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US4685937A
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US
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Composite abrasive particles for magnetic abrasive polishing and process for preparing the same
Assignee: Kureha Corp
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Filing: 1986-04-28
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Granted: 1987-08-11
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Expires: 2006-04-28
Abstract
Abstract Composite abrasive particles for use in magnetic abrasive polishing in which three phases of corundum-phase alumina, α-iron and iron-alumina spinel are detected by the powder X-ray diffractometry and which contains 48 wt % or more of iron and 11 wt % or more of aluminum. The composite abrasive particles are prepared by mixing starting materials of powders of aluminum and an iron oxide in such a ratio that three phases of corundum-phase alumina, α-iron and iron-alumina spinel may coexist and so that iron may be contained in an amount of 48 wt % or more and aluminum may be contained in an amount of 11 wt % or more, subjecting the materials to a solid-phase exothermic reaction, and breaking the resultant solid product.
Inventors
- 👤 Saburo Hori
- 👤 Nobuhiro Watanabe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 14:07
CPC Classifications
C; C22; C22C; C22C29/00; C22C29/12; C04; C04B; C04B35/00; C04B35/622; C04B35/64; C04B35/65; C04B35/651; C09; C09K; C09K3/00; C09K3/14; C09K3/1436
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
45 words
Composite abrasive particles for use in magnetic abrasive polishing in which three phases of corundum-phase alumina, α-iron and iron-alumina spinel are detected by the powder X-ray diffractometry and which contain 48 wt % or more of iron and 11 wt % or more of aluminum.
Claim 2
Dependent Claim
45 words
Composite abrasive particles for use in magnetic abrasive polishing in which three phases of corundum-phase alumina, α-iron and iron-alumina spinel are detected by the powder X-ray diffractometry and which contain 48 wt % or more of iron and 11 wt % or more of aluminum.
Claim 3
Dependent Claim
27 words
Composite abrasive particles for use in magnetic abrasive polishing as claimed in claim 1, wherein said abrasive particles have a particle diameter of 44 μm or less.
Claim 4
Dependent Claim
169 words
A process for preparing composite abrasive particles for use in magnetic abrasive polishing having three phases of corundum-phase alumina, α-iron and iron-alumina spinel detected by the powder X-ray diffractometry and containing iron in an amount of 48 wt % or more and aluminum in an amount of 11 wt % or more, which process is characterized in that starting materials of powders of aluminum and an iron oxide are mixed in such a ratio that three phases of corundum-phase alumina, α-iron and iron-alumina spinel may coexist and so that iron may be contained in an amount of 48 wt % or more and aluminum may be contained in an amount of 11 wt % or more; the materials are molded or charged into a container with an end opened and heated, at an end thereof, in an atmosphere of an inert gas to initiate a solid-phase exothermic reaction and allow the reaction to sequentially proceed lamellarly by the reaction heat; and the resultant solid product is subjected to breaking.
Claim 5
Dependent Claim
169 words
A process for preparing composite abrasive particles for use in magnetic abrasive polishing having three phases of corundum-phase alumina, α-iron and iron-alumina spinel detected by the powder X-ray diffractometry and containing iron in an amount of 48 wt % or more and aluminum in an amount of 11 wt % or more, which process is characterized in that starting materials of powders of aluminum and an iron oxide are mixed in such a ratio that three phases of corundum-phase alumina, α-iron and iron-alumina spinel may coexist and so that iron may be contained in an amount of 48 wt % or more and aluminum may be contained in an amount of 11 wt % or more; the materials are molded or charged into a container with an end opened and heated, at an end thereof, in an atmosphere of an inert gas to initiate a solid-phase exothermic reaction and allow the reaction to sequentially proceed lamellarly by the reaction heat; and the resultant solid product is subjected to breaking.
Claim 6
Dependent Claim
33 words
A process for preparing composite abrasive particles as claimed in claim 3, wherein the materials are added with powders of iron and/or aluminum oxide to adjust the composition or control the reaction temperature.
Claim 7
Dependent Claim
37 words
A process for preparing composite abrasive particles as claimed in claim 3, wherein the reaction temperature of the solid-phase exothermic reaction is higher than a melting point of iron and lower than a melting point of alumina.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-08-10 | 1991-02-09 | 1991-08-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-10 | 1995-02-09 | 1995-08-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-10 | 1999-02-09 | 1999-08-11 | $7700.00 | Window Closed / Lapsed |