base film target: 100Cr magnetic film Target: Co-3ONi-7,5Cr Protective film: High-density carbon The electromagnetic conversion characteristics of the obtained magnetic recording medium according to the present invention were measured under the following conditions.

Head used: Mn-Zn ferrite mini Winchester - Track radius 16pm, gap length 1.0pm, gap depth 20pm, number of turns 16'r x 2 Flying height: 0.3pm 1F 1.25MHz 2F 2.5 mouse - Rotation speed: 3600 rpm Measurement location: Measurement at a portion R = 62 mm from the center of the disc The reproduction output characteristics measured were as follows.

Reproduction output (2.5MHz, Iw=80mA)=
1.2mV playback output (5MHz, Iw = 80m
A) = 0.9mV resolution (Iw = 80mA)
= 87% override = -30 dB As is clear from the measurement results, it can be seen that the magnetic recording medium according to the present invention has characteristics as a high-density recording medium.

Example 6 A total of three types of magnetic recording media, two types obtained in Example 4 and one type manufactured in the same manner as Example 4, were subjected to a scratch test. The results are shown in Table 2.

In the table, present invention 1 is a magnetic recording medium using base film No. 1 in Table 1, and present invention 2 is a magnetic recording medium using base film No. 9 in Table 1.
This is a magnetic recording medium that uses

In the test, various loads were applied to a diamond needle with a tip diameter of 102 mm, and the adhesion strength was evaluated by moving the disk and peeling off the film.

Margin below Table 2

[Brief explanation of the drawing]

FIG. 1A is a graph showing the results of X-ray diffraction of the components of the composite base film according to the present invention, and FIG. 1B is a graph showing the results of X-ray diffraction of the components of the target alloy. FIG. 2 is a graph showing the relationship between Cr film thickness and coercive force.

Claims (1)

[Scope of Claims] 1. A magnetic recording medium in which a base film and a magnetic film are laminated on a non-magnetic substrate, wherein the base film contains Cr37 at% to 6 Cr.
1. A magnetic recording medium comprising a composite film of a Cr film and a nonmagnetic or weakly magnetic alloy film comprising 0 at%, the balance being Fe and unavoidable impurities. 2. A magnetic recording medium in which a base film and a magnetic film are laminated on a non-magnetic substrate, wherein the base film is a composite film of a non-magnetic or weakly magnetic alloy film and a Cr film represented by the following compositional formula. A magnetic recording medium characterized by: FexCryMz, where M is Al, Si, Ti, V, Mn, Co, Ni, Cu, Zr
, Nb, Mo, Tc, Ru, Rh, Pd, Y, Hf, T
is at least one selected from a, W, x, y, and z represent at% of each element, and satisfy the following conditions. x+y+z=100, 35≦y+z≦60, 20≦y, z; (a) When M is at least one selected from Al and Si, z≦25 (b) M is Ti, Nb, Mo, Tc, Ru , Rh, Pd
, W, z≦15 (c) When M is at least one selected from V, Mn, z≦20 (d) When M is at least one selected from Zr, Y, Ta, Hf In the case of one type, z≦10 (e) M is at least one selected from Co, Ni, and Cu
For seeds, z≦8