Patent EP0480678A2 successfully refreshed from Google Patents.
EP0480678A2
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EP
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Lapping abrasive of aluminazirconia system and method for producing the same
Assignee: Japan Abrasive Co Ltd
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Filing: 1991-10-08
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Granted: —
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Expires: 2011-10-08
Abstract
Abstract Alumina-zirconia lapping abrasives containing at most 30% tetragonal zirconia and optionally containing at least one oxide selected from the group consisting of yttrium oxide, calcium oxide, magnesium oxide, titanium oxide and other rare earth oxides in the form of solid solutions, which are obtainable and preferably obtained by fusing alumina-zirconia abrasive materials, quenching fused materials to obtain an ingot, crushing the ingot and subjecting the crushed ingot to a heat treatment at a higher temperature than the phase transition temperature of zirconia.
Inventors
- 👤 Masahiro c/o Japan Abrasive Co. Ltd. Tamamaki
- 👤 Yoshihiro c/o Japan Abrasive Co. Ltd. Onoda
- 👤 Takanobu c/o Japan Abrasive Co. Ltd. Takahashi
- 👤 Koji c/o Japan Abrasive Co. Ltd. Tsuda
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 05:54
CPC Classifications
C; C09; C09K; C09K3/00; C09K3/14
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
50 words
An alumina-zirconia material suitable for use as a lapping abrasive obtainable by subjecting alumina-zirconia to a heat treatment at a higher temperature than the phase transition temperature of zirconia whereby the proportion of tetragonal zirconia is reduced to at most 30% based on the total zirconia content of the material.
Claim 2
Dependent Claim
28 words
A material as claimed in claim 1, wherein the zirconia content is in the range of 10 to 60, advantageously in the range of 35 to 50, wt%.
Claim 3
Dependent Claim
58 words
A material as claimed in claim 1 or claim 2, wherein at least one oxide selected from the group consisting of yttrium oxide, calcium oxide, magnesium oxide, titanium oxide and other rare earth oxide is contained in the form of solid solution as stabilizer, advantageously in the total amount of 0.05 to 7% by weight of the material.
Claim 4
Independent Claim
48 words
A method for producing a material suitable for use as a lapping abrasive, which comprises subjecting a finely divided alumina-zirconia material to a heat treatment at a temperature higher than the phase transition temperature of zirconia, whereby the proportion of tetragonal zirconia is reduced to at most 30%.
Claim 5
Dependent Claim
33 words
A method as claimed in claim 4, wherein the finely divided material is obtained by fusing an alumina-zirconia abrasive material, quenching the fused material to obtain an ingot, and subsequently crushing the ingot.
Claim 6
Dependent Claim
30 words
A method for producing alumina-zirconia lapping abrasives as claimed in claim 4 or claim 5, wherein said heat treatment is executed at 650°C ± 50°C for 3 to 10 hours.
Claim 7
Dependent Claim
41 words
A neutral or weakly acidic composition comprising a material as defined in any one of claims 1 to 3 or a material obtained by a method as claimed in any one of claims 4 to 6, water and an acidic compound.
Claim 8
Dependent Claim
43 words
An abrasive composition as claimed in claim 7, wherein the alumina-zirconia lapping abrasive is present in a proportion of 5 to 50 wt%, and has an average grain size of 0.5 to 50 µm and a maximum grain size of below 100 µm.
Claim 9
Dependent Claim
24 words
An abrasive composition as claimed in claim 7 or claim 8, wherein said acidic compound is ammonium chloride or an acidic sulfate or nitrate.
Claim 10
Dependent Claim
37 words
An abrasive composition as claimed in any one of claims 7 to 9, wherein the concentration of acidic compound is in the range of 0.05 to 20 wt%, advantageously in the range of 0.1 to 0.3 wt%.
Claim 11
Dependent Claim
17 words
An alumina-zirconia lapping abrasive in which the tetragonal zirconia constitutes at most 30% of the zirconia content.
References Cited (Backward Citations)
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