Claims
- 1. A monolithic ceramic capacitor comprising:
at least three dielectric ceramic layers; at least one pair of internal electrodes each of which is disposed between a different pair of dielectric ceramic layers; a pair of external electrodes, each of which is electrically connected to a different one of said pair of internal electrodes; wherein the dielectric ceramic layers comprise a non-reducing dielectric ceramic comprising Ca, Zr and Ti as metallic elements, free of Pb, and having a perovskite primary crystal phase and other crystal phases; wherein the ratio of the maximum peak intensity of secondary crystal phases to the maximum peak intensity at 2θ=25° to 35° of the perovskite primary crystal phase in a CuKα X-ray diffraction pattern is about 12% or less, wherein the secondary crystal phases include all the crystal phases other than the perovskite primary crystal phase; and wherein the internal electrodes comprise a base metal.
- 2. A monolithic ceramic capacitor according to claim 1, wherein the base metal is at least one member selected from the group consisting of elemental nickel, a nickel alloy, elemental copper and a copper alloy.
- 3. A monolithic ceramic capacitor according to claim 2, wherein said ratio is about 5% or less.
- 4. A monolithic ceramic capacitor according to claim 2, wherein said ratio is about 3% or less.
- 5. A monolithic ceramic capacitor according to claim 1, wherein said ceramic is represented by the formula ApBO3 in which A comprises Ca, B comprises Zr and Ti, and p is about 0.98 to 1.02.
- 6. A monolithic ceramic capacitor according to claim 5, wherein said ratio is about 5% or less.
- 7. A monolithic ceramic capacitor according to claim 5, wherein p is about 0.99 to 1.01.
- 8. A method for making a non-reducing dielectric ceramic comprising Ca, Zr and Ti as metallic elements, free of Pb, and having a ratio of the maximum peak intensity of secondary crystal phases to the maximum peak intensity at 20=25° to 35° of a perovskite primary crystal phase in a CuKα X-ray diffraction pattern of about 12% or less, wherein the secondary crystal phases include all the crystal phases other than the perovskite primary crystal phase, the method comprising the steps of:
(A) providing a calcined powder for providing the B-site component of a dielectric ceramic represented by the general formula ApBO3; (B) providing powder for providing the A-site component; (C) mixing the calcined B-site component powder and the A-site component powder to prepare an uncalcined primary material powder; (D) calcining the uncalcined primary material powder to prepare a calcined primary material powder; (E) adjusting the composition of the calcined primary material powder to realize the desired value of p by adding at least one of the A-site component powder and B-site component powder to the calcined primary material powder to prepare a secondary material powder; and (F) molding and sintering the secondary material powder under a neutral or reducing atmosphere.
- 9. A method for making a non-reducing dielectric ceramic according to claim 8, further comprising calcining a B-site component powder.
- 10. A method for making a non-reducing dielectric ceramic according to claim 9, wherein the B-site component powder which is calcined has an average particle diameter of about 0.5 μm or less.
- 11. A method for making a non-reducing dielectric ceramic according to claim 9, wherein the uncalcined B-site component powder is calcined at a temperature of about 1,050° C. to 1,200° C. for 1 to 2 hours.
- 12. A method for making a non-reducing dielectric ceramic according to claim 11, wherein the calcined primary material powder has an average particle diameter of about 0.8 μm or less.
- 13. A method for making a non-reducing dielectric ceramic according to claim 11, wherein the provided powders are such that the calcined primary material powder is a ceramic powder having a composition represented by
- 14. A method for making a non-reducing dielectric ceramic according to claim 13, wherein the secondary material powder is a ceramic powder having a composition represented by (Ca1-v-wSrvBaw)p(Zr1-x-yTixHfy)O3, and wherein p is adjusted to a value of about 0.98 to 1.02.
- 15. A method for making a non-reducing dielectric ceramic according to claim 14, wherein p is adjusted to a value of about 0.98 to 1.02.
- 16. A method for making a non-reducing dielectric ceramic according to claim 15, wherein the B-site component powder which is calcined has an average particle diameter of about 0.5 μm or less.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2000-106907 |
Apr 2000 |
JP |
|
Parent Case Info
[0001] This is a division of application Ser. No. 09/828,013, filed Apr. 7, 2001.
Divisions (1)
|
Number |
Date |
Country |
Parent |
09828013 |
Apr 2001 |
US |
Child |
10427978 |
May 2003 |
US |