JPH0467431A - Formation of protective lubricating film of magnetic recording medium - Google Patents

Abstract

PURPOSE:To enhance the adhesive strength of a lubricating film to the surface of a medium and to improve and stabilize as the protective lubricating film between a magnetic film and a magnetic head by ending the prescribed film forming operation in a film forming chamber, then depositing a liquid lubricant by evaporation on the surface of the medium in this chamber. CONSTITUTION:The application of the lubricant to the surface of the magnetic recording medium after the prescribed film forming operation in the film forming chamber ends is executed in the film forming chamber. There is no contact with the atm. at this time and the contamination of the medium surface is completely averted. Then, the adhesive property at the boundary between the medium surface and the lubricating film is improved and the orientability of the coated film constituting molecules to the medium surface is enhanced. The adhesive strength of the coated film to the medium surface is intensified in this way. The migration at the time of use with an actual machine and the resistance to the damage of the film surface by sliding contact with a magnetic head are improved. The lubricating function is maintained over a long period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for forming a protective lubricant film covering the surface of a magnetic recording medium.

[Conventional technology]

Ferromagnetic metals (Co-based, Co-Cr-based, Co-Cr-Ni
For metal thin film magnetic recording media whose recording layer is a magnetic film made of a magnetic film made of Manufactured by.

In order to stabilize its function and service life as a recording medium, it is necessary to make smooth contact with the recording/reproducing magnetic head that faces the magnetic film surface in close proximity, and to prevent wear and damage between the magnetic film and the magnetic head. Needless to say, this is necessary.

Conventionally, a liquid lubricant (such as perfluoropolyether) has been applied to the surface of the magnetic film as a protective lubricant film for this purpose. Even when a solid protective film, such as a carbonaceous film such as diamond-like carbon or graphite-like carbon, is layered on the surface of a magnetic film, the contact of the magnetic head with the solid protective film is made smooth. Therefore, it is common to apply a liquid lubricant to the surface of the solid protective film. The thickness of the lubricating film is approximately 10 to 40
It's a person.

[Problem to be solved by the invention]

Applying a liquid lubricant to the surface of a magnetic film formed on a non-magnetic substrate or the surface of a solid protective film laminated on the film surface (hereinafter, the surface is also referred to as the "surface of the medium"), In order to stably function as a protective lubricant film that alleviates friction and wear between the medium surface and the magnetic head, it is necessary to firmly adhere the lubricant film to the medium surface.

If the adhesion is insufficient, the centrifugal force that accompanies high-speed rotation of the magnetic recording medium during the recording/reproduction process will cause migration of the liquid lubricant on the medium surface, and repeated contact with the magnetic head will cause the lubricant to migrate. This is because it scatters and disappears, significantly reducing the lubricating effect. As a method of increasing the adhesion force, a liquid lubricant is applied to the surface of the medium and then heat treated at a temperature of about 100° C., but the effect is not sufficient.

The present invention has been made for the purpose of increasing the adhesion of the lubricant film to the medium surface and improving and stabilizing the function as a protective lubricant film between the magnetic film, the magnetic layer, and the throat.

[Means and effects for solving the problems] The present invention provides a coating film of a liquid lubricant on the surface of a metal thin film type magnetic recording medium that is manufactured through a predetermined film forming operation such as sputtering in a film forming chamber. In the method for forming a lubricant on the surface of a magnetic recording medium after completing a predetermined film forming operation in the film forming chamber,
) to be carried out in the film-forming chamber, and (ii
) When taking it out of the film forming chamber, after taking it out,
The feature is that it must be done within 4 hours.

The present invention will be explained in detail below.

Magnetic recording media manufactured by subjecting a non-magnetic substrate to a film forming operation using a sputtering method, etc., are exposed to oxygen, moisture, and carbon dioxide over time during storage after being taken out into the atmosphere from the film forming chamber. , contamination due to adsorption of molecular-level substances such as hydrocarbons is inevitable.

The present invention is designed to prevent the presence of such contaminants adsorbed on the surface of a magnetic recording medium (the surface of the magnetic film, or the surface of the solid protective film if a solid protective film is laminated on the film surface) from the surface of the medium. In view of the fact that this is a major factor preventing a homogeneous and strong adhesion relationship with the liquid lubricant, the liquid lubricant is applied to the media surface while the media surface is maintained in a substantially clean state. That's what I did.

According to the first method of the present invention, when the lubricant is applied to the surface of the medium in the film forming chamber, there is no contact with the atmosphere, and contamination of the surface of the medium is completely avoided.

Furthermore, even when applying lubricant after taking the magnetic recording medium out of the film forming chamber, if the lubricant is applied within 24 hours, the influence of contamination on the medium surface is small.
Improved coating adhesion can be obtained. Of course, the shorter the elapsed time until the lubricant is applied after being taken out from the chamber, the better. According to the inventor's experiments, within 5 to 6 hours after removal from the chamber, approximately the same coating adhesion as that applied in the chamber can be ensured.

The material of the liquid lubricant used in the present invention is of course not limited, and various known lubricants such as perfluoropolyether may be arbitrarily selected. There are no restrictions on the application method, including a dip coating method in which the medium is immersed in a specified liquid lubricant, a spin coating method in which the liquid lubricant is sprayed while rotating the medium, or a liquid lubricant that is heated and evaporated to be deposited on the surface of the medium. This may be carried out according to a known method such as a vapor deposition method. When applying a lubricant in a film-forming chamber, a container containing liquid lubricant is placed in the film-forming chamber in advance. It is also possible to perform coating.

According to the present invention, by applying a lubricant to the surface of a magnetic recording medium in a film forming chamber or immediately after taking it out from the same chamber, the adhesion between the surface of the medium and the lubricant film is improved. , the orientation of the molecules constituting the coating film on the media surface is increased, and as a result, the adhesion of the coating film to the media surface is strengthened, which improves the resistance to damage to the film surface due to migration during actual machine use and sliding contact of the magnetic head. However, good lubrication function is maintained over a long period of time.

〔Example〕

[I] Test magnetic disk aluminum alloy substrate (N'i-P electroless plating treatment)
, a chromium film (thickness: 1500), a CoNiCr alloy magnetic film (thickness near 00), and a carbon film (thickness:
300 people) used a 3.5'' type magnetic recording medium in which the films were laminated in this order and the film surface was burnished.

(Perfluoropolyether (rAM2001J manufactured by Montegisson) was used as the coating lubricant for III liquid lubricant. The film thickness was 30 mm in each case.
As a person.

(1) Test disk No. 1 After completion of sputtering film formation in a film forming chamber, a coating film was formed by heating the lubricant in a crucible containing liquid lubricant previously installed in the same chamber and using a vapor deposition method.

(2) Test disk No. 2 to 4 After taking out the disk on which sputtering film formation was completed in the film forming chamber, a coating film was formed by dip coating method. Elapsed time: No, 2:5 Hr, No, 3:20
Hr.

No. 4: 30 hours.

(3) Test disk No. 015 After applying lubricant under the same conditions as test disk No. 4, heat treatment (100° CXIHr) was performed in a heating chamber containing a built-in resistance heating element.

(IV) C3S test A CSS test (Contact 5tartSt.
The friction coefficient (μ) after 104 repetitions was compared with that before the test. The disk rotation speed was 3600 rpm. The magnetic head used was a thin film head.

The above test results are shown in Table 1. Sample No. 4 is an example in which a long time elapsed before the coating film was formed after being taken out from the film forming chamber, and the friction coefficient after the C8S test was significantly increased. This significant increase in the coefficient of friction is due to the fact that the healthy surface morphology of the lubricant coating before the test was lost due to migration and repeated contact with the magnetic head during the C3S test process. On the other hand, the change in the friction coefficient of Nα1, which was formed in the film forming chamber, was small;
It maintains a low coefficient of friction even after the C3S test. Also,
Even when forming a coating after taking it out of the coating chamber, the N
By regulating the elapsed time until coating film formation as shown in o, 2 and Nα3 and performing the coating within a certain period of time, a significant increase in the friction coefficient can be avoided and a low friction coefficient can be maintained.

It should be noted that the increase in the friction coefficient of Nα5, which was heat-treated after coating film formation, was slightly smaller (although it has improved lubrication performance compared to Nα4, it is not comparable to that of the invention example). Not cloudy.

From these facts, it can be seen that the lubricant film forming method of the present invention is extremely effective in increasing the adhesion of the lubricant film to the disk surface and stabilizing the lubricating function and improving durability.

〔Effect of the invention〕

The protective lubricant film formed on the surface of a magnetic recording medium by the method of the present invention has strong adhesion to the surface of the medium, and is susceptible to damage to the film surface due to migration or sliding contact of the magnetic head during the repeated process of recording and reproducing operations. (1) Since a good lubrication effect is maintained over a long period of time, it is effective in protecting the magnetic film and magnetic head, contributing to improved reliability and stability as a recording medium.

Claims (1)

[Claims] 1. A method for forming a coating film of a liquid lubricant on the surface of a metal thin film type magnetic recording medium manufactured through a predetermined film forming operation such as sputtering in a film forming chamber, comprising: 1. A method for forming a protective lubricant film on a magnetic recording medium, the method comprising: after completing a predetermined film forming operation within a film chamber, a liquid lubricant is deposited on the surface of the medium within the same chamber. 2. In a method of forming a coating film of a liquid lubricant on the surface of a metal thin film type magnetic recording medium manufactured through a predetermined film forming operation such as sputtering in a film forming chamber, A method for forming a protective lubricant film on a magnetic recording medium, which comprises applying a liquid lubricant to the surface of the magnetic recording medium within 24 hours after the magnetic recording medium is removed from the chamber.