Claims
- 1. A ceramic substrate comprising:
- a substrate comprising a nitride ceramic sintered sheet;
- a metallized layer formed on said substrate and comprising molybdenum, tungsten or a mixture thereof as a main component and at least one group IVb activation metal element;
- and a uniform layer of a compound comprising yttria and alumina at the interface between said nitride ceramic sintered sheet and said metallized layer and uniformly penetrating said metallized layer.
- 2. The ceramic substrate according to claim 1, wherein said metallized layer is formed by coating a metallizing paste comprising molybdenum, tungsten or a mixture thereof, and yttria and alumina solely or in the form of a compound of yttria and alumina and sintering it.
- 3. The ceramic substrate according to claim 1, wherein said metallized layer is formed by;
- coating a paste comprising a compound of yttria and alumina on said substrate;
- coating a metallizing paste thereon; and firing them.
- 4. A ceramic substrate comprising:
- a nitride ceramic substrate; and
- a conductive metallized layer mainly comprised of at least one of Mo and W, a group IVb active metal element and at least one metal selected from the group consisting of Co, Ni, Fe, Mn, Cr and V, formed on said substrate.
- 5. A ceramic substrate comprising:
- a nitride ceramic substrate;
- an intermediate reactive layer mainly comprised of a compound containing a grain boundary constituent phase component of said ceramic substrate, and a compound of a group IVb active metal; and
- a conductive metallized layer mainly comprised of at least one of molybdenum and tungsten, a nitride of a group IVb active metal and a composite compound comprising an oxide of a group IVb active metal and an oxide of Co, Ni, Fe, Mn, Cr or V, formed on said substrate with the interposition of said intermediate reactive layer.
- 6. The ceramic substrate according to claim 5, wherein said conductive metallized layer further comprises at least one compound selected from the group consisting of a nickel compound and a calcium compound.
- 7. The ceramic substrate according to claim 5, wherein the group IVb active metal comprises titanium.
- 8. The ceramic substrate according to claim 5, wherein said composite compound comprises an oxide of a group IVb active metal and an oxide of cobalt.
- 9. The ceramic substrate according to claim 5, wherein the nitride ceramic substrate comprises an aluminum nitride ceramic substrate.
- 10. The ceramic substrate according to claim 1, wherein said group IVb activation metal element is selected from the group consisting of titanium, zirconium and hafnium.
- 11. The ceramic substrate according to claim 1, wherein said nitride ceramic sintered sheet comprises an aluminum nitride sintered sheet.
- 12. The ceramic substrate according to claim 1, wherein said metallized layer comprises about 3 to 25% by weight of said compound comprising yttria and alumina.
- 13. The ceramic substrate according to claim 1, wherein said nitride ceramic sintered sheet includes at least about 5% by weight of Y.sub.2 O.sub.3.
- 14. A circuit substrate comprising a ceramic substrate according to claim 1.
- 15. A metallizing composition for use in a nitride ceramic substrate comprising from about 26 to 90% by weight of molybdenum and tungsten, from about 5 to 70% by weight of an oxide of a group IVb active metal, and from about 2 to 20% by weight of at least one compound of a metal selected from the group consisting of Co, Ni, Fe, Mn, Cr and V.
- 16. The metallizing composition for use in a nitride ceramic substrate according to claim 15, wherein said group IVb active metal comprises titanium.
- 17. The metallizing composition for use in a nitride ceramic substrate according to claim 15, wherein said compound comprises a compound of cobalt.
- 18. A metallizing composition for use in a nitride ceramic comprising from about 26 to 90% by weight of molybdenum and tungsten, from about 5 to 70% by weight of an oxide of a group IVb active metal, and from about 2 to 20% by weight of at least one compound of a metal selected from the group consisting of Co, Ni, Fe, Mn, Cr and V.
- 19. The metallizing composition for use in a nitride ceramic according to claim 18, wherein the metallizing composition further comprises from about 2 to 15% by weight of a nickel or calcium compound.
- 20. The metallizing composition for use in a nitride ceramic according to claim 18, wherein said group IVb active metal comprises titanium.
- 21. The metallizing composition for use in a nitride ceramic according to claim 18, wherein said compound comprises a compound of cobalt.
- 22. A method for preparing a ceramic substrate comprising:
- providing a substrate comprising a nitride ceramic sintered sheet;
- coating on said ceramic substrates a metallizing paste comprising molybdenum, tungsten or a mixture thereof as a main component, at least one of titanium, zirconium and hafnium as an activation metal and at least one of yttria and alumina; and
- firing the coated substrate in an inert atmosphere at a temperature of from 1600.degree. to 1900.degree. C. to prepare a ceramic substrate comprising a uniform layer of a compound comprising yttria and alumina at the interface between said nitride ceramic sintered sheet and a metallized layer formed from said metallizing paste, wherein said compound comprising yttria and alumina also uniformly penetrates said metallized layer.
- 23. A method for preparing a ceramic substrate comprising:
- coating a paste comprising a compound of yttria and alumina on a substrate comprising a nitride ceramic sintered sheet;
- coating on the yttria and alumina compound coating a metallizing paste comprising molybdenum, tungsten or a mixture thereof as a main component and at least one of titanium, zirconium and hafnium as an activation metal; and
- firing the coated substrate in an inert atmosphere at a temperature of from 1600.degree. to 1900.degree. C. to prepare a ceramic substrate comprising a uniform layer of a compound comprising yttria and alumina at the interface between said nitride ceramic sintered sheet and a metallized layer formed from said metallized paste, wherein said yttria and alumina compound also uniformly penetrates said metallized layer.
Priority Claims (4)
Number |
Date |
Country |
Kind |
62-73989 |
Mar 1987 |
JPX |
|
62-76164 |
Mar 1987 |
JPX |
|
62-76165 |
Mar 1987 |
JPX |
|
63-43858 |
Feb 1988 |
JPX |
|
Parent Case Info
This application is a division of application Ser. No. 07/174,902, filed Mar. 29, 1988, now U.S. Pat. No. 4,883,704.
US Referenced Citations (4)
Number |
Name |
Date |
Kind |
4659611 |
Iwase et al. |
Apr 1987 |
|
4740403 |
Oomen et al. |
Apr 1988 |
|
4770953 |
Horiguchi et al. |
Sep 1988 |
|
4883704 |
Sato et al. |
Nov 1989 |
|
Divisions (1)
|
Number |
Date |
Country |
Parent |
174902 |
Mar 1988 |
|