JPS59185028A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a recording medium of a thin ferromagnetic metallic film type having excellent weatherability by forming a thin magnetic metallic film contg. much oxygen near the surface on a non-magnetic base and forming a Cr compd. layer having the film thickness of a specific value thereon. CONSTITUTION:A plastic film of polyethylene terephthalate, polyimide, or polycarbonate is preferably as a base, and a non-magnetic metal such as Al, Cu, SUS or the like or an iorg. material such as glass, ceramic or the like is also usable. The magnetic metallic material is a metal such as Fe, Co, Ni or the like and a ferromagnetic alloy consisting essentially of Fe-Co, Fe-Ni, etc., and particularly preferably Co or an alloy contg. 75wt% Co. The chromium compd. layer to be formed on the thin ferromagnetic metallic film layer is Cr, Cr-O or one or both thereof contg. impurities such as Fe, Ni and Si, and the film thickness is 10-120Angstrom . If the film thickness is larger than 120Angstrom , the electromagnetic conversion characteristic is deteriorated by the increase in the space loss and lubricity is deteriorated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording medium, and more particularly to a metal thin film type magnetic recording medium with improved weather resistance.

Most magnetic recording media are made of magnetic powder made of oxide magnetic powder or alloy magnetic powder on a non-magnetic support, such as vinyl chloride-vinyl acetate copolymer, styrene-butadiene copolymer, epoxy resin, polyurethane resin, etc. It is obtained by coating it with a binder and drying it.

In recent years, magnetic recording media suitable for high-density recording have become even more desirable, and ferromagnetic metal thin films have been formed using vacuum deposition, sputtering, ion blating, plating, etc. on the binder film described above. Thin film magnetic recording media formed on a support are attracting attention.

However, ferromagnetic metal thin films have the disadvantage of being susceptible to corrosion. In order to overcome all of these drawbacks, improvements have been proposed in the past. For example, 94 Kaisho θ-7o<t
To2 has a magnetic metal thin film on it.・0.2μm to 0
．． It is disclosed that an o7μmocr203 film is provided. 1, special lm45E! r/'17'l.

No. 7 discloses providing a rainbow chromium oxide layer by treating a magnetic metal thin film with a solution containing a chromium compound.

However, when overcoating a ferromagnetic metal thin film with a Cr metal frame of approximately 309λ or more, the slipperiness deteriorates (Japanese Patent Application Laid-open No. 73732/1983). The process of immersing the magnetic metal gamma membrane in a liquid, etc., is complicated in terms of the process, and in order to prevent defects such as pinholes, the subsequent treatment is also done using the same method. A treatment method that utilizes all technologies is desired.

The present invention has been made in consideration of the above-mentioned points in the prior art.

An object of the present invention is to provide a ferromagnetic gold ingot thin film magnetic recording medium with excellent weather resistance.

The above-mentioned object of the present invention is to provide a magnetic metal thin film containing a large amount of oxygen near the surface on a non-magnetic support, and a magnetic metal thin film containing a large amount of oxygen in the vicinity of the surface, and
This is achieved by forming a Cr compound layer with a thickness of 0λ.

The magnetic recording medium of the present invention includes a nonmagnetic support and a ferromagnetic metal thin film provided thereon. Examples of the support used in the present invention include polyethylene terephthalate, polyimide, and polyamide. Plastic films such as polyvinyl chloride, cellulose triacetate, polycarbonate, polyethylene naphthalate are preferred, but At,
Non-magnetic metals such as Cu and 5LIS, or inorganic supports such as glass and ceramics can also be used. These supports may be coated with inorganic particles (calcium carbonate, carbon black particles, etc.) which may be provided with a layer containing simulant rice and a binder on the opposite side of the ferromagnetic metal thin film. The binder is preferably nitrocellulose, polyurethane, isocyanate, polyester, or a mixture thereof.

When the support is a plastic film, the surface roughness (Ra) is preferably 00012 μm or less.

The magnetic gold peach material 4C used in the present invention is Po/Fe.
, Co, metals such as Ni, Aid F e -Co,
Fe-N i, c, -N ib Fe-Co -N
1sFe-Cu, Co-Cu, Ni-Cu, I'e-
Ur, Co-Cr, N1-Ur, Fe-Co-(,:r
, 1-1-C□-Cr%Fe-Co-Ni-Ur%
It is a ferromagnetic alloy that has a K-value. Particularly preferred is C.
O or Co is 7! It is an alloy that contains a precipitate content.

Furthermore, W, IVio, 'f I, +'v1 as additives
It may also contain a small amount of g, 5IAt, etc.

The metal thin film of the present invention is obtained by oblique vapor deposition on a support in the above-mentioned phosphorescent acid-based atmosphere. This membrane is <t-o
o~kooooo people are preferred.

When a metal is obliquely vapor-deposited onto a support, if all the oxygen is supplied to the fish-covered portion on the running side of the support, more oxygen will be contained near the surface of the ferromagnetic metal thin film.

Examples 1l-1' of the oxygen content profile are shown in FIG. Figure 1 is S/? This is a graph showing the relationship between the ivy hour and the amount of components in the thin film, as measured by Auger electron spectroscopy.

The chromium compound layer formed on the ferromagnetic metal thin film layer is C
r, Cr-0 or b is one or both of these and Fe, N
i, Mnb Contains all impurities such as Si, film thickness is 70~
It is 1.2OA. ) If the g thickness is larger than /,tOA, the weather resistance properties will continue to improve, but the space loss will increase ((y), the bt magnetic conversion properties will deteriorate, and the slipperiness of the magnetic recording medium will become worse.

In order to improve running characteristics and still durability characteristics, a lubricating layer may be further provided on the magnetic recording medium according to the present invention.

The f'L/)@lubricant layer formed on the Cr compound layer contains higher fatty acids, fatty acid esters, or a combination thereof. Specifically, higher fatty acids include lauric acid, myristic acid, ξlumitic acid, stearic acid, behenic acid, oleic acid, linoleic acid, linoleic acid, arachidonic acid, etc., and fatty acid esters include methyl stearate. , ethyl nomylumitate, stearin monoglyceride, etc.). The lubricating layer may be formed using a steam oven method, an ion blasting method, or a conventional coating method.

According to the present invention, a chromium compound 1' layer with a film thickness of 10-/2 OA is entirely formed on a gold-plated magnetic thin film containing a large amount of oxygen near the surface (for example, CO or a soot alloy containing Co). However, as compared to the conventional example, this method can be reduced to a large extent by a large amount.

That is, in the conventional overcoat thin Ge metal thin film,
The hydroxyl groups that entered the overcoat through the 111 gap made direct contact with the magnetic metal thin film layer, causing the magnetic metal to move smoothly.

For this f′L, in non-invention, white taste 1 is ↑OrigataC
In the unlikely event that the bar coat is firmly applied to the gold 4-imide thin film containing a large amount of oxygen near the surface,
The surface of the magnetic metal thin film is coated with an oxide layer that has excellent weather resistance! Due to the effect of K, the invasion of hydroxyl groups is prevented, and even if they invade the magnetic gold circle thin N/m, corrosion hardly progresses, and even if it occurs, it takes a very long time +Mjk. The following will be explained according to examples.

Example 1 Polyethylene terephthalate film (J123μm)
To! Composition Co in 112 element atmosphere of ×/θ torr
, 6Niα2 alloy was deposited with oblique incidence at a total incident angle≠50,
1-Thickness with Ce, Ni, 0 distribution shown in Figure 7/
A thin M layer of magnetic metal of 4t00A is formed to create a θ trap. After that, add 1. DoX/0't
A chromium layer with a thickness of 30A was formed by vapor deposition at a vacuum level of 30A.

As explained above, all evaluations of weather resistance properties were carried out using the trap medium.

A total of one song was carried out by keeping it in a thermostat at 0%RH for 2 weeks and observing all the corrosion after 'fc, but no rust was observed.

Example 2 An acidic gas f/005CCf was flowed onto a fl-metallic magnetic thin film formed by the same method as in Example 1 under a bacterial atmosphere at a vacuum level of x/0' torr.
3°! A high frequency power of 2 μHz was applied to all 200 watts of the coil to generate a discharge, and two layers of evaporation were performed under this atmosphere to form a Cr2O3 film with a thickness of 5 OA.

When the same riot characteristics as in Example 1 were evaluated using this medium, it was found that the spontaneous growth of rust similar to that in Examples 1 and 1 was almost non-existent and trapping. -Maπ, Cr 2 (J3
Regarding the film layer, ESCA measurements confirmed that the first layer had this composition.

Comparative example 1. An alloy of composition C□, 6NiO,2 was deposited on a 23 μ>n thick polyethylene terephthalate film base under AX/0” torr (D compatibility) with a total incident angle of t3° and a total thickness of oblique incidence evaporation/≠ooAt , i) Formed a waiting film layer 3?
0-10-5t+7)
When the weather resistance characteristics were evaluated in the same manner as in Example 1 using this medium, no rust was observed. 1. Find the rate of decrease in saturation magnetization (demagnetization 3rd) before and after performing the above evaluation,
The results are shown in Table 1 together with the samples of Examples 1 and 2.

Table-/

[Brief explanation of the drawing]

Figure 1 shows the relationship between the amount of components in a ferromagnetic metal thin film and the sputtering time measured using Auger electron spectroscopy. This is a graph showing. Particularly, ff Applicant Fuji Photo Film Co., Ltd. Figure 1 Suharshita M version (a, u) Procedural amendment - Month 1955/f1 Mr. Commissioner of the Patent Office 1, Indication of the case Showa SR 2016 Patent application No. A.A.
4' No. 2, Title of the invention Magnetic recording medium 3, Relationship to the case of the person making the amendment Patent applicant Location 210 Nakanuma, Minamiashigara City, Kanagawa Name (520) Fuji Photo Film Co., Ltd. Subject of amendment Part 1 of the specification Column 5 of “Detailed Description of the Invention” Contents of amendment (1) Specification cylinder! Page 20, "Contains." is corrected to "May contain." (2) Same book, page 7, line 10 (CO, 1NiO, 2Jf[C
oO, lN10. Correct as jJ. (3) Same book, page 16, line 16 [COlzaNiO, 2Jf “
Co O, ZaNiO, Ko” and correct it.

Claims (1)

[Claims] A ferromagnetic metal thin film and a chromium compound layer are provided in this order on a non-magnetic support, the ferromagnetic metal thin film contains a large amount of oxygen near the surface, and the chromium compound layer has a thickness of lO to C20.
A magnetic recording medium characterized by A.