JPS60157726A - Surface treatment of magnetic storage medium - Google Patents

Abstract

PURPOSE:To form a hard hydrocarbonaceous film having a low coefft. of kinematic friction when a hydrocarbonaceous protective film is formed on the surface of a magnetic storage medium having a magnetic metallic thin film on the surface of the substrate in a plasma decomposition and polymn. apparatus using the storage medium as one of electrodes, by introducing gas contg. hydrocarbon into the reactor and applying voltage between the electrodes under reduced pressure. CONSTITUTION:The internal pressure of an evacuated reactor is adjusted to 0.001-10Torr, preferably 0.01-10Torr with a gaseous mixture of a gaseous starting material with satd. or unsatd. hydrocarbon such as C2H2, C2H4, C2H6, CH4 or C4H10, and DC or AC voltage of 200-2,000V or high frequency voltage of 200-2,000V and 100kHz-20MHz is applied between electrodes 2, 3. Stable plasma is generated, and a highly cross-linked hydrocarbonaceous protective film is formed on the surface of a magnetic storage medium 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for surface treatment of magnetic storage media, particularly for treating the surface of (iH) magnetic storage media, such as magnetic drums or magnetic disks used for recording, storage, or computer viewing machines. The present invention relates to a surface treatment method for magnetic recording media to form a hydrogen-based protective film.

In recent years, for the purpose of improving recording efficiency, magnetic storage media have been developed in which a ferromagnetic metal thin film made of iron, cobalt, nickel, or an alloy thereof is formed on a substrate by methods such as vacuum distillation, sputtering, and plating. A manufacturing method has been proposed. Thin-film metal magnetic storage media created by these methods have excellent high-density recording properties, but when used in recording/writing devices, they are required to run at high speeds by physically contacting magnetic heads, etc. Since it will be used for begging, it needs to be wear resistant. In order to improve the wear resistance of such magnetic storage media, (5i02.Si3N4.C and A
It has been proposed to form a thin film such as 1□03 by sputtering or the like. However, although these protective films are hard, they have a drawback that their adhesion is weak due to large internal stress, and that either the protective film or the magnetic head is easily worn out or damaged due to their large coefficient of friction. In order to improve this drawback, studies are being conducted on the combined use of these protective films and lubricants. However, when a lubricant is used in combination, new problems such as spacing loss and head stick tend to occur.

The purpose of the present invention is to solve these drawbacks, and the purpose of the present invention is to apply ionized plasma decomposition polymerization of a hydrocarbon-based gas to the surface of a magnetic storage medium to form a hydrocarbon that is highly crosslinked, hard, and has a small coefficient of dynamic friction. The present invention aims to improve the wear resistance of a magnetic storage medium by forming an elementary film, and to provide an excellent second-side processing method for a magnetic storage medium that is free from problems such as spacing loss and head stick.

That is, the present invention uses an ionized plasma decomposition polymerization apparatus in which a magnetic storage medium Z having a magnetic metal thin film 2 provided on the surface of the substrate is used as one electrode, and the other electrode is placed at a predetermined distance from the other electrode. When forming the hydrocarbon protective film on the surface of the storage medium, a gas having the hydrocarbon film is introduced into the reactor and a voltage is applied between the electrodes under reduced pressure.

The present invention will be further explained in detail below.

The present invention applies a voltage between electrodes under reduced pressure when forming a hydrocarbon protective film on the surface of a magnetic storage medium using an ion plasma decomposition polymerization apparatus.
According to the present invention, a highly crosslinked hydrocarbon protective film with excellent wear resistance can be formed on the bottom surface of a magnetic storage medium. Although the reaction mechanism in plasma or on electrodes is not clear, when an appropriate voltage is applied to a magnetic storage medium on which a hydrocarbon protective film Y is to be formed in a hydrocarbon-containing gas, plasma is generated and ionized hydrocarbons are It is thought that the decomposition and polymerization occur in and around the rainwater, forming a crosslinked hydrocarbon protective film on the magnetic storage medium.

The hydrocarbon protective film formed according to the present invention has no melting point, is insoluble in solvents, and has a C-
There is absorption of H bonds, and c
/H ratio of about 5 to 5 moles, it seems to be composed of highly crosslinked hydrocarbons.

Furthermore, the hydrocarbon protective film is very hard and has a very small coefficient of friction.

The thickness of the hydrocarbon protective film according to the present invention is as follows.

200OA'la0: If the thickness exceeds 200OA'la0, the spacing loss will become severe, which is not preferable.

In the present invention, when forming a hydrocarbon protective film on a magnetic storage medium, an underlayer is not particularly required, but Au,
Pt, N1-P, NIB+ AI, Cr, Nll Rh
.

It may be formed in advance by plating a non-magnetic underlayer such as Pd+Tin SI, evaporation method, or the like.

Further, the thickness of the base layer is preferably 200 OA or less, more preferably 1000 Å or less. Raw material gas and C2H2
, C2H4+ Saturated or unsaturated hydrocarbons such as C2H6, CH4, C4H1゜, C6H6+ C6H,
Hydrocarbons that are liquid at room temperature and pressure are gasified, such as
Or these gaseous hydrocarbons and Ar+ He, Ne,
It is a mixed gas with gases other than hydrocarbons such as H2.

Next, conditions for forming a hydrocarbon protective film using these raw material gases will be explained. The pressure inside the reaction vessel is preferably 0.001 to 1Q Torr.
~10 Torr.

In addition, 200 to 2000 V (7) direct current (DC
)' Voltage or alternating current (Ac) 4 voltage applied or 200-2000V 100 KHz ~ 20 MHz
A high frequency pressure is applied. In this way, a stable plasma is generated and a highly crosslinked hydrocarbon protective film is formed on the electrode.

The present invention will be further explained in detail below using Example 'Y6.

Example 1 (1) Production of a plated disk After electroless plating with non-magnetic N1-PY to a thickness of 50 μm on a mirror-polished aluminum plate with a diameter of 9 mm and a thickness of 2 mm, mirror polishing was performed to a thickness of 60 μm. Furthermore, using the plating solution shown in Table 1, electroless plating was performed under conditions of pH 7.5 and solution temperature 75°C to a thickness of 0.1 μm, composition C3-Ni-P.
(Co: 80% + Nl: 15 sections, P: 5%)
A magnetic film (hereinafter referred to as plated disk A) was prepared.

Nippon Kanigen Co., Ltd. is used as a pre-treatment for electroless plating.
The product name 1 "Schuma Sensitizer" and the product name 1 "Schuma Activator" Z were used.

Table 1 (Unit 9/Numa) Using the ionization plasma decomposition polymerization apparatus shown in Figure 1,
A highly cross-linked hydrocarbon protective film having a thickness of 80 OA was formed on the plated disk hole under the conditions shown in Table 2 using various hydrocarbon gas raw materials.

For comparison, product name 1 cFs-3 manufactured by Tokuda Seisakusho Co., Ltd.
Carbon films (Experiment/167)S were formed on the plating disk holes using a ``ES type'' sputtering device by using oscilloscope sputtering using carbon (purity 99.99%) and 5iO2 (purity 99.99%) as targets.
102 film (experimental stage 8) was made to a thickness of Y800A. These evaluation physical properties are shown in Table 6.

Table 2 Table 6 Example 2 Non-magnetic N1-P was applied to a 50 μm thick plate of ABS resin (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name: 1Denka ABS-ME) with the same diameter of 9 cm and a thickness of 6 mm. After plating, thickness 6
After mirror polishing to 0 .mu.m, electroless plating was carried out using the plating solution shown in Table 4 under conditions of pH 7, 5M and temperature 75=C to create a composition having a thickness of 0.1 .mu.m. Furthermore, C
o-N1-P (Co: 80%, Ni: 15%.

P25%) magnetic film (hereinafter referred to as plated disk B) 7
As a pretreatment for electroless plating, Nippon Kanigen (a)'s trade name 1 Schumer Sensitizer' and trade name 1 Schumer Activator'7 were used.

1 4 □1st place ヮ/,) Using the ionization plasma decomposition device shown in Figure 1,
Using each briquette hydrocarbon gas as a raw material, a hydrocarbon protective film of 800 AJ was formed on the plating disk B. The formation conditions 7 are shown in Table 5.

For comparison, product name ICFS-S manufactured by Tokuda Seisakusho Co., Ltd.
Plating disk B using ES type Subanotari/Ging device
Carbon (99.99% purity) and 5i02 on top
(purity 99.99%) Each carbon film (Central Iogi/+
613, 5i021 model (experiment yf614)
I created the version applied to JDA.

The evaluation results are shown in Table 6 below.

Table 5 Table 6 Example 6 The plated disk hole obtained in Example 1 was coated with S, i (purity 99. Section 99), and Cr.
(Purity: 99.99%) As a target, a 200M thick base layer of S1 film and Cr film was formed, and then hydrocarbon gas was added on top of it using the ionization plasma decomposition polymerization apparatus shown in Figure 1. Hydrocarbon-7 cross-linked with a cylinder diameter of 800λ was formed by changing the cylindrical shape.

Below are the forming rods and their 7 polished rice Tables 7 and 8.

No. 7 Table No. 8 Example 4 Using the ionized plasma decomposition device shown in Fig. 1,
Using C2H6 gas as a raw material, a highly crosslinked hydrocarbon film having a thickness of 800 A was formed on the plated disk hole obtained in Example 1 under certain conditions. Seven formation conditions and evaluation results are shown below in Tables 9 and 10, respectively.

Table 9 (E) Abbreviation of RF-Radio Frequency Table 10 The evaluation physical properties of Examples and Comparative Examples were measured by the following method.

1) Measurement of Dynamic Friction Coefficient Measurement was carried out using a sliding property measuring device having the structure shown in Fig. 2, using a sapphire ball with a diameter of 2 am, a head load of 5 μ, and a relative speed of 5 ml/sec.

2) Measuring the number of sliding movements Using the device shown in Figure 2, the head is a 2 mmφ sapphire ball, the head loads are i1o, y, and the relative speed is 10 m1sec.
The number of times the Hoki membrane was slid under these conditions was defined as the number of times it would take to break.

3) C8S (Contact Start Stop) test head is M-3350 type, head phrase i9.8
．． 9, and the rotation speed is 3600 r, p, m.

Under the condition of 0N-OFF Osec cycle, the number of cycles until a head crash occurs is set to be ``number of cycles''<css number.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the apparatus used in the embodiment of the present invention, and FIG.
The figure is an explanatory diagram of a device for measuring the dynamic friction coefficient and the number of sliding motions of a magnetic recording medium. How many? 1: Magnetic storage medium 10: Magnetic storage medium 2: Electrode 11
°Holder 3: Electrode 12: Zaphire bulb 4: Reaction vessel 13 Two-plate spring 5: Reaction vessel stand 14° strain r″'-shiro: Gas supply port 15: xy stage 7: Exhaust pipe
16: Motor 17: Frame

Claims (1)

[Claims] A magnetic storage medium with a magnetic metal thin film 2 provided on the surface of the substrate is used as one electrode, and the other electrode is placed at a predetermined distance from this electrode using an ionization plasma decomposition polymerization device. A method for surface treatment of a magnetic storage medium, which comprises introducing a hydrocarbon-containing gas into a gas line and applying a voltage between the electrodes under reduced pressure, before forming a hydrocarbon protective film.