33results about "Base layer manufacture" patented technology

Disks for use in hard disk drives (HDD) or other magnetic recording apparatus. The disks are configured based on a finding that internal stress within a disk can make the disk more resistant to shock forces. In one example, a disk is provided that has a substrate with a thickness of no more than 0.5 millimeters and an internal stress no less than 300 megapascals. The relatively high internal stress within the substrate of the disk serves to reduce the magnitude of deflections caused by mechanical shocks to an HDD in which the disk is installed, as compared to other disks of equal thickness but with relatively less internal stress. Multi-platter stacks of the disks are described. Methods are also described for fabricating such disks and for rejecting disks that do not meet certain internal stress-based criteria. Substrates are also described.

The present invention relates to an aluminum alloy disc blank for a magnetic disc, characterized by being formed of an aluminum alloy containing Fe: 0.005 to 1.800 mass%, the balance consisting of Al and unavoidable impurities, and a flatness change of the aluminum alloy disc blank for a magnetic disc being 2.0 μm or less when the aluminum alloy disc blank for a magnetic disc is kept in the atmosphere at 50°C or lower for 336 hours.

To provide a method for producing a magnetic recording medium capable of having a magnetic layer with high crystal orientation and few defects, a magnetic recording medium, and a magnetic storage device.SOLUTION: A method of producing a magnetic recording medium 1 includes: a step of forming a magnesium oxide underlayer 20 on a surface of a substrate 10 by a sputtering method with using a target containing magnesium oxide; and a step of forming a magnetic layer 30 on the surface side of the magnesium oxide underlayer 20, in which the target containing the magnesium oxide is heated to more than 600°C when forming the magnesium oxide underlayer 20.SELECTED DRAWING: Figure 1

A method of manufacturing a magnetic recording medium includes burnishing, with an abrasive material, a surface of a stack including a magnetic recording layer and a protective layer stacked on a substrate in order of the magnetic recording layer and the protective layer. The burnishing of the surface of the stack includes using a long abrasive tape including abrasive grains as the abrasive material fixed onto a support in a state of being wound in roll form, and pressing the abrasive tape, supplied from the state of being wound in the roll form, against the surface of the stack so as to rub the surface of the stack. The abrasive tape in the state of being wound in the roll form is subjected to vacuum treatment in advance such that loose abrasive grains are reduced.

The present invention addresses the problem of providing a method for manufacturing a magnetic recording medium capable of improving the productivity of a magnetic recording medium. A method for manufacturing a magnetic recording medium according to the present invention comprises a polishing step for polishing the surface of a laminate in which a magnetic recording layer and a protective layer are laminated in this order on a substrate with a polishing material, the polishing step includes a step of using a long abrasive tape in a state in which abrasive grains, which are the abrasive material, are adhered to a support body, and pressing and rubbing the abrasive tape, which is supplied from the state in which the abrasive tape is wound in the state in which the abrasive tape is wound in the state in which the abrasive tape is wound in the state in which the abrasive tape is wound in the state in which the abrasive tape is wound in the state in which the abrasive tape is wound, against the surface of the laminate. The grinding belt in which abrasive grains that are dissociated by the vacuum treatment have been reduced in advance is used as the grinding belt that is wound in the roll shape.

A substrate for a magnetic disk, characterized by being composed of an aluminum alloy containing one or two or more of Fe: 8.5 mass% or less, Mn: 2.5 mass% or less, Ni: 6.5 mass% or less, and Mg: 4.5 mass% or less, with the remainder composed of Al and unavoidable impurities, a resonance frequency being f (Hz), a density being p (g / cm 3 ), and a plate thickness being t (mm), (f x p / t) being 3800 or more, and a magnetic disk using the substrate for a magnetic disk.

The invention provides a method for manufacturing a magnetic recording medium capable of improving the productivity of the magnetic recording medium. This method for manufacturing a magnetic recording medium comprises: a finishing step for finishing the surface of a laminated body in which a magnetic recording layer and a protective layer are laminated in this order on a substrate by means of an abrasive material, said finishing step comprising: using a long abrasive tape in a state in which the abrasive tape is wound into a roll; and a scraping step for scraping the surface of the laminated body by pressing the abrasive tape, which is supplied from the state of being wound into the roll shape and in which abrasive grains are adhered to a support as the abrasive material, on the surface of the laminated body, using the abrasive tape from which free abrasive grains have been removed by being rewound in advance, and scraping the surface of the laminated body by pressing the abrasive tape on the surface of the laminated body. And the grinding belt is wound into the roll shape.

The present application relates to a kind of thin mechanical hard disk with aluminium round sheet, the aluminium round sheet thickness is 0.5~0.8mm, diameter is 95.0~98.2mm, surface flatness is less than 5 μm;The present application also relates to a kind of flatness control method of thin mechanical hard disk with aluminium round sheet, including the following steps: aluminium coiled material striping, stamping blanking, flattening and primary annealing treatment, rough grinding treatment, secondary annealing treatment, fine grinding treatment;Wherein aluminium round sheet is flattened and primary annealing treatment when pressure is 120‑200Kg, annealing heating rate is 80℃ / h~200℃ / h, cooling rate is 30℃ / h~70℃ / h after annealing ends, annealing holding temperature is 320°C~360°C, holding time is 2h~5h.The flatness value of aluminium round sheet of the present application is not higher than 5 μm, can guarantee the stable performance of mechanical hard disk, reduce the influence of mechanical hard disk disc in work, guarantee the stable flatness of aluminium round sheet, flatness has no rebound phenomenon, and the processing yield is high.

To provide a glass for a magnetic recording medium substrate, a magnetic recording medium substrate, a magnetic recording medium, a glass spacer for a magnetic recording / reproducing device, and a magnetic recording / reproducing device, each of which has excellent chemical resistance and impact resistance.SOLUTION: A glass for a magnetic recording medium substrate is an amorphous glass with a SiO2 content of 54 mol% or more and 62 mol% or less, a MgO content of 15 mol% or more and 28 mol% or less, a Li2O content of 0.2 mol% or more, and a Na2O content of 5 mol% or less.SELECTED DRAWING: None

To provide a substrate for a magnetic disk, a magnetic disk, an annular-shaped substrate, and a manufacturing method for a substrate for a magnetic disk, to make it difficult for the annular-shaped substrate from a holding member that holds the annular-shaped substrate when double-sided grinding or polishing is performed on the annular-shaped substrate.SOLUTION: A glass substrate for a magnetic disk (magnetic disk substrate) 1 includes a pair of main surface 1p and outer peripheral end surface 5, the outer peripheral end surface has a pair of chamfered surfaces 1c, each of which is connected to the main surface, and a side wall surface 1t extending between the pair of chamfered surfaces and curved outwardly so as to be convex, and the side wall surface 1t has a radius of curvature Rt of 1100 μm or more in a cross-section along the plate thickness T direction of the magnetic disk substrate. To prevent the generation of fine particles, it is preferable that the outer peripheral end surface of the magnetic disk substrate is smoothed. In addition, it is preferable to align the outer peripheral end surface to a target shape.SELECTED DRAWING: Figure 2

A method for manufacturing a magnetic recording medium includes burnishing a surface of a laminated structure using an abrasive material, the laminated structure including a magnetic recording layer and a protective layer successively laminated on a substrate. The burnishing includes using a long abrasive tape including abrasive grains as the abrasive material fixed on a support in a state wound in a roll shape, and pressing the abrasive tape supplied from the state wound in the roll shape against the surface of the laminated structure, thereby abrading the surface of the laminated structure. The abrasive tape in the state wound in the roll shape is re-rolled in advance to remove loose abrasive grains therefrom.

A glass plate configured to be cut into glass substrates for magnetic recording disks is described. The glass plate includes a first surface. For surface features of the first surface having a characteristic wavelength of 60 to 500 micrometers (μm), the root mean square of the surface topography of the surface features determined using surface analysis on the first surface with incident light and reflected light is given as microwaviness. The maximum value of the microwaviness of any region of the first surface may be greater than or equal to 1.2 nanometers (nm) and less than or equal to 2.8 nm. After the surface analysis, the glass plate may be cut into glass substrates in response to determining that the maximum value of the microwaviness is within the range. Further, a method of manufacturing glass substrates from the glass plate is described.

A production method of a magnetic recording medium including a nonmagnetic substrate, a base layer over the nonmagnetic substrate, a seed layer over the base layer, and a magnetic recording layer over the seed layer. The production method of the magnetic recording medium includes forming the seed layer through a process including: forming a film including two elements, represented by element α and element β, such that the element α is mainly a columnar crystal having an fcc structure and the element β is mainly an amorphous structure; and etching a surface of the film to form a surface in which the element α and the element β are phase-separated from each other.

To provide a manufacturing method of a magnetic recording medium capable of further increasing the recording density by enhancing the perpendicular orientation of a magnetic recording layer, and to provide a magnetic recording and reproducing device equipped with the magnetic recording medium manufactured by the manufacturing method.SOLUTION: A method of manufacturing a magnetic recording medium according to the present invention is a method of manufacturing a magnetic recording medium including, on a non-magnetic substrate, an underlayer, a seed layer, and a magnetic recording layer in this order, wherein the seed layer is formed by forming a film containing two elements of an element α and an element β such that the element α mainly forms a columnar crystal having an fcc structure and the element β mainly forms an amorphous structure, and then etching a surface of the film to form a surface in which the element α and the element β are phase-separated from each other.SELECTED DRAWING: Figure 1

To provide a glass for a magnetic recording medium substrate having excellent chemical resistance and impact resistance.SOLUTION: A glass for a magnetic recording medium substrate or a glass spacer for a magnetic recording / reproducing device which is an amorphous glass, in which an SiO2 content is 56 mol% or more, an MgO content is 15 mol% or more and 28 mol% or less, an Li2O content is 0.2 mol% or more, an Na2O content is 5 mol% or less, a total content (Al2O3+MgO+CaO) of Al2O3, MgO and CaO is 29 mol% or more and 36.50 mol% or less, a total content (SiO2+MgO+Li2O+Al2O3+CaO) of SiO2, MgO, Li2O, Al2O3 and CaO is 95.0 mol% or more, a molar ratio [(SiO2+MgO) / Li2O] of a total content of SiO2 and MgO to the Li2O content is 13 or more, and a molar ratio [CaO / (Al2O3+MgO)] of a CaO content to a total content of Al2O3 and MgO is 0.10 or less.SELECTED DRAWING: None

A non-metallic media substrate includes a disc-shaped substrate body having at least one media storage surface on a face thereof. The substrate body has a center opening having an inner diameter and an outer diameter surface, and the substrate body has a thickness. The substrate further includes an annular groove at the outer diameter of the media substrate, the annular groove having chamfered edges and an internal concavity extending toward the inner diameter.

The purpose of the present invention is to provide: a method for manufacturing a magnetic recording medium, which can improve the vertical orientation of a magnetic recording layer and can further increase the recording density; and a magnetic recording / reproducing device provided with a magnetic recording medium manufactured by the manufacturing method. The method for manufacturing a magnetic recording medium according to the present invention is a method for manufacturing a magnetic recording medium provided with an underlayer, a seed layer, and a magnetic recording layer in this order on a non-magnetic substrate, the seed layer being formed by forming a film containing two elements, i.e., an element [alpha] and an element [beta], the element [alpha] being mainly a columnar crystal having an fcc structure, and the element [beta] being mainly a columnar crystal having an fcc structure. After the film is formed such that the element [beta] mainly has an amorphous structure, the surface of the film is etched to form a surface in which the element [alpha] and the element [beta] are separated from each other.

A glass sheet configured to be cut into glass substrates for magnetic recording disks is described. The glass sheet includes a first surface. For surface features of the first surface with a feature wavelength of 60 to 500 micrometers (μm), a root mean square of a surface topography of the surface features determined using a surface analysis on the first surface with incident and reflected light is given as a microwaviness. A maximum value of the microwaviness of any arbitrary region of the first surface may be between 1.2 nanometers (nm) and 2.8 nm, inclusive of 1.2 nm and 2.8 nm. After the surface analysis, the glass sheet may be cut into the glass substrates in response to determining that the maximum value of the microwaviness is in the noted range. Further, a method of fabricating glass substrates from a glass sheet is described.

The glass plate of one embodiment is a rectangular plate having a thickness of less than 0.68 mm. In this glass plate, the flatness of a square measurement area of 100 mm per side, said square measurement area being cut out from the center area of the glass plate excluding the edge areas on both of the long side direction and the short side direction of the glass plate, is 30 μm or less. When the measurement area is subjected to a first heat treatment in which the measurement area is maintained at 700°C for 4 hours and then cooled from 700°C to 400°C at a speed of 50°C / hour, the heat shrinkage of the measurement area is 130 ppm or less. When the measurement area is subjected to a second heat treatment in which the measurement area is maintained at Tg-160°C [wherein Tg (°C) stands for the glass transition temperature of the glass plate] for 60 seconds and then cooled to room temperature in air, the resulted amount of change in the flatness of the measurement area is 10 μm or less.

The present invention provides a glass substrate for magnetic disks that can suppress deterioration of flatness due to heat treatment for forming a magnetic recording layer, a disc-shaped glass used in such a glass substrate for magnetic disks, a glass plate, and a method for manufacturing a glass plate. [Solution] A rectangular glass plate with a thickness of less than 0.68 mm, wherein the flatness of a 100 mm square area to be measured, cut from the central region of the glass plate excluding the end regions on both sides in the short and long directions, is 30 μm or less; the thermal shrinkage rate of the area to be measured after a first heat treatment in which the area to be measured is maintained at 700°C for 4 hours and then cooled from 700°C to 400°C at a rate of 50°C / hour is 130 ppm or less; and when the glass transition temperature of the glass plate is expressed as Tg (°C), the change in the flatness of the area to be measured after a second heat treatment in which the area to be measured is maintained at Tg-160°C for 60 seconds and then cooled to room temperature in the air is 10 μm or less.

To provide a manufacturing method of a magnetic recording medium capable of enhancing productivity of the magnetic recording medium.SOLUTION: A method for manufacturing a magnetic recording medium according to the present invention includes a burnishing step of burnishing, with an abrasive, a surface of a laminate in which a magnetic recording layer and a protective layer are laminated in this order on a substrate, the burnishing step includes a step of using a long polishing tape in which abrasive grains are fixed as the polishing material on a support in a state of being wound in a roll shape, and pressing the polishing tape supplied from the state of being wound in a roll shape against the surface of the laminate to rub the surface, in which the polishing tape in which free abrasive grains are reduced by performing a vacuum treatment in advance is used as the polishing tape in the state of being wound in a roll shape.SELECTED DRAWING: Figure 2

Various apparatuses, systems, methods, and media are disclosed to provide a magnetic recording medium having a tungsten (W) pre-seed layer. The W pre-seed layer has higher electrical conductivity than a CrTi pre-seed layer having a similar thickness. In one embodiment, the W pre-seed layer is made of about 95 atomic percent or greater than 95 atomic percent W. The W pre-seed layer has a lower resistivity than the CrTi pre-seed layer. Thus, if similar electrical conductivity is achieved, the thickness of the W pre-seed layer can be reduced compared to the thickness of the CrTi pre-seed layer. Magnetic recording materials deposited on top of the W pre-seed layer having the reduced thickness provide comparable crystalline orientation and recording performance to those magnetic recording materials deposited on top of a thicker CrTi pre-seed layer having similar electrical conductivity.

The present invention intends to provide a magnetic disk that is flat while being thin and hardly causes physical errors.The present invention provides a magnetic disk having a hole in the center, a thickness of 0.60 mm or less, TIRs on circles having different radial distances r1 (mm) and r2 (mm) denoted by TIR1 (μm) and TIR2 (μm), and an amount of radial variation ΔTIR for TIRs of 0.50 μm / mm or less in an outer circumferential region of the magnetic disk with r / R=0.70 to 0.99, where “R” is a disk radius (mm), “r” is a radial distance (mm) measured from the disk center, and the ΔTIR is represented by an absolute value |(TIR1−TIR2) / (r1−r2)| of the ratio of the difference (TIR1−TIR2) between the TIR1 and the TIR2 to the difference (r1−r2) between r1 and r2 of the magnetic disk.

In a method for manufacturing a glass plate that includes chamfering processing for chamfering an edge surface of a glass plate, the chamfering processing includes a step of forming a chamfered surface by irradiating the edge surface of the glass plate with a laser beam, and a step of heating the glass plate before the chamfered surface is formed. When a temperature of the glass blank at which the glass blank is heated is Tp [° C.], a glass transition point of the glass blank is Tg [° C.], and an average coefficient of linear thermal expansion of the glass blank is α [1 / ° C.], (Tg−Tp)≤−5.67×107·α+840 is satisfied.

The present invention provides a magnetic disk that is thin and flat and is less likely to have physical errors. The present invention is a magnetic disk having a hole in a center portion and a thickness dimension of 0.60 mm or less, wherein, when the radius of the disk is set as R (mm), the radial distance measured from the center of the disk is set as r (mm), TIR at the outer peripheral side region of the disk where r / R is 0.70 or more and 0.99 or less is set as TIR1 (μm) and TIR2 (μm) when measured on the circumferences at different radial distances r1 (mm) and r2 (mm), and the radial variation amount ΔTIR of TIR represented by the absolute value of the ratio of the difference (TIR1-TIR2) between TIR1 and TIR2 to the difference (r1-r2) between the radial distance r1 and the radial distance r2 of the disk |(TIR1-TIR2) / (r1-r2)| is 0.50 μm / mm or less.

An annular glass plate has an outer circumferential edge surface, an inner circumferential edge surface, and a thickness not larger than 0.6 mm. The outer circumferential edge surface and the inner circumferential edge surface are constituted by molten surfaces. The molten surfaces in the outer circumferential edge surface and the inner circumferential edge surface each have an arithmetic average surface roughness Ra not larger than 0.1 μm and the surface roughness of the molten surface in the inner circumferential edge surface is larger than the surface roughness of the molten surface in the outer circumferential edge surface. The molten surfaces in the inner circumferential edge surface and the outer circumferential edge surface do not bulge relative to both main surfaces of the annular glass plate.

The present invention intends to provide a substrate for a magnetic disk and a method for manufacturing same, and a magnetic disk capable of holding high flatness after long-term use despite being thin, coping with a high capacity of hard disk, and improving long-term reliability thereof. In the substrate according to the present invention, when a process for heating a substrate at 120° C. for 30 minutes and then cooling the substrate at −40° C. for 30 minutes is defined as one cycle, the flatness PV of a surface of the substrate measured at 25° C. after a thermal impact test in which the cycle is repeatedly performed 200 times is not more than 12 μm. The present invention further encompasses a magnetic disk having a similar flatness PV under the same conditions. The present invention still further encompasses a method for manufacturing the substrate for a magnetic disk.

A disk for use in a hard disk drive (HDD) or other magnetic recording device. The disk is configured based on the discovery that internal stress within the disk can make the disk more resistant to impact forces. In one example, a disk is provided having a substrate with a thickness of no more than 0.5 millimeters and an internal stress of no less than 300 megapascals. The relatively higher internal stress within the substrate of the disk is used to reduce the magnitude of deflection of an HDD in which the disk is installed caused by mechanical impact, as compared to other disks of the same thickness but having a relatively smaller internal stress. A multi-disk stack of disks is described. Methods for manufacturing such disks and for rejecting disks that do not meet certain internal stress-based criteria are also described. Substrates are also described.

A magnetic disk substrate includes an aluminum alloy including one type or two or more types of Fe: 8.5 mass % or less, Mn: 2.5 mass % or less, Ni: 6.5 mass % or less, and Mg: 4.5 mass % or less, a balance being Al and unavoidable impurities, wherein, when f (Hz) is a resonance frequency, ρ (g / cm3) is a density, and t (mm) is a plate thickness, (f×ρ / t) is 3800 or greater; and a magnetic disk using the magnetic disk substrate.

A glass sheet configured to be cut into glass substrates for magnetic recording disks is described. The glass sheet includes a first surface. For surface features of the first surface with a feature wavelength of 60 to 500 micrometers (μm), a root mean square of a surface topography of the surface features determined using a surface analysis on the first surface with incident and reflected light is given as a microwaviness. A maximum value of the microwaviness of any arbitrary region of the first surface may be between 1.2 nanometers (nm) and 2.8 nm, inclusive of 1.2 nm and 2.8 nm. After the surface analysis, the glass sheet may be cut into the glass substrates in response to determining that the maximum value of the microwaviness is in the noted range. Further, a method of fabricating glass substrates from a glass sheet is described.