Ceramic material and electroceramic component comprising the ceramic material

1. A ceramic material with negative temperature coefficient of resistance with the general formula:

[{(SE 1 III ,SE 2 III ) 1−x (M 1 II ,M 2 II ) x }(Cr 1−y−z Mn y (Me 1 III ,Me 2 III ) z )O 3 ]

wherein (SE 1 III ,SE 2 III ) are rare-earth metal cations and SE 1 III can be equal to SE 2 III or stands for different rare-earth metal cations for mixtures of SE 1 III and SE 2 III , M 1 III can be equal to M 2 II or their mixtures with variable percentages and stands for bivalent metal cations, and Me 1 III and Me 2 III are redox-stable, trivalent metal cations that can be equal or different and the following applies: 0<x<1 0<z≦0.3; 0<y<1−z.

2. The ceramic material according to claim 1 , with the general formula:

[{(SE 1 III ,SE 2 III ) 1−x (M 1 II ,M 2 II ) x }(Cr III 1−x−y−z+tCr IV x−t Mn III y−t Mn IV t (Me 1 III ,Me 2 III ) z )O 3 ]

wherein the following applies with respect to the parameters:

x+y+z<1; 0<x<1 0<z≦0.3; 0≦t≦x where, for 0<t<x, the following applies: t≦y<1+t−x−z, for t=0 the following applies: 0<y≦1−x−z, and for t=x, the following applies: x<y<1−z.

3. The ceramic material according to claim 2 , with the general formula for t=0 or t=x:

Y III 1−x Ca II x (Cr III 1−x−y−z Cr IV x Mn III y Al III z )O 3 or

Y III 1−x Ca II x (Cr III 1−y−z Mn IV x Mn III y−x Al III z )O 3 .

4. The ceramic material according to claim 1 , wherein SE 1 III and SE 2 III comprise cations selected from the group consisting of Y III , Ce III , Sm III and La III .

5. The ceramic material according to claim 1 , wherein Me 1 III and Me 2 III comprise metal cations selected from the group consisting of Al III and Ga III .

6. The ceramic material according to claim 1 , wherein x: 0.01≦x≦0.5.

7. The ceramic material according to claim 1 , wherein y: 0.01≦y≦0.7.

8. The ceramic material according to claim 1 , wherein z: 0.05≦z≦0.3.

9. The ceramic material according to claim 1 , wherein the material is constructed as a phase-homogeneous Perovskite mixed-crystal system of a first electrically semiconductive Perovskite system and a second electrically non-conductive Perovskite system.

10. The ceramic material according to claim 9 , wherein the first electrically semiconductive Perovskite system comprises SE III 1−x M II x (Cr 1-y Mn y )O 3 and the second electrically non-conductive Perovskite system comprises SE III Me III O 3 .

11. The ceramic material according to claim 1 , wherein the bivalent metal cations M 1 II ,M 2 II are selected from Ca II , Sr II .

12. A method for producing the ceramic material according to claim 1 , the method comprising:

preparing a mixture of compounds SE III 2 O 3 , M II CO 3 , Cr 2 O 3 , Mn 2 O 3 , Mn 3 O 4 , MnCO 3 and Me III 2 O 3 in desired quantities; and

sintering the mixture, wherein the ceramic material has a general formula of:

[{(SE 1 III ,SE 2 III ) 1−x (M 1 II ,M 2 II ) x }(Cr 1−y−z Mn y (Me 1 III ,Me 2 III ) z )O 3 ]

wherein (SE 1 III ,SE 2 III ) are rare-earth metal cations and SE 1 III can be equal to SE 2 III or stands for different rare-earth metal cations for mixtures of SE 1 III and SE 2 III , M 1 II can be equal to M 2 II or their mixtures with variable percentages and stands for bivalent metal cations, and Me 1 III and Me 2 III redox-stable, trivalent metal cations that can be equal or different and the following applies: 0<x<1 0<z≦0.3; 0<y<1−z.

13. The method according to claim 12 , further comprising calcining the mixture of the compounds before the sintering.

14. The method according to claim 12 , wherein a phase-homogeneous Perovskite mixed-crystal system is formed.

15. The method according to claim 12 , further comprising adding a sintering aid.

16. An electroceramic component comprising:

a ceramic material having a general formula of:

[{(SE 1 III ,SE 2 III ) 1−x (M 1 II ,M 2 II ) x }(Cr 1−y−z Mn y (Me 1 III ,Me 2 III ) z )O 3 ]

wherein (SE 1 III ,SE 2 III ) are rare-earth metal cations and SE 1 III can be equal to SE 2 III or stands for different rare-earth metal cations for mixtures of SE 1 III and SE 2 III , M 1 II can be equal to M 2 II or their mixtures with variable percentages and stands for bivalent metal cations, and Me 1 III and Me 2 III redox-stable, trivalent metal cations that can be equal or different and the following applies: 0<x<1 0<z≦0.3; 0<y<1−z.

17. The electroceramic component according to claim 16 comprising:

a ceramic base body that contains the ceramic material; and

electrically conductive electrode faces adjacent the ceramic base body.

18. The electroceramic component according to claim 16 , wherein x: 0.01≦x≦0.5.

19. The electroceramic component according to claim 16 , wherein y: 0.01≦y≦0.7.

20. The electroceramic component according to claim 16 , wherein z: 0.05≦z≦0.3.