JPS60258727A - Magnetic storage medium - Google Patents

Abstract

PURPOSE:To prevent wear and head stick by forming a thin plasma-polymerized film of hydrocarbon onto a thin film consisting of a non-magnetic metal, the oxide, carbide and nitride of an inorg. compd. and carbon thereby forming two- layered protective films. CONSTITUTION:The 1st protective film 3 consisting of at least one kind selected from the non-magnetic metal such as Rh, the oxide such as SiO2, the carbon such as graphite, the carbide such as SiC and the nitride such as CrN and the 2nd protective film 4 formed by the plasma polymn. of the hydrocarbon are formed on a thin ferromagnetic metallic film 2 on a non-magnetic base material. The hydrocarbon (e.g.: C2H2, C4H10, etc.) is fed as it is into a reactor 8 or is fed therein after the hydrocarbon is gasified to form the gaseous raw material. The inside of the reactor is evacuated to 0.001-10Torr and, for example, 200- 2,000V DC voltage is impressed between electrodes 6 and 7 to generate plasma. The plasma polymn. is thus effected on a magnetic storage medium 5 installed on the electrode 6.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to the formation of a protective film on the surface of a magnetic storage medium, which is preferably used for magnetic recording, audio recording, or computer magnetic drums or magnetic disks. The invention relates to magnetic storage media.

(Prior art) In recent years, ferromagnetic metal thin films made of iron (Fe), cobalt (CO), nickel (Ni), or alloys thereof have been developed using methods such as vacuum evaporation, sputtering, or plating to improve recording density. Magnetic storage media formed on a substrate are known. However, although the thin-film fully-shrinkable magnetic storage media created by these methods have excellent high-density recording properties, when used in recording and reproducing devices, they must physically come into contact with magnetic spatulas, etc., and run at high speeds. Therefore, it is required to have excellent wear resistance, and for this purpose various methods have been proposed for forming a protective film on the surface of a ferromagnetic metal thin film. for example,
(1) Non-magnetic metal such as Rh1Cr1Ni-P, 5in2, Al2O3, 0r203,
Oxides such as TiO2, ZrO2, Sin, XWC, N
bO.

Carbides such as B4C and OrN, TiN, N
bN A method of forming a thin film of at least one selected from nitrides such as XZrN by a plating method, a sputtering method, a CVD method, etc. (JP-A-50-104602, JP-A-50-16
(2) A method of applying a lubricant such as wax on the protective film is mentioned.

(Problems to be Solved by the Present Invention) Although the protective films obtained by the method (1) are all hard, they have a large coefficient of friction and either the protective film or the magnetic head is easily worn out, and the method (2) This method has the drawback that problems such as so-called "slip staking" in which the lubricant and the magnetic head stick together tend to occur.

(Means for Solving the Problems) The present invention provides a magnetic storage medium in which a protective film is formed on a ferromagnetic metal thin film on a non-magnetic substrate, in which the protective film is made of a non-magnetic metal, an oxide or carbide of an inorganic compound, The conventional problems have been solved by forming a thin film of nitrides and carbons and a plasma-polymerized thin film of hydrocarbon thereon to form a two-layer structure.

In other words, the present invention provides a magnetic storage medium in which a protective film is formed on a ferromagnetic metal thin film on a nonmagnetic substrate, in which the protective film is made of a nonmagnetic metal such as Rk, 0rXNi-P, 5in2
, A1□Or5, Cr2o5, T10□, ZrO2 and other oxidations, substances, graphite, carbons such as tire-like carbon, 810 XWe, TiC, NbO, B, O
Carbides such as OrN XTiN, NbN XZ
It consists of at least one kind of thin film selected from nitrides such as rN (hereinafter referred to as the first protective film) and a delaminate polymeric thin film of hydrocarbon (hereinafter referred to as the second protective film) formed thereon. This is a magnetic storage medium with special characteristics.

Next, a method for manufacturing the magnetic storage medium of the present invention will be explained. As shown in FIG. 1, the magnetic storage medium of the present invention comprises a base 1, a magnetic field 2, a first protective film 3, and a second protective film 4.

The substrate used in the present invention may be either inorganic or organic, but must be non-magnetic.

Specific examples of inorganic substances include aluminum, aluminum alloys, copper, non-magnetic metals or alloys such as silicon, glass, ceramics such as Al2O3, 5102, ABS resin, polycarbonate resin, polyimike resin, etc. Examples include synthetic resins such as lyester resins.

The shape, size, etc. of these substrates vary depending on the intended purpose, but those with excellent surface precision are preferred.

Next, a ferromagnetic metal thin film is coated on the base material by a conventional method, and a specific example of the ferromagnetic metal is Ni-Co-P.

Examples include Co-P and Co-W. As a coating method, an electrolytic plating method, an electroless plating method, or the like is used. These conditions are not particularly limited, and the thickness is 0.1
It is about μm.

Next, after directly or etching the surface of the ferromagnetic metal thin film, the inorganic material forming the first protective film described above is applied by plating, sputtering, or vacuum deposition (including carbon dioxide).
A first protective film is formed by uniformly coating the film using an appropriate method such as VD) method.

Among these methods for forming the first retention film, a film formed by sputtering is preferred because it is superior to other methods in terms of adhesion, stability, uniformity, and workability. However, the present invention is not limited to these methods, and the object of the present invention can also be achieved by a plating method, a vacuum evaporation method, or the like.

Next, a hydrocarbon polymerized film is formed on the surface of the first protective film using a Zoladema polymerization apparatus to form a second protective film. Specific examples of hydrocarbons used in the present invention include C2H2, C2H2,
Examples include 2H,, C2H6, CH4, and C4H0°. These are used as raw material gases as they are or by gasification, but gases other than hydrocarbon gases such as ArXWe, Ne, and H2 can be used in combination with these gases.

The operating conditions for the 12171 reactor are as follows:
, 001 to 10 torr and 200 to 2000 V between the electrodes.
A DC or AC voltage of 200 to 2000 V and a high frequency voltage of 1Q KHz to 20 MHz may be applied. The hydrocarbon plasma polymerized film, which is the second protective film, has a different structure from the conventional carbon film, in that hydrogen exists in a 0/H molar ratio of about 10 to 50 moles, and there are almost no C=C bonds. be. This plasma-polymerized hydrocarbon film has an extremely small coefficient of friction due to O--H bonds existing in its structure, and does not cause any stick-stake phenomenon. Moreover, it is in complete contact with the first protective film.

The two-layer protective film that has been broken onto the magnetic storage medium in this way is in close contact with the ferromagnetic metal thin film, and these protective films are extremely hard and have a very small coefficient of friction. Therefore, it is particularly excellent as a protective film for magnetic storage media.

/I (The total thickness of the protective film consisting of two layers of the invention is:
It is 2000X or less, preferably 1000A or less. If it becomes thicker than this, the spacing loss will increase (which is not preferable).

Further, in the present invention, the hydrocarbon plasma polymerized film of the second protective film can be produced using a commercially available plasma polymerization apparatus. However, it is also possible to carry out sequential processing in the same container as sputtering or vapor deposition.

l Figure 2 is an explanatory diagram of a plasma polymerization apparatus. anti′)
The responder 8 is constructed so as to be kept airtight on a reaction container stand 9, and the reaction container stand 9 is provided with a gas supply port 10 and an exhaust pipe 11 connected to an exhaust pump. To produce a magnetic storage medium using this apparatus, a plasma is generated in the reaction vessel 8 by an electrode 6, and a second thin film placed on the electrode 6 is deposited on the magnetic storage medium 5. The same potential as that of the electrode 6 may be applied to perform plasma polymerization on this magnetic storage medium.

Example 1 Production of a plated disk After electroless plating of non-magnetic N1-P to a thickness of 50 μm on a mirror-polished aluminum plate with a diameter of 9 cm and a thickness of 2 mm,
Mirror-polished to a thickness of μm, and then using the plating solution shown in Table 1, plating conditions pF (7,5, dtliN75
Co-Ni-P (Co: 8Q, Ni
: 15, P: 5%) was electrolessly plated (hereinafter referred to as plated disk A) to a thickness of 0.1 μm.゛Nippon Kanigen (
Schumer sensitizer and Schumer activator manufactured by Co., Ltd. were used.

Table 1 Unit: 9/l Sputtering equipment manufactured by Tokuda Seisakusho Co., Ltd. (product name "C")
FS-8F8S"), and Mari l-"z"/),
Now, Hitachi Chemical @)'s high-density car♂゛/(product name:
-18J), sputtering was performed in an Ar gas atmosphere to form a carbon film with a thickness of 2 on the plating disk A.
00X, 400X, and 500X were produced.

Using the plasma polymerization apparatus shown in FIG. 2, plasma polymerized films were formed on disks A with different thicknesses of carbon films under the conditions shown in Table 2.

Table 6 shows the evaluation results. For comparison, the results of forming only a carbon film are also shown in Experiment/169.

10.11.

Table 6 Example 2 Sputtering equipment manufactured by Tokuda Seisakusho Co., Ltd. Product name [OFS
-3KSJ is used, and as tarded, Or
, 5in2, TiN, SiC gas pressure 7×1
Sputtering was performed by supplying high-frequency power of 1 KW under an atmosphere of 0-3 tall argon, and on top of the plated disk prepared in Example 1, Or, 5i02,
A first protective film was formed from TiN and SiO to a thickness of 400 Å.

Next, a hydrocarbon plasma polymerized film was formed on these using the plasma polymerization apparatus shown in FIG. 2 to form a second protective film.

Tables 4 and 5 show these conditions and measurement results of physical properties, etc.

Experiment/1616.17.18, 19. and 20 show comparative examples, in which experiment AI6 was the case where the second protective film was formed without covering the first protective film, and experiments 17 to 20 were the cases where only the first protective film was formed.

The physical properties of the examples were measured by the following method.

(1) ASS (Contact Start Stop) Test Using a fixed disk drive device, the number of cycles until a head crash occurred was measured.

Head: IBM-3350 type (Made of Mn-Zn) Head load: 9.5.9 Rotation speed: 3600r, p, m ON - OFF 3 Q seconds cycle (2) Dynamic friction coefficient measurement The measurement was performed using a rotating device shown in FIG.

Head 2 M-3350 type (Made of Mn-Zn) Head load: 9.5g Relative speed: 43cfn/5ec (Effect of the invention) The effects of the product of the present invention are summarized as follows.

(1) The coefficient of friction is extremely small.

(2) No two-stick phenomenon occurs.

(3) The hFI membrane has good adhesion and can be used repeatedly.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of an example of the present invention, Figure 2 is an explanatory diagram of a plasma polymerization apparatus used in an example of the present invention, and Figure 3 is an explanatory diagram of a dynamic friction coefficient measuring apparatus used for evaluation of products of the present invention. It is. Reference numeral 1...Substrate 2...Magnetic layer 3...First protective film 4...Second retentive film 5...Plating disk A 6...Electrode 7...Electrode 8...Reaction vessel 9... Reaction container stand 10... Gas supply port 11... Exhaust pipe 12... Magnetic storage medium 13... Holder 14
... Head 15 ... Leaf spring 16 ... Distortion degree 17 ... XY
Stage 18... Motor 19... Frame 20.
...Amplifier and recorder patent applicant Denki Kagaku Kogyo Co., Ltd.

Claims (1)

[Claims] In a magnetic storage medium in which a protective film is formed on a ferromagnetic metal thin film on a nonmagnetic substrate, the protective film is Rh. Non-magnetic metals such as Or, N1-P, S10□, Al2O
,,0r203, oxides such as TlO2, ZrO2, graphite, carbons such as diamond-like carbon, SiC
! . WC! , Tie, N1) OXB, C! Carbides such as and CrN. A magnetic storage medium comprising at least one thin film selected from nitrides such as TiN, NbN, XZrN, etc., and a plasma polymerized thin film of hydrocarbon formed thereon.