CERAMIC COMPONENT AND METHOD FOR PRODUCING THE CERAMIC COMPONENT

Abstract

A ceramic component having a ceramic main part containing AxByC1−x−vTi1—y+wO3* (Mn2P2O7)z*Du, in which A is a first dopant selected from a group including neodymium, praseodymium, cerium, and lanthanum, B is a second dopant selected from a group including niobium, tantalum, and vanadium, C is selected from a group including calcium, strontium, and barium, and D includes a metal selected from a group including aluminum, nickel, and iron. x is the proportion of A, y is the proportion of B, v is the proportion of A vacancies, w is the proportion of excess titanium, z is the proportion of Mn2P2O7, u is the proportion of D, and the following applies: 0.0≤x≤0.1, 0.0≤y<0.1, 0≤v<1.5*x, 0≤w<0.05, 0.01≤z<0.1, 0≤u<0.05. A method for producing the ceramic component is also disclosed.

Claims

1. A ceramic component having a ceramic base body, which as the main constituent comprises a ceramic material having the general empirical formula A.sub.xB.sub.yC1−.sub.x−vTi.sub.1−y+wO.sub.3*(Mn.sub.2P.sub.2O.sub.7).sub.z*D.sub.u, wherein A is a first doping which is selected from a group of first metals comprising neodymium, praseodymium, cerium and lanthanum, B is a second doping which is selected from a group of second metals comprising niobium, tantalum and vanadium, C is a main constituent of a base ceramic material selected from a group of third metals comprising calcium, strontium and barium and D is an additive which comprises at least one first compound containing a fourth metal selected from a group of fourth metals comprising aluminum, nickel and iron, wherein x is the molar proportion of A, y is the molar proportion of B, v is the molar proportion of A vacancies, w is the molar proportion of a titanium excess, z is the molar proportion of Mn.sub.2P.sub.2O.sub.7, u is the molar proportion of D and the following holds true for the molar proportions: 0.0≤x<0.1, 0.0≤y<0.1, 0≤v<1.5*x, 0≤w<0.05, 0.01≤z<0.1, 0≤u<0.05.

2. The ceramic component as claimed in claim 1, wherein the first doping comprises at least two first metals and/or the second doping comprises at least two second metals and/or the main constituent of the base ceramic material comprises at least two third metals. and/or the main constituent of the base ceramic material comprises at least two third metals.

3. The ceramic component as claimed in claim 1, wherein the additive comprises at least one first compound and one second compound, each of which contains a fourth metal, wherein the first compound contains a fourth metal which differs from the fourth metal present in the second compound.

4. The ceramic component as claimed in claim 1, wherein the ceramic base body has a multiplicity of ceramic layers and inner electrodes which are arranged between the ceramic layers, wherein the inner electrodes contain nickel as the main constituent.

5. The ceramic component as claimed in claim 1, wherein the ceramic component is of a capacitor.

6. The ceramic component as claimed in claim 1, wherein the ceramic base body has a sintered density of more than 90%.

7. A method for producing a ceramic component as claimed in claim 1, wherein the method has the following sub-steps: providing a base ceramic material having the general empirical formula CTiO.sub.3, wherein C is a main constituent of the base ceramic material comprising a third metal selected from a group of third metals comprising calcium, strontium, barium, adding Mn.sub.2P.sub.2O.sub.7, a first dopant which contains a first metal and/or a second dopant which contains a second metal and/or a Ti-containing compound and/or an additive which comprises at least one first compound containing a fourth metal to the ceramic material, with subsequent mixing to obtain a mixture, wherein the first metal is selected from a group of first metals comprising neodymium, praseodymium, cerium and lanthanum, the second metal is selected from a group of second metals comprising niobium, tantalum and vanadium, the third metal is selected from a group of third metals comprising calcium, strontium and barium, and the fourth metal is selected from a group of fourth metals comprising aluminum, nickel and iron, grinding the mixture to obtain a ground mixture, producing ceramic green sheets from the ground mixture, applying inner electrodes to the ceramic green sheets, stacking the ceramic green sheets to obtain a stack of green sheets, pressing the stack of green sheets to obtain a pressed stack of green sheets, singulating the pressed stack to obtain singulated green structural parts, decarburizing the singulated structural parts to obtain decarburized structural parts, sintering the decarburized structural parts to obtain sintered structural parts, tempering the sintered structural parts to obtain ceramic base bodies, applying metallizations to and firing metallizations on outer surfaces of the ceramic base bodies to obtain ceramic components.

8. The method as claimed in claim 7, wherein the main constituent of the base ceramic material comprises at least two third metals.

9. The method as claimed in claim 7, wherein the first dopant contains at least two first metals and/or the second dopant contains at least two second metals.

10. The method as claimed in claim 7, wherein additives comprising at least aluminium and nickel are added.

11. The method as claimed in claim 7, wherein a metal-containing paste containing nickel is used for applying the inner electrodes.

12. The method as claimed in claim 7, wherein the decarburized stack of green sheets is sintered at a temperature of between 1200 and 1250° C. and for a holding time of one to five hours.

13. The method as claimed in claim 7, wherein the decarburized stack of green sheets is sintered in a reducing atmosphere.

14. The method as claimed in claim 7, wherein a passivation of glass is applied to the ceramic base body.

15. The ceramic component as claimed in claim 5, which has a structure of type 0603 or smaller.

16. The ceramic component as claimed in claim 5, wherein the capacitor has a capacity smaller or equal to 10 nF.

17. The ceramic component as claimed in claim 5, wherein the capacitor has an ESD-voltage of above 8 kV.

18. The ceramic component as claimed in claim 1, wherein a passivation of glass is attached to the ceramic base body.

19. The method as claimed in claim 7, wherein the tempering is carried out in air.

Description

[0064] The invention will be described in more detail below on the basis of an exemplary embodiment with the associated figure.

[0065] FIG. 1 shows a ceramic component having a ceramic base body.

[0066] The figure and the size ratios in the figure are not true to scale.

[0067] FIG. 1 shows a ceramic component having a ceramic base body 1 with internal inner electrodes 2 and two metallizations 3, which are attached to two opposite outer surfaces 1′ of the ceramic base body 1. In addition, the ceramic base body 1 has a passivation 4 of glass. The ceramic component is in the form of a multilayer capacitor. The ceramic base body contains, as the main constituent, a ceramic material with the empirical formula La.sub.0.2Ba.sub.0.194Sr.sub.0.776Ti.sub.1O.sub.3*(Mn.sub.2P.sub.2O.sub.7).sub.0.01 and thus corresponds to the composition of the first example shown in Table 1.

[0068] A base ceramic material with the empirical formula Ba.sub.0.2Sr.sub.0.8TiO.sub.3 was provided for the production of a ceramic base body for an exemplary embodiment. Lanthanum oxide as the first dopant, titanium dioxide as the titanium-containing compound, and manganese pyrophosphate were added to the base ceramic material. The sum of the molar proportions of the base ceramic material, the first dopant, the titanium-containing compound and the manganese pyrophosphate is 100 mol %. Thus, the molar proportion of the base compound is 97 mol %, the molar proportion of the first dopant is 1 mol %, the molar proportion of the titanium-containing compound is 1.5 mol % and the molar proportion of manganese pyrophosphate is 0.5 mol %. Subsequently, the base ceramic material, the first dopant, the titanium-containing compound and the manganese pyrophosphate were mixed together and ground to obtain a ground mixture.

[0069] From the ground mixture ceramic green sheets were produced, to which inner electrodes were applied by means of a metal-containing paste containing nickel. In a subsequent step, the printed green sheets were stacked to form a stack of green sheets and were pressed to obtain a pressed stack of green sheets. After this, the pressed stack of green sheets was singulated and then the singulated structural parts were decarburized at 600° C. and sintered at 1250° C. for four hours in a reducing atmosphere in order to obtain a ceramic base body 1. In a further step, metallizations 3 were applied to two opposite outer surfaces 1′ of the ceramic base body 1. Finally, the ceramic base body 1 was subjected to a passivation 4 of glass.

[0070] The invention is not restricted to the above exemplary embodiment. In particular, the ceramic material can comprise a composition corresponding to Examples 2 to 7 from Table 1.

[0071] The ceramic material can, however, also comprise a composition which differs from the compositions shown in Examples 1 to 7 in Table 1, Examples 1 to 7 being considered to be preferred. The use of the ceramic material is also not restricted to a capacitor.

LIST OF REFERENCE DESIGNATIONS

[0072] 1 Ceramic base body [0073] 1′ Outer surface [0074] 2 Inner electrodes [0075] 3 Outer metallization [0076] 4 Passivation