JP2002226970A - Co TARGET AND PRODUCTION METHOD THEREFOR - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a Co powder sintered target in which the amount of oxygen is suppressed, and a production method therefor. SOLUTION: The Co powder sintered target has a composition containing, by atom, >10 to 25% B, and in which the amount of oxygen is controlled to <=100 ppm. Further, 5 to 30% Pt, 10 to 30% Cr, >0 to 10% Ta, >0 to 30% Ni and >0 to 15% (Ti+Zr+Hf+V+Nb+Mo+W+Cu+Ag+Au+Ru+Rh+Pd+ Os+Ir+rare earth elements) can be incorporated therein. The target can be obtained by adding >10 to 25% B to an alloy essentially consisting of Co and dissolving the same to cause deoxidizing treatment, thereafter subjecting the obtained alloy to rapid solidification treatment into powder, and next sintering the powder. Alternatively, the powder and metal powder, specifically, the metal powder of one or more kinds of elements selected from Cu, Ag, Au, Ru, Rh, Pd, Os, Ir and Pt are mixed, and next, the powdery mixture is sintered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a Co-based target used for forming a magnetic film of a magnetic recording medium for a magnetic disk drive or the like, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, Co-based magnetic films have been developed to enable high-density magnetic recording.
Additions have been made. Such a Co-based magnetic film is
It was usually formed by sputtering.
As described in Japanese Patent Publication No. 2806228 and the like, a target usually manufactured by a melting and casting method is used for this sputtering.

[0003]

In order to obtain the above-mentioned Co-based magnetic film, a powder sintered target has been proposed, for example, as described in JP-A-3-138365. With the recent demand for higher coercivity for magnetic films, P
Co must contain a large amount of t, Cr, Ta, and the like.
With the increase in the amount of alloying elements added, segregation of components during casting and difficulty in uniformizing the structure by plastic working become problems.
On the other hand, the powder sintering method has an advantage that a structure in which the additive elements are uniformly dispersed can be obtained. Also, as another technology,
As described in JP-A-5-263230, a powder sintering technique in which B is added for improving magnetic properties is known.

However, the biggest drawback of the powder method is that since it is once handled as a powder, the amount of oxygen is inevitably higher than that of a cast material. Since oxygen has a great effect on magnetic recording characteristics, powder sintering has not been used extensively from the viewpoint that the oxygen content should be reduced as much as possible rather than variation in thin film composition due to component segregation. An object of the present invention is to provide a novel Co-based target in which an increase in the amount of oxygen, which is a drawback of a powder sintered material capable of obtaining a uniform structure, is suppressed, and a method for producing the same.

[0005]

Means for Solving the Problems The present inventor has found that a powder-sintered target with low oxygen can be obtained by maximizing the deoxidizing effect by adding B in the process of manufacturing the powder-sintered target. The present invention has been reached.

That is, the novel target of the present invention is:
This is a powder sintered target, which is a Co-based target containing B in an amount of more than 10 at% and 25 at% or less and an oxygen content of 100 ppm or less.

Preferably, 30 ≧ Pt ≧ 5 at%, 30
≧ Cr ≧ 10at%, 10 ≧ Ta> 0at%, 30 ≧ N
i> 0 at% can be contained. More preferably, Ti, Zr, Hf, V, Nb, Mo, W, Cu,
One, two or more elements selected from Ag, Au, Ru, Rh, Pd, Os, Ir and rare earth elements can be contained in a total amount of more than 0 at% and 15 at% or less.

[0008] The above-mentioned target of the present invention is deoxidized by adding B in an amount of more than 10 at% to 25 at% or less and dissolving it in a Co-based alloy, and then rapidly cooling and solidifying the obtained alloy. C, and then sintering the powder to form a powder sintered target.
It can be obtained by a method for producing an o-based target.

Alternatively, the above-mentioned target of the present invention
B exceeds 25% in Co-based alloys.
After deoxidation by adding and dissolving at% or less, the obtained alloy is rapidly solidified to obtain a powder, and the powder and a metal powder, specifically, Cu, Ag, Au, Ru, R, R
a Co-based target characterized by mixing metal powders of one or more elements selected from h, Pd, Os, Ir and Pt, and then sintering the mixed powder to obtain a powder sintered target , Preferably, a method of manufacturing a Co-based target, which is characterized by performing a heat treatment after sintering.

In the case of the method for producing a Co-based target of the present invention, an atomizing method can be used as the rapid solidification treatment method, or a hot isostatic pressing method can be used as the sintering method.

[0011]

The greatest feature of the present invention is that the oxygen content of a Co-based powder sintering target is reduced to 100 ppm or less, which has not been considered conventionally. In the present invention, a low-oxygen powder sintered target was realized by B
In the proper addition of B has a high affinity for oxygen,
Because of the high sublimability of the oxide, the rapidly solidified powder obtained by adding B to the molten metal at the time of preparing the rapidly solidified powder or the molten metal at the time of forming the master ingot (master alloy) and subjecting it to deoxidation treatment with B in advance. It became possible to remarkably reduce the amount of oxygen of.

In the present invention, it is preferable to sinter the rapidly solidified powder adjusted to the target composition as it is, but Cu, Ag, Au, Ru, Rh, Pd, Os, I
In the case of expensive additional elements such as r and Pt,
Rapidly solidified powder of Co-based alloy to which B has been added and Cu, Ag, A
One, two or more metal powders selected from u, Ru, Rh, Pd, Os, Ir and Pt may be mixed and the resulting mixed powder may be sintered. Rapid solidification of Co-based alloys containing B and Cu, Ag, Au, Ru, Rh, P
one or two selected from d, Os, Ir and Pt
If more than one kind of metal powder is mixed and the obtained mixed powder is sintered, it should be subjected to heat treatment or hot working after sintering, if necessary, to make the structure uniform. Is also possible.

As a method for producing the rapidly solidified powder, there are methods such as an atomizing method and a spin melt method. However, powder production using a gas atomizing method is preferable in view of the packing density and yield of the powder. As a sintering method, there are a hot press method, a hot isostatic press method (hereinafter, HIP), and the like.
Considering the density and the like of the sintered body, HIP to which high pressure can be applied is preferable.

As a preferable composition of the target of the present invention, an element capable of improving the characteristics as a magnetic recording film is added. More specifically, 25 ≧ B> 10 at%, 30 ≧ P
t ≧ 5 at%, 30 ≧ Cr ≧ 10 at%, 10 ≧ Ta>
0 at% and 30 ≧ Ni> 0 at% can be added.
Further, Ti, Zr, Hf, V, Nb, Mo, W, Cu,
It is also possible to add one or more elements selected from Ag, Au, Ru, Rh, Pd, Os, Ir and rare earth elements in a total amount of more than 0 at% and 15 at% or less. Of course, the invention is not limited to this range. Hereinafter, the effects of the added elements will be described.

[0015] B addition is the most important element of the present invention. A sputtered film produced using the Co-based target of the present invention is often used as a magnetic layer of a magnetic recording medium. Conventionally, the magnetic layer in the above-described magnetic recording medium has 1
Since they were formed of layers, they had to have all the characteristics such as high coercive force and high squareness ratio. Therefore, a Co-based film containing B in excess of 10% as in the present invention has not been studied because an increase in coercive force cannot be expected. However, at present, the above-mentioned magnetic layer is formed of a plurality of layers. Therefore, each phase has been changed to require different characteristics.

In the case of the present invention, a sputtered film made of a Co-based target to which B is added in excess of 10 at% cannot increase the coercive force as described above, but has a great effect of reducing the noise of the sputtered film. Things. And B
By adding more than 10 at% to 25 at% or less, an effect of reducing the amount of oxygen is obtained. However, the reason why the upper limit of B addition is 25 at% or less is that 25
This is because, if added in excess of%, adverse effects such as the sputtered film becoming amorphous appear significantly. Further, the effect of reducing the amount of oxygen, which is a feature of the present invention, is achieved by adding B exceeding 10 at%, and is also preferable for obtaining a target having an oxygen amount of 100 ppm or less.

The addition of Pt has the effect of increasing the magnetic anisotropy by dissolving in Co and increasing the coercive force of the film, and can be added. 5at for a clear increase in coercive force
% Or more is preferable. Further, the addition exceeding 30 at% remarkably lowers the original magnetic properties of Co. Therefore, when adding, the preferred range is 30 ≧ Pt ≧ 5 at%.

The addition of Cr has the effect of segregating to the grain boundaries in the film and making the grain boundaries non-magnetic, thereby magnetically separating the ferromagnetic Co grains. The division is not sufficient, and the addition exceeding 30 at% lowers the magnetization of the film itself, so that 30 ≧ Cr ≧
It is preferably set to 10 at%. Addition of Ta has the effect of reducing the crystal grain size of the film, and also has the effect of segregating non-magnetic elements such as Cr at the grain boundaries. The effect is recognized even if a small amount is added. Therefore, it is preferable that 10 ≧ Ta> 0 at%.

The addition of Ni has the effect of increasing the magnetic anisotropy by forming a solid solution with Co and increasing the coercive force of the film.
at% or less can be added. 5a to increase coercive force
A remarkable effect is seen by adding t% or more,
In addition, since addition exceeding 30 at% lowers the original properties of Co, it is preferable that 30 ≧ Ni> 0 at%, more preferably 30 ≧ Ni ≧ 5 at%.

Further, Ti, Zr, Hf, V, Nb, M
o, W, Cu, Ag, Au, Ru, Rh, Pd, Os,
The addition of Ir and rare earth elements is a group of elements having a common effect of improving magnetic properties. Ti, Zr, H
f and the rare earth element are the effects of refining the crystal grains of the film, V and Nb are the same effects as the above-mentioned Ta, Mo and W are the same effects as the above-mentioned Cr, and Cu, Ag and Au are the Co grains due to the grain boundary segregation. Splitting effect, Ru, Rh, Pd, Os
And Ir have an effect equivalent to that of Pt described above, and these elements are effective when added in a small amount.
If it exceeds at%, the magnetic properties and crystallinity of the film are impaired, so that the total amount is preferably more than 0 at% and 15 at% or less.

[0021]

EXAMPLES (Example 1) B was added by vacuum melting and casting to perform deoxidation treatment, a master alloy mainly composed of Co was produced, and gas atomization was performed using the produced master alloy.
Table 1 shows the composition of the produced powder. The gas atomization was performed in an Ar atmosphere. Table 1 shows the average particle size and oxygen content of the produced atomized powder. Table 1
Samples 5 and 10, which are comparative examples in the middle, were manufactured in the same manner as described above, except that deoxidation treatment was performed by adding B.

The produced atomized powder is subjected to H under the conditions of 1000 ° C. (temperature), 100 MPa (pressure), and 3 hours (hour).
Sintered by IP, then φ101 × 5 by machining
A target of t (mm) was produced. Table 2 shows the oxygen analysis values of the manufactured targets. As shown in Table 2, it can be seen that the target produced by sintering the atomized powder obtained by adding B and deoxidizing to oxygen has a low oxygen content, and in particular, has a target of 100 ppm or less.

[0023]

[Table 1]

[0024]

[Table 2]

Example 2 A gas atomized powder having the composition shown in Table 3 was produced in the same manner as in Example 1. However, the atmosphere at the time of gas atomization was Ar atmosphere. Table 3 shows the average particle size and oxygen content of the produced atomized powder. The average particle size and oxygen content of the used Pt powder are also shown in Table 3.

The Pt powder shown in Table 3 was added to the produced atomized powder and mixed, and then 1000 ° C. (temperature) and 100 MPa
(Pressure), sintering by HIP under the condition of 3h (time),
A target of φ101 × 5t (mm) having the composition shown in Table 6 was produced. Table 4 shows the oxygen analysis values of the manufactured targets. As shown in Table 4, the target produced by mixing and sintering the Pt powder with the Co-based atomized powder to which B was added and deoxidized was reduced in oxygen amount, and in particular, could be reduced to 100 ppm or less. You can see that.

[0027]

[Table 3]

[0028]

[Table 4]

Example 3 A gas atomized powder having the composition shown in Table 5 was produced in the same manner as in Example 1. However, the atmosphere at the time of gas atomization was Ar atmosphere. Table 5 shows the average particle size and oxygen content of the produced atomized powder.

The produced atomized powder is subjected to H under the conditions of 1000 ° C. (temperature), 100 MPa (pressure), and 3 hours (hour).
It was sintered by IP to produce a target of φ101 × 5t (mm). Table 6 shows the oxygen analysis values of the manufactured targets. As shown in Table 6, the target of the present invention produced by sintering the atomized powder that has been deoxidized by adding B has a low oxygen amount, and
It turns out that it is below ppm.

[0031]

[Table 5]

[0032]

[Table 6]

Example 4 Co-20Cr-10Pt-
A target of 15B (at%) was produced by the production method shown in Table 7. Table 8 shows the impurity oxygen analysis values of the manufactured target. The atomized powder was prepared in the same manner as in Examples 1 and 2, and the sintering condition of the sintered material was 1000.
The melting and casting materials were melted in an induction heating furnace in a vacuum and cast into iron molds under the conditions of 1 ° C. × 100 MPa × 3 h and the diffusion treatment conditions of the material subjected to the diffusion treatment were 1100 ° C. × 10 h. A target of × 5t (mm) was produced.

Using a substrate in which a Cr underlayer was sputter-deposited on a NiP-plated Al substrate, a method shown in Table 7 was applied on the substrate under the conditions of a substrate temperature of 150 ° C., an Ar pressure of 0.66 Pa, and a DC power of 500 W. Different Co-20Cr-10P
Film formation was performed using a t-15B (at%) target. In order to investigate the variation in the characteristics of the magnetic film, a film-forming substrate having a total film-forming time of 1 hour to 5 hours at 1-hour intervals was prepared, and a VSM was prepared.
Table 9 shows the measurement results of the coercive force Hc measured with a (vibrating sample magnetometer). However, Table 9 is shown as a relative value with the coercive force at 1 hour of Sample 1 being 100. From Table 9, it can be seen that the target of the present invention has a small variation at the time of film formation, the target having a high oxygen content has a low coercive force, and the molten / cast material has a slightly larger variation over time than the target of the present invention. .

[0035]

[Table 7]

[0036]

[Table 8]

[0037]

[Table 9]

[0038]

According to the present invention, it is possible to stably supply a uniform and low-oxygen Co-based target for producing a Co-based magnetic film for a magnetic recording medium used for a magnetic disk drive or the like. This technology has become indispensable for the production of recording media.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C22C 19/07 C22C 19/07 G G11B 5/851 G11B 5/851 (72) Inventor Hideshi Ueno Yasugi Shimane 2107 No. 2 Yasugi-cho, Hitachi Metals F-term (reference) at Yasugi Plant 4K017 AA04 DA03 EK01 4K018 AA10 BA04 EA11 KA29 4K029 BA24 BC06 BD11 DC04 DC09 5D112 AA05 BB05 FB02

Claims (11)

[Claims] 1. A powder sintered target, wherein B is 10
At least 25 at% or more and at least 100 at%
A Co-based target characterized by being at most ppm. 2. 30 ≧ Pt ≧ 5 at%, 30 ≧ Cr ≧ 1
The Co-based target according to claim 1, wherein the Co-based target is mainly composed of 0 at% and the balance Co. 3. The carbon according to claim 1, wherein 10 ≧ Ta> 0 at% is contained.
o system target. 4. The Co according to claim 1, wherein 30% Ni> 0 at% is contained.
System target. 5. Ti, Zr, Hf, V, Nb, Mo,
W, Cu, Ag, Au, Ru, Rh, Pd, Os, Ir
The Co-based target according to any one of claims 1 to 4, wherein a total amount of one or more elements selected from rare earth elements is more than 0 at% and 15 at% or less. 6. B at 10 at is added to a Co-based alloy.
%, Added and melted in an amount of 25 at% or less and then deoxidized, and then the obtained alloy is rapidly solidified to obtain a powder, and then the powder is sintered to obtain a powder sintered target. A method for producing a Co-based target. 7. An alloy mainly composed of Co-based alloy containing B at 10 at.
% And added at not more than 25 at% and melted, followed by deoxidation by quenching and solidifying the obtained alloy into powder, mixing the powder and metal powder, and then sintering the mixed powder. And producing a powdered sintered target. 8. An alloy mainly composed of Co-based alloy containing B at 10 at.
% And added at 25 at% or less and melted, followed by deoxidation treatment, and then quenching and solidifying the obtained alloy to form a powder. The powder and Cu, Ag, Au, Ru, Rh, Rh, P
one or two selected from d, Os, Ir and Pt
The method for producing a Co-based target according to claim 7, wherein a metal powder of at least one kind of element is mixed, and then the mixed powder is sintered to obtain a powder sintered target. 9. The method according to claim 7, wherein heat treatment is performed after sintering. 10. The method for producing a Co-based target according to claim 6, wherein an atomizing method is used as the rapid solidification treatment method. 11. The method for producing a Co-based target according to claim 6, wherein a hot isostatic pressing method is used as a sintering method.