Abstract: A lubricant for a magnetic recording medium capable of forming a lubricant layer having excellent adhesion to a protective layer is provided. A lubricant for a magnetic recording medium contains a fluorine-containing ether compound in which a group having an ethylenic carbon-carbon double bond is disposed at one or both terminals of a perfluoroalkyl polyether chain. It is preferable that the group having the ethylenic carbon-carbon double bond is disposed at one terminal of the perfluoroalkyl polyether chain, and a hydroxyl group is disposed at other terminal. It is preferable that the lubricant for a magnetic recording medium contains a compound in which one or more functional groups selected from a hydroxyl group, an amino group, an amido group and a carboxyl group is disposed at one or both terminals of a perfluoroalkyl polyether chain.

Abstract: A fluorine-containing ether compound represented by formula (1) shown below. R4—CH2—R3—CH2—R2—CH2—R1—CH2—R2—CH2—R3—CH2—R4??(1) (In formula (1), R1 and R3 represent different perfluoropolyether chains, R2 represents a linking group containing one or more polar groups, and R4 represents a terminal group containing two or more polar groups.

Abstract: A fluorine-containing ether compound represented by a formula (1) shown below. R4—CH2—R3—CH2—R2—CH2—R1—CH2—R2—CH2—R3—CH2—R5??(1) In formula (1), R1 and R3 represent the same or different perfluoropolyether chains, R2 represents a linking group containing at least one polar group, one or both of R4 and R5 represent a terminal group containing two or more polar groups, and R4 and R5 are different.

Abstract: A fluorine-containing ether compound represented by Formula (1) is provided, R1—R2—CH2—R3—CH2—R4??(1) (In Formula (1), R1 is an alkyl group that may have a substituent, R2 is a divalent linking group bonded to R1 via an ethereal oxygen, R3 is a perfluoropolyether chain, and R4 is an end group which is different from R1-R2 and includes two or three polar groups, in which each of the polar groups is bonded to a different carbon atom, and the carbon atoms bonded to the polar groups are bonded to each other via a linking group containing a carbon atom not bonded to the polar groups.).

Abstract: A compound of the formula (1), lubricant containing the compound and magnetic disk R1—C6H4O—CH2CH(OH)CH2OCH2—R2—CH2—O—CH2CH(OH)CH2—OC6H4—R1 ??(1) wherein R1 is alkoxyl having 1 to 4 carbon atoms, amino or amido, R2 is —CF2CF2O(CF2CF2CF2O)zCF2CF2— or —CF2CF2CF2O(CF2CF2CF2CF2O)nCF2CF2CF2—, z is a real number of 1 to 15, n is a real number of 0 to 4.

Abstract: Copoly(imide oxetane) materials are disclosed that can exhibit a low surface energy while possessing the mechanical, thermal, chemical and optical properties associated with polyimides. The copoly(imide oxetane)s are prepared using a minor amount of fluorinated oxetane-derived oligomer with sufficient fluorine-containing segments of the copoly(imide oxetane)s that migrate to the exterior surface of the polymeric material to yield low surface energies. Thus the coatings and articles of manufacture made with the copoly(imide oxetane)s of this invention are characterized as having an anisotropic fluorine composition. The low surface energies can be achieved with very low content of fluorinated oxetane-derived oligomer. The copolymers of this invention can enhance the viability of polyimides for many applications and may be acceptable where homopolyimide materials have been unacceptable.

Abstract: The invention concerns a threaded tubular component for drilling or working hydrocarbon wells, said tubular component having at one of its ends (1; 2) a threaded zone (3; 4) produced on its outer or inner peripheral surface depending on whether the threaded end is male or female in type, characterized in that at least a portion of the end (1; 2) is coated with a lubricating dry film (12) the matrix (13) of which comprises at least one migrating sliding agent (9) belonging to the oils or waxes family and principally distributed at the surface of the lubricating dry film (12) such that the coefficient of friction of the film (12) is less than 0.07 at loads of less than 40 N while the coefficient of friction of the film (12) is more than 0.1 at loads of more than 200 N.

Abstract: According to one embodiment, a lubricant includes a multidentate perfluoropolyether having a chemical structure of: Re—Rz—Ri—Rz—Ri—Rz—Re, where Rz includes at least one perfluoroethyl ether unit, and where Re and Ri each include at least one functional group configured to attach to a surface. According to another embodiment, the aforementioned lubricant may be suitable for use in a sub-nanometer thick lubricant layer for various applications, and particularly useful for magnetic recording media.

Abstract: Lubricants having perfluoropolyether side chains which have a high thermal stability and high shear modulus.

Abstract: In one embodiment, a magnetic recording medium includes a magnetic recording layer adapted to store magnetic information, a protective film positioned above the recording layer, the protective film being adapted to reduce wear to the magnetic recording layer, and a lubricant positioned above the protective film, the lubricant being adapted to provide a stable head-to-disk interface, wherein the lubricant includes a first lubricant, the first lubricant including a material having the following chemical formula: wherein Rf represents: and wherein Y is a repeating chain including carbon and fluorine.

Abstract: A method of fabricating a magnetic recording medium by sequentially forming a magnetic recording layer, a protection layer, and a lubricant layer on a stacked body, includes forming the lubricant by depositing a first lubricant on the stacked body after forming the protection layer, by vapor-phase lubrication deposition, without exposing the stacked body to atmosphere, and depositing a second lubricant that is dissolved in an organic solvent onto the stacked body after depositing the first lubricant.

Abstract: A surface agent includes two end portions and a middle portion disposed between the end portions. The end portions include a terminal section and a midsection. The terminal section includes at least one surface active functional group. The midsection includes at least one perfluoroethyl ether unit. The middle portion includes at least one perfluorobutyl ether unit.

Abstract: Disclosed herein are compounds of formula I: X-(L-Z)p-L-R[L-(Z-L)p-Y]q??(I) wherein L is a perfluoropolyether; R is q can be an integer equal to or greater than 1; p can independently be integers from 0 to 7; X and Y can independently be chosen from: —OH, —CH2CH2OH, CH2CH2OCH2CH2OH, —CH2CH(OH)CH2OH, —C6H5, —CH2C6H5, —CH2CH(OH)CH3, F, —CF3, —CF2CF3, piperonyl, triazine, benzotriazole, and derivatives thereof; and Z, if present, can independently be chosen from: —C6H4—, —CH2C6H4CH2—, —CH2CH(OH)CH2—, —CH2CH(OH)CH2CH(OH)CH2—, —CH(OH)CH(OH)CH2—, —CH(CH2OH)—, or —CH(C6H5)—.

Abstract: Provided is a magnetic disk that is excellent in durability, particularly in LUL durability and CFT properties, and thus has high reliability despite the low flying height of a magnetic head following the rapid increase in recording density in recent years and despite the very strict environmental resistance following the diversification of applications. A magnetic disk (10) has at least a magnetic layer (6), a carbon-based protective layer (7), and a lubricating layer (8) provided in this order over a substrate (1). The lubricating layer (8) contains a compound having a perfluoropolyether main chain in a structure thereof and having a polar group other than at ends of a molecule thereof.

Abstract: A lubricant for a magnetic disk that is excellent in heat resistance and is suitably used in a magnetic disk to be mounted on a magnetic recording device of a thermally assisted magnetic recording system and a magnetic disk provided with a lubricant layer containing this lubricant. The lubricant for a magnetic disk contains a compound where perfluoropolyether groups each having a perfluoropolyether main chain in its structure and a phosphazene ring at an end are linked to each other through a linking group. The linking group is an aliphatic group or a phosphazene ring. In a magnetic disk having at least a magnetic recording layer, a protective layer, and a lubricant layer on a substrate, the lubricant layer contains the lubricant for a magnetic disk.

Abstract: Provided is a magnetic disk comprising a lubricating layer formed of a lubricant. The lubricant constituting the lubricating layer has excellent properties, for example, excellent fluidity, surface energy, and CFT properties. By virtue of the excellent properties, the magnetic disk has a high level of reliability despite a low flying height of a magnetic head due to a recent rapid increase in recording density and a very severe environment resistance requirement due to diversification of applications. The magnetic disk comprises a substrate and at least a magnetic layer, a protective layer, and a lubricating layer provided in that order over the substrate.

Abstract: A magnetic recording medium includes a nonmagnetic substrate provided on which are, in the order recited; an underlayer; a magnetic layer; a protective layer comprised of carbon; and a lubricating layer composed of a lubricant mixture composed of a lubricant represented by Formula (I) below where m is an integer equal to or greater than 1, and R1 and R2 are divalent straight chains consisting of both —CH2 CF2 — or both —CH2 CF2CF2—; and a lubricant represented by Formula (II) below where p and q are integers equal to or greater than 0, provided that p =q =0 is excluded. A method of manufacturing the magnetic recording medium is likewise disclosed.

Abstract: A lubricant containing a compound (A) comprising a perfluoropolyether having a main-chain structure of the formula (1) and having a polar group at each of opposite terminals thereof, and a compound (B) comprising a perfluoropolyether having a main-chain structure of the formula (1) and having a nonpolar group at at least one terminal thereof —(CF2CF2CF2O)a-??(1) wherein a is a real number of 5 to 30.

Abstract: A cyclophosphazene compound of the formula (I), and lubricants and magnetic disks using the compound wherein n is 2, 3 or 4, m is an integer of 1 to 12, R is C1-4 fluoroalkyl and Rf is —CF2O(CF2CF2O)x(CF2O)yCF2— or —CF2CF2O(CF2CF2CF2O)zCF2CF2— in which x, y and z are each 0 or a positive real number to give a number average molecular weight of 500 to 4000 to a fluoropolyether of the formula HOCH2—Rf—CH2OH including said Rf, the fluoropolyether having a molecular weight distribution (PD) of 1.0 to 1.5.

Abstract: Compounds of formula I: wherein X are independently —(CH2)b—, wherein b is 0 or an integer from 1 to 6; Rf are independently —CF2O(CF2CF2O)p(CF2)qCF2—, —CF2CF2O(CF2CF2CF2O)rCF2CF2—, or —CF2CF2CF2O(CF2CF2CF2CF2O)sCF2CF2CF2—, or derivatives thereof, wherein p, q, r and s are independently integers so that Mn of Rf is about 150 to 4500; and Z are independently chosen from groups that comprise —OH, —(OH)2, —COOCH3, —F, —CF3, or —CF2CF3, with the caveat that not all Z are the same.

Abstract: Compositions for use in lubricating thin film storage media are provided, as well as storage media formed using the compositions, the compositions including one or more central cores having a cyclic group, and a plurality of arms extending from the central cores, wherein each arm comprises phenol or piperonyl. Methods of preparing the compositions are also provided. Methods of preparing storage media that incorporate the compositions therein are further provided.

Abstract: Disclosed is a lubricant composition comprising at least one kind of compound represented by following formula (1): where X represents a cyclic group that may be substituted; Y represents a divalent or higher-valent linking group having at least one polar group and having no aromatic cyclic group; p1 represents an integer of 1 to 4; p2, p3, and p4 each represent an integer of 0 to 4; q represents an integer of 0 to 30; n represents an integer of 1 to 10; s represents an integer of 1 to 4; and t represents an integer of 2 to 10.

Abstract: A compound of the formula (1), lubricant containing the compound and magnetic disk R1—C6H4O—CH2CH(OH)CH2OCH2—R2—CH2—O—R3??(1) wherein R1 is hydrogen, alkoxyl having 1 to 4 carbon atoms, amino or amido, R2 is —CF2O(CF2CF2O)x(CF2O)yCF2—, —CF2CF2O(CF2CF2CF2O)z—CF2CF2— or —CF2CF2CF2O(CF2CF2CF2CF2O)nCF2CF2CF2—, x and y are each an integer of 0 to 15, z is an integer of 1 to 15, n is an integer of 0 to 4, R3 is —CH2CH(OH)CH2OH, —CH2CH(OH)CH2OCH2CH(OH)CH2OH or —(CH2)mOH, m is an integer of 2 to 6.

Abstract: Lubricant with non-terminal functional groups. The location of the functional groups minimizes free chain length and molecular weight of a lubricant while simultaneously maximizing evaporation temperature. The locations of the functional groups to the backbone of the molecule of the lubricant allows for shorter lengths of free backbone length between functional groups attached to a lubricated surface. The lubricant lubricates mechanical devices including hard disk drives. The lubricant can also be added to media or other mechanical parts in conjunction with other lubricants.

Abstract: A magnetic disk in which at least a magnetic layer, a protective layer, and the lubrication layer are sequentially provided on a substrate, the lubrication layer contains a lubricant compound for a magnetic disk, having a perfluoropolyether main chain in the molecular structure and a structure indicated as follows at a position close to the center of the molecule: -0-CH2—CH(OH)—CH2—CH2—CH(OH)—CH2-0- or -0-CH2—CH(OH)—CH(OH)—CH2-0-.

Abstract: Compositions including one or more a central cores having a cyclic group, and a plurality of arms extending from the central cores, wherein the arms comprise perfluoropolyethers (PFPEs) or its derivatives. Methods of preparing the compositions are also provided. Methods of preparing storage media that incorporate the compositions therein are further provided.

Abstract: A lubricant containing a compound of the formula (I) wherein n is substantially 2, 3 or 4, R is C1-4 fluoroalkyl and Rf is —CF2O(CF2CF2O)x(CF2O)yCF2— or —CF2CF2O(CF2CF2CF2O)zCF2CF2— in which x, y and z are each 0 or a positive real number to give a number average molecular weight of 500 to 2000 to a fluoropolyether of the formula HOCH2—Rf—CH2OH including said Rf, the fluoropolyether having a molecular weight distribution (PD, weight average molecular weight/number average molecular weight) of 1.0 to 1.5.

Abstract: A lubricant containing a compound (A) comprising a perfluoropolyether having a main-chain structure of the formula (1) and having a polar group at each of opposite terminals thereof, and a compound (B) comprising a perfluoropolyether having a main-chain structure of the formula (1) and having a nonpolar group at least one terminal thereof —(CF2CF2CF2O)a-??(1) wherein a is a real number of 5 to 30.

Abstract: A compound of the formula (1), lubricant containing the compound and magnetic disk C6H4—(O—Z—R—X)2??(1) wherein Z is —CH2CH2O— or —CH2CH(OH)CH2O—, R is —CH2CF2CF2CF2O(CF2CF2CF2CF2O)nCF2CF2CF2CH2—, n is a real number of 0 to 20, X is —OH, —O(CH2)mOH, —OCH2CH(OH)CH2OH, —OCH2CH(OH)CH2O—C6H5 or —OCH2CH(OH)CH2O—C6H4—OCH3, m is an integer of 1 to 6.

Abstract: In one embodiment, a magnetic disk medium includes a nonmagnetic substrate, a magnetic recording layer above the nonmagnetic substrate, a protective layer above the magnetic recording layer, and a lubricant layer above the protective layer, the lubricant layer including a mixture of a compound having one or more cyclophosphazene groups and a lubricant formulated R1-OCH2CF2CF2O(CF2CF2CF2O)mCF2CF2CH2O—R2, wherein R1 and R2 are alkyl chains having at least two hydroxyl groups each, and m is an integer indicating a number of repeating units. According to another embodiment, a magnetic disk medium lubricant includes a mixture of a compound having one or more cyclophosphazene groups and a lubricant formulated as above, such that a magnetic head is provided stable flight above the lubricant layer in conditions having relative humidity of greater than about 40%.

Abstract: A surface agent includes two end portions and a middle portion disposed between the end portions. The end portions include a terminal section and a midsection. The terminal section includes at least one surface active functional group. The midsection includes at least one perfluoroethyl ether unit. The middle portion includes at least one perfluorobutyl ether unit.

Abstract: According to one embodiment, a lubricant includes a perfluoropolyether having a chemical structure of: wherein Rf is at least one of: —CF2O(CF2CF2O)m(CF2O)nCF2— and —CF2CF2O(CF2CF2CF2O)kCF2CF2—, with m representing 0 or a positive integer, n representing 0 or a positive integer, and k representing 0 or a positive integer, and wherein R1 to R4 are selected from a group consisting of —H or with at least one of R1 to R4 being

Abstract: A lubricant according to one embodiment includes a first ingredient and a second ingredient, said first ingredient as the main constituent being a first perfluoropolyether compound represented by the formula (1) which has a weight-average molecular weight of 500 to 6000 and a dispersity smaller than 1.

Abstract: An object of the present invention is to provide a perpendicular magnetic recording medium including a suitable lubricating layer with sufficient durability, moisture resistance, and contamination resistance and also maintaining an R/W characteristic. In a typical structure of the present invention, a method of manufacturing a perpendicular magnetic recording medium 100 including a magnetic recording layer 122, a medium protective layer 126, and a lubricating layer 128 in this order on a base 110 includes: a CF bond density measuring step of measuring a CF bond density of a lubricant; and a lubricating layer forming step of forming a lubricating layer with the lubricant when the measured CF bond density is 2.0×1022 to 2.7×1022 atoms/cm3.

Abstract: Lubricant with non-terminal functional groups. The location of the functional groups minimizes free chain length and molecular weight of a lubricant while simultaneously maximizing evaporation temperature. The locations of the functional groups to the backbone of the molecule of the lubricant allows for shorter lengths of free backbone length between functional groups attached to a lubricated surface. The lubricant lubricates mechanical devices including hard disk drives. The lubricant can also be added to media or other mechanical parts in conjunction with other lubricants.

Abstract: A surface agent includes two end portions and a middle portion disposed between the end portions. The end portions include a terminal section and a midsection. The terminal section includes at least one surface active functional group. The midsection includes at least one perfluoroethyl ether unit. The middle portion includes at least one perfluorobutyl ether unit.

Abstract: According to one embodiment, a lubricant includes a perfluoropolyether having a chemical structure of wherein Rf is at least one of —CF2O(CF2CF2O)m(CF2O)nCF2— and —CF2CF2O(CF2CF2CF2O)kCF2CF2—, with m representing 0 or a positive integer, n representing 0 or a positive integer, and k representing 0 or a positive integer, and wherein R1 to R4 are selected from a group consisting of —H or with at least one of R1 to R4 being

Abstract: In a magnetic disk that has at least a magnetic layer, a carbon-based protective layer, and a lubricating layer formed in this order over a substrate, the lubricating layer contains a lubricant compound including a compound which has a perfluoropolyether main chain in a structure thereof, an aromatic group located at a position except each end of a molecule thereof, and a polar group at each end of the molecule.

Abstract: Lubricant with non-terminal functional groups. The location of the functional groups minimizes free chain length and molecular weight of a lubricant while simultaneously maximizing evaporation temperature. The locations of the functional groups to the backbone of the molecule of the lubricant allows for shorter lengths of free backbone length between functional groups attached to a lubricated surface. The lubricant lubricates mechanical devices including hard disk drives. The lubricant can also be added to media or other mechanical parts in conjunction with other lubricants.

Abstract: A magnetic recording medium having high bonding capability between the surface lubricant and the diamond-like carbon (DLC) protective layer in the surface of the magnetic recording medium is disclosed. The lubricant is a fluorine-containing lubricant for magnetic recording media represented by the following formula (1), (2) or (3), wherein the substituents R1, R2, R3, R4, R5 and R6 in the terminal part of the lubricant each independently represent an organic group, and at least one of the substituents R1 and R2, at least one of the substituents R3 and R4, and at least one of the substituents R5 and R6 each have an isocyanate group: Also disclosed is a magnetic recording medium using the lubricant.

Abstract: In one embodiment, a magnetic disk medium includes a nonmagnetic substrate, a magnetic recording layer above the nonmagnetic substrate, a protective layer above the magnetic recording layer, and a lubricant layer above the protective layer, the lubricant layer including a mixture of a compound having one or more cyclophosphazene groups and a lubricant formulated R1-OCH2CF2CF2O(CF2CF2CF2O)mCF2CF2CH2O—R2, wherein R1 and R2 are alkyl chains having at least two hydroxyl groups each, and m is an integer indicating a number of repeating units. According to another embodiment, a magnetic disk medium lubricant includes a mixture of a compound having one or more cyclophosphazene groups and a lubricant formulated as above, such that a magnetic head is provided stable flight above the lubricant layer in conditions having relative humidity of greater than about 40%.

Abstract: Provided is an ether composition containing at least two ether compounds each of which has from 1 to 4 groups represented by formula (X) and from 0 to 3 groups represented by formula (Z), where the total number of groups represented by formula (X) and (Z) is 4: HO—(CH2CH2O)a.(CH2CH(OH)CH2O)b-Q-??(X), CF3(CF2)sO(CF2CF2O)g—??(Z), where a, b, s, g and Q are defined herein. The ratio (CF3/(OH+CF3)) of the total molar amount of CF3 groups in the groups represented by formula (Z) to the sum of the total molar amount of CF3 groups in the groups represented by formula (Z) and the total molar amount of OH groups in the groups represented by formula (X) is from 0.01 to 0.5.

Abstract: A protection layer containing carbon as a major component is deposited by plasma CVD. The protection layer has film quality such that, when a spectrum is obtained by excluding photoluminescence from a Raman spectrum in a wavenumber band from 900 cm?1 to 1800 cm?1 obtained by exciting the protection layer with an argon ion laser beam having a wavelength of 514.5 nm and the spectrum is subjected to waveform separation by the Gaussian function to split a D peak appearing around 1350 cm?1 and a G peak appearing around 1520 cm?1, the ratio Dw/Gw between a half width Dw of the D peak and a half width Gw of the G peak exceeds 0 and is not greater than 2.7.

Abstract: In order to obtain a magnetic recording disk that exhibits high reliability even if the flying height of a magnetic head becomes very narrow, a lubricant is specified in terms of both molecular structure and quantitative data. That is, a lubricating layer 14 of the magnetic recording disk 1 is formed by a lubricant which contains perfluoropolyether compounds represented by the following chemical formula (Chemical Formula 1) and which has a first component content of 71.7%, a second component content of 15.7%, a third component content of 11.7%, a fourth component content of 0.3%, and a fifth component content of 0.6%: X—OCH2CF2—(CF2O)m(C2F4O)n—CF2OCH2O—X??(Chemical Formula 1) m, n=9 to 11 first component: X=X1=CH2CH(OH)CH2OH second component: X=X2=CH2CH(OH)CH2OCH2CH(OH)CH2OH third component: X=X3=H fourth component: X=X4=CF3 fifth component: X=X5=CF2Cl.

Abstract: A compound of the formula (I), and lubricant, and magnetic disk each using the same A-(CH2—Rf—CH2O—B—O)n—CH2—Rf—CH2-A??(I) wherein n is an integer of 1 to 4, A is a group of the formula (a) below, and B is a group of the formula (b) below, p being 1 or 2, R being C1-4 fluoroalkyl, Rf is —CF2O(CF2CF2O)x(CF2O)yCF2— or —CF2CF2O(CF2CF2CF2O)zCF2CF2—, x, y and z being each a real number of 0 to 50.

Abstract: Embodiments of the present invention provide a magnetic disk having a lubricating layer formed on the surface thereof, which meets all the requirements for adhesiveness, adequate flowability, and strong binding power. In a particular embodiment, a magnetic disk has a magnetic layer, a protective layer, and a lubricating layer which are formed on a non-magnetic substrate, which is characterized in that said lubricating layer is comprised of a lubricant containing a first ingredient and a second ingredient, said first ingredient as the main constituent being a first perfluoropolyether compound represented by the formula (1) below, which has a weight-average molecular weight of 500 to 6000 and a dispersity smaller than 1.

Abstract: A composite lubricant for recording disk media, a recording disk media including a layer of the composite lubricant, and method of manufacturing the same are described. The composite lubricant may include a non-phosphazene component and a phosphazene component where the non-phosphazene component is a difunctional perfluoropolyether compound terminated with first and second polar end groups, the first polar end group comprising a first number of hydroxyls and the second polar end includes a second number of hydroxyls, greater than the first number of hydroxyls. The phosphazene component may be a difunctional perfluoropolyether compound terminated with a phosphazene functional group and with a third polar end group, the third polar end group comprising a third number of hydroxyls equal to the second number of hydroxyls.

Abstract: A patterned disk for a hard disk drive. The patterned disk includes a magnetic material over a substrate. The magnetic material includes a plurality of grooves. The grooves are filled with a lubricant that is hardened with UV exposure or some other hardening process. The lubricant provides a protective cover for the magnetic material exposed by the grooves. The use of lubricants in the fabrication of disks is known, thus the process does not introduce a process step that requires special equipment and/or process development.

Abstract: A magnetic recording medium for use in a thermally assisted recording system is disclosed. The magnetic recording medium comprises at least a magnetic layer, a protective layer and a lubricant layer formed on a nonmagnetic substrate, wherein a lubricant of the lubricant layer exhibits such a heat resistance that an amount of volatilization when the magnetic layer is heated to a temperature not lower than a temperature Tw is less than 1% with respect to an initial amount of the lubricant in an unheated condition. The present invention addresses a problem of the heat resistance performance of the lubricant for use in magnetic recording media and provides a magnetic recording medium exhibiting high heat resistance.

Abstract: Disclosed is a magnetic disk which has a lubricant layer with excellent heat resistance and high adhesiveness and is free from fly-stiction failure or corrosion failure even at an extremely low flying height of 10 nm or lower. Also disclosed is a magnetic disk which has a lubricant layer with good thermal properties and can exert a stable action over a wide temperature range. The magnetic disk comprises a substrate (1), and a magnetic layer (3), a carbon-containing protective layer (4) and a lubricant layer (5) provided on the substrate (1), wherein the lubricant layer (5) contains a magnetic disk lubricant comprising a compound having a phosphazene ring and two or more hydroxyl and/or carboxyl groups in the molecule.