JPS6297127A - Magnetic recording medium and its production - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium having the improved wear resistance together with high reliability and a long lifetime, by forming an area where a magnetic thin film and a protecting film are welded between these two films. CONSTITUTION:A desired magnetic thin film and its precursor magnetic thin film or the thin film of a precursor material are formed on a nonmagnetic supporter. Then a wear-resistance film or its precursor thin film is formed on the first thin film of the supporter. Then a heat treatment is applied at a prescribed temperature to turn the above-mentioned films into the desired magnetic thin films and protecting films respectively. At the same time, the dispersion is produced among those films to form a solid solution area on the interface between the magnetic thin film and the protecting film. Thus the adhesion properties can be improved between both films by producing the dispersion between them by the heat treatment. This improves both wear resistance and reliability of a magnetic recording medium.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic recording medium comprising a magnetic thin film provided on a non-magnetic support, and particularly to a highly reliable magnetic recording medium with excellent wear resistance. .

[Conventional technology]

As the capacity of magnetic storage devices increases, the magnetic recording media used therein are required to have increasingly higher recording density characteristics and higher reliability. Coated magnetic recording media, in which magnetic powder such as γ-Fe2O3 is dispersed in a resin binder and coated on a non-magnetic support, have been commonly used in the past. Therefore, thin film magnetic recording media in which a magnetic thin film is formed on a nonmagnetic substrate by a vapor deposition method, a plating method, a sputtering method, or the like are attracting attention.

In this thin-film magnetic recording medium, it is possible to make the magnetic layer thinner, and since the magnetic layer contains a non-magnetic resin binder, it is possible to increase the magnetic flux density, and as a result, high recording density is possible. becomes.

However, in this type of magnetic recording medium, the problem that the magnetic layer is destroyed due to sliding contact between the magnetic recording medium and the magnetic head is more likely to occur than in coated magnetic recording media, and the sliding contact between the magnetic head and the magnetic layer is more likely to occur. However, it is an important issue to treat the surface of the magnetic layer in order to provide sufficient wear resistance. For example, in magnetic disk drives, a so-called contact start-stop (hereinafter referred to as C8S) system has been adopted, in which the magnetic head and the medium come into sliding contact when the rotation of the magnetic disk medium starts and stops. K requires sufficient wear resistance to withstand this.
It has become.

In order to ensure the wear resistance of such magnetic recording media, conventionally, All OB, 8101, Ti01.5in
A method has been proposed in which a protective film made of a highly hard material such as N4, WC, TiC, SiC, or B4C is formed on the magnetic layer. (Special Publication No. 55-39047, Japanese Patent Publication No. 53-2
1901. JP-A-53-21902, JP-A-58-18
5029, JP-A-59-[Problems with Prior Art] The above-mentioned protective film is usually formed on a magnetic thin film by sputtering. However, these protective films often do not have sufficient adhesion to the magnetic thin film, and the protective film peels off due to sliding contact with the magnetic head, and this peeled off film gets stuck between the magnetic head and the protective film. Other parts of the protective film were scraped off, and the magnetic thin film was also destroyed.

In addition, the mimagnetic thin film is a thin film whose main component is 7-Fe2OB, and when a protective film is to be formed on this thin film by sputtering, it is necessary to first use α-Fe, Q, or Fe2O.
A thin film mainly composed of Then, this is placed in a sputtering chamber again and a protective film is formed by sputtering. However, this method complicates the process because the material must be taken out and put into the sputtering chamber, which poses a problem in mass production.

[Purpose of the invention]

An object of the present invention is to provide a highly reliable magnetic recording medium in which an a-retaining film is formed on a magnetic thin film with good adhesion, thereby having excellent wear resistance.

Another object is to form a protective film made of a compound with good adhesion on a thin film made of a magnetic oxide by a simple method.
An object of the present invention is to provide a highly reliable magnetic recording medium that has excellent wear resistance.

[Structure of the invention]

The magnetic recording medium of the present invention comprises a magnetic thin film formed on a non-magnetic support, and a wear-resistant protective film formed thereon, and between the magnetic thin film and the wear-resistant protective film. It is characterized by forming a region in which both of these films are dissolved in solid solution. According to this magnetic recording medium, the bonding strength and adhesion between the magnetic thin film and the protective film are significantly increased by the formation of the solid solution region, and as shown in the CC8 test described below, the wear resistance is increased and the protective film is protected. There is no peeling of the film, and a highly reliable and long-life magnetic recording medium can be provided.

The method for manufacturing a magnetic recording medium of the present invention involves forming a desired magnetic thin film, its precursor magnetic thin film 1, or a thin film of a precursor material on a nonmagnetic support, and then forming a wear-resistant film or a thin film of its precursor material thereon. By forming a thin film and heat-treating it at a predetermined temperature, the above-mentioned films can be made into the desired magnetic thin film and wear-resistant protective film, respectively, and at the same time, diffusion can occur between these films to cause a hardening at the interface between the two. It consists of forming a melting region.

According to this method, diffusion occurs between the magnetic thin film and the protective film due to the heat treatment, and the adhesion between the two is improved, thereby making it possible to provide the above-mentioned excellent magnetic recording medium/body. Furthermore, according to the method of the present invention, the desired magnetic thin film, its precursor magnetic thin film or precursor thin film, and the protective film or its precursor film may be formed in sequence and then subjected to heat treatment.
For example, when performing vacuum film formation such as sputtering, a precursor oxide film for a magnetic thin film is sputter-formed as in the conventional method, and then vacuum leaked and transferred to a heat treatment furnace to form a predetermined magnetic thin film. After that, load it into the sputtering equipment again and keep it W! The troublesome procedure of sputtering a film is simplified. That is, in the method of the present invention, sputtering film formation can be performed successively without vacuum leakage, and then processing can be performed in a heat treatment furnace, which is efficient. Nevertheless, as described above, the characteristics of the magnetic recording medium obtained by the method of the present invention are superior to those of the conventional ones.

In order to sufficiently improve the adhesion and wear resistance intended by the present invention, the thickness of the solid solution region should be 100 Å or more, preferably 20 Å or more.
Set it to 0λ or more. This sufficiently improves the C8S resistance. The thickness of the solid solution region is controlled by the heat treatment temperature and time. The higher the heat treatment temperature and the longer the heat treatment time, the greater the thickness of the solidified region. The heat treatment is usually performed at a temperature of 100°C or higher. If it is less than this, it takes too much time to form a solid solution region of a predetermined thickness.

A typical example of magnetic oxide that forms magnetic thin films is γ-Fe.
It is 2O3 or an oxide mainly composed of 2O3. Such a thin film is made by forming, for example, a 20 g α-Fe thin film by sputtering, and reducing it in a furnace with a reducing atmosphere to obtain Fe.
r4 thin film and further oxidized in an oxidizing atmosphere furnace to form γ-
This is done by forming a Fe*Os thin film. Another method is to form a Fe104 thin film by sputtering and oxidize it in a furnace with an oxidizing atmosphere to form a γ-Fe20g thin film. In other examples, the magnetic thin film is Co, Co--P, Co--Ni, or Co--Cr.

Metals such as Co-N1-P can be used.

In one embodiment of the present invention, the conversion to the γ-Fe*Os thin film described above is performed after forming a protective film or a thin film of its precursor on the surface of the α-Fe20B or Fe@04 thin film. α-Fe20B and Fe3O3 due to heat treatment? −
During the conversion into the FetOH magnetic thin film, the protective film or its precursor will be converted into the protective film, and a solid solution layer of both will be formed between the two films.

As the protective film or its precursor, Al2O3, Ti
O Goose Os.

TiOx, 510t, AI, Ti%Si, etc. can be used, and these can be converted into A ly Os , T 10 during heat treatment.
t, SiOH, etc. is converted into a wear-resistant protective film. The protective film must not only be sufficiently wear resistant but also capable of forming a solid solution region by diffusion with the magnetic thin film.

The method of the present invention can typically be performed by sputtering. In the present invention, Fe, α-F are contained in the same vacuum chamber.
Targets such as e20B, Fe3O4, AI,
A target such as Al1 O8 is set up, and a film is formed by sputtering these targets onto a nonmagnetic support. Next, reduction and oxidation are performed in a heat treatment furnace to transform each layer into a predetermined magnetic thin film and wear-resistant oxide, and to make the interface between them a solid solution region. As mentioned above, this method is superior to conventional methods. Figure 3 illustrates this point. FIG. 4(a) shows the method of the present invention, and FIG. 2(b) shows the conventional method. As shown in the figure, there are more steps indicated by double frames in the conventional method than in the method of the present invention. As described above, the present invention simplifies the process, thereby shortening the manufacturing time of the magnetic recording medium.

Co was used as the magnetic thin film without using a precursor.

Cr, Co-P, Co-N1-PlCo-Ni, Co-
A magnetic metal thin film such as Cr can be used. In this case, the magnetic thin film and Al2O3, TiO. 0. A protective thin film is successively formed by sputtering, and then placed in a heat treatment furnace and heat treated in a non-oxidizing atmosphere. Thereby, a solid solution region can be formed between the protective film and the magnetic metal.

The thickness of the solid-dissolved region can be measured by ESCA analysis, Auger analysis, RBS analysis, etc.

For example, Auger analysis is performed by observing the profile of atoms constituting a protective film and a magnetic thin film in the thickness direction. FIG. 1 shows an example in which Al, O, and protective films are formed on a Co--Ni thin film. The half-width d of the part where the distributions of AI and Co overlap can be considered as a solid solution region, but even if there is no solid solution region, d is not zero due to the resolution of the Auger analyzer (20 to 100 Therefore, the actual thickness of the solid-dissolved region is the value obtained by subtracting this value from d, that is, in the Auger analyzer used by the present inventors, Since the half width when there is no region is about 60, the actual thickness of the solid solution region is defined as d-60.

[Example 1] As a substrate, a 50 μm N1-P plating layer was formed on an aluminum alloy, and the surface thereof was polished. The shape is a disc with an outer diameter of 130fi, an inner diameter of 40mm, and a thickness of 19m.

A KCr thin film was formed on this substrate by a sputtering method for 3000 people, and a Co-20wt%Ni thin film was formed thereon by a sputtering method for 500 people. Furthermore, Al2O3, TiO.
300 people formed a protective film for O. This was heat-treated at each temperature for 1 hour in a nitrogen atmosphere to complete a magnetic disk.

Regarding the completed magnetic disk, the thickness of the solid solution region (a-SO) was measured by Auger analysis, and the C8S test was performed. The results are shown in Table 1.

The C8S test was conducted as follows.

C8S Test The C8S test was conducted using a Winchester type Mn-Zn ferrite head (95I load). C
8S was carried out by repeating the cycle shown in FIG. The number of C8S is the number of times until the recording/reproduction output becomes less than half of the initial value, up to a maximum of a o, o o o times.

Looking at the results in Table 1, it can be seen that forming a solid solution region improved the C8 characteristics compared to K, and the thickness of the solid solution region was reduced to 100%.
It can be seen that when the thickness is increased to 200 Å or more, the improvement is markedly improved, and when the thickness is increased to 200 Å or more, the improvement is further improved.

Table 1 [Example 2] As a substrate, an aluminum alloy substrate on which a 2 μm thick alumite layer was formed by anodizing was used. The shape is outer diameter 15 Q I
EII, it has a disk shape with an inner diameter of 40 m and a thickness of 19 m. With iron as a target on this substrate, A r +
O* atmosphere (mixing ratio 5o, degree of vacuum 5 x 10 Torr)
α-Fe, O, film was formed by sputtering at 2000
Formed a person. Furthermore, on top of this, Al2O3, TiO. O, a protective film was formed by sputtering.

Next, the α-FezO@ film was reduced to a Fe104 film by reduction in a hydrogen atmosphere furnace for 2 hours. At this time, AI, O, and the film are also partially reduced to become a film containing Al2O3 and TiO. The reduction temperatures are shown in Table 2. Further, the Fe104 film was oxidized in air at 310° C. for 1 hour to form a γ-Fe@OH film, and the protective film was an AI, O, film.

The above steps can be summarized in a flowchart as shown in Figure 3 (
It will be like a). In contrast, the conventional method
As shown in Figure (b), it can be seen that the steps surrounded by double squares are omitted in the present invention, thereby shortening the manufacturing time of the magnetic recording medium.

The thickness of the solid-dissolved region (a-SO) of the completed magnetic disk was measured by Auger analysis, and the C8S test was performed. The results are shown in Table 2. On the other hand, the conventional method (third
A similar test was performed on the magnetic disk formed in Figure (b)), and d-60 = 0, C85 = 14,00.
0 times'.

In contrast, the superiority of the present invention is clear from Table 2.

Table 2 Figure 1 is a diagram showing the method of measuring the thickness of the solid solution region.
FIG. 2 is a diagram showing the C8S test method, and FIG. 3 is a process comparison diagram of the method of Example 2 and the conventional method.

Figure 1 Broiled side or 5ty > Ringu (X) Figure 2 Time (description) Procedural amendment December 1985 170 Indication of the case of Mr. Uga Urabe, Commissioner of the Patent Office 1985 Patent Application No. 23641, Title of invention: Magnetic recording medium and person who corrects its S orientation

Claims (10)

[Claims] (1) In a magnetic recording medium in which a magnetic thin film is formed on a non-magnetic support and a protective film is further formed, there exists a region between the magnetic thin film and the protective film in which the magnetic thin film and the protective film are solidly dissolved. Features of magnetic recording media. (2) The magnetic recording medium according to claim 1, wherein the solid solution region has a thickness of 100 Å or more. (3) The magnetic recording medium according to claim 1, wherein the solid solution region is 200 Å or more. (4) Protective film is Al_2O_3, TiO_2 and Si
The magnetic recording medium according to any one of claims 1, 2, and 3, characterized in that the magnetic recording medium contains at least one of O_2 as a main component. (5) A first thin film made of a magnetic thin film (B), its precursor magnetic thin film (A), or a precursor of the magnetic thin film (B) is formed on a nonmagnetic support, and a magnetic thin film (B) is formed on the first thin film. A second thin film made of an abrasive oxide or its precursor is formed, and heat treatment is performed to transform the first thin film into the magnetic thin film (B).
A method of manufacturing a magnetic recording medium, characterized in that the second thin film is a wear-resistant oxide film. (6) The first thin film is α-Fe_2O_3 or Fe_3
A patent characterized in that the second thin film has at least one main component selected from the group consisting of Al, Al_2O_3, Ti, TiO_2, Si, and SiO_2. A method for manufacturing a magnetic recording medium according to claim 5. (7) The magnetic thin film (B) is mainly composed of γ-Fe_2O_3, and the wear-resistant oxide film is mainly composed of at least one of Al_2O_3, TiO_2, and SiO_2. Or the method for manufacturing a magnetic recording medium according to item 6. (8) A solid solution region is present at the interface between the magnetic thin film (B) and the wear-resistant oxide film, according to any one of claims 5, 6, and 7. A method for manufacturing a magnetic recording medium. (9) The method for manufacturing a magnetic recording medium according to claim 8, wherein the solid solution region has a thickness of 100 Å or more. (10) The method for manufacturing a magnetic recording medium according to claim 8, wherein the solid solution region has a thickness of 200 Å or more.