28results about "Base layers for recording layers" patented technology

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.

A glass for magnetic recording medium substrate is an amorphous oxide glass. In terms of mol %, SiO2 content ranges from 45 to 68%, Al2O3 from 5 to 20%, total content of SiO2 and Al2O3 60 to 80%, B2O3 from 0 to 5%, MgO from 3 to 28%, CaO from 0 to 18%, total content of BaO and SrO 0 to 2%, total content of alkali earth metal oxides from 12 to 30%, total content of alkali metal oxides from 3.5 to 15%, and at least one kind selected from the group made of Sn oxide and Ce oxide being included, a total content of Sn oxide and Ce oxide ranges from 0.05 to 2.00%, a glass transition temperature ≥625° C., a Young's modulus ≥83 GPa, a specific gravity ≤2.85, and an average linear expansion coefficient at 100 to 300° C.≥48×10−7 / ° C.

A main object of the present technology is to improve reliability and resolution of a magnetic recording tape by controlling distribution of the binder in the underlayer and a magnetic surface.The present technology provides a magnetic recording medium including: a magnetic layer; an underlayer; and a base layer in this order, in which the underlayer contains a chlorine-containing binder, and in the underlayer, a part having a chlorine count equal to or more than a threshold described below has a thickness of 130 nm or less, and a core portion level difference Rk is 5.5 nm or less and an average thickness of the underlayer is 1100 nm or less in a bearing curve created on the basis of height data of a magnetic layer side surface acquired using an atomic force microscope.[Threshold]=[an⁢ average⁢ chlorine⁢ count⁢ in⁢ the⁢ underlayer]+⁠6×
[a⁢ standard⁢ deviation⁢ determined⁢ in⁢ calculation⁢ of⁢ the⁢ average⁢ chlorine⁢ count]

Provided are: a magnetic tape cartridge in which a magnetic tape is accommodated; and a magnetic recording / playback device including the magnetic tape cartridge. The magnetic tape includes a polyethylene naphthalate support having a Young's modulus in the width direction of 10,000 MPa or more. A medium life of the magnetic tape calculated using a linear function of logarithm logeT of A and T is 3 years or more, which is derived from a value of A and a value of logarithm logeT of T which are respectively obtained when A is the maximum value of the absolute value of the difference between the servo band interval obtained before storage under an environment of 32 °C and a relative humidity of 80% and the servo band interval obtained after storage for the storage time T under said environment, and T is 24 hours, 48 hours, 72 hours, 96 hours, or 120 hours.

To provide an alkali-free glass panel that has excellent productivity and also has sufficiently high strain points and Young's moduli.SOLUTION: An alkali-free glass panel has a glass composition containing, in mol%, SiO2 64-72%, Al2O3 11-15%, B2O3 0-4%, Li2O+Na2O+K2O 0-0.5%, MgO 5-12%, CaO 7-12%, SrO 0-1%, BaO 0-1%, and MgO+CaO+SrO+BaO 15-19% with the mol% ratio B2O3 / Al2O3 of 0.1-0.4 and the mol% ratio MgO / CaO of 0.1-1.5.SELECTED DRAWING: Figure 1

The purpose of the present invention is to provide a magnetic recording medium that has excellent running stability even when stored in a high-temperature environment.　The present invention provides a magnetic recording medium in which, when dynamic viscoelasticity measurement is performed on the magnetic recording medium at a frequency of 10 Hz and a heating rate of 2°C / min, the average value A(E") of the loss elastic modulus E" in the temperature range of 60°C to 65°C is 0.06 GPa or less, and the average height Rpk of the protruding peaks measured using a non-contact profilometer using optical interference is 2.4 nm or less.

To provide a magnet tape which may contribute to operational stability improvement of a drive during recording and / or reproduction after prolonged storage.SOLUTION: A magnetic tape comprising a non-magnetic support body and a magnetic layer containing ferromagnetic powder is provided, the magnetic tape exhibiting a nonlinear component of a signal phase difference of 17.5 nm or less after 10-day storage in an environment with temperature of 60°C and relative humidity of 20%. Also provided are a magnetic tape cartridge comprising the magnetic tape, and a magnetic tape device.SELECTED DRAWING: None

To provide a substrate for magnetic recording media that has high heat resistance and specific modulus, and has low manufacturing costs. [Solution] The magnetic recording medium substrate according to this disclosure has a heat-resistant film on the surface of a steatite sintered body made of one or more alloys selected from the group consisting of SiO2, SiC, Si3N4, and Al2O3.

To provide a substrate for magnetic recording media that has high heat resistance and specific modulus, and has low manufacturing costs. [Solution] The magnetic recording medium substrate according to this disclosure includes a steatite sintered body.

Provided is a magnetic tape cartridge group including a plurality of magnetic tape cartridges. The magnetic tape contained in the magnetic tape cartridges includes a polyethylene naphthalate support having a Young's modulus of 10000 MPa or greater in the width direction. The arithmetic mean of media life calculated according to a linear function derived from the value of A determined for different values of N and the logarithm value of total storage time T for storage for N cycles is 3 years or more and 3σ is 1 year or less, where A is the maximum absolute value of the difference between a servo band interval determined before prescribed storage and a servo band interval determined after the prescribed storage for 100 magnetic tape cartridges.

To provide a magnet tape which may contribute to operational stability improvement of a drive during recording and / or reproduction after prolonged storage.SOLUTION: A magnetic tape comprising a non-magnetic support body and a magnetic layer containing ferromagnetic powder is provided, the magnetic tape exhibiting a nonlinear component of tape width deformation of 100 nm or less after 10-day storage in an environment with temperature of 60°C and relative humidity of 20%. Also provided are a magnetic tape cartridge comprising the magnetic tape, and a magnetic tape device.SELECTED DRAWING: None

Provided is a magnetic tape apparatus. While magnetic tape is traveling within the magnetic tape apparatus, the angle θ formed by the axis of an element array of a magnetic head relative to the width direction of the magnetic tape is changed. The media life calculated according to a linear function of A and the logarithm logeT of T, derived from values of A determined with N equal to each of 1, 2, 3, 4 and 5 and from the value of the logarithm logeT of the total storage time T for storage for N cycles, is five years or more, where A is the maximum absolute value of the difference between a servo band interval determined before storage and a servo band interval determined after storage for N cycles, prescribed storage being one cycle. The media life is T when A satisfies the formula a: A=1.5−B+C.

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.

To stably provide a biaxially oriented polyester film which has excellent dimensional stability in all temperature and humidity ranges of low temperature and low humidity, low temperature and high humidity, high temperature and low humidity, and high temperature and high humidity, and satisfies both of excellent surface smoothness and slitting property.SOLUTION: A biaxially oriented polyester film where, on at least one outermost layer surface (face B), the number of projections with a height of 50 nm or more is 50,000 / mm2 or less, the number of projections with a height of 100 nm or more is 15,000 / mm2 or less, and a surface average roughness SaB of the layer is larger than the surface average roughness SaA of another outermost surface (face A).SELECTED DRAWING: None

One aspect of the present disclosure provides a polishing liquid for a magnetic disk substrate, the polishing liquid being capable of reducing waviness on a surface of the magnetic disk substrate.　One aspect of the present disclosure relates to a polishing liquid for a magnetic disk substrate, the polishing liquid comprising silica particles (component A) and an acid (component B), wherein the maximum ammonia desorption temperature of the silica particles measured by an ammonia temperature-programmed desorption method is 150°C-250°C.

Provided is a magnetic-tape cartridge group containing a plurality of magnetic tape cartridges. A magnetic tape included in the magnetic tape cartridges contains a polyethylene-naphthalate support element having a widthwise Young's modulus of 10,000 MPa or greater. For 100 reels of magnetic tape cartridges, letting the maximum absolute value of the difference between a servo band interval found prior to storage under a prescribed environment, and a servo band interval found following storage for a storage time T under the prescribed environment be A, then the arithmetic mean of media life calculated by a linear function derived from the value of A and the value of the logarithm of T, loge T, is four years or more, and the 3σ is one year or less.

Provided are a magnetic recording medium and a magnetic recording cartridge. An average thickness of the magnetic recording medium tT is tT≤5.3 μm, a ratio (A2 / A1) of an average creep slope A2 at a temperature of 32° C. and a humidity of 80% RH to an average creep slope A1 at a temperature of 32° C. and a humidity of 20% RH is 1.440 or less, and a ratio (Tan δ2 / Tan δ1) of an average Tan δ2 at a temperature of 32° C. and a humidity of 80% RH to an average Tan δ1 at a temperature of 32° C. and a humidity of 20% RH is less than 1.2100. The magnetic recording cartridge includes the magnetic recording medium, a memory and a case that accommodates the magnetic recording medium and the memory.

Provided is a magnetic tape device. While the magnetic tape is running in the magnetic tape device, an angle θ formed by an axis line of an element array of a magnetic head with respect to the width direction of the magnetic tape is changed. A medium life calculated using a linear function of logarithm logeT of A and T is 5 years or more, which is derived from a value of A and a value of logarithm logeT of T which are respectively obtained when A is the maximum value of the absolute value of the difference between the servo band interval obtained before storage under a predetermined environment and the servo band interval obtained after storage for the storage time T under said environment, and T is a plurality of predetermined times. The medium life is T when A satisfies a predetermined expression. The magnetic tape includes a polyethylene naphthalate support having a Young's modulus in the width direction of 10,000 MPa or more.

Provided is a disc device capable of suppressing a decrease in stability of positioning of a magnetic head with respect to a disc. A disc device of one embodiment has a piezoelectric element and a flexible member. The piezoelectric element has a first electrode and a second electrode. The flexible member has a first portion and a second portion to which the second electrode is joined. The first portion has a first surface to which the first electrode is joined. The second portion has a second surface to which a magnetic head is joined. The magnetic head has a third surface facing the first surface and the second surface. An end portion of the first surface and the third surface in a first direction faces each other. An end portion of the second surface and the third surface in a second direction faces each other. A distance between the end portion of the first surface and the third surface in the first direction is longer than a distance between the end portion of the second surface and the third surface in the second direction.

In one embodiment, a polishing solution for magnetic disk substrates is provided that can reduce waviness on the surface of the magnetic disk substrate. [Solution] In one embodiment, this disclosure relates to a polishing solution for magnetic disk substrates comprising silica particles (component A) and an acid (component B), wherein the maximum ammonia desorption temperature of the silica particles, as measured by an ammonia temperature rise desorption method, is 150°C or higher and 250°C or lower.

The present invention provides an abrasive composition for magnetic disk substrates that achieves a high polishing speed and reduces shallow pitting on the substrate surface without using alumina particles. [Solution] The polishing composition for magnetic disk substrates contains colloidal silica, wet silica particles, sorbitan fatty acid ester and / or sucrose fatty acid ester, acid and / or salt thereof, an oxidizing agent, and water, wherein the proportion of particles with a particle diameter of 30 to 70 nm in the colloidal silica is 10 to 90% by volume, the sorbitan fatty acid ester is at least one compound selected from sorbitan monolaurate, sorbitan monomyristate, etc., and the sucrose fatty acid ester is at least one compound selected from sucrose monolaurate, sucrose monomyristate, sucrose monopalmitate, etc.

Provided are a magnetic tape cartridge in which a magnetic tape is accommodated, and a magnetic recording playback device including the magnetic tape cartridge. The magnetic tape includes a polyethylene naphthalate support having a Young's modulus of 10000 MPa or greater in the width direction. The media life calculated according to a linear function derived from the value of A and the value of the logarithm logeT of total storage time T for storage for N cycles is 3 years or more, where A is the maximum absolute value of the difference between a servo band interval before storage of the magnetic tape and a servo band interval determined after storage for N cycles, with prescribed storage being one cycle.

Embodiments of the present invention relate to a magnetic recording apparatus. According to one embodiment, the magnetic recording apparatus includes: a disc-shaped recording medium having a recording surface coated with a lubricant; a magnetic head including a recording element, a light source, and a light-emitting element that illuminates the recording surface of the recording medium; and a controller including a light source control circuit that controls the driving current value of the light source, a cleaning execution circuit that performs a cleaning action to remove deposits adhering to the magnetic head, and a setting circuit that sets a cleaning interval for performing the cleaning action.