WO2014136751A1 - Substrat en verre pour supports d'enregistrement d'information, et support d'enregistrement d'information - Google Patents

Substrat en verre pour supports d'enregistrement d'information, et support d'enregistrement d'information Download PDF

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Publication number
WO2014136751A1
WO2014136751A1 PCT/JP2014/055396 JP2014055396W WO2014136751A1 WO 2014136751 A1 WO2014136751 A1 WO 2014136751A1 JP 2014055396 W JP2014055396 W JP 2014055396W WO 2014136751 A1 WO2014136751 A1 WO 2014136751A1
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WIPO (PCT)
Prior art keywords
glass substrate
information recording
recording medium
glass
sio
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PCT/JP2014/055396
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English (en)
Japanese (ja)
Inventor
大士 梶田
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Hoya株式会社
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Application filed by Hoya株式会社 filed Critical Hoya株式会社
Priority to JP2015504317A priority Critical patent/JP6029740B2/ja
Publication of WO2014136751A1 publication Critical patent/WO2014136751A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/095—Glass compositions containing silica with 40% to 90% silica, by weight containing rare earths
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C21/00—Treatment of glass, not in the form of fibres or filaments, by diffusing ions or metals in the surface
    • C03C21/001—Treatment of glass, not in the form of fibres or filaments, by diffusing ions or metals in the surface in liquid phase, e.g. molten salts, solutions
    • C03C21/002—Treatment of glass, not in the form of fibres or filaments, by diffusing ions or metals in the surface in liquid phase, e.g. molten salts, solutions to perform ion-exchange between alkali ions
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C3/00—Glass compositions
    • C03C3/04—Glass compositions containing silica
    • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
    • C03C3/097—Glass compositions containing silica with 40% to 90% silica, by weight containing phosphorus, niobium or tantalum
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/62—Record carriers characterised by the selection of the material
    • G11B5/73—Base layers, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer
    • G11B5/739—Magnetic recording media substrates
    • G11B5/73911—Inorganic substrates
    • G11B5/73921—Glass or ceramic substrates

Definitions

  • the present invention relates to a glass substrate for an information recording medium and an information recording medium mounted as part of the information recording medium in an information recording apparatus such as a hard disk drive (HDD).
  • HDD hard disk drive
  • Patent Document 1 Japanese Patent Laid-Open No. 2005-015328
  • Patent Document 2 Japanese Patent Laid-Open No. 2005-314159
  • the Tg which is an index of heat resistance of the glass substrate, is improved to 600 ° C. or higher.
  • a high-temperature heat treatment at about 600 ° C. is performed during the film formation of the Fe—Pt magnetic material on the glass substrate.
  • the present invention has been made to solve the above-described problems, and suppresses deformation of the glass substrate and suppresses diffusion of Li from the glass substrate during film formation of the magnetic recording medium and high-temperature annealing.
  • a glass substrate for an information recording medium and an information recording medium are provided.
  • the glass substrate for information recording medium is a glass substrate for heat assist recording.
  • the information recording medium according to the present invention has a magnetic recording layer on the glass substrate for information recording medium described above.
  • the glass substrate for an information recording medium and the information recording capable of suppressing the deformation of the glass substrate and suppressing the diffusion of Li from the glass substrate at the time of film formation and high temperature annealing of the magnetic recording medium.
  • a medium can be provided.
  • FIG. 2 is a perspective view showing an information recording device 30.
  • FIG. It is a top view which shows the glass substrate 1 manufactured by the manufacturing method of the glass substrate for information recording media based on this Embodiment.
  • FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2.
  • FIG. 5 is a cross-sectional view taken along line VV in FIG. 4.
  • FIG. 1 is a perspective view showing the information recording apparatus 30.
  • the information recording apparatus 30 includes the glass substrate 1 manufactured by the method for manufacturing a glass substrate for information recording medium (hereinafter also simply referred to as a glass substrate) in the embodiment as the information recording medium 10.
  • the information recording device 30 includes an information recording medium 10, a housing 20, a head slider 21, a suspension 22, an arm 23, a vertical shaft 24, a voice coil 25, a voice coil motor 26, a clamp member 27, and a fixing screw. 28.
  • a spindle motor (not shown) is installed on the upper surface of the housing 20.
  • An information recording medium 10 such as a magnetic disk is rotatably fixed to the spindle motor by a clamp member 27 and a fixing screw 28.
  • the information recording medium 10 is rotationally driven by this spindle motor at, for example, several thousand rpm.
  • a compression stress layer 12 see FIG. 5
  • a magnetic recording layer 14 see FIGS. 4 and 5 are formed on the glass substrate 1. To be manufactured.
  • the arm 23 is attached so as to be swingable around the vertical axis 24.
  • a suspension 22 formed in a leaf spring (cantilever) shape is attached to the tip of the arm 23.
  • a head slider 21 is attached to the tip of the suspension 22 so as to sandwich the information recording medium 10.
  • a voice coil 25 is attached to the opposite side of the arm 23 from the head slider 21.
  • the voice coil 25 is clamped by a magnet (not shown) provided on the housing 20.
  • a voice coil motor 26 is constituted by the voice coil 25 and the magnet.
  • a predetermined current is supplied to the voice coil 25.
  • the arm 23 swings around the vertical axis 24 by the action of electromagnetic force generated by the current flowing through the voice coil 25 and the magnetic field of the magnet.
  • the suspension 22 and the head slider 21 also swing in the direction of the arrow AR1.
  • the head slider 21 reciprocates on the front and back surfaces of the information recording medium 10 in the radial direction of the information recording medium 10.
  • a magnetic head (not shown) provided on the head slider 21 performs a seek operation.
  • the head slider 21 While the seek operation is performed, the head slider 21 receives a levitation force due to the air flow generated as the information recording medium 10 rotates. Due to the balance between the levitation force and the elastic force (pressing force) of the suspension 22, the head slider 21 travels with a constant flying height with respect to the surface of the information recording medium 10. By the traveling, the magnetic head provided on the head slider 21 can record and reproduce information (data) on a predetermined track in the information recording medium 10.
  • the information recording apparatus 30 on which the glass substrate 1 is mounted as a part of the members constituting the information recording medium 10 is configured as described above.
  • FIG. 2 is a plan view showing glass substrate 1 manufactured by the method for manufacturing a glass substrate for information recording medium according to the present embodiment.
  • 3 is a cross-sectional view taken along the line III-III in FIG.
  • the glass substrate 1 (glass substrate for information recording medium) used as a part of the information recording medium 10 (see FIGS. 4 and 5) has a main surface 2, a main surface 3, It has the inner peripheral end surface 4, the hole 5, and the outer peripheral end surface 6, and is formed in a disk shape as a whole.
  • the hole 5 is provided so as to penetrate from one main surface 2 toward the other main surface 3.
  • a chamfer 7 is formed between the main surface 2 and the inner peripheral end surface 4 and between the main surface 3 and the inner peripheral end surface 4.
  • a chamfered portion 8 (chamfer portion) is formed between the main surface 2 and the outer peripheral end surface 6 and between the main surface 3 and the outer peripheral end surface 6, a chamfered portion 8 (chamfer portion) is formed.
  • the size of the glass substrate 1 is, for example, 0.8 inch, 1.0 inch, 1.8 inch, 2.5 inch, or 3.5 inch. It is possible to make the size smaller than this or larger than this.
  • the thickness of the glass substrate is, for example, 0.30 mm to 2.2 mm from the viewpoint of preventing breakage.
  • the glass substrate has an outer diameter of about 64 mm, an inner diameter of about 20 mm, and a thickness of about 0.8 mm.
  • the thickness of the glass substrate is a value calculated by averaging the values measured at a plurality of arbitrary points to be pointed on the glass substrate. From the viewpoint of increasing the hardness of the glass substrate, the Vickers hardness of the glass substrate 1 is preferably 610 kg / mm 2 or more.
  • FIG. 4 is a plan view showing an information recording medium 10 provided with a glass substrate 1 as an information recording medium.
  • FIG. 5 is a cross-sectional view taken along the line VV in FIG.
  • the information recording medium 10 includes a glass substrate 1, a compressive stress layer 12, and a magnetic recording layer 14.
  • the compressive stress layer 12 is formed so as to cover the main surfaces 2 and 3, the inner peripheral end face 4, and the outer peripheral end face 6 of the glass substrate 1.
  • the magnetic recording layer 14 is formed so as to cover a predetermined region on the main surfaces 2 and 3 of the compressive stress layer 12.
  • the magnetic recording layer 14 is formed on both the compressive stress layer 12 formed on the main surface 2 and the compressive stress layer 12 formed on the main surface 3 (both sides). Is formed.
  • the magnetic recording layer 14 may be provided only on the compression stress layer 12 (one side) formed on the main surface 2, or on the compression stress layer 12 (one side) formed on the main surface 3. It may be provided.
  • the magnetic recording layer 14 is formed by spin-coating a thermosetting resin in which magnetic particles are dispersed on the compressive stress layer 12 on the main surfaces 2 and 3 of the glass substrate 1 (spin coating method).
  • the magnetic recording layer 14 may be formed by a sputtering method or an electroless plating method performed on the compressive stress layer 12 on the main surfaces 2 and 3 of the glass substrate 1.
  • the thickness of the magnetic recording layer 14 is about 0.3 ⁇ m to 1.2 ⁇ m for the spin coating method, about 0.04 ⁇ m to 0.08 ⁇ m for the sputtering method, and about 0.05 ⁇ m to about the electroless plating method. 0.1 ⁇ m. From the viewpoint of thinning and high density, the magnetic recording layer 14 is preferably formed by sputtering or electroless plating.
  • a Co-based alloy or the like containing Ni or Cr as a main component is added for the purpose of adjusting the residual magnetic flux density. Is preferably used.
  • Fe—Pt magnetic materials have been used as magnetic layer materials suitable for heat-assisted recording.
  • the surface of the magnetic recording layer 14 may be thinly coated with a lubricant.
  • a lubricant include those obtained by diluting perfluoropolyether (PFPE), which is a liquid lubricant, with a solvent such as Freon.
  • the magnetic recording layer 14 may be provided with a base layer or a protective layer as necessary.
  • the underlayer in the information recording medium 10 is selected according to the type of magnetic film. Examples of the material for the underlayer include at least one material selected from nonmagnetic metals such as Cr, Mo, Ta, Ti, W, V, B, Al, and Ni.
  • the underlayer provided on the magnetic recording layer 14 is not limited to a single layer, and may have a multilayer structure in which the same or different layers are stacked.
  • a multilayer underlayer such as Cr / Cr, Cr / CrMo, Cr / CrV, NiAl / Cr, NiAl / CrMo, or NiAl / CrV may be used.
  • Examples of the protective layer for preventing wear and corrosion of the magnetic recording layer 14 include a Cr layer, a Cr alloy layer, a carbon layer, a hydrogenated carbon layer, a zirconia layer, and a silica layer. These protective layers can be formed continuously with an in-line type sputtering apparatus together with the underlayer and the magnetic film. These protective layers may be a single layer, or may have a multilayer structure composed of the same or different layers.
  • protective layers may be formed on the protective layer or instead of the protective layer.
  • colloidal silica fine particles are dispersed and coated on a Cr layer with tetraalkoxylane diluted with an alcohol solvent, and then fired to form a silicon oxide (SiO2) layer. May be.
  • the glass substrate manufacturing method S100 in the present embodiment includes a plate-like glass forming step S10, a cut-out forming step S20, a blasting step S30, a lapping step S40, an end surface polishing step S50, a rough polishing step S60, a cleaning step S65, and a chemical strengthening step. S70, precision polishing process S80, and scrub cleaning process S90 are provided.
  • the magnetic thin film forming step S200 is performed on the glass substrate obtained through the scrub cleaning step S90. Through the magnetic thin film forming step S200, the information recording medium 10 (see FIGS. 4 and 5) is obtained.
  • the details of the steps S10 to S90 constituting the glass substrate manufacturing method S100 will be described in order.
  • a glass sheet is manufactured using a known glass forming method such as a direct press method, a float method, a down draw method, a redraw method, or a fusion method using a molten glass as a material.
  • a known glass forming method such as a direct press method, a float method, a down draw method, a redraw method, or a fusion method using a molten glass as a material.
  • the blended raw material is put into a platinum crucible in an electric furnace heated to 1300 to 1550 ° C., etc., melted and clarified, stirred and homogenized, cast into a preheated mold, and gradually cooled into a glass block.
  • the direct press method can be directly molded from a melted glass into a target glass molded product, and is therefore suitable for producing a large amount of sheet glass having the same shape.
  • molten glass is supplied to a press mold and pressed with a press mold while the glass is in a softened state to form a sheet glass. After being held for 1 to 3 hours at a temperature near the glass transition point, it is gradually cooled.
  • the glass substrate 1 has a Vickers hardness of 610 kg / mm 2 or more.
  • a material of the glass substrate for example, amorphous glass or crystallized glass can be used.
  • chemical strengthening can be appropriately performed, and a glass substrate for an information recording medium excellent in flatness of the main surface and substrate strength can be provided.
  • blasting step S30 a plurality of particles (abrasive grains) 200 are sprayed on the main surfaces 2 and 3 of the glass substrate 1 formed by the plate-like glass forming step S10, whereby the main of the glass substrate (glass substrate precursor) 1 is obtained. Surfaces 2 and 3 are ground (first grinding step).
  • the average Ra of the glass substrate 1 is set to about 2.0 ⁇ m.
  • lapping step S40 In the lapping step (second grinding step) S40, lapping (second grinding) is performed on the main surface of the glass substrate 1 using a lapping machine (not shown). Both main surfaces of the glass substrate 1 are ground by the lapping machine.
  • End face polishing step S50 In the end surface polishing step S50, the inner peripheral end surface and the outer peripheral end surface of the glass substrate 1 are polished using a polishing brush having a spiral brush bristle material. While supplying the polishing slurry between the polishing brush and each end surface of the glass substrate 1, the polishing brush is rotated in contact with each end surface. With the glass substrate 1 immersed in the polishing liquid, the polishing brush may be rotated in contact with each end face.
  • the glass substrate 1 whose inner peripheral end face and outer peripheral end face are polished has its main surfaces 2 and 3 polished roughly in a plurality of times.
  • the main surfaces 2 and 3 are polished in two steps of the first and second rough polishing steps.
  • the first rough polishing step is mainly intended to remove scratches and distortions remaining on the main surfaces 2 and 3 in the lapping step, and the second rough polishing step The purpose is to finish the main surfaces 2 and 3 in a mirror shape.
  • the glass substrate 1 is subjected to a cleaning process using an acidic cleaning liquid.
  • the purpose of this cleaning treatment is to remove from the surface of the glass substrate 1 any of cerium oxide, zirconium oxide, or zirconium silicate used as a polishing slurry in the rough polishing step S60, which is the previous step.
  • the surface of the glass substrate 1 is etched using a cleaning liquid containing sulfuric acid and / or hydrofluoric acid. Wash.
  • the polishing slurry such as cerium oxide, zirconium oxide, or zirconium silicate adhering to the surface of the glass substrate 1 is appropriately removed by a strongly acidic cleaning liquid such as sulfuric acid and / or hydrofluoric acid. Thereafter, the glass substrate 1 is cleaned using an acidic cleaning solution.
  • the cleaning liquid used in the cleaning step S65 varies depending on the chemical resistance of the glass substrate 1, but a concentration of about 1% to 30% is preferable for sulfuric acid, and 0.2% to 5% for hydrofluoric acid. A concentration of about is preferred. Cleaning using these cleaning liquids may be performed while applying ultrasonic waves in a cleaning machine in which an aqueous solution is stored.
  • the frequency of the ultrasonic wave used at this time is preferably 78 kHz or higher.
  • the glass substrate 1 is chemically strengthened.
  • the chemical strengthening liquid for example, a mixed liquid of potassium nitrate (50 wt%) and sodium sulfate (50 wt%) can be used.
  • the chemical strengthening liquid is heated to, for example, 300 ° C. to 480 ° C.
  • the cleaned glass substrate 1 is preheated to 300 ° C. to 480 ° C., for example.
  • the glass substrate 1 is immersed in the chemical strengthening solution for 3 hours to 4 hours, for example.
  • the plurality of glass substrates 1 can be held in their respective holders so that the entire main surfaces 2 and 3 of the glass substrate 1 are chemically strengthened. preferable.
  • alkali metal ions lithium ions and sodium ions
  • salts sodium ions
  • potassium ions potassium ions
  • the surface of the glass substrate 1 is strengthened by the formation of the compressive stress layer, and the glass substrate 1 has good impact resistance.
  • the glass substrate 1 subjected to the chemical strengthening treatment is appropriately washed.
  • the glass substrate 1 is further cleaned using pure water or IPA (isopropyl alcohol) after being cleaned with sulfuric acid. Thereafter, the chemically strengthened layer may be removed.
  • IPA isopropyl alcohol
  • precision polishing step S80 After the chemical strengthening step S70, a precision polishing process is performed on the glass substrate 1.
  • the precision polishing step S80 is intended to finish the main surface of the glass substrate 1 in a mirror shape.
  • the precision polishing step S80 similarly to the rough polishing step S60 described above, the glass substrate 1 is precisely polished using a double-side polishing machine (see FIG. 11).
  • the composition of the polishing abrasive grains contained in the polishing liquid (slurry) used and the polishing pad used are different.
  • the grain size of the abrasive grains in the polishing liquid supplied to the main surfaces 2 and 3 of the glass substrate 1 on which the compressive stress layer is formed is made smaller than in the rough polishing step S60. Soften the hardness.
  • the polishing pad used in the precision polishing step S80 is, for example, a soft foam resin polisher.
  • the precision polishing step S80 uses loose abrasive grains, and includes a first polishing step with abrasive grains mainly composed of Ce and a second polishing step of polishing with abrasive grains mainly composed of Si.
  • the glass substrate 1 may be temporarily stored in water after being removed from the polishing pad of the double-side polishing machine. By storing in water, it is possible to reduce the amount of foreign matter such as polishing wrinkles or loose abrasive grains adhering to the glass substrate 1 after precision polishing while preventing the surface of the glass substrate 1 from drying after precision polishing. After the glass substrate 1 is stored in water for a predetermined time, the glass substrate 1 is set in a scrub cleaning device and scrub cleaning is performed on the glass substrate 1.
  • a cleaning liquid such as a detergent or pure water is used.
  • the pH of the cleaning solution used for scrub cleaning is preferably 9.0 or more and 12.2 or less. Within this range, the ⁇ potential can be easily adjusted and scrub cleaning can be performed efficiently.
  • both scrub cleaning with a detergent and scrub cleaning with pure water may be performed.
  • the glass substrate 1 By using a detergent and pure water, the glass substrate 1 can be more appropriately cleaned.
  • the glass substrate 1 may be further rinsed with pure water between scrub cleaning with a detergent and scrub cleaning with pure water.
  • the glass substrate 1 may be further subjected to ultrasonic cleaning.
  • ultrasonic cleaning with chemical solution such as sulfuric acid aqueous solution, ultrasonic cleaning with pure water, ultrasonic cleaning with detergent, ultrasonic cleaning with IPA, and / or steam drying with IPA, etc. Further, it may be performed.
  • the manufacturing method S100 of the glass substrate 1 in the present embodiment is configured as described above. By using manufacturing method S100 of glass substrate 1, glass substrate 1 of this embodiment shown in Drawing 2 and Drawing 3 can be obtained.
  • Magnetic thin film forming step S200 A magnetic recording layer is formed on the main surfaces 2 and 3 (or one of the main surfaces 2 and 3) of the glass substrate 1 after the scrub cleaning process is completed.
  • the magnetic recording layer includes, for example, an adhesion layer made of a Cr alloy, a soft magnetic layer made of a CoFeZr alloy, an orientation control underlayer made of Ru, a perpendicular magnetic recording layer made of a CoCrPt alloy, a protective layer made of a C system, and an F system.
  • an adhesion layer made of a Cr alloy
  • a soft magnetic layer made of a CoFeZr alloy
  • an orientation control underlayer made of Ru
  • a perpendicular magnetic recording layer made of a CoCrPt alloy
  • a protective layer made of a C system
  • F system an F system
  • the glass substrate 1 for an information recording medium used in the embodiment according to the present invention will be described in more detail.
  • the glass substrate 1 in the present embodiment is displayed in mol%, SiO 2 : 56 to 71%, Al 2 O 3 : 5 to 15%, B 2 O 3 : 0 to 3% Li 2 O: 0.1 to 6%, Na 2 O: 0.1 to 4%, K 2 O: 0-2%, MgO: 3 to 13%, CaO: 4-21%, SrO: 0 to 3%, BaO: 0 to 3%, ZnO: 0 to 3%, ZrO 2 : 0 to 3%, CeO 2 : 0-2%, SnO 2 : 0-2%, TiO 2 : 0-5%, and Nb 2 O 5 : 0 to 3%, And a content range of SiO 2 + Al 2 O 3 + B 2 O 3 : 64 to 80%, Li 2 O + Na 2 O + K 2 O: 0.2-6% MgO + CaO + SrO + BaO + ZnO: 14 to 28%, (Nb 2 O 5 + TiO 2
  • % indicating a glass composition indicates “mol%” unless otherwise specified.
  • An addition notation of a chemical formula such as “SiO 2 + Al 2 O 3 + B 2 O 3 ” indicates the total amount of components represented by such chemical formula.
  • SiO 2 + Al 2 O 3 + B 2 O 3 indicates the total amount of SiO 2 , Al 2 O 3 and B 2 O 3 .
  • the glass composition is preferably composed of only the components shown above except for inevitable impurities.
  • the deformation of the glass substrate 1 and the diffusion of Li from the glass substrate 1 can be suppressed during the formation of the magnetic recording medium and the high-temperature annealing.
  • the glass substrate for information recording medium of the present embodiment showing the above characteristics is particularly suitable as a glass substrate for heat-assisted recording.
  • Thermally assisted recording performs information recording while locally heating a magnetic recording medium.
  • the use of the above-described Fe—Pt magnetic material is required to realize high-density recording. This is because the glass substrate is required to have particularly high heat resistance.
  • SiO 2 is an important component for forming a glass network structure.
  • such SiO 2 is 56 to 71% (the expression of such a numerical range in this embodiment means that the lower limit value and the upper limit value are included in the range. Therefore, “56 “ ⁇ 71%” means “56% or more and 71% or less”).
  • the content of SiO 2 is less than 56%, glass formation becomes difficult, and chemical durability may be deteriorated. On the other hand, if it exceeds 71%, the meltability deteriorates. Therefore, the content range of SiO 2 needs to be in the range of 56 to 71%. Among these, the range of 58 to 69% is preferable.
  • Al 2 O 3 is an important component that forms a network structure together with SiO 2 , and has a function of improving not only heat resistance but also ion exchange performance.
  • the content of Al 2 O 3 is less than 5%, chemical durability and ion exchange performance may be deteriorated. Conversely, if it exceeds 15%, the ion exchange performance is lowered, and the meltability is further deteriorated. For this reason, the content range of Al 2 O 3 needs to be 5 to 15%. Among them, the range of 7 to 13% is preferable.
  • B 2 O 3 is a component that forms a network structure with SiO 2 , and has a function of lowering the melting temperature, so is contained as necessary. If it exceeds 3%, Tg (glass transition point), which is an index of heat resistance, is lowered. Therefore, the content of B 2 O 3 needs to be in the range of 0 to 3%. Among these, the range is preferably 0 to 2%.
  • the total amount of SiO 2 + Al 2 O 3 + B 2 O 3 was 64 to 80%. These are important components for forming a glass network structure, and if it is less than 65%, glass formation becomes difficult. On the other hand, if it exceeds 80%, the viscosity is too high and the meltability deteriorates. Among these, the range is preferably 66 to 78%.
  • Li 2 O is a component necessary for improving chemical durability and further improving meltability.
  • the content of Li 2 O is less than 0.1%, the effect of suppressing the dissolution of Li and the effect of improving the meltability cannot be obtained sufficiently.
  • the Li 2 O content needs to be in the range of 0.1 to 6%. Among these, the range is preferably 0.2 to 5%.
  • Na 2 O is a component necessary for improving the meltability.
  • the content of Na 2 O is less than 0.1%, the viscosity increases, the liquidus temperature rises, and the meltability deteriorates. Conversely, if it exceeds 4%, the chemical durability is lowered. Therefore, the content of Na 2 O needs to be in the range of 0.1 to 4%. Among these, the range is preferably 0.2 to 3%.
  • K 2 O Since K 2 O has the effect of improving the meltability, it may be contained as necessary. When the content of K 2 O exceeds 2%, Tg is lowered and chemical durability is also deteriorated. Therefore, the content range of K 2 O is set to 0 to 2%. Among these, the range is preferably 0 to 1%.
  • the total amount of Li 2 O + Na 2 O + K 2 O was in the range of 0.2 to 6%. If the total amount is less than 0.2%, a sufficient improvement effect of meltability cannot be obtained. On the other hand, if the total amount exceeds 6%, Tg decreases, sufficient heat resistance cannot be obtained, and chemical durability deteriorates. More preferably, it is in the range of 0.4 to 5.5%.
  • MgO has the effect of improving heat resistance and improving meltability. If the content of MgO is less than 3%, the effect of improving the heat resistance and the effect of improving the meltability cannot be obtained. Conversely, if the content exceeds 13%, the glass structure becomes unstable and the devitrification resistance is reduced. It becomes worse and it becomes difficult to mold. Therefore, the MgO content range is set to 3 to 13%. Among these, the range of 5 to 11% is preferable.
  • CaO has the effect of improving the meltability and maintaining the Tg. If the content of CaO is less than 4%, the effect of improving the meltability and the effect of maintaining Tg cannot be obtained sufficiently. Conversely, if the content exceeds 21%, the glass structure becomes unstable and the chemical durability is improved. It will get worse. Therefore, the CaO content range is set to 4 to 21%. Among these, the range of 6 to 19% is preferable.
  • the SrO content range is set to a range of 0 to 3%. Among these, the range is preferably 0 to 2%.
  • BaO has the effect of improving the meltability and also has the effect of maintaining Tg, so it is contained as necessary.
  • the content range of BaO is set to 0 to 3%. Among these, the range is preferably 0 to 2%.
  • the content range of ZnO is set to 0 to 3%. Among these, the range is preferably 0 to 2%.
  • the total amount of MgO + CaO + SrO + BaO + ZnO was in the range of 14 to 28%. If it is less than 14%, the effects of improving Young's modulus and improving meltability cannot be obtained sufficiently. On the contrary, when the total amount exceeds 28%, the chemical durability deteriorates. More preferably, it is in the range of 16 to 26%.
  • TiO 2 has the effect of softening high temperature viscosity and improving chemical durability. If the content of TiO 2 exceeds 5%, the glass structure becomes unstable, devitrification resistance deteriorates, and molding becomes difficult. Therefore, the content range of TiO 2 is set to a range of 0 to 5%. Among these, the range of 0 to 4% is preferable.
  • Nb 2 O 5 has the effect of improving the chemical durability while improving the meltability.
  • the content range of Nb 2 O 5 is set to 0 to 3%. Among these, the range is preferably 0 to 2%.
  • the content range was set to 0 to 3%. Among these, the range is preferably 0 to 2%.
  • CeO 2 and SnO 2 play a role as a clarifying agent, and may be contained as necessary.
  • the content range was set to 0 to 2%.
  • the range is preferably 0 to 1%.
  • the raw material that plays a role as a fining agent such as Sb 2 O 3, and it may be contained in the range of 0 to 2%.
  • (Nb 2 O 5 + TiO 2 ) / SiO 2 is preferably in the range of 0.01 to 0.06. If the ratio is less than 0.01, the chemical durability is deteriorated. If the ratio exceeds 0.06, the chemical durability is adversely affected.
  • the durability as a skeleton is greatly improved by entering a part of the network structure of the glass, and the diffusion rate of Li ions in the glass is also suppressed. Therefore, the diffusion to the magnetic thin film is suppressed.
  • a desirable range is from 0.012 to 0.05. Nb 2 O 5 and TiO 2 do not have these effects unless one of them is essential.
  • Li 2 O / (Li 2 O + Na 2 O + K 2 O) is preferably in the range of 0.30 to 0.99. If the amount is less than 0.03, the Li elution amount is deteriorated. Therefore, it is essential to contain Li 2 O in a predetermined amount or more. On the other hand, when only Li 2 O is contained at 1.00, elution of Na and K deteriorates. By containing Li 2 O / (Li 2 O + Na 2 O + K 2 O) at a predetermined ratio, a synergistic effect with Nb 2 O 5 and TIO 2 is shown, and the Li diffusion rate is suppressed. A desirable range is from 0.50 to 0.95.
  • FIG. 7 to FIG. 9 show the glass compositions in each example and each comparative example.
  • a predetermined amount of raw material powder is weighed into a platinum crucible and mixed so as to have the glass composition described in Examples 1 to 15. Then, it melt
  • the stirring blade was taken out and allowed to stand for 3 hours, and then the melt was poured into a mold to obtain a glass block. Thereafter, the glass block was held in the vicinity of the glass transition point of each glass for 2 hours, and then slowly cooled to remove strain.
  • the obtained glass block was sliced into a 2.5-inch disk shape having a thickness of about 1.0 mm, and the inner and outer circumferences were concentrically cut out using a cutter to obtain a disk-shaped glass substrate. Rough polishing and polishing were performed on both surfaces of the glass substrate.
  • the glass substrate was washed to produce a glass substrate for an information recording medium having a thickness of 0.8 mm shown in each example and each comparative example.
  • the following physical property evaluation was performed on the produced glass substrate for an information recording medium.
  • Glass material physical properties were measured by the following methods, respectively.
  • ⁇ Glass transition point (Tg)> Using a differential heat measuring device (trade name: EXSTAR6000, manufactured by Seiko Instruments Inc.), heating and measuring a glass sample adjusted to a powder form in a temperature range of room temperature to 900 ° C. at a rate of temperature increase of 10 ° C./min. was used to measure the glass transition point.
  • EXSTAR6000 differential heat measuring device
  • ⁇ Li elution amount> The surface of the glass substrate was polished with cerium oxide to obtain a smooth surface with an Ra value of 2 nm or less. Thereafter, the surface of the glass substrate was washed and immersed in 50 ml of RO water at 80 ° C. for 24 hours. Thereafter, the eluate was analyzed and calculated using an ICP emission spectroscopic analyzer.
  • ⁇ Heat resistance test> An Fe—Pt alloy film was formed on a glass substrate, and then judged by the flatness after heat treatment at 600 ° C. ⁇ 1 hour. The flatness was measured using a white light interference type surface shape measuring instrument (Optiflat (manufactured by Phase Shift Technology)). The glass substrate of each example had a flatness before heat treatment of about 2.0 to 2.3 mm.
  • HDD test> An Fe—Pt alloy film was formed on a glass substrate, then heat-treated at 600 ° C. for 1 hour, and then evaluated by the number of reading errors when operating at 15000 rpm. The evaluation was performed 100 sheets in each example and each comparative example, and the total number of errors in the hard disk drive (HDD) test is shown in FIGS. The mol% values shown in FIGS. 7 to 9 are rounded off to the first decimal place and used to the first decimal place as significant figures.
  • the number of errors in the hard disk drive (HDD) test shown in FIGS. 7 to 9 the number of errors is evaluated as 0 to 2 times “A”, the number of errors is evaluated as 3 to 5 times “B”, and the number of errors is The evaluation “C” was 6 times or more.
  • the glass substrate for hard disk drive (HDD) in each example is different from the glass substrate for HDD in each comparative example in the formation of the magnetic recording medium and the glass substrate during high-temperature annealing. No deformation has occurred. Furthermore, each glass component is contained in a predetermined ratio, and both (Nb 2 O 5 + TiO 2 ) / SiO 2 and Li 2 O / (Li 2 O + Na 2 O + K 2 O) are within a predetermined range. As a result, it was possible to obtain a good SNR characteristic by containing Li ions and suppressing the diffusion of Li, and as a result, excellent evaluation was obtained in a hard disk drive (HDD) test.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Organic Chemistry (AREA)
  • Ceramic Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Glass Compositions (AREA)
  • Magnetic Record Carriers (AREA)
  • Manufacturing Of Magnetic Record Carriers (AREA)

Abstract

Le substrat en verre ci-décrit pour supports d'enregistrement d'information contient, en % en mol, 56-71 % de SiO2, 5-15 % d'Al2O3, 0-3 % de B2O3, 0,1-6 % de Li2O, 0,1-4 % de Na2O, 0-2 % de K2O, 3-13 % de MgO, 4-21 % de CaO, 0-3 % de SrO, 0-3 % de BaO, 0-3 % de ZnO, 0-3 % de ZrO2, 0-2 % de CeO2, 0-2 % de SnO2, 0-5 % de TiO2 et 0-3 % de Nb2O5, tout en satisfaisant les rapports de composition de verre suivants, SiO2 + Al2O3 +B2O3 de 64-80 %, Li2O + Na2O + K2O de 0,2-6 %, MgO + CaO + SrO + BaO + ZnO de 14-28 %, (Nb2O5 + TiO2)/SiO2 = 0,01-0,06 et Li2O/(Li2O + Na2O + K2O) = 0,30-0,99.
PCT/JP2014/055396 2013-03-05 2014-03-04 Substrat en verre pour supports d'enregistrement d'information, et support d'enregistrement d'information WO2014136751A1 (fr)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2019055911A (ja) * 2014-10-08 2019-04-11 コーニング インコーポレイテッド 金属酸化物濃度勾配を有するガラスおよびガラスセラミック
WO2023235211A1 (fr) * 2022-05-31 2023-12-07 Corning Incorporated Articles en verre jaune à ions échangeables

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000357318A (ja) * 1999-04-13 2000-12-26 Asahi Glass Co Ltd 情報記録媒体基板用ガラスおよび情報記録媒体用ガラス基板
JP2001172043A (ja) * 1999-12-20 2001-06-26 Asahi Glass Co Ltd 情報記録媒体基板用ガラスおよび情報記録媒体用ガラス基板
WO2012057338A1 (fr) * 2010-10-29 2012-05-03 Hoya株式会社 Substrat de verre destiné à être utilisé dans un support de stockage magnétique, support de stockage magnétique et ébauche d'un substrat de verre destiné à être utilisé dans un support de stockage magnétique

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000357318A (ja) * 1999-04-13 2000-12-26 Asahi Glass Co Ltd 情報記録媒体基板用ガラスおよび情報記録媒体用ガラス基板
JP2001172043A (ja) * 1999-12-20 2001-06-26 Asahi Glass Co Ltd 情報記録媒体基板用ガラスおよび情報記録媒体用ガラス基板
WO2012057338A1 (fr) * 2010-10-29 2012-05-03 Hoya株式会社 Substrat de verre destiné à être utilisé dans un support de stockage magnétique, support de stockage magnétique et ébauche d'un substrat de verre destiné à être utilisé dans un support de stockage magnétique

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2019055911A (ja) * 2014-10-08 2019-04-11 コーニング インコーポレイテッド 金属酸化物濃度勾配を有するガラスおよびガラスセラミック
WO2023235211A1 (fr) * 2022-05-31 2023-12-07 Corning Incorporated Articles en verre jaune à ions échangeables

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