JPS58222441A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To improve the corrosion resistance of a magnetic medium, by sticking a rust preventive agent consisting essentially of unsatd. aliphat. and alicyclic compds. on a thin film of a ferromagnetic metal contg. oxygen. CONSTITUTION:A rust preventive agent consisting essentially of unsatd. aliphat. and alicyclic compds. in stuck on the ferromagnetic thin film which consists essentially of Co, Fe, etc. composed of a diagonal or perpendicular columnar crystal and is formed on a nonmagnetic substrate by a method such as sputtering or the like in a vacuum where a slight amt. of gaseous oxygen exists. Such rust preventive agent is made to exist at least on the surface of the ferromagnetic thin film and, if possible, in the inside thereof, or in contact with the boundary to the base on which the ferromagnetic thin film is formed in order to provide the effect thereof. The adequate amt. thereof is about 0.5-500mg for each 1m<2> of the magnetic recording medium. It is also possible to use additives such as an ordinary lubricant, antistatic agent, etc. together with the rust preventive agent.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a ferromagnetic metal F with improved corrosion resistance in high humidity.
The present invention relates to a J7 film type magnetic recording medium.

Fe and Ni are deposited on the surface of a substrate made of a plastic film such as polyester or polyimide, or a non-magnetic material such as an aluminum plate or a glass plate, by vapor deposition, ion blasting, sputter linking, etc. in a vacuum.

A magnetic recording medium in which a ferromagnetic thin film containing CO or an alloy thereof and containing oxygen is formed is suitable for high-density recording such as video signal distribution. Due to its small size of 0.5 to 0.5 μm, if it is left in high humidity environments, especially in environments where there are large temperature changes and condensation may occur, corrosion is likely to occur on the surface, and if this corrosion progresses to a certain extent, the electromagnetic conversion characteristics will deteriorate. influence,
It also deteriorates practical properties such as hardness and abrasion resistance.

When suppressing this corrosion with a rust preventive agent, there are strict limits on the thickness of the protective film that can be formed on the surface of the magnetic layer due to spacing loss between the head and the magnetic layer. A sufficiently effective rust preventive agent was desired. F
A ferromagnetic thin film mainly composed of e, Ni, Co, or an alloy thereof and containing oxygen has a higher coercive force and excellent corrosion resistance than thin films made of pure metals. In other words, because it is partially oxidized, phase 1 - rust preventive agent - which exhibits a rust preventive effect is not necessarily suitable for the seven known ones used for bulk metals such as Fe, Co, and Ni. However, when these rust preventives are actually applied, they may actually promote corrosion, so it is necessary to find a new one that is compatible with ferromagnetic thin films containing oxygen. became.

As a result of various inspections, the present inventors have found that a rust preventive agent for a ferromagnetic thin film containing oxygen is suitable for use as a rust preventive agent for a ferromagnetic thin film containing oxygen. That is, the present invention provides a magnetic recording medium in which a ferromagnetic metal thin film containing oxygen is formed on a non-magnetic substrate. It is characterized by having a rust agent adhered to it.

Polyester film is used as a non-magnetic substrate.

Plastic films such as polyimide films.

Metal plates such as aluminum plates and stainless steel plates, inorganic plates such as glass plates, etc. are used, and evaporation or sputtering is performed on these plates directly or through a non-magnetic thin film layer in a vacuum in the presence of a trace amount of oxygen gas. , made of diagonal or vertical columnar crystals with a thickness of 0.06~ by ion blating or other methods.
0.5 μm Go.

,. , Fe-Ni. . -1#'lli, Fe
-Go.

Unsaturated aliphatic and alicyclic compounds are formed on a single-layer or multi-layer ferromagnetic thin film that is mainly composed of Fe-N1-Go and contains oxygen in an atomic ratio of 3 to 45% with respect to the magnetic metal. Apply a rust preventive agent as the main ingredient.

The unsaturated aliphatic and alicyclic compounds in the present invention include 1.5-hexadiene, 2.4-hexadiene, 2.
6-Simethyl-1,6-hexadiene.

1.6-hebutadiene, 2.3-dimethyl-1,3-butadiene, isoprene, 3-methyl-2,4hexadiene, 1-hepion, 1-octene, 1-decene, cyclopentadiene, cyclohexene, 1 -Methyl-1-cyclohexene, cycloActene.

Examples include 1,5-cyclooctadiene and norbornene.

The rust preventive agent in the present invention is mainly composed of a medium or a mixture of two or more of these, and preferably at least 8
0% or more) If necessary, organic compounds other than unsaturated aliphatic and alicyclic compounds, such as naphthols and hydroquinones.

'11 Acetophenones, quinones, etc. are added in small amounts.

These anti-corrosion agents exhibit their effects by being present at least on the surface of the ferromagnetic thin film, if possible inside, or in contact with the interface with the base on which the ferromagnetic thin film is formed. The appropriate amount d2 magnetic recording medium 1m2
Right! l) Approximately 0.5 to 600 ■. Specifically, the rust preventive agent is applied on the surface of the ferromagnetic thin film, either by itself or mixed with a film-forming agent such as a polymer compound, diluted with a solvent if necessary. There is a method in which rust preventive vapor is applied to the surface of the ferromagnetic thin film, and if the magnetic recording medium is in the form of a tape, it is placed on the back side of the tape and transferred to the surface of the ferromagnetic thin film when the tape is rolled up. Well-known means such as the method described below can be used. Also, 1 normal lubricant, along with rust preventive agent,
It is also possible to use an additive such as an antistatic agent.

Next, embodiments of the present invention will be specifically described.

Co Ni alloy (Ni content: 20wt%
) continuous oblique vapor deposition (low incident angle component less than 300 cut)
A sample in which an oxygen-containing CoNi ferromagnetic film with a thickness of 100K was formed on a film (sample A) and a sample in which oxygen was formed on a film with a vacuum degree of 5 x 1O-6 Torr and without introducing oxygen gas under the same conditions as above were prepared. A sample FIB (trial FIB) was prepared in which a CoNi ferromagnetic thin film was formed. As a result of measuring the amount of oxygen in the film mainly using Auger electron spectroscopy, it was found that the average amount of oxygen in the film of Sample A was 10% in terms of the atomic ratio (Moriguchi Tsuyoshi It was less than 1% for B.A rust preventive agent mainly composed of unsaturated aliphatic and alicyclic compounds was dissolved in ethyl alcohol, acetone, toluene, etc., and applied and dried (coating amount (adjusted to 10 to 1 o mVm'), then 5 ooc, 90% R,H
During this period, the specimens were taken out and observed under a microscope to examine the state of rust formation. The results are shown in the table below.

1111 As is clear from the table, the rust preventive agent containing unsaturated aliphatic and alicyclic compounds as a main component had a great rust preventive effect on the oxygen-containing QoNi film. Which effect is 1 oxygen content 3 ~
The same is true for a 45% C3oNi R film (Ni1Q to 55 wt%), and as explained above, the corrosion resistance in high humidity can be easily improved according to the present invention.

Claims (1)

[Claims] A ferromagnetic metal thin film containing oxygen is formed on a nonmagnetic substrate, and a rust preventive agent containing an unsaturated aliphatic or alicyclic compound as a main component is attached to the ferromagnetic metal thin film. magnetic recording medium.