WO2022034873A1

WO2022034873A1 - Fe-pt-bn-based sputtering target and method for manufacturing same

Info

Publication number: WO2022034873A1
Application number: PCT/JP2021/029467
Authority: WO
Inventors: 孝充山本; 正紘西浦; 健太黒瀬; 弘典小林; 恭伸渡邉; 朋子松田
Original assignee: 田中貴金属工業株式会社
Priority date: 2020-08-12
Filing date: 2021-08-03
Publication date: 2022-02-17
Also published as: JP2022032462A; TW202223109A; TWI774507B; JP7462511B2

Abstract

The present invention addresses the problem regarding particle generation in a Fe-Pt-BN-based sputtering target having a high relative density. This Fe-Pt-BN-based sputtering target is characterized by containing carbon (C) and boron oxide and BN or a non-magnetic component formed of boron oxide and BN, and by having a relative density of 88% or more, and an oxygen content more than 4000 wtppm but not more than 10,000 wtppm, and is characterized in that the ratio of a water soluble boron concentration (wt%) with respect to the total boron concentration (wt%) as determined through a specific procedure is 1.0% or more.

Description

Fe-Pt-BN-based sputtering target and its manufacturing method

The present invention relates to a BN-containing sputtering target used for manufacturing a magnetic thin film and a method for manufacturing the same, and more particularly to a Fe-Pt-BN-based sputtering target containing Fe, Pt and BN (boron nitride) and a method for manufacturing the same.

As a sputtering target for manufacturing a granular structure magnetic thin film of a magnetic recording medium such as a hard disk drive, an oxide such as SiO ₂ , B (boron), C (carbon) containing Fe or Co, which is a ferromagnetic metal, as a main component. , A sintered body containing a non-magnetic material such as BN (boron nitride) is used. BN exhibits excellent performance as a lubricant, but it is difficult to produce a high-density sintered body due to its inferior sinterability, particles are generated during sputtering, product yield is reduced, and machinability is reduced. There was a problem such as bad.

In order to solve this problem, a method of alloying BN and SiO ₂ to improve sinterability (Japanese Patent No. 5567227) and Fe-Pt alloy powder are used to suppress the formation of iron oxide. A method of reducing the oxygen content of a sputtering target (Japanese Patent No. 5689543), a method of adding an AgCu alloy or an AuCu alloy to improve sinterability (Japanese Patent No. 6285043 and Japanese Patent No. 6084711). Etc. have been proposed.

According to Japanese Patent No. 5567227, hexagonal BN particles, which are non-magnetic materials, are dispersed in an Fe-Pt-based base metal together with quartz or amorphous SiO ₂ particles, which is generated during sputtering. Hexagonal system by providing a high-density sputtering target with a reduced amount of particles, and by containing 1 mol% or more of SiO ₂ with respect to BN and containing BN and SiO ₂ in a solid-dissolved state. It is disclosed that the sputterability of BN can be significantly improved. As a specific manufacturing method, the mixed powder obtained by mixing the raw material powders of Fe, Pt, SiO ₂ and BN at 300 rpm for 2 hours using a medium stirring mill is hot-pressed and then hot isotropically pressed. It is described that processing is performed. Further, the obtained Fe-Pt-based magnetic material sintered body is crystallized because the X-ray diffraction peak intensity ratio of the hexagonal BN (002) plane to the background strength is 1.50 or more in the cross section with respect to the pressurized surface. It is described that the X-ray diffraction peak intensity ratio of the surface of the cristobalite (101), which is SiO ₂ , is 1.40 or less. Further, in a comparative example (Fe-Pt-BN system, Fe-Pt-BN-oxide system, and Fe-Pt-BN-non-magnetic material system) manufactured under the same manufacturing conditions except that SiO ₂ is not contained. It is described that the X-ray diffraction peak intensity ratio of the hexagonal BN (002) plane is about the same as that of the example, but the number of particles is remarkably large at 645 or more. However, there is no mention of the FE-EPMA observation results for the comparative example, and it is unclear what kind of dispersion situation it is.

Japanese Patent No. 5689543 states that by using Fe-Pt alloy powder, it is possible to produce a Fe-Pt-BN-based magnetic material sintered body in which the amount of oxygen is reduced to 4000 wtppm or less. Discloses that the machinability is improved and the occurrence of cracking and chipping can be suppressed. As a specific manufacturing method, Fe-Pt alloy powder having a particle size of 0.5 μm or more and 10 μm or less and a mixed powder in which BN powder is put into a mortar and uniformly mixed are hot-pressed and then hot isotropically pressed. It is described that processing is performed. On the other hand, a comparative example (Fe-Pt-BN system, Fe-Pt-BN-) produced under the same production conditions except that Fe powder, Pt powder and BN powder were mixed at 300 rpm for 2 hours using a medium stirring mill. In the non-magnetic material system), it is described that the oxygen content is as high as 11500 wtppm or more, iron oxide is formed, and chipping occurs. It has been introduced that if the generation of chipping can be suppressed, the generation of abnormal discharge and particles is small, but there is no mention of the generation of particles in the examples and comparative examples, and whether or not the generation of particles could be suppressed. It is unknown.

According to Japanese Patent No. 6285043 and Japanese Patent No. 6084711, a low sintering temperature is obtained by adding a low melting point AgCu alloy or AuCu alloy to a FePt-based sintered body sputtering target containing C and / or BN. Discloses that the density of the sintered body is increased. Japanese Patent No. 6285043 states that the melting point of an AgCu alloy composed of Ag and Cu drops to 779.1 ° C. due to a eutectic reaction, and Japanese Patent No. 6084711 contains an AuCu alloy composed of Au and Cu. It is described that the melting point is lowered to 910 ° C. by the eutectic reaction. In Japanese Patent No. 6285043, as Comparative Example 4, Fe powder, Pt powder, BN powder, and Au powder are treated with a medium stirring mill at 300 rpm for 2 hours, and then Ag powder and BN powder are treated with a V-shaped mixer. It is described that after mixing, the mixed powder was further sintered and hot isotropically pressure-processed using a 150 μm sieve, and the number of particles increased significantly to 833. Similarly, in Japanese Patent No. 6084711, Fe powder, Pt powder, BN powder, and Au powder are treated with a medium stirring mill at 300 rpm for 2 hours, and then Au powder and BN powder are mixed with a V-shaped mixer. It is described that the number of particles increased significantly to 256 when the mixed powder was further sintered and hot isotropically pressure-processed using a 150 μm sieve after the combination.

As described above, in the above patent document, particles are generated by the Fe-Pt-BN-based sintered body by adding SiO ₂ , AgCu alloy or AuCu alloy at the same level as the main component, or by reducing the amount of oxygen to 4000 wtppm or less. However, if even one of these conditions is not satisfied, the number of particles cannot be reduced. Further, by adding SiO ₂ , AgCu alloy or AuCu alloy at the same level as the main component, when the composition to be formed does not contain these elements, the difference from the composition to be formed is large, and the film is desired. There is a possibility that the magnetic characteristics of will not be obtained. Therefore, when the composition to be formed does not contain SiO ₂ , AgCu alloy or AuCu alloy, it is difficult to improve the sinterability of BN and reduce the generation of particles.

Japanese Patent No. 5567227 Japanese Patent No. 5689543 Japanese Patent No. 6285043 Japanese Patent No. 6084711

An object of the present invention is to solve the problem of particle generation of a Fe-Pt-BN-based sputtering target having a high relative density by an approach different from the invention disclosed in the above-mentioned Patent Documents 1 to 4.

In the Fe-Pt-BN-based sputtering target, the BN has a high melting point and it is difficult to obtain a uniform and fine structure. When the uniform and fine structure is obtained, the BN is finely pulverized and the composite material is calcined. By inhibiting the formation, confirming that the sinterability deteriorates, and converting at least a part of BN into boron oxide to lower the melting point, the sinterability of the BN-containing composite material is improved. , It was found that the generation of particles can be reduced, and the present invention was completed.

According to the present invention, it is a Fe-Pt-BN based sputtering target.
Contains non-magnetic components consisting of BN and boron oxide
Relative density is 88% or more,
The oxygen content is more than 4000 wtppm and 10,000 wtppm or less.
Provided is an Fe-Pt-BN-based sputtering target characterized in that the ratio of the water-soluble boron concentration (wt%) to the total boron concentration (wt%) determined by the following procedure is 1.0% or more. ..
(How to determine the water-soluble boron concentration with respect to the total boron concentration)
(1) A 4 mm square sample piece is cut from the sputtering target, and the sample piece is crushed to prepare a crushed product.
(2) The pulverized product is classified using a sieve having a mesh size of 106 μm and a sieve having a mesh size of 300 μm, and 0.50 g of the powder remaining on the sieve having a mesh opening of 106 μm after passing through the sieve having a mesh opening of 300 μm is converted into 100 ml of pure water at 25 ° C. After soaking and leaving for 1 hour, it is filtered through a filter paper of type 5 A specified in JIS P 3801.
(3) The filtrate is measured up in a 200 ml volumetric flask, and the B concentration in the liquid is determined by ICP analysis.
(4) Only 200 ml of pure water was subjected to ICP analysis to determine the blank B concentration.
(5) Subtract the blank B concentration from the B concentration in the liquid and multiply by 200 ml of the liquid volume to calculate the eluted water-soluble B mass.
(6) The water-soluble B concentration per 1 g of powder was calculated from the water-soluble B mass in the powder mass of 0.50 g.
(7) The powder on the sieve having an opening of 106 μm was weighed in (2) above, and after alkali melting, the total B concentration in 1 g of the powder was calculated by ICP analysis.
(8) The water-soluble B concentration in 1 g of the powder is divided by the total B concentration in 1 g of the powder.

Further, according to the present invention, it is a Fe-Pt-BN-based sputtering target.
Contains non-magnetic components consisting of BN and boron oxides and carbon (C)
Relative density is 88% or more,
The oxygen content is more than 4000 wtppm and 10,000 wtppm or less.
Provided is an Fe-Pt-BN-based sputtering target characterized in that the ratio of the water-soluble boron concentration (wt%) to the total boron concentration (wt%) obtained in the above procedure is 1.0% or more. ..

It is preferable that O is present in the region where B exists on the cut surface of the Fe-Pt-BN-based sputtering target.

The Fe-Pt-BN-based sputtering target preferably contains Pt in an amount of 10 mol% or more and 55 mol% or less.

The Fe-Pt-BN-based sputtering target preferably contains BN of 10 mol% or more and 55 mol% or less.

The Fe-Pt-BN-based sputtering target preferably further contains C in an amount of 0 mol% or more and 20 mol% or less.

The Fe-Pt-BN-based sputtering target can further contain one or more elements selected from Ag, Au, Co, Cr, Cu, Ge, Ir, Ni, Pd, Rh, and Ru.

Further, according to the present invention, there is provided a method for manufacturing the Fe-Pt-BN-based sputtering target. In the production method of the present invention, the raw material powder is mixed in any of the following embodiments (A) to (E) in a medium stirring mill at a rotation speed of 100 rpm or more and 200 rpm or less for a total of 2 hours or more and 6 hours or less. It comprises preparing a mixture and collecting and sintering a powder of the raw material powder mixture that has passed through a sieve having an opening of 300 μm, and is characterized by oxidizing at least a part of the surface of the BN powder.

(A) First, only the BN powder is mixed in a medium stirring mill having an atmosphere containing oxygen and / or water, and then the remaining raw material powder is put into the medium stirring mill, and then the inside of the medium stirring mill is filled with argon gas. A mode of mixing after creating an atmosphere.
(B) First, only the BN powder is crushed with a medium stirring mill having an argon gas atmosphere, then brought into contact with a gas containing oxygen and / or water, and then the remaining raw material powder is put into the medium stirring mill, and then the medium stirring is performed. A mode in which the inside of the mill is mixed as an argon gas atmosphere.
(C) An embodiment in which the raw material powder is mixed in a medium stirring mill in an argon gas atmosphere, and then the mixed powder is brought into contact with a gas containing oxygen and / or water.
(D) The raw material powder is mixed in a medium stirring mill in an argon gas atmosphere, the mixing is interrupted before the predetermined mixing time elapses, the mixture is brought into contact with a gas containing oxygen and / or water, and then the mixing is performed again. Aspect to resume.
(E) An embodiment in which the raw material powder is mixed in a medium stirring mill having an atmosphere containing argon gas and oxygen and / or water.

More specifically, when the non-magnetic component consists of BN and a boron oxide, the raw material powder mixture is preferably prepared in any of the following embodiments (A1) to (E1).
(A1) First, only BN powder is mixed in a medium stirring mill having an atmosphere containing oxygen and / or water, then Fe powder and Pt powder are charged into the medium stirring mill, and then argon is mixed in the medium stirring mill. A mode of mixing after creating a gas atmosphere.
(B1) First, only the BN powder is pulverized with a medium stirring mill having an argon gas atmosphere, and then brought into contact with a gas containing oxygen and / or water. Then, Fe powder and Pt powder are charged into the medium stirring mill, and then the medium. A mode in which the inside of a stirring mill is mixed as an argon gas atmosphere.
(C1) An embodiment in which BN powder, Fe powder and Pt powder are mixed in a medium stirring mill in an argon gas atmosphere, and then the mixed powder is brought into contact with a gas containing oxygen and / or water.
(D1) BN powder, Fe powder and Pt powder are mixed in a medium stirring mill in an argon gas atmosphere, and the mixing is interrupted before the predetermined mixing time elapses, and the mixture is brought into contact with a gas containing oxygen and / or water. After that, the embodiment in which the mixing is restarted again.
(E1) An embodiment in which BN powder, Fe powder and Pt powder are mixed in a medium stirring mill having an atmosphere containing argon gas and oxygen and / or water.

When the non-magnetic component is composed of BN, boron oxide and carbon (C), the raw material powder mixture is preferably prepared in any of the following embodiments (A2) to (E2).
(A2) First, only BN powder is mixed in a medium stirring mill having an atmosphere containing oxygen and / or water, then C powder, Fe powder and Pt powder are charged into the medium stirring mill, and then the medium stirring mill is used. A mode in which the inside is made into an argon gas atmosphere and then mixed.
(B2) First, only the BN powder is pulverized with a medium stirring mill having an argon gas atmosphere, and then brought into contact with a gas containing oxygen and / or water, and then the C powder, Fe powder and Pt powder are charged into the medium stirring mill. , A mode in which the inside of the medium stirring mill is mixed as an argon gas atmosphere.
(C2) An embodiment in which BN powder, C powder, Fe powder and Pt powder are mixed in a medium stirring mill in an argon gas atmosphere, and then the mixed powder is brought into contact with a gas containing oxygen and / or water.
(D2) BN powder, C powder, Fe powder and Pt powder are mixed in a medium stirring mill in an argon gas atmosphere, and the mixing is interrupted before a predetermined mixing time elapses, and a gas containing oxygen and / or water is contained. A mode in which mixing is restarted again after contacting with.
(E2) An embodiment in which BN powder, C powder, Fe powder and Pt powder are mixed in a medium stirring mill having an atmosphere containing argon gas and oxygen and / or water.

The sintering is preferably performed at a sintering temperature of 600 ° C. or higher and 1200 ° C. or lower, and a sintering pressure of 30 MPa or higher and 200 MPa or lower.

The Fe-Pt-BN-based sputtering target of the present invention has a relative density of 88% or more, and can reduce the number of particles generated during magnetron sputtering.
Further, since the Fe-Pt-BN-based sputtering target of the present invention can reduce the generation of particles without adding SiO ₂ , AgCu alloy, AuCu alloy, etc., it does not affect the magnetic properties of the sputtered film. ..

FIG. 1 is a schematic diagram of the structure of the Fe-Pt-BN-based sputtering target of the present invention [FIG. 2] EPMA image of the Fe-Pt-BN-based sputtering target of Example 2 [FIG. 3] All of the examples and comparative examples. Graph showing the relationship between the ratio of the water-soluble boron concentration to the boron concentration and the oxygen content [Fig. 4] Graph showing the relationship between the ratio of the water-soluble boron concentration to the total boron concentration and the number of particles in Examples and Comparative Examples [Fig.] 5] Graph showing the relationship between the oxygen content and the number of particles in Examples and Comparative Examples Preferred Embodiment

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited thereto.

[First Embodiment]
The Fe-Pt-BN based sputtering target of the first embodiment contains a non-magnetic component composed of BN and a boron oxide, has a relative density of 88% or more, and has an oxygen content of more than 4000 wtppm and 10,000 wtppm or less. The ratio of the water-soluble boron concentration (wt%) to the total boron concentration (wt%) determined by the following procedure is 1.0% or more.
(How to determine the water-soluble boron concentration with respect to the total boron concentration)
(1) A 4 mm square sample piece is cut from the sputtering target, and the sample piece is crushed to prepare a crushed product.
(2) The pulverized product is classified using a sieve having a mesh size of 106 μm and a sieve having a mesh size of 300 μm, and 0.50 g of the powder remaining on the sieve having a mesh opening of 106 μm after passing through the sieve having a mesh opening of 300 μm is converted into 100 ml of pure water at 25 ° C. After soaking and leaving for 1 hour, it is filtered through a filter paper of type 5 A specified in JIS P 3801.
(3) The filtrate is measured up in a 200 ml volumetric flask, and the B concentration in the liquid is determined by ICP analysis.
(4) Only 200 ml of pure water was subjected to ICP analysis to determine the blank B concentration.
(5) Subtract the blank B concentration from the B concentration in the liquid and multiply by 200 ml of the liquid volume to calculate the eluted water-soluble B mass.
(6) The water-soluble B concentration per 1 g of powder was calculated from the water-soluble B mass in the powder mass of 0.50 g.
(7) The powder on the sieve having an opening of 106 μm was weighed in (2) above, and after alkali melting, the total B concentration in 1 g of the powder was calculated by ICP analysis.
(8) The water-soluble B concentration in 1 g of the powder is divided by the total B concentration in 1 g of the powder.

The Fe-Pt-BN-based sputtering target of the present invention contains oxygen of more than 4000 wtppm and 10,000 wtppm or less, preferably more than 4000 wtppm and 8,000 wtppm or less, and has a water-soluble boron concentration (wt%) with respect to the total boron concentration (wt%). ) Is 1.0% or more, preferably 2.0% or more, and more preferably 2.0% or more and 10.05 or less. The detection of water-soluble boron in the above ratio is proof that BN and B are insoluble in water and therefore contain boron oxides such as boron oxide B ₂ O ₃ .

That is, in the Fe-Pt-BN based sputtering target of the present invention, the ratio of the water-soluble boron concentration (wt%) to the total boron concentration (wt%) is 1.0% or more, preferably 2.0% or more, more preferably. Contains an amount of boron oxide of 2.0% or more and 10.0% or less.

When the ratio of water-soluble boron to total boron and the oxygen content are within the above ranges, at least a part of the high melting point BN is replaced with the low melting point boron oxide, and the Fe-Pt-BN composite material is baked. The connection is improved. As described in detail in Examples and Comparative Examples described later, O is present in the region where B exists on the cut surface of the Fe-Pt-BN-based sputtering target of the present invention by EPMA analysis (analytical conditions will be described later). Can be confirmed. Since O is present in the region where B is present on the cut surface, the state in which at least a part of BN is replaced with boron oxide having a low melting point is a state in which boron oxide is present on the surface of BN as shown in the schematic diagram of FIG. It is considered that (B ₂ O ₃ ) is formed.

Further, the Fe-Pt-BN-based sputtering target of the present invention has a relative density of 88% or more, preferably 90% or more. If the relative density is less than 88%, it cannot be put into practical use as a sputtering target.

The Fe-Pt-BN-based sputtering target of the present invention contains a non-magnetic component consisting of BN and a boron oxide. In the present invention, the non-magnetic component acts as a grain boundary material for separating the metal component in the granular structure magnetic thin film after being sputtered. The Fe-Pt-BN-based sputtering target of the present invention does not contain SiO ₂ , which causes particle generation.

The Fe-Pt-BN-based sputtering target of the present invention preferably contains Pt in an amount of 10 mol% or more and 55 mol% or less, preferably 15 mol% or more and 50 mol% or less. By setting the Pt content in the above range, the magnetic properties of the Fe-Pt-based alloy after film formation can be well maintained.

The Fe-Pt-BN-based sputtering target of the present invention preferably contains BN of 10 mol% or more and 55 mol% or less, preferably 15 mol% or more and 50 mol% or less, and more preferably 20 mol% or more and 45 mol% or less. Within the above range, BN functions as a grain boundary material for the granular structure magnetic thin film of the magnetic recording medium.

The Fe-Pt-BN based sputtering target of the present invention may further contain one or more metal elements selected from Ag, Au, Co, Cr, Cu, Ge, Ir, Ni, Pd, Rh and Ru. The total amount of these additional metal elements can be 0 mol% or more and 20 mol% or less, preferably 0 mol% or more and 15 mol% or less of the entire Fe-Pt-BN-based sputtering target, and if it is within the above range, it is Fe-Pt-based. The magnetic properties of the alloy can be maintained well.

In the Fe-Pt-BN based sputtering target of the present invention, BN powder, Fe powder and Pt powder are mixed in a medium stirring mill at a rotation speed of 100 rpm or more and 200 rpm or less for a total of 2 hours or more and 6 hours or less to prepare a raw material powder mixture. This includes preparing and collecting and sintering the powder of the raw material powder mixture that has passed through a sieve having an opening of 300 μm, and at least BN powder is oxygenated and / or water is added when preparing the raw material powder mixture. It can be produced by a method characterized by preparing a raw material powder mixture in which at least a part of the surface of the BN is oxidized by contacting with the contained gas.

If the rotation speed of the medium stirring mill is too low, the BN cannot be uniformly dispersed, and if the rotation speed is too high, fine particles are formed, the relative density decreases, and it cannot be put into practical use as a sputtering target, which is preferable. do not have. Further, if the mixing time is too short, water-soluble boron is not sufficiently formed, and if the mixing time is too long, water-soluble boron is sufficiently formed, but the oxygen content is high, and the desired magnetic properties may not be obtained. There is sex. In addition, if the oxygen content is too high, the oxidation of Fe, which is the main component, proceeds and the iron oxide increases, causing crack chipping when the Fe-Pt-BN-based sintered body is processed into a sputtering target. , The machinability of the sintered body may deteriorate.

In the production method of the present invention, the mode of contact between the BN surface and the gas containing oxygen and / or water when the raw material powder is mixed can be arbitrarily selected from the following (A1) to (E1).
(A1) First, only BN powder is mixed in a medium stirring mill having an atmosphere containing oxygen and / or water, then Fe powder and Pt powder are put into the medium stirring mill, and then argon in the medium stirring mill is used. A mode of mixing as a gas atmosphere.
(B1) First, only the BN powder is pulverized with a medium stirring mill having an argon gas atmosphere, and then brought into contact with a gas containing oxygen and / or water. Then, Fe powder and Pt powder are charged into the medium stirring mill, and then the medium. A mode in which the inside of a stirring mill is mixed as an argon gas atmosphere.
(C1) An embodiment in which BN powder, Fe powder and Pt powder are mixed in a medium stirring mill in an argon gas atmosphere, and then the mixed powder is brought into contact with a gas containing oxygen and / or water.
(D1) BN powder, Fe powder and Pt powder are mixed in a medium stirring mill in an argon gas atmosphere, and the mixing is interrupted before the predetermined mixing time elapses, and the mixture is brought into contact with a gas containing oxygen and / or water. After that, the embodiment in which the mixing is restarted again.
(E1) An embodiment in which BN powder, Fe powder and Pt powder are mixed in a medium stirring mill having an atmosphere containing argon gas and oxygen and / or water.

In the case of embodiments (A1) to (E1), the amount of oxygen and / or the amount of water contained in the medium stirring mill or mixing so that the oxygen content of the mixed powder after stirring and mixing is more than 4000 wtppm and 10,000 wtppm or less. Adjust the amount of oxygen and / or the amount of water in contact with the powder. The amount of oxygen and / or the amount of water can be adjusted by adjusting the oxygen partial pressure of the oxygen-containing atmosphere and / or the dew point of the water-containing atmosphere according to the mass of the mixed powder and the volume of the medium stirring mill.

In the case of the embodiment (A1), the condition for stirring only the BN powder in the medium stirring mill in an oxygen-containing atmosphere is, for example, 1 hour or more and 3 hours or less at a rotation speed of 100 rpm or more and 200 rpm or less, and after charging Fe powder and Pt powder. The total of the stirring and mixing time is 2 hours or more and 6 hours or less. As the oxygen-containing atmosphere in which only the BN powder is agitated, for example, an argon gas atmosphere containing 30 vol% oxygen can be preferably mentioned.

In the case of the aspect (B1), it is necessary that the BN powder is not too finely divided as a condition for stirring only the BN powder in the medium stirring mill in an argon gas atmosphere. The time shall be less than the time, and the total of the stirring and mixing time after adding the Fe powder and the Pt powder shall be 2 hours or more and 6 hours or less. As an embodiment in which the crushed BN powder is brought into contact with a gas containing oxygen and / or moisture, an embodiment in which the powder is taken out from a medium stirring mill, spread in a vat in the air and left for a predetermined time can be preferably mentioned. By bringing the fine particles of the BN powder into contact with the atmosphere, the surface area of the BN that comes into contact with oxygen becomes larger than in the embodiment (C1), and the surface of the BN is easily oxidized to form a boron oxide.

In the case of the embodiment (C1), the BN powder, Fe powder and Pt powder may be mixed in a medium stirring mill in an argon gas atmosphere, and then the mixed powder may be brought into contact with a gas containing oxygen and / or water for, for example, 30 minutes or more. can. The mixing conditions in the medium stirring mill are, for example, a rotation speed of 100 rpm or more and 200 rpm or less and a total of 2 hours or more and 6 hours or less. As the embodiment in which the mixed powder is brought into contact with a gas containing oxygen and / or water, the embodiment in which the mixed powder is spread in a vat in the air and left for a predetermined time can be preferably mentioned.

In the case of the aspect (D1), for example, BN powder, Fe powder and Pt powder are mixed in a medium stirring mill filled with argon gas, stirring and mixing are stopped at least once during the stirring mixing time, and the mixed powder is stirred in the medium. It can be taken out of the mill, contacted with a gas containing oxygen and / or water for 30 minutes or more, and then stirred and mixed again in a medium stirring mill filled with argon gas. The number of contacts between the mixed powder and the gas containing oxygen and / or water during mixing can be 1 or more and 5 or less. The mixing conditions in the medium stirring mill are, for example, a rotation speed of 100 rpm or more and 200 rpm or less and a total of 2 hours or more and 6 hours or less. Similar to the embodiments (B1) and (C1), the embodiment in which the mixed powder is brought into contact with a gas containing oxygen and / or water is preferably an embodiment in which the mixed powder is spread in a vat in the air and left for a predetermined time. Can be done.

In the case of the embodiment (E1), the condition for mixing the BN powder, Fe powder and Pt powder in a medium stirring mill having an atmosphere containing argon gas and oxygen and / or water is, for example, 2 hours at a rotation speed of 100 rpm or more and 200 rpm or less. It shall be 6 hours or less. As the atmosphere containing argon gas and oxygen and / or water, for example, an argon gas atmosphere containing 30 vol% oxygen can be preferably mentioned.

In the case of the mixing of the above aspects (A1) to (E1), the ratio of the water-soluble boron concentration to the total boron concentration in the Fe-Pt-BN-based sputtering target indicates the ratio of the decomposition of BN to the formation of boron oxide. .. The decomposition of BN, that is, the formation of boron oxide, proceeds by first pulverizing the BN and then oxidizing B by contact with oxygen or water. If the BN is pulverized too much, the relative density decreases. Therefore, it is necessary to set the mixing conditions in the medium stirring mill to such an extent that the boron oxide is not excessively formed.

When one or more metal elements selected from Ag, Au, Co, Cr, Cu, Ge, Ir, Ni, Pd, Rh, and Ru are contained as additional components, a single metal powder containing these additional elements or Alloy powder (hereinafter referred to as "metal powder") can be added together with Fe powder and Pt powder in any of the above embodiments (A1) to (E1).

As the Fe powder, it is preferable to use an average particle size of 1 μm or more and 10 μm or less. If the average particle size is too small, the risk of ignition and the concentration of unavoidable impurities may increase, and if the average particle size is too large, BN cannot be uniformly dispersed, which is not preferable.

As the Pt powder, it is preferable to use one having an average particle size of 0.1 μm or more and 10 μm or less. If the average particle size is too small, the concentration of unavoidable impurities may increase, and if the average particle size is too large, BN cannot be uniformly dispersed, which is not preferable.

As the BN powder, it is preferable to use an average particle size of 2 μm or more and 10 μm or less. If it is out of the above range, the desired dispersion state cannot be achieved, which is not preferable.

As the metal powder used as the other additional component, it is preferable to use a metal powder having an average particle size of 0.1 μm or more and 20 μm or less. If the average particle size is too small, the concentration of unavoidable impurities may increase, and if the average particle size is too large, it cannot be uniformly dispersed, which is not preferable.

Sintering is preferably performed at a sintering temperature of 600 ° C. or higher and 1200 ° C. or lower, preferably 700 ° C. or higher and 1100 ° C. or lower, and a sintering pressure of 30 MPa or higher and 200 MPa or lower, preferably 50 MPa or higher and 100 MPa or lower. If the sintering temperature is too low, the relative density becomes low, and if the sintering temperature is too high, more BN than boron oxide ₍ _B2O3 ) is formed may be decomposed, which is not preferable.

[Second Embodiment]
The Fe-Pt-BN based sputtering target of the second embodiment contains a non-magnetic component composed of C, BN and boron oxide, has a relative density of 88% or more, and has an oxygen content of more than 4000 wtppm and 10,000 wtppm or less. The ratio of the water-soluble boron concentration (wt%) to the total boron concentration (wt%) determined by the procedure described in the first embodiment is 1.0% or more.

The Fe-Pt-BN-based sputtering target of the second embodiment contains C as a non-magnetic component in addition to the BN and boron oxide of the first embodiment. The Fe-Pt-BN-based sputtering target of the second embodiment does not contain SiO ₂ which causes particle generation, as in the first embodiment.

The Fe-Pt-BN-based sputtering target of the present invention preferably contains BN of 10 mol% or more and 55 mol% or less, preferably 15 mol% or more and 50 mol% or less, and more preferably 20 mol% or more and 45 mol% or less.

When C is contained as a non-magnetic component, the total of BN and C is preferably 10 mol% or more and 55 mol% or less, preferably 15 mol% or more and 50 mol% or less, and more preferably 20 mol% or more and 45 mol% or less. In this case, it is desirable that C is 20 mol% or less in excess of 0 mol%, preferably 15 mol% or less in excess of 0 mol%. Within the above range, C functions together with BN as a grain boundary material for the granular structure magnetic thin film of the magnetic recording medium.

The Fe-Pt-BN-based sputtering target of the second embodiment is the same as the Fe-Pt-BN-based sputtering target of the first embodiment except that C is further contained as a non-magnetic material.

In the Fe-Pt-BN based sputtering target of the second embodiment, BN powder, C powder, Fe powder and Pt powder are mixed in a medium stirring mill at a rotation speed of 100 rpm or more and 200 rpm or less for a total of 2 hours or more and 6 hours or less. The raw material powder mixture is prepared, and the powder of the raw material powder mixture that has passed through a sieve having an opening of 300 μm is collected and sintered, and at least the BN surface is prepared when preparing the raw material powder mixture. It can be produced by a method characterized by contacting with a gas containing oxygen and / or water to oxidize at least a part thereof.

The raw material powder mixture can be prepared in any of the following embodiments (A2) to (E2).
(A2) First, only BN powder is mixed in a medium stirring mill having an atmosphere containing oxygen and / or water, then C powder, Fe powder and Pt powder are charged into the medium stirring mill, and then the medium stirring mill is used. A mode in which the inside is made into an argon gas atmosphere and then mixed.
(B2) First, only the BN powder is pulverized with a medium stirring mill having an argon gas atmosphere, and then brought into contact with a gas containing oxygen and / or water, and then the C powder, Fe powder and Pt powder are charged into the medium stirring mill. , A mode in which the inside of the medium stirring mill is mixed as an argon gas atmosphere.
(C2) An embodiment in which BN powder, C powder, Fe powder and Pt powder are mixed in a medium stirring mill in an argon gas atmosphere, and then the mixed powder is brought into contact with a gas containing oxygen and / or water.
(D2) BN powder, C powder, Fe powder and Pt powder are mixed in a medium stirring mill in an argon gas atmosphere, and the mixing is interrupted before a predetermined mixing time elapses, and a gas containing oxygen and / or water is contained. A mode in which mixing is restarted again after contacting with.
(E2) An embodiment in which BN powder, C powder, Fe powder and Pt powder are mixed in a medium stirring mill having an atmosphere containing argon gas and oxygen and / or water.

In the case of embodiments (A2) to (E2), the amount of oxygen and / or the amount of water contained in the medium stirring mill or mixing so that the oxygen content of the mixed powder after stirring and mixing exceeds 4000 wtppm and becomes 10,000 wtppm or less. Adjust the amount of oxygen and / or the amount of water in contact with the powder. The amount of oxygen and / or the amount of water can be adjusted by adjusting the oxygen partial pressure of the oxygen-containing atmosphere and / or the dew point of the water-containing atmosphere according to the mass of the mixed powder and the volume of the medium stirring mill.

In the case of the embodiment (A2), the condition for stirring only the BN powder in the medium stirring mill in an oxygen-containing atmosphere is, for example, 1 hour or more and 3 hours or less at a rotation speed of 100 rpm or more and 200 rpm or less, and C powder, Fe powder and Pt powder are used. The total of the stirring and mixing time after charging is 2 hours or more and 6 hours or less. As the oxygen-containing atmosphere in which only the BN powder is agitated, for example, an argon gas atmosphere containing 30 vol% oxygen can be preferably mentioned.

In the case of the embodiment (B2), it is necessary that the BN powder is not too finely divided as a condition for stirring only the BN powder in the medium stirring mill in an argon gas atmosphere. The time is not more than the time, and the total of the stirring and mixing time after adding the C powder, the Fe powder and the Pt powder is 2 hours or more and 6 hours or less. As an embodiment in which the crushed BN powder is brought into contact with a gas containing oxygen and / or moisture, an embodiment in which the powder is taken out from a medium stirring mill, spread in a vat in the air and left for a predetermined time can be preferably mentioned. By bringing the fine particles of the BN powder into contact with the atmosphere, the surface area of the BN that comes into contact with oxygen becomes larger than in the embodiment (C2), and the surface of the BN is easily oxidized to form a boron oxide.

In the case of the embodiment (C2), the BN powder, the C powder, the Fe powder and the Pt powder are mixed in a medium stirring mill in an argon gas atmosphere, and then the mixed powder is contacted with a gas containing oxygen and / or water for, for example, 30 minutes or more. Let me. The mixing conditions in the medium stirring mill are, for example, a rotation speed of 100 rpm or more and 200 rpm or less and a total of 2 hours or more and 6 hours or less. As the embodiment in which the mixed powder is brought into contact with a gas containing oxygen and / or water, the embodiment in which the mixed powder is spread in a vat in the air and left for a predetermined time can be preferably mentioned.

In the case of the aspect (D2), for example, BN powder, C powder, Fe powder and Pt powder are mixed in a medium stirring mill filled with argon gas, stirring and mixing are stopped at least once during the stirring and mixing time, and the mixed powder is mixed. Can be taken out of the medium stirring mill and contacted with a gas containing oxygen and / or water for 30 minutes or more, and then stirred and mixed again in the medium stirring mill filled with argon gas. The number of contacts between the mixed powder and the gas containing oxygen and / or water during mixing can be 1 or more and 5 or less. The mixing conditions in the medium stirring mill are, for example, a rotation speed of 100 rpm or more and 200 rpm or less and a total of 2 hours or more and 6 hours or less. Similar to the embodiments (B2) and (C2), the embodiment in which the mixed powder is brought into contact with a gas containing oxygen and / or water is preferably an embodiment in which the mixed powder is spread in a vat in the air and left for a predetermined time. Can be done.

In the case of the embodiment (E2), the condition for mixing the BN powder, C powder, Fe powder and Pt powder in a medium stirring mill having an atmosphere containing argon gas and oxygen and / or water is, for example, a rotation speed of 100 rpm or more and 200 rpm or less. 2 hours or more and 6 hours or less. As the atmosphere containing argon gas and oxygen and / or water, an argon gas atmosphere containing 30 vol% oxygen and / or water is preferable.

In the case of the mixing of the above aspects (A2) to (E2), the ratio of the water-soluble boron concentration to the total boron concentration in the Fe-Pt-BN-based sputtering target indicates the ratio of the decomposition of BN to the formation of boron oxide. .. The decomposition of BN, that is, the formation of boron oxide, proceeds by first pulverizing the BN and then oxidizing B by contact with oxygen or water. If the BN is pulverized too much, the relative density decreases. Therefore, it is necessary to set the mixing conditions in the medium stirring mill to such an extent that the boron oxide is not excessively formed.

When one or more metal elements selected from Ag, Au, Co, Cr, Cu, Ge, Ir, Ni, Pd, Rh, and Ru are contained as additional components, a single metal powder containing these additional elements or Alloy powder (hereinafter referred to as "metal powder") can be added together with Fe powder and Pt powder in any of the above embodiments (A2) to (E2).

As the C powder, it is preferable to use an average particle size of 2 μm or more and 10 μm or less. If it is out of the above range, the desired dispersion state cannot be achieved, which is not preferable.

Since the BN powder, Fe powder, Pt powder, other additional components, and sintering conditions are the same as those described in the first embodiment, duplicate explanations are omitted.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The method for measuring the relative density of the sputtering target, the number of particles, the oxygen content and the ratio of the water-soluble boron concentration to the total boron concentration in the following Examples and Comparative Examples is as follows.

[Relative density]
Pure water is used as the replacement liquid, and the density is measured by the Archimedes method. The mass of the sintered body is measured, and the buoyancy (= volume of the sintered body) is measured with the sintered body suspended in the replacement liquid. Divide the mass (g) of the sintered body by the volume of the sintered body (cm ³ ) to obtain the measured density (g / cm ³ ). The ratio to the theoretical density calculated based on the composition of the sintered body (measured density / theoretical density × 100) is the relative density.

[Number of particles]
The sintered body prepared under the mixing and sintering conditions shown in Table 2 is processed to a diameter of 153 mm and a thickness of 2 mm, and bonded to a Cu packing plate having a diameter of 161 mm and a thickness of 4 mm with indium to prepare a sputtering target. do. This sputtering target is attached to a magnetron sputtering apparatus, discharged for 4 hours under an Ar gas atmosphere having an output of 500 W and a gas pressure of 1 Pa, and then the number of particles adhering to the substrate is measured by a particle counter by sputtering for 40 seconds.

[Oxygen content]
(1) A 2 mm square sample piece is cut from the sputtering target with a bolt clipper, and 0.1 g of the analytical sample is weighed.
(2) Measure with an oxygen / nitrogen analyzer under the condition of a maximum temperature of 2648 ° C.

[Ratio of water-soluble boron concentration to total boron concentration]
(1) A 4 mm square sample piece is cut from a sputtering target with a bolt clipper, and the sample piece is crushed to prepare a crushed product.
(2) The pulverized product is classified using a sieve having a mesh size of 106 μm and a sieve having a mesh size of 300 μm, and 0.50 g of the powder remaining on the sieve having a mesh opening of 106 μm after passing through the sieve having a mesh opening of 300 μm is converted into 100 ml of pure water at 25 ° C. After soaking and leaving for 1 hour, it is filtered through a filter paper of type 5 A specified in JIS P 3801.
(3) The filtrate is measured up in a 200 ml volumetric flask, and the B concentration in the liquid is determined by ICP analysis.
(4) Only 200 ml of pure water was subjected to ICP analysis to determine the blank B concentration.
(5) Subtract the blank B concentration from the B concentration in the liquid and multiply by 200 ml of the liquid volume to calculate the eluted water-soluble B mass.
(6) Calculate the water-soluble B concentration per 1 g of powder from the water-soluble B mass in 0.50 g of powder mass, and (7) 0.15 g of powder on a sieve with an opening of 106 μm and Na ₂ CO in (2) above. Put 0.5 g of ₃ powder (sodium carbonate special grade manufactured by Kanto Chemical Co., Ltd.) and 2.0 g of Na ₂ O ₂ powder (sodium peroxide grade 1 manufactured by Kanto Chemical Co., Ltd.) in a zirconium pit.
(8) After heating at 700 ° C. for 50 seconds, heat at 900 ° C. for 200 seconds, and then alkali-melt under the condition of heating at 900 ° C. for 200 seconds while rotating the crucible.
(9) The crucible after the alkali melting is immersed in a mixed solution of 40 ml of pure water and 30 ml of hydrochloric acid (special grade hydrochloric acid manufactured by Kanto Chemical Co., Inc.) for 1 hour.
(10) The solution was made up in a 100 ml volumetric flask, the solution was diluted 25 times, the concentration B in the solution was determined by ICP analysis, and the total concentration B per 1 g of powder was calculated.
(11) The water-soluble B concentration per 1 g of powder is divided by the total B concentration per 1 g of powder.

[EPMA analysis]
A 2 mm square sample piece was cut from a sputtering target, polished with a SiC polishing paper having a particle size of 1200, and then buffed with a diamond spray of 1 μm. -8500F) was used for analysis.

[Example 1]
190.28 g of Fe powder having an average particle diameter of 7 μm so as to have a composition of Fe-31.5Pt-30BN (ratio is mol%, the balance is Fe and unavoidable impurities. The same applies to the following Examples and Comparative Examples). 543.83 g of Pt powder having an average particle diameter of 1 μm and 65.90 g of BN powder having an average particle diameter of 4 μm were weighed and put into a medium stirring mill (medium: zirconia balls), and the atmosphere in the medium stirring mill was replaced with argon gas. Then, the mixture was mixed at 150 rpm for 4 hours. The mixed powder was classified with a sieve having an opening of 300 μm, and the passed powder was spread on a vat and contacted with the atmosphere for 30 minutes to form a boron oxide (B ₂ O ₃ ) in the vicinity of BN particles in the mixed powder. The powder was sintered under the conditions of a sintering pressure of 66 MPa, a sintering temperature of 900 ° C., and a holding time of 1 hour to obtain a sintered body.

After measuring the relative density of this sintered body, the sintered body was processed into a sputtering target and the number of particles was measured. Next, a sample piece was cut out from the sputtering target, and the ratio of the water-soluble boron concentration to the total boron concentration and the oxygen content were measured. The relative density was 93.8%, the number of particles was 53, the ratio of the water-soluble boron concentration to the total boron concentration was 3.6%, and the oxygen content was 6275 wtppm.

[Example 2]
143.73 g of Fe powder with an average particle diameter of 7 μm, 501.08 g of Pt powder with an average particle diameter of 1 μm, 63.88 g of BN powder with an average particle diameter of 4 μm, and an average particle diameter so as to have the composition of Fe-30Pt-30BN-10C. 10.30 g of 3 μm C powder was weighed and charged into a medium stirring mill (medium: zirconia balls), the atmosphere in the medium stirring mill was replaced with argon gas, and the mixture was mixed at 150 rpm for 4 hours. The mixed powder was classified with a sieve having an opening of 300 μm, and the passed powder was spread on a vat and contacted with the atmosphere for 30 minutes to form B ₂ O ₃ in the vicinity of BN particles in the mixed powder. The powder was sintered under the conditions of a sintering pressure of 66 MPa, a sintering temperature of 900 ° C., and a holding time of 1 hour to obtain a sintered body.

After measuring the relative density of this sintered body, the sintered body was processed into a sputtering target and the number of particles was measured. Next, a sample piece was cut out from the sputtering target, and the ratio of the water-soluble boron concentration to the total boron concentration and the oxygen content were measured. The relative density was 92.9%, the number of particles was 38, the ratio of the water-soluble boron concentration to the total boron concentration was 3.1%, and the oxygen content was 6033 wtppm.

In addition, a 2 mm square sample piece was cut from the spatter rig target and EPMA analysis was performed. The results are shown in FIG. From FIG. 2, it can be seen that the regions where B and N exist coincide with each other, the region where O exists overlaps with the region where B and N exist, and does not overlap with the region where Fe and Pt exist. Therefore, it is considered that O exists in the region where BN exists and forms a boron oxide.

[Example 3]
A sintered body was obtained and evaluated in the same manner as in Example 2 except that the mixing condition of the raw material powder was changed to 150 rpm for 2 hours. The relative density was 95.6%, the number of particles was 83, the ratio of the water-soluble boron concentration was 1.8%, and the oxygen content was 4106 wtppm.

[Example 4]
First, only 100.00 g of BN powder having an average particle diameter of 4 μm was put into a medium stirring mill (medium: zirconia balls), and the atmosphere in the medium stirring mill was set as a mixed gas atmosphere of 30 vol% O ₂ and Ar gas at 150 rpm for 2 hours. Mixed.

Next, 143.73 g of Fe powder having an average particle diameter of 7 μm, 501.08 g of Pt powder having an average particle diameter of 1 μm, and 63.88 g of the crushed BN powder so as to have the composition of Fe-30Pt-30BN-10C. 10.30 g of C powder having an average particle diameter of 3 μm is weighed and put into a medium stirring mill (medium: zirconia balls), the atmosphere in the medium stirring mill is replaced with argon gas, and the mixture is mixed at 150 rpm for 2 hours to prepare the raw material. A powder mixture was prepared.
The prepared raw material powder mixture was sintered under the conditions of a sintering pressure of 66 MPa, a sintering temperature of 900 ° C., and a holding time of 1 hour to obtain a sintered body.

Using the obtained sintered body, the relative density, the number of particles, the ratio of the water-soluble boron concentration to the total boron concentration, and the oxygen content were measured in the same manner as in Example 2. The relative density was 94.8%, the number of particles was 57, the ratio of the water-soluble boron concentration was 3.5%, and the oxygen content was 5665 wtppm.

[Example 5]
First, only 100.00 g of BN powder having an average particle diameter of 4 μm is put into a medium stirring mill (medium: zirconia balls), the atmosphere in the medium stirring mill is set as an Ar gas atmosphere, mixed at 150 rpm for 2 hours and pulverized, and then BN. The powder was spread on a bat and contacted with the atmosphere for 30 minutes to form a boron oxide (B ₂ O ₃ ) in the vicinity of the BN particles in the mixed powder.

Next, 143.73 g of Fe powder having an average particle diameter of 7 μm, 501.08 g of Pt powder having an average particle diameter of 1 μm, 63.88 g of the crushed BN powder, and an average particle diameter so as to have the same composition as in Example 4. Weigh 10.30 g of 3 μm C powder, put it into a medium stirring mill (medium: zirconia balls), replace the inside of the medium stirring mill with argon gas, and mix at 150 rpm for 2 hours to prepare the raw material powder mixture. Prepared.
The prepared raw material powder mixture was sintered under the conditions of a sintering pressure of 66 MPa, a sintering temperature of 900 ° C., and a holding time of 1 hour to obtain a sintered body.

Using the obtained sintered body, the relative density, the number of particles, the ratio of the water-soluble boron concentration to the total boron concentration, and the oxygen content were measured in the same manner as in Example 2. The relative density was 94.0%, the number of particles was 48, the ratio of the water-soluble boron concentration was 5.4%, and the oxygen content was 7706 wtppm.

[Example 6]
Each raw material powder was weighed so as to have the same composition as in Example 4, and the BN powder, C powder, Fe powder and Pt powder were put into the medium stirring mill to create an Ar gas atmosphere containing 30 vol% of oxygen in the medium stirring mill. Then, the mixture was mixed at 150 rpm for 2 hours to prepare a raw material powder mixture.
The prepared raw material powder mixture was sintered under the conditions of a sintering pressure of 66 MPa, a sintering temperature of 900 ° C., and a holding time of 1 hour to obtain a sintered body.

Using the obtained sintered body, the relative density, the number of particles, the ratio of the water-soluble boron concentration to the total boron concentration, and the oxygen content were measured in the same manner as in Example 2. The relative density was 92.9%, the number of particles was 78, the ratio of the water-soluble boron concentration was 2.9%, and the oxygen content was 4638 ppm.

[Example 7]
Fe-31.5Pt-7Ag-30BN, Fe powder 145.91 g with an average particle diameter of 7 μm, Pt powder 509.70 g with an average particle diameter of 1 μm, Ag powder with an average particle diameter of 10 μm 62.63 g, average. A raw material powder mixture was prepared in the same manner as in Example 1 except that 61.76 g of BN powder having a particle diameter of 4 μm was weighed, and a sintered body was obtained.

Using the obtained sintered body, the relative density, the number of particles, the ratio of the water-soluble boron concentration to the total boron concentration, and the oxygen content were measured in the same manner as in Example 1. The relative density was 95.2%, the number of particles was 49, the ratio of the water-soluble boron concentration was 4.1%, and the oxygen content was 5981 wtppm.

[Example 8]
151.43 g of Fe powder with an average particle diameter of 7 μm, 528.97 g of Pt powder with an average particle diameter of 1 μm, and 35.51 g of Co powder with an average particle diameter of 3 μm so as to have a composition of Fe-31.5 Pt-7Co-30BN. A raw material powder mixture was prepared in the same manner as in Example 1 except that 64.10 g of BN powder having a particle diameter of 4 μm was weighed, and a sintered body was obtained.

Using the obtained sintered body, the relative density, the number of particles, the ratio of the water-soluble boron concentration to the total boron concentration, and the oxygen content were measured in the same manner as in Example 1. The relative density was 93.7%, the number of particles was 41, the ratio of the water-soluble boron concentration was 4.8%, and the oxygen content was 5883 wtppm.

[Example 9]
148.33 g of Fe powder with an average particle diameter of 7 μm, 518.15 g of Pt powder with an average particle diameter of 1 μm, 60.74 g of Rh powder with an average particle diameter of 10 μm, so as to have a composition of Fe-31.5 Pt-7Rh-30BN. A raw material powder mixture was prepared in the same manner as in Example 1 except that 62.79 g of BN powder having a particle diameter of 4 μm was weighed, and a sintered body was obtained.

Using the obtained sintered body, the relative density, the number of particles, the ratio of the water-soluble boron concentration to the total boron concentration, and the oxygen content were measured in the same manner as in Example 1. The relative density was 92.5%, the number of particles was 43, the ratio of the water-soluble boron concentration was 3.8%, and the oxygen content was 6121 wtppm.

[Example 10]
172.79 g of Fe powder having an average particle diameter of 7 μm, 603.60 g of Pt powder having an average particle diameter of 1 μm, and 65.83 g of BN powder having an average particle diameter of 4 μm are weighed so as to have a composition of Fe-35Pt-30BN. A raw material powder mixture was prepared in the same manner as in Example 1 except that the mixture was put into a stirring mill and mixed at a rotation speed of 150 pm for 3 hours to obtain a sintered body, which was water-soluble boron with respect to relative density, number of particles, and total boron concentration. The percentage of concentration and oxygen content were measured. The relative density was 95.0%, the number of particles was 67, the ratio of the water-soluble boron concentration was 3.4%, and the oxygen content was 5372 wtppm.

[Example 11]
Except for weighing 157.91 g of Fe powder having an average particle diameter of 7 μm, 551.60 g of Pt powder having an average particle diameter of 1 μm, and 75.58 g of BN powder having an average particle diameter of 4 μm so as to have a composition of Fe-32.5 Pt-35BN. Prepared a raw material powder mixture in the same manner as in Example 10, obtained a sintered body, and measured the relative density, the number of particles, the ratio of the water-soluble boron concentration to the total boron concentration, and the oxygen content. The relative density was 94.1%, the number of particles was 77, the ratio of the water-soluble boron concentration was 3.3%, and the oxygen content was 4833 wtppm.

[Example 12]
Except for weighing 129.51 g of Fe powder having an average particle diameter of 7 μm, 452.40 g of Pt powder having an average particle diameter of 1 μm, and 94.19 g of BN powder having an average particle diameter of 4 μm so as to have a composition of Fe-27.5 Pt-45BN. Prepared a raw material powder mixture in the same manner as in Example 10, obtained a sintered body, and measured the relative density, the number of particles, the ratio of the water-soluble boron concentration to the total boron concentration, and the oxygen content. The relative density was 91.4%, the number of particles was 94, the ratio of the water-soluble boron concentration was 2.8%, and the oxygen content was 5296 wtppm.

[Example 13]
173.45 g of Fe powder with an average particle diameter of 7 μm, 605.89 g of Pt powder with an average particle diameter of 1 μm, 44.05 g of BN powder with an average particle diameter of 4 μm, and an average particle diameter so as to have the composition of Fe-35Pt-20BN-10C. A sintered body was obtained in the same manner as in Example 2 except that 10.66 g of 3 μm C powder was put into a medium stirring mill (medium: zirconia ball) and mixed at a rotation speed of 150 rpm for 3 hours, and the relative density and the number of particles were obtained. , The ratio of the water-soluble boron concentration to the total boron concentration and the oxygen content were measured. The relative density was 96.2%, the number of particles was 61, the ratio of the water-soluble boron concentration was 3.7%, and the oxygen content was 5141 wtppm.

[Example 14]
148.73 g of Fe powder with an average particle diameter of 7 μm, 501.08 g of Pt powder with an average particle diameter of 1 μm, 63.88 g of BN powder with an average particle diameter of 4 μm, and an average particle diameter so as to have the composition of Fe-30Pt-30BN-10C. 10.30 g of 3 μm C powder was put into a medium stirring mill (medium: zirconia balls), and a sintered body was obtained in the same manner as in Example 2 except that the mixing conditions of the raw material powder were changed to 3 hours at a rotation speed of 150 rpm. The relative density, the number of particles, the ratio of the water-soluble boron concentration to the total boron concentration, and the oxygen content were measured. The relative density was 95.1%, the number of particles was 62, the ratio of the water-soluble boron concentration was 3.3%, and the oxygen content was 5308 wtppm.

[Example 15]
A sintered body was obtained in the same manner as in Example 14 except that the sintering conditions of the raw material powder mixture were changed to a sintering pressure of 66 MPa and the sintering temperature was changed to 700 ° C., and water solubility with respect to relative density, number of particles, and total boron concentration was obtained. The ratio of the boron concentration and the oxygen content were measured. The relative density was 93.3%, the number of particles was 82, the ratio of the water-soluble boron concentration was 2.9%, and the oxygen content was 5224 wtppm.

[Example 16]
A sintered body was obtained in the same manner as in Example 2 except that the mixing condition of the raw material powder was changed to 6 hours at a rotation speed of 150 pm, and the relative density, the number of particles, the ratio of the water-soluble boron concentration to the total boron concentration and the oxygen content were obtained. The amount was measured. The relative density was 90.7%, the number of particles was 33, the ratio of the water-soluble boron concentration was 7.3%, and the oxygen content was 7688 wtppm.

[Example 17]
To have the composition of Fe-25Pt-10Au-30BN-10C, 116.99 g of Fe powder having an average particle diameter of 7 μm, 408.33 g of Pt powder having an average particle diameter of 1 μm, 62.40 g of BN powder having an average particle diameter of 4 μm, and an average. 10.06 g of C powder having a particle diameter of 3 μm and 165.05 g of Au powder having an average particle diameter of 1 μm were put into a medium stirring mill (medium: zirconia balls) and baked in the same manner as in Example 2 except that they were mixed at 150 rpm for 3 hours. Bounds were obtained and the relative density, number of particles, ratio of water-soluble boron concentration to total boron concentration and oxygen content were measured. The relative density was 96.1%, the number of particles was 55, the ratio of the water-soluble boron concentration was 2.5%, and the oxygen content was 4935 wtppm.

[Example 18]
The composition of Fe-25Pt-10Ag-30BN-10C is 116.89 g of Fe powder having an average particle diameter of 7 μm, 408.33 g of Pt powder having an average particle diameter of 1 μm, 62.34 g of BN powder having an average particle diameter of 4 μm, and an average. A sintered body was obtained in the same manner as in Example 17 except that 10.06 g of C powder having a particle diameter of 3 μm and 90.31 g of Ag powder having an average particle diameter of 10 μm were charged into a medium stirring mill (medium: zirconia balls). The density, number of particles, ratio of water-soluble boron concentration to total boron concentration and oxygen content were measured. The relative density was 95.7%, the number of particles was 49, the ratio of the water-soluble boron concentration was 2.8%, and the oxygen content was 5184 wtppm.

[Example 19]
121.19 g of Fe powder with an average particle diameter of 7 μm, 423.33 g of Pt powder with an average particle diameter of 1 μm, 64.63 g of BN powder with an average particle diameter of 4 μm, and an average of 64.63 g of Fe powder having an average particle diameter of 7 μm so as to have the composition of Fe-25Pt-10Cu-30BN-10C. A sintered body was obtained in the same manner as in Example 17 except that 10.43 g of C powder having a particle diameter of 3 μm and 55.16 g of Cu powder having an average particle diameter of 3 μm were charged into a medium stirring mill (medium: zirconia balls). The density, number of particles, ratio of water-soluble boron concentration to total boron concentration and oxygen content were measured. The relative density was 95.9%, the number of particles was 66, the ratio of the water-soluble boron concentration was 2.6%, and the oxygen content was 4799 wtppm.

[Example 20]
The composition of Fe-25Pt-10Rh-30BN-10C is 119.55 g of Fe powder having an average particle diameter of 7 μm, 417.61 g of Pt powder having an average particle diameter of 1 μm, 63.76 g of BN powder having an average particle diameter of 4 μm, and an average. A sintered body was obtained in the same manner as in Example 17 except that 10.28 g of C powder having a particle diameter of 3 μm and 88.12 g of Rh powder having an average particle diameter of 10 μm were charged into a medium stirring mill (medium: zirconia balls). The density, number of particles, ratio of water-soluble boron concentration to total boron concentration and oxygen content were measured. The relative density was 94.0%, the number of particles was 88, the ratio of the water-soluble boron concentration was 2.8%, and the oxygen content was 5041 wtppm.

[Example 21]
112.65 g of Fe powder with an average particle diameter of 7 μm, 393.51 g of Pt powder with an average particle diameter of 1 μm, 60.08 g of BN powder with an average particle diameter of 4 μm, so as to have the composition of Fe-25Pt-10Ge-30BN-10C. Same as Example 17 except that 9.69 g of C powder having a particle diameter of 3 μm and 58.61 g of Ge powder having an average particle diameter of 10 μm were put into a medium stirring mill (medium: zirconia balls) and the sintering temperature was changed to 700 ° C. The sintered body was obtained, and the relative density, the number of particles, the ratio of the water-soluble boron concentration to the total boron concentration, and the oxygen content were measured. The relative density was 97.0%, the number of particles was 60, the ratio of the water-soluble boron concentration was 2.3%, and the oxygen content was 5222 wtppm.

[Comparative Example 1]
A sintered body was obtained in the same manner as in Example 2 except that the mixing condition was changed to 30 minutes at 150 rpm, and the relative density, the number of particles, the ratio of the water-soluble boron concentration to the total boron concentration and the oxygen content were measured. .. The relative density was 95.4%, the number of particles was 563, the ratio of the water-soluble boron concentration was 0.2%, and the oxygen content was 1318 wtppm.

[Comparative Example 2]
A sintered body was obtained in the same manner as in Example 2 except that the mixing conditions were changed to 150 rpm for 12 hours, and the relative density, the ratio of the water-soluble boron concentration to the total boron concentration, and the oxygen content were measured. The relative density was 87.4%, the ratio of the water-soluble boron concentration was 13.8%, and the oxygen content was 12066 wtppm. Since the relative density is as low as 87.4% and it is not practical as a sputtering target, the number of particles was not measured.

[Comparative Example 3]
A sintered body was obtained in the same manner as in Example 2 except that the mixing condition was changed to 5 minutes at 300 rpm, and the relative density, the number of particles, the ratio of the water-soluble boron concentration to the total boron concentration and the oxygen content were measured. .. The relative density was 96.3%, the number of particles was 1376, the ratio of the water-soluble boron concentration was 0.1%, and the oxygen content was 483 wtppm.

[Comparative Example 4]
A sintered body was obtained in the same manner as in Example 2 except that the mixing condition was changed to 30 minutes at 300 rpm, and the relative density, the number of particles, the ratio of the water-soluble boron concentration to the total boron concentration and the oxygen content were measured. .. The relative density was 91.4%, the number of particles was 713, the ratio of the water-soluble boron concentration was 0.6%, and the oxygen content was 2046 ppm.

[Comparative Example 5]
A sintered body was obtained in the same manner as in Example 2 except that the mixing conditions were changed to 300 rpm for 2 hours, and the relative density, the ratio of the water-soluble boron concentration to the total boron concentration, and the oxygen content were measured. The relative density was 86.5%, the ratio of the water-soluble boron concentration was 2.2%, and the oxygen content was 4467 wtppm. Since the relative density is as low as 86.5% and it is not practical as a sputtering target, the number of particles was not measured.

[Comparative Example 6]
A sintered body was obtained in the same manner as in Example 2 except that the mixing conditions were changed to 460 rpm for 6 hours, and the relative density, the ratio of the water-soluble boron concentration to the total boron concentration, and the oxygen content were measured. The relative density was 79.2%, the ratio of the water-soluble boron concentration was 10.2%, and the oxygen content was 8782 wtppm. Since the relative density is as low as 79.2% and it is not practical as a sputtering target, the number of particles was not measured.

The relationship between the ratio of the water-soluble boron concentration to the total boron concentration and the oxygen content in Examples and Comparative Examples is shown in FIG. 3, and the relationship between the ratio of the water-soluble boron concentration to the total boron concentration and the number of particles generated is shown in FIG. The relationship between the oxygen content and the number of particles generated is shown in FIG.

From FIG. 4, the number of particles exceeds 500 in the range where the ratio of the water-soluble boron concentration (wt%) to the total boron concentration (wt%) is less than 1.0%, but the water solubility with respect to the total boron concentration (wt%). It can be seen that the number of particles is as small as 100 or less in the range where the ratio of the boron concentration (wt%) is 1.0% or more.

From FIG. 5, it can be seen that the number of particles exceeds 500 in the range where the oxygen concentration is less than 4000 wtppm, but the number of particles is very small, 100 or less in the range where the oxygen concentration is 4000 wtppm or more and 10,000 wtppm or less.

From the above results, Examples 1 to 21 in which the ratio of the water-soluble boron concentration (wt%) to the total boron concentration (wt%) is 1.0% or more and the oxygen content is more than 4000 ppm and 10,000 ppm or less are relative densities. In Comparative Examples 1 to 6 in which the relative density is 88% or more, the number of particles is less than 100, the conditions of both high relative density and low number of particles are satisfied, and the above requirements are not satisfied, the relative density is less than 88%. It can be seen that it cannot be put into practical use as a sputtering target (Comparative Examples 2, 5 and 6), or even if the relative density is 88% or more, the number of particles exceeds 500, which is extremely large (Comparative Examples 1, 3 and 4).

Claims

Fe-Pt-BN-based sputtering target
Contains non-magnetic components consisting of BN and boron oxide
Relative density is 88% or more,
The oxygen content is more than 4000 wtppm and 10,000 wtppm or less.
Fe-Pt-BN-based sputtering target characterized in that the ratio of the water-soluble boron concentration (wt%) to the total boron concentration (wt%) determined by the following procedure is 1.0% or more.
(How to determine the water-soluble boron concentration with respect to the total boron concentration)
(1) A 4 mm square sample piece is cut from the sputtering target, and the sample piece is crushed to prepare a crushed product.
(2) The pulverized product is classified using a sieve having a mesh size of 106 μm and a sieve having a mesh size of 300 μm, and 0.50 g of the powder remaining on the sieve having a mesh opening of 106 μm after passing through the sieve having a mesh opening of 300 μm is converted into 100 ml of pure water at 25 ° C. After soaking and leaving for 1 hour, it is filtered through a filter paper of type 5 A specified in JIS P 3801.
(3) The filtrate is measured up in a 200 ml volumetric flask, and the B concentration in the liquid is determined by ICP analysis.
(4) Only 200 ml of pure water was subjected to ICP analysis to determine the blank B concentration.
(5) Subtract the blank B concentration from the B concentration in the liquid and multiply by 200 ml of the liquid volume to calculate the eluted water-soluble B mass.
(6) The water-soluble B concentration per 1 g of powder was calculated from the water-soluble B mass in the powder mass of 0.50 g.
(7) The powder on the sieve having an opening of 106 μm was weighed in (2) above, and after alkali melting, the total B concentration in 1 g of the powder was calculated by ICP analysis.
(8) The water-soluble B concentration in 1 g of the powder is divided by the total B concentration in 1 g of the powder.
The Fe-Pt-BN-based sputtering target according to claim 1, wherein C is further contained as a non-magnetic component.
The Fe-Pt-BN-based sputtering target according to claim 1 or 2, wherein O is present in the region where B exists on the cut surface of the Fe-Pt-BN-based sputtering target.
The Fe-Pt-BN-based sputtering target according to any one of claims 1 to 3, wherein the Pt is contained in an amount of 10 mol% or more and 55 mol% or less.
The Fe-Pt-BN-based sputtering target according to any one of claims 1 to 4, wherein the BN is contained in an amount of 10 mol% or more and 55 mol% or less.
The Fe-Pt-BN-based sputtering target according to any one of claims 1 to 5, further comprising C in an amount of 0 mol% or more and 20 mol% or less.
The invention according to any one of claims 1 to 6, further comprising one or more elements selected from Ag, Au, Co, Cr, Cu, Ge, Ir, Ni, Pd, Rh, and Ru. Fe-Pt-BN-based sputtering target.
The method for manufacturing a Fe-Pt-BN-based sputtering target according to any one of claims 1 to 7.
The following (A) to (E):
(A) First, only the BN powder is mixed in a medium stirring mill having an atmosphere containing oxygen and / or water, and then the remaining raw material powder is put into the medium stirring mill, and then the inside of the medium stirring mill is filled with argon gas. Mix after creating an atmosphere;
(B) First, only the BN powder is crushed with a medium stirring mill having an argon gas atmosphere, then brought into contact with a gas containing oxygen and / or water, and then the remaining raw material powder is put into the medium stirring mill, and then the medium stirring is performed. Mix the inside of the mill as an argon gas atmosphere;
(C) The raw material powder is mixed in a medium stirring mill in an argon gas atmosphere, and then the mixed powder is brought into contact with a gas containing oxygen and / or water;
(D) The raw material powder is mixed in a medium stirring mill in an argon gas atmosphere, the mixing is interrupted before the predetermined mixing time elapses, the mixture is brought into contact with a gas containing oxygen and / or water, and then the mixing is performed again. Resume; or (E) mix the raw material powder in a medium stirring mill in an atmosphere containing argon gas and oxygen and / or water;
To prepare a raw material powder mixture by mixing in a medium stirring mill at a rotation speed of 100 rpm or more and 200 rpm or less for a total of 2 hours or more and 6 hours or less, and to open the raw material powder mixture. A method for producing a Fe-Pt-BN-based sputtering target, which comprises collecting powder that has passed through a 300 μm sieve and sintering the powder.
The method for manufacturing a Fe-Pt-BN-based sputtering target according to claim 1.
The following (A1) to (E1):
(A1) First, only BN powder is mixed in a medium stirring mill having an atmosphere containing oxygen and / or water, then Fe powder and Pt powder are charged into the medium stirring mill, and then argon is mixed in the medium stirring mill. Mix after creating a gas atmosphere;
(B1) First, only the BN powder is pulverized with a medium stirring mill having an argon gas atmosphere, and then brought into contact with a gas containing oxygen and / or water. Then, Fe powder and Pt powder are charged into the medium stirring mill, and then the medium is used. Mix the inside of the stirring mill as an argon gas atmosphere;
(C1) After mixing the BN powder, Fe powder and Pt powder in a medium stirring mill in an argon gas atmosphere, the mixed powder is brought into contact with a gas containing oxygen and / or water;
(D1) BN powder, Fe powder and Pt powder are mixed in a medium stirring mill in an argon gas atmosphere, and the mixing is interrupted before the predetermined mixing time elapses, and the mixture is brought into contact with a gas containing oxygen and / or water. After that, the mixing is restarted again; or (E1) the BN powder, Fe powder and Pt powder are mixed in a medium stirring mill in an atmosphere containing argon gas and oxygen and / or water;
To prepare a raw material powder mixture by mixing in a medium stirring mill at a rotation speed of 100 rpm or more and 200 rpm or less for a total of 2 hours or more and 6 hours or less, and to open the raw material powder mixture. A method for producing a Fe-Pt-BN-based sputtering target, which comprises collecting powder that has passed through a 300 μm sieve and sintering the powder.
The method for manufacturing a Fe-Pt-BN-based sputtering target according to claim 2.
The following (A2) to (E2):
(A2) First, only BN powder is mixed in a medium stirring mill having an atmosphere containing oxygen and / or water, then C powder, Fe powder and Pt powder are charged into the medium stirring mill, and then the medium stirring mill is used. After making the inside into an argon gas atmosphere, mix;
(B2) First, only the BN powder is pulverized with a medium stirring mill having an argon gas atmosphere, and then brought into contact with a gas containing oxygen and / or water, and then the C powder, Fe powder and Pt powder are charged into the medium stirring mill. , The inside of the medium stirring mill is mixed as an argon gas atmosphere;
(C2) The BN powder, C powder, Fe powder and Pt powder are mixed in a medium stirring mill in an argon gas atmosphere, and then the mixed powder is brought into contact with a gas containing oxygen and / or water;
(D2) BN powder, C powder, Fe powder and Pt powder are mixed in a medium stirring mill in an argon gas atmosphere, and the mixing is interrupted before the predetermined mixing time elapses, and the gas containing oxygen and / or water is contained. After contacting with, the mixing is restarted again; or (E2) the BN powder, C powder, Fe powder and Pt powder are mixed in a medium stirring mill in an atmosphere containing argon gas and oxygen and / or water;
To prepare a raw material powder mixture by mixing in a medium stirring mill at a rotation speed of 100 rpm or more and 200 rpm or less for a total of 2 hours or more and 6 hours or less, and to open the raw material powder mixture. A method for producing a Fe-Pt-BN-based sputtering target, which comprises collecting powder that has passed through a 300 μm sieve and sintering the powder.
The production method according to any one of claims 8 to 10, wherein the sintering is performed at a sintering temperature of 600 ° C. or higher and 1200 ° C. or lower, and a sintering pressure of 30 MPa or higher and 200 MPa or lower.