JPS6182321A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve running property, corrosion resistance and durability by forming successively the 1st layer having corrosion resistance, the 2nd layer having lubricity and 3rd layer having corrosion resistance on a magnetic layer of a thin magnetic film type magnetic recording medium. CONSTITUTION:The thin magnetic metallic film type magnetic layer 2 consisting of a magnetic material such as cobalt-nickel or cobalt-phosphorus is formed by a method such as electroplating on a non-magnetic substrate 1. The 1st layer 3 having corrosion resistance (e.g.; chromium layer, titanium layer) is then formed on the layer 2 to about >=2nm thickness by a method such as sputtering. The 2nd layer 4 having lubricity (e.g.; carbon layer, molybdenum disulfide layer) is formed thereon to about >=5nm thickness. The 3rd layer 5 having corrosion resistance (e.g.; chromium layer, titanium layer) is formed thereon to about 1-7nm thickness, by which the intended magnetic recording medium is obtd.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to magnetic recording media.

[Prior art and its problems]

In recent years, for high-density recording, for example, C01Co-Ni, C
A magnetic material such as o-'P or Co-N1-P is placed on the substrate,
For example, metal thin film type magnetic recording media formed by means such as sputtering, electroplating, or electroless plating have been proposed.

However, this type of metal thin film magnetic recording medium has drawbacks such as severe abrasion of the magnetic layer and poor corrosion resistance.

Therefore, in order to solve this drawback, for example, 5iO
It has been proposed to provide a layer such as = or C.

However, those with an SrOs film have excellent corrosion resistance but have poor lubricity, and those with a carbon film have excellent lubricity but have poor corrosion resistance. There are drawbacks such as:

Therefore, based on this knowledge, the present inventor attempted to fabricate a prototype in which an S t O2 film was provided on the magnetic layer and a carbon layer was provided on this 8 t Ox film, but this magnetic recording The medium had cracks in the SiO□ film layer due to the stress of carbon, and the phenomenon of rusting was significant, so it was completely problematic for practical use.

[Disclosure of the invention]

The present inventor has discovered that, for example, chromium,
Titanium, Fe-Cr alloy, Ni-Cr alloy, Co-C
A first layer having corrosion resistance such as r alloy is provided, and on this first layer, for example, carbon, molybdenum disulfide,
A second layer having lubricating properties such as carbon nitride or boron nitride is provided, and on this second layer, for example, rim, titanium, F, etc.
Magnetic recording with a third layer having corrosion resistance such as e-Cr alloy, Ni-Cr alloy, Co -, Cr alloy, molybdenum, TiC, TiN, zinc, aluminum, Fe-Ni alloy, Fe-Ni-Cr alloy It was discovered that the medium has rich lubricity and excellent corrosion resistance.

In other words, even with a metal thin film type magnetic recording medium in which a lubricious layer such as carbon is provided on the magnetic layer, and a corrosion resistant layer such as chromium is provided on this layer, there is a significant improvement in runnability and corrosion resistance. Although it is recognized,
By configuring as described above, stress is alleviated, the durability of the protective film layer on the metal thin film type magnetic layer is significantly improved, corrosion resistance is further improved, durability is further improved, and runnability is improved. He discovered that it is also a good thing.

The first layer having corrosion resistance such as carbon and chromium preferably has a thickness of about 2 nm or more, preferably about 2 to 1100 nm, and the second layer having lubricity such as carbon. Preferably, the thickness is about 5 nm or more, preferably about 5 to 100 nm, and the third layer having corrosion resistance, such as chromium, has a thickness of about 1 to 7 nm.
It is preferred that the thickness of the first layer, the second layer, and the third layer be less than or equal to about 200 nm. In other words, if the first layer is too thin, the stress relieving effect will be weak. If the first layer is too thin, for example, 0.5 m, the stress relieving effect will be small. ? This is because if the layer is too thin, it will not have sufficient lubricating effect.
Also, if the third layer is too thin, there will be a problem in terms of corrosion resistance, and if it is too thick, the lubricating effect of the underlying second layer will be reduced. If it is too long, the distance between the magnetic layer and the magnetic head will be too long, which is unfavorable in terms of recording and reproducing characteristics.

[Example 1] The drawing is an explanatory cross-sectional view of a magnetic recording medium according to the present invention.

In the figure, reference numeral 1 denotes a disk-shaped aluminum base body on which a non-magnetic N1-P plating layer is provided, for example.

Reference numeral 2 denotes a metal thin film type magnetic layer, such as a Co--P plating layer, provided on the non-magnetic N1-P plating layer.

3, the substrate 1 on which the magnetic layer 2 is formed is placed in, for example, a DC magnetron sputtering device, and is sputtered with a
Sputter etching is performed in argon gas at Torr, and then a layer of about 2 nm or more, for example 3Q, is formed on the magnetic layer 2.
The first layer has corrosion resistance, such as a nm-thick Co O, s Cr O, bilayer.

4 is about 5 formed on the first layer 3 having corrosion resistance.
The second layer has lubricity, such as a carbon layer with a thickness of nm or more, for example, 3Q nm.

5 is approximately 1 to 5 formed on the second layer 4 having lubricity.
70 m, a third layer with corrosion resistance, for example a 2 m thick C008Cr02 layer.

The magnetic disk of the above embodiment was mounted on an IBM 3350 type nozzle with a flying height of 0.25 μm and a gap length of 1.4 μm.
When a C8S test was conducted using a head disk for a magnetic disk, there was no damage to the head or magnetic disk even after 20,000 passes, and no decrease in reproduction output was observed.

In addition, the above magnetic disk was placed in a dew-condensing atmosphere at 60°C for 2 hours.
When the error rate was examined after being left for 50 hours, almost no increase in the error rate was observed, indicating extremely excellent corrosion resistance.

[Example 2] A magnetic disk was constructed in exactly the same manner as in Example 1 except that the thickness of the second layer 4 having lubricity was set to approximately 100 nm or more, for example, 300 nm.

The magnetic disk of this example was left in a dew-condensing atmosphere at 60°C for 250 hours and the error rate was examined. There was almost no increase in the error rate, and the disk had excellent corrosion resistance, and the flying height was 0. .25μm, gap length 1.4μm
A C8S test was conducted using an IBM 3350 type hard disk head, and there was no damage to the head or magnetic disk even after 20,000 passes.

However, compared to that of Example 1, a decrease in reproduction output was observed, and the magnetic disk of Example 1 was inferior.

[Example 3] A magnetic disk was constructed in exactly the same manner as in Example 1 except that the thickness of the second layer 4 having lubricity was set to 5 nm or less, for example, 2 nm.

A corrosion resistance test was performed on the magnetic disk of this example by leaving it in an atmosphere of condensation at 60°C for 250 hours, and it was found to have excellent corrosion resistance.
Since a head crash occurred in the second run, the running performance was inferior to that of Example 1.

[Example 4] A magnetic disk was constructed in exactly the same manner as in Example 1 except that the thickness of the third layer 5 having corrosion resistance was set to 8 nm or more, for example, 1Q nm.

A corrosion resistance test was performed on the magnetic disk of this example by leaving it in an atmosphere of condensation at 60°C for 250 hours, and it was found to have excellent corrosion resistance.
Since a head crash occurred in the second run, the running performance was inferior to that of Example 1.

[Comparative example]

In Example 1, a magnetic disk was constructed in the same manner as in Example 1, except that no layer having corrosion resistance was provided.

When we conducted a corrosion resistance test by leaving this magnetic disk in an atmosphere of condensation at 60°C for 24 hours, we found that the surface of the magnetic disk was completely corroded and the magnetization was completely reduced, indicating that it had no durability at all. Met.

〔effect〕

It has good running properties and corrosion resistance, and is highly durable.

[Brief explanation of the drawing]

The drawing is an explanatory cross-sectional view of one embodiment of a magnetic recording medium according to the present invention. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Magnetic layer, 3... First layer having corrosion resistance, 4... Second layer having lubricity, 5...
- Third layer with corrosion resistance. Procedural amendment March g, 1985

Claims (2)

[Claims] (1) A first layer having corrosion resistance is placed on the magnetic layer.
1. A magnetic recording medium comprising: a second layer having lubricity on the layer; and a third layer having corrosion resistance on the second layer. (2) In the magnetic recording medium according to claim 1, the first layer has a thickness of about 2 nm or more, the second layer has a thickness of about 5 nm or more, and the third layer has a thickness of about 1 to 1 nm. 7nm.