Claims
- 1. A zirconia base sintered body comprising a sintered substrate containing 30% by volume or more of tetragonal zirconia and a coating film of a thickness no less than 0.1 micron disposed thereon, wherein the diffusion coefficient of oxygen in material forming said coating film at a temperature of no higher than 550.degree. C. is at least 10.sup.3 less than that of oxygen in said tetragonal zirconia at a temperature no higher than said temperature, said sintered body being stable within a range of 200.degree.-400.degree. C. in an oxygen-containing atmosphere.
- 2. A sintered body as defined in claim 1, in which the material forming said coating film is one selected from the group consisting of glasses having a softening point of no lower than 600.degree. C.; and metal carbides, metal nitrides, metal borides, metal oxides and solid solution thereof having a melting point of no lower than 600.degree. C.
- 3. A sintered body as defined in claim 1, in which said coating film is of a multi-layer structure wherein different materials are laminated on each other.
- 4. A sintered body as defined in claim 1, in which said tetragonal zirconia in said substrate is partially stabilized.
- 5. A sintered body as defined in claim 2, in which said coating film is formed of one or more selected from the group consisting of Al.sub.2 O.sub.3, Cr.sub.2 O.sub.3, SiC, TiC, WC, Si.sub.3 N.sub.4, TiN, AlN, TiB.sub.2 and a solid solution thereof.
- 6. A sintered body as defined in claim 1, in which the difference in the diffusion coefficient of oxygen is at least 10.sup.5.
- 7. A sintered body as defined in claim 5, in which said tetragonal zirconia is partially stabilized by a stabilizer of at least one selected from the group consisting of Y.sub.2 O.sub.3 and Yb.sub.2 O.sub.3.
- 8. A zirconia base sintered structural element for an internal combustion engine, comprising a sintered substrate containing 30% by volume or more of tetragonal zirconia and a coating film of a thickness no less than 0.1 micron disposed thereon, wherein the diffusion coefficient of oxygen in material forming said coating film at a temperature of no higher than 550.degree. C. is smaller than that of oxygen in said tetragonal zirconia at said temperature by at least 10.sup.3.
- 9. A zirconia base sintered nonsensitive supporting element for an oxygen sensor for use in an internal combustion engine, comprising a sintered substrate containing 30% by volume or more tetragonal zirconia and a coating film of a thickness no less than 0.1 micron disposed thereon, wherein the diffusion coefficient of oxygen in material forming said coating film at a temperature of no higher than 550.degree. C. is smaller than that of oxygen in said tetragonal zirconia at said temperature by at least 10.sup.3.
Priority Claims (1)
Number |
Date |
Country |
Kind |
59-279163 |
Dec 1984 |
JPX |
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Parent Case Info
This application is a continuation of U.S. application Ser. No. 749,237, filed June 27, 1985, now abandoned.
US Referenced Citations (11)
Non-Patent Literature Citations (2)
Entry |
EP 0166445, Jan. '86, Kogima 428/701. |
Digest of Proceedings of the Spring Conference 1984 at Kyoto, 22-24 May 1984, Powder and Powder Metallurgy Association (Japan), Low-Temperature Degradation of PSZ Toyota Central Research & Development Labs., Inc. |
Continuations (1)
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Number |
Date |
Country |
Parent |
749237 |
Jun 1985 |
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