JP2897309B2 - Magnetic storage - Google Patents

Description

The present invention relates to a magnetic storage device, for example, a magnetic disk device,
The present invention relates to a magnetic storage body used for a magnetic drum device or the like.

2. Description of the Related Art In general, there are the following recording / reproducing methods for a magnetic storage device including a recording / reproducing magnetic head (hereinafter, referred to as a head) and a magnetic storage unit. That is, at the start of the operation, after setting the head and the magnetic storage surface in contact with each other, a required rotation is given to the magnetic storage to create a space for an air layer between the head and the magnetic storage surface, and recording is performed in this state. -This is a method of reproduction (contact start / stop method, hereinafter referred to as CSS). In this method, the rotation of the magnetic storage body stops at the end of the operation, and at this time, the head and the surface of the magnetic storage body are brought into contact friction as in the start of the operation.

The frictional force generated between the head and the magnetic storage body in these contact frictional states may cause the head and the magnetic storage body to wear, and eventually cause the head and the magnetic medium to be damaged. Also, in the initial contact friction state, a slight change in the attitude of the head makes the load applied to the head non-uniform. In some cases, scratches may be formed on the surface of the head and the magnetic storage body, which are a plastic substrate coated with, or a ceramic substrate coated with metal or plastic. Further, due to the prolonged contact between the head and the magnetic storage body, the two are attracted to each other and are hard to separate.

In order to prevent the destruction and adsorption of the magnetic storage medium due to the contact and sliding with the head, a conventional method is disclosed in Japanese Patent Application Laid-Open No. 52-49805.
As seen in the publication, the surface of the magnetic storage medium is coated with a lubricant such as perfluoropolyether. Also JP
64-9961 JP, JP-A-63-77996 or JP-A-62-77996
As disclosed in Japanese Patent No. 45562, a lubricant using an alkyl perfluoroalkaneamide, an amine salt of perfluoroalkylcarboxylic acid or an ester of perfluorocarboxylic acid is disclosed.

[Problems to be Solved by the Invention] However, a lubricant such as perfluoropolyether has poor load-bearing capacity, and slides with the head or performs CSS many times.
In the repetition of the above, it was not possible to prevent the magnetic memory from being damaged. There is also a disadvantage that the removed lubricant is thickly localized and adsorbed on the contact sliding surface between the magnetic storage medium and the head and cannot be separated. Lubricants using alkyl perfluoroalkaneamides or perfluoroalkylcarboxylic acid amine salts or perfluorocarboxylic acid esters have poor chemical stability and are easily hydrolyzed by moisture in the air, resulting in the deterioration of lubricating properties over time. There are drawbacks such as a change, or insufficient adsorption capacity required for the lubricant molecules to be retained on the surface of the magnetic storage medium.

An object of the present invention is to provide a magnetic memory which solves the conventional problems as described above.

Means for Solving the Problems In the present invention, a magnetic medium is coated on a base body, and a general formula: R ¹ —NHCOO—R ² ... [I (Wherein, R ¹ and R ² may be the same or different and each represent a hydrocarbon group having 4 or more carbon atoms or a fluorinated hydrocarbon group.) A magnetic storage body having a structure formed by:

As shown in FIG. 1, the basic structure of the magnetic storage medium of the present invention is such that a magnetic medium 2 is coated on a base body 1 and further comprises a compound represented by the general formula [I] on the medium. It has a structure in which the lubricant 4 is coated, or has a structure in which the protective film 3 is coated between the magnetic medium 2 and the lubricant 4 as shown in FIG.

The base body 1 includes alloy metals such as aluminum alloy, titanium alloy, and stainless steel, polyester, polyimide, polyamide imide, polyether sulfone, polysulfone, aromatic polyether, epoxy resin, urea resin, melamine resin, polycarbonate, diallyl phthalate. Plastics such as resin, acrylic resin, phenol resin, polyphenylene sulfide, polyphenylene ether, polyacetal resin, polybutylene terephthalate, bismaleimide triazine resin, polyoxybenzylene resin, polyaminobismaleimide resin, polyphenylene oxide, polyphenylene sulfide, glass,
Ceramics such as silicon, germanium, alumina, silica, diamond, etc., or anodized aluminum alloy coated with anodized aluminum, Ni-P plating film, Cr, FeNi, stainless steel, Mo
Alternatively, a metal such as W is used.

Next, as the magnetic medium 2 coated on the substrate 1, oxides such as Fe ₃ O ₄ , γ-Fe ₂ O ₃ , barium ferrite, CrO ₂ , nitrides such as Fe ₃ N ₄ , carbides such as ₅ C _2, C
o, CoNi, CoNiP, CoMnP, CoMnNiP, CoRe, CoPt, CoNiPt, CoCr, C
oCrTa, CoNiRe, CoMnReP, CoFeCr, CoV, CoRu, CoOs, CoPtCr, C
Metals containing cobalt such as oPtV, CoRh, CoCrRh, CoNiMo, CoNiCr, CoNiW, CoSm, metals containing iron such as FeNd, FeMg, FeNd, FeAg, FePD, FeTb, or metals containing manganese such as MnAl, MnCuAl are used. Can be Alternatively, a resin in which fine particles of the above various magnetic substances are mixed and dispersed may be used.

Lubricants comprising a compound represented by the above general formula [I] containing a urethane bond used in the present invention include the following compounds.

_{RNHCOOR ... [Ia] R f NHCOOR} ... [Ib] RNHCOOR f ... [Ic] R f NHCOOR f ... [Id] wherein R has 4 or more carbon atoms, preferably an 11 or a hydrocarbon group having a carbon number, R _f represents a fluorinated hydrocarbon group having 4 or more carbon atoms, part or all of which is substituted with a fluorine atom.

The protective film 3 is made of a silicon compound such as SiO ₂ , Si ₃ N ₄ , SiC, a silicate polymer, Al ₂ O ₃ , CoO, Co ₃ O ₄ , Co ₂ O ₃ , α-Fe ₂ O ₃ , Cr ₂ O ₃ , Cr
Metal oxides such as O ₃ , TiO ₂ , ZrO ₂ , ZnO, PbO, NiO, MoO ₂ , SnO ₂ , metal nitrides such as TiN, ZrN, CrN, TaN, BN, MoS ₂ , WS
_2, metal sulfides such as TaS _2, TiC, ZrC, CrC, metal carbides such as TaC, metal fluoride such as graphite fluoride, W, Cr, Ir, NiB,
NiP, FeCr, NiCr, Sn, Pb, Zn, Tl, Au, Ag, Cu, Ga, Ru, Rh, Mn, Mo,
Metals or alloys such as Os, Ta or their alloys, Si, G
e, B, C (amorphous, diamond-like or mixtures thereof,
Alternatively, a semiconductor such as graphite or a mixture thereof, or a plastic such as polytetrafluoroethylene, phenol resin, or polyimide is used.

[Action] The lubricant used in the present invention has a high load-bearing capacity and excellent abrasion resistance due to the urethane bond contained in the molecule thereof, has high heat resistance, and further has a protective film or a magnetic medium. Excellent adsorption capacity. This is because the urethane bond contained in the lubricant material of the present invention is chemically stable, does not dissociate with water unlike an amine salt, and has a bond distance of a polar group rather than an amide bond or an ester bond. It is considered that the reason for this is that the holding ability on the surface of the magnetic storage body is large because of its long polarity. In addition, due to the lubricating properties of hydrocarbon groups or fluorinated hydrocarbon groups, it has properties such as low friction coefficient, excellent wear resistance, low surface tension, and low adhesion between the head and magnetic memory. I have.

[Example] Hereinafter, an example of the present invention will be described.

Example 1 A nickel-phosphorous plating film was coated on an aluminum alloy substrate, and a mirror-finished substrate having a surface roughness of 0.02 μm was coated with a cobalt-nickel-phosphorous alloy as a magnetic medium by 0.05%.
Plated to a thickness of μm. Next, a polysilicic acid (silicic acid polymer) as disclosed in JP-A-52-20804 was coated on the magnetic medium to a thickness of 50 nm by a spin coating method and baked at 250 ° C. Next, a chlorsen solution of a compound having the following structure (1) as a lubricant was spin-coated on the protective film to coat the protective film to a thickness of 1 nm, thereby producing a magnetic disk.

C ₁₈ H ₃₇ NHCOOC ₁₇ H ₃₅ … (1) When the wear resistance of this magnetic disk was evaluated by 100,000 CSS tests, there was no change in the initial friction coefficient of 0.1.
Further, no scratches were observed on the surfaces of the head and the magnetic disk. In addition, when the head and the magnetic disk were left for 70 hours and the suction force acting during the measurement was measured, the increase was only 1.3 times that when the head was not left. The friction coefficient did not change even after the magnetic disk was left in an environment at a temperature of 40 ° C. and a humidity of 80% for 20 days, and no scratch was observed on the surface of the magnetic disk even after 100,000 CSS tests.

Example 2 In Example 1, a carbon film coated by a sputtering method was used as a protective film, and a chlorsen solution of a compound having the following structure (2) as a lubricant was spin-coated thereon to a thickness of 1 nm. A magnetic disk was produced in the same manner as in Example 1 except that the coated disk was used.

C ₁₈ H ₃₇ NHCOOC ₂ H ₄ C ₁₀ F ₂₁ … (2) When the wear resistance of this magnetic disk was evaluated by 100,000 CSS tests, there was no change in the initial friction coefficient of 0.07.
Further, no scratches were observed on the surfaces of the head and the magnetic disk. In addition, when the head and the magnetic disk were left for 70 hours and the suction force acting during the measurement was measured, the increase was only 1.2 times as much as when the head was not left. The friction coefficient did not change even after the magnetic disk was left for 20 days in an environment at a temperature of 40 ° C. and a humidity of 80%, and no scratch was observed on the surface of the magnetic disk even after 100,000 CSS tests.

Example 3 In Example 1, nickel-phosphorus was coated to a thickness of 10 nm as a protective film by an electroless plating method, and baked and oxidized at 300 ° C. to obtain N.
Example 1 was repeated except that a protective film made of iO was formed, and a chlorcene solution of a compound having the following structure (3) was spin-coated and coated to a thickness of 1 nm as a lubricant on the protective film. A magnetic disk was made in the same manner.

C ₁₂ F ₂₅ NHCOOC ₁₈ H ₃₇ … (3) When the wear resistance of this magnetic disk was evaluated by 100,000 CSS tests, there was no change in the initial friction coefficient of 0.07.
Further, no scratches were observed on the surfaces of the head and the magnetic disk. In addition, when the head and the magnetic disk were left for 70 hours and the suction force acting during the measurement was measured, the increase was only 1.2 times as much as when the head was not left. The friction coefficient did not change even after the magnetic disk was left for 20 days in an environment at a temperature of 40 ° C. and a humidity of 80%, and no scratch was observed on the surface of the magnetic disk even after 100,000 CSS tests.

Example 4 In Example 1, a protective film coated with 20 nm of diamond-like carbon by a chemical vapor method was used, and a Freon solution of a compound having the following structure (4) was spin-coated as a lubricant to a thickness of 1 nm. A magnetic disk was prepared in the same manner as in Example 1 except that the magnetic disk was used.

C ₁₂ F ₂₅ NHCOOC ₂ H ₄ C ₁₂ F ₂₅ … (4) When the wear resistance of this magnetic disk was evaluated by 100,000 CSS tests, there was no change in the initial friction coefficient of 0.15.
Further, no scratches were observed on the surfaces of the head and the magnetic disk. When the head and the magnetic disk were allowed to stand for 70 hours, the attraction force acting during that time was measured. As a result, there was no increase in the attraction force compared to when the head was not left. The friction coefficient did not change even after the magnetic disk was left in an environment of a temperature of 40 ° C. and a humidity of 80% for 20 days, and no scratch was observed on the surface of the magnetic disk even after 100,000 CSS tests.

Example 5 In Example 1, a chlorcene solution of a compound having the following structure (5) was spin-coated directly on a magnetic medium made of a resin containing magnetic particles of γ-Fe ₂ O ₃ as a lubricant. A magnetic disk was prepared in the same manner as in Example 1, except that the magnetic disk was coated to a thickness of 1 nm.

C ₃₁ H ₆₃ NHCOOC ₃₁ H ₆₃ … (5) When the wear resistance of this magnetic disk was evaluated by 100,000 CSS tests, there was no change in the initial friction coefficient of 0.1.
Further, no scratches were observed on the surfaces of the head and the magnetic disk. In addition, when the head and the magnetic disk were left for 70 hours and the suction force acting during the measurement was measured, the increase was only 1.3 times that when the head was not left. The friction coefficient did not change even after the magnetic disk was left for 20 days in an environment at a temperature of 40 ° C. and a humidity of 80%, and no scratch was observed on the surface of the magnetic disk even after 100,000 CSS tests.

Example 6 A substrate was used in which Cr was coated on a NiP plating layer to a thickness of 1 μm on a NiP plating layer, and a CoNi alloy was coated thereon as a magnetic medium to a thickness of 0.05 μm by a sputtering method. SiO ₂ as a protective film by sputtering
Was coated with 20 nm, and a chlorcene solution of a compound having the following structure (6) was spin-coated as a lubricant to coat to a thickness of 1 nm, thereby producing a magnetic disk.

C ₇ F ₁₅ NHCOOC ₁₅ H ₃₀ (CH ₃ ) ₂ … (6) When the abrasion resistance of this magnetic disk was evaluated by 100,000 CSS tests, there was no change in the initial friction coefficient of 0.1.
Further, no scratches were observed on the surfaces of the head and the magnetic disk. In addition, when the head and the magnetic disk were left for 70 hours and the suction force acting during the measurement was measured, the increase was only 1.2 times as much as when the head was not left. The friction coefficient did not change even after the magnetic disk was left for 20 days in an environment at a temperature of 40 ° C. and a humidity of 80%, and no scratch was observed on the surface of the magnetic disk even after 100,000 CSS tests.

Comparative Example 7 A magnetic disk was prepared in the same manner as in Example 1 except that a lubricant coated with 1 nm of perfluoropolyether having the following structure (7) was used.

F (C ₂ F ₄ O) ₃ (CF ₂ O) ₁₅ CF ₃ ... (7) When the wear resistance of this magnetic disk was evaluated by 20,000 CSS tests, the coefficient of friction increased seven times as compared with that before the test. ,
Scratches reaching the magnetic medium occurred on the surfaces of the head and the magnetic disk. When the head and the magnetic disk were allowed to stand for 70 hours, the attraction force acting during that time was measured.

Comparative Example 2 A magnetic disk was produced in the same manner as in Example 1, except that the lubricant coated with 1 nm of an alkyl perfluoroalkaneamide having the following structure (8) was used as a lubricant.

C ₁₈ H ₃₇ NHCOOC ₇ F ₁₅ … (8) When the wear resistance of this magnetic disk was evaluated by the 20,000 times CSS test, the friction coefficient increased four times as compared with that before the test.
Scratches reaching the magnetic medium occurred on the surfaces of the head and the magnetic disk. Further, the coefficient of friction after leaving the magnetic disk in an environment of a temperature of 40 ° C. and a humidity of 80% for 20 days increased five times that before the test, and the surface of the magnetic disk was found to be scratched in the 5,000 CSS tests.

Comparative Example 3 A magnetic disk was prepared in the same manner as in Example 1, except that a lubricant coated with a perfluoroalkylcarboxylic acid amine salt having the following structure (9) was used in a thickness of 1 nm.

^{_{C 18 H 37 N + H 3}} - OOCC 7 H 15 ... (9) was evaluated wear resistance CSS test of the magnetic disk 20000 times, the coefficient of friction increases to six times before the test,
Scratches reaching the magnetic medium occurred on the surfaces of the head and the magnetic disk. The magnetic disk is kept at 40 ° C and 80% humidity.
The coefficient of friction after standing for 20 days in the above environment increased 5 times that before the test, and scratches were recognized on the surface of the magnetic disk in the 5,000 CSS tests.

Comparative Example 4 A magnetic disk was prepared in the same manner as in Example 1 except that a lubricant coated with 1 nm of a perfluorocarboxylic acid ester having the following structure (10) was used.

C ₁₈ H ₃₇ OOCC ₇ F ₁₅ … (10) When the wear resistance of this magnetic disk was evaluated by 20,000 CSS tests, the coefficient of friction increased four times that before the test, and the surface of the head and the magnetic disk became magnetic. Scratches reaching the media occurred. In addition, the coefficient of friction after leaving the magnetic disk in an environment of 40 ° C. and 80% humidity for 20 days increased five times that before the test, and scratches were recognized on the surface of the magnetic disk in the 5,000 CSS tests. .

[Effects of the Invention] As described above in detail, the magnetic memory of the present invention
The coefficient of friction against sliding with the head is small, and it has excellent abrasion resistance.It does not generate adsorption force even after prolonged static contact with the magnetic head, and is chemically stable even in high humidity conditions. The reliability can be improved much more than that of the magnetic storage medium.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of one embodiment of a magnetic memory according to the present invention.
FIG. 2 is a partial sectional view of another embodiment of the magnetic memory of the present invention. DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... Magnetic medium 3 ... Protective film 4 ... Lubricant

Claims (1)

(57) [Claims] 1. A magnetic medium is coated on a substrate, and a general formula: R ¹ —NHCOO—R ² (where R ¹ and R ² are the same, either directly on the magnetic medium or via a protective film) Or a hydrocarbon group having 4 or more carbon atoms or a fluorinated hydrocarbon group, respectively.) A magnetic material characterized by having a structure coated with a lubricating oil comprising a compound represented by the formula: Memory body.