Patent US4582812A successfully refreshed from Google Patents.
US4582812A
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Aluminum oxide substrate material for magnetic head and method for producing the same
Assignee: Nippon Tungsten Co Ltd
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Filing: 1984-08-09
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Granted: 1986-04-15
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Expires: 2004-08-09
Abstract
Abstract Aluminum oxide substrate material for magnetic heads having improved toughness consisting essentially of: (1) 100 parts by weight, consisting of aluminum oxide and 30 to 50 parts by weight of (TiC+TiO2), and that provided TiO2/(TiC+TiO2)x100=5 to 15, (2) 0.5 to 5 parts by weight of addition of free cutting comprising at least one from the group of MgO, NiO, Cr2O3 and ZrO2, and (3) 0.05 to 2 parts by weight of Y2O3. The method of hot-forming aluminum oxide substrate material for magnetic head having improved sinterability consisting of (a) preparing a green compact by molding a raw material mixture which contains: (1) 100 parts by weight, consisting of aluminum oxide and 30 to 50 percent by weight of (TiC+TiO2), and that provided TiO2/(TiC+TiO2)x100=5 to 15, (2) 0.5 to 5 parts by weight of machinability agents comprising at least one from the group of MgO, NiO, Cr2O3 and ZrO2, and (3) 0.05 to 2 parts by weight of Y2O3 (b) optionally presintering said green compacts; and effecting sintering.
Inventors
- 👤 Mitsuhiko Furukawa
- 👤 Michito Miyahara
- 👤 Takashi Kitahira
- 👤 Kiyohito Misumi
- 👤 Masaharu Shiroyama
- 👤 Toshiaki Wada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:52
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/01; C04B35/10; C04B35/111; G; G11; G11B; G11B5/00; G11B5/10; G11B5/127; G11B5/187; G11B5/255; G11B5/31; G11B5/3103; G11B5/3106
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
79 words
A magnetic head slider comprising a substrate consisting essentially of: (a) 100 parts by weight, consisting of aluminum oxide and 30 to 50 parts by weight of (TiC+TiO 2 ), and provided that TiO 2 /(TiC+TiO 2 )×100=5 to 15%; (b) greater than one to 5 parts by weight of a machinability agent which is MgO, NiO, Cr 2 O 3 or ZrO 2 ; and (c) 0.05 to 2 parts by weight of Y 2 O 3 .
Claim 2
Dependent Claim
79 words
A magnetic head slider comprising a substrate consisting essentially of: (a) 100 parts by weight, consisting of aluminum oxide and 30 to 50 parts by weight of (TiC+TiO 2 ), and provided that TiO 2 /(TiC+TiO 2 )×100=5 to 15%; (b) greater than one to 5 parts by weight of a machinability agent which is MgO, NiO, Cr 2 O 3 or ZrO 2 ; and (c) 0.05 to 2 parts by weight of Y 2 O 3 .
Claim 3
Independent Claim
149 words
A method of preparing a magnetic head slider comprising the following steps: (1) preparing a green compact by molding a raw material mixture which contains: (a) 100 parts by weight, consisting of aluminum oxide and 30 to 50 parts by weight of (TiC+TiO 2 ), and provided that TiO 2 /(TiC+TiO 2 )×100=5 to 15%; (b) 0.5 to 5 parts by weight of a machinability agent which is MgO, NiO, Cr 2 O 3 or ZrO 2 ; and (c) 0.05 to 2 parts by weight of Y 2 O 3 ; (2) presintering said green compact in a reducing or inert atmosphere to produce a presintered compact which has a density of more than 94 percent of the theoretical density; (3) subjecting said presintered body to hot isostatic pressing to effect sintering; and (4) machining the resulting sintered body to provide a substrate for the magnetic head slider.
Claim 4
Independent Claim
149 words
A method of preparing a magnetic head slider comprising the following steps: (1) preparing a green compact by molding a raw material mixture which contains: (a) 100 parts by weight, consisting of aluminum oxide and 30 to 50 parts by weight of (TiC+TiO 2 ), and provided that TiO 2 /(TiC+TiO 2 )×100=5 to 15%; (b) 0.5 to 5 parts by weight of a machinability agent which is MgO, NiO, Cr 2 O 3 or ZrO 2 ; and (c) 0.05 to 2 parts by weight of Y 2 O 3 ; (2) presintering said green compact in a reducing or inert atmosphere to produce a presintered compact which has a density of more than 94 percent of the theoretical density; (3) subjecting said presintered body to hot isostatic pressing to effect sintering; and (4) machining the resulting sintered body to provide a substrate for the magnetic head slider.
Claim 5
Independent Claim
119 words
A method of preparing a magnetic head slider comprising the following steps: (1) preparing a green compact by molding a raw mixture which contains: (a) 100 parts by weight, consisting of aluminum oxide and 30 to 50 parts by weight of (TiC+TiO 2 ), and provided that TiO 2 /(TiC+TiO 2 )×100=5 to 15%; (b) 0.5 to 5 parts by weight of a machinability agent which is MgO, NiO, Cr 2 O 3 or ZrO 2 ; and (c) 0.05 to 2 parts by weight of Y 2 O 3 ; (2) subjecting said green compact to a hot pressing to effect sintering; and (3) machining the resulting sintered body to provide a substrate for the magnetic head slider.
Claim 6
Independent Claim
119 words
A method of preparing a magnetic head slider comprising the following steps: (1) preparing a green compact by molding a raw mixture which contains: (a) 100 parts by weight, consisting of aluminum oxide and 30 to 50 parts by weight of (TiC+TiO 2 ), and provided that TiO 2 /(TiC+TiO 2 )×100=5 to 15%; (b) 0.5 to 5 parts by weight of a machinability agent which is MgO, NiO, Cr 2 O 3 or ZrO 2 ; and (c) 0.05 to 2 parts by weight of Y 2 O 3 ; (2) subjecting said green compact to a hot pressing to effect sintering; and (3) machining the resulting sintered body to provide a substrate for the magnetic head slider.
Claim 7
Dependent Claim
19 words
The method according to claim 2, wherein the TiC is of a slightly rounded shape prepared by low-temperature carbide-forming.
Claim 8
Dependent Claim
19 words
The method according to claim 2, wherein the amount of machinability agent is greater than one part by weight.
Claim 9
Dependent Claim
32 words
The method according to claim 2 wherein step (3) is effected in an inert gas atmosphere at about 1400° C. and under a pressure of at least about 1000 kg/cm 2 .
Claim 10
Dependent Claim
33 words
The method according to claim 3 wherein step (2) is effected in an inactive atmosphere at 1350° C. to 1850° C. and under a pressure of at least about 200 kg/cm 2 .
Claim 11
Dependent Claim
19 words
The method according to claim 3 wherein the TiC is of a slightly rounded shape prepared by low-temperature carbide-forming.
Claim 12
Dependent Claim
19 words
The method according to claim 3 wherein the amount of machinability agent is greater than one part by weight.
Claim 13
Dependent Claim
26 words
A magnetic head slider comprising a substrate having an improved machinability and being substantially pore-free, the substrate having been produced by the method of claim 5.
Claim 14
Dependent Claim
26 words
A magnetic head slider comprising a substrate having an improved machinability and being substantially pore-free, the substrate having been produced by the method of claim 9.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-04-14 | 1989-10-14 | 1990-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-14 | 1993-10-14 | 1994-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-14 | 1997-10-14 | 1998-04-15 | $7700.00 | Window Closed / Lapsed |