Ceramic Material, Varistor and Methods of Preparing the Ceramic Material and the Varistor

Patent metadata

Field	Value
Publication number	US-2019103206-A1
Application number	US-201716085940-A
Country	US
Kind code	A1
Filing date	Mar 14, 2017
Priority date	Mar 17, 2016
Publication date	Apr 4, 2019
Grant date	—

Abstract

A ceramic material, a varistor and methods for forming a ceramic material and a varistor are disclosed. In an embodiment, a ceramic material includes ZnO as a main component and additives selected from the group consisting of an Al 3+ -containing solution, a Ba 2+ -containing solution, and at least one compound containing a metal element, wherein the metal element is selected from the group consisting of Bi, Sb, Co, Mn, Ni, Y, and Cr.

First claim

1 - 14 . (canceled)

15 . A ceramic material comprising:
ZnO as a main component; and additives selected from the group consisting of an Al 3+ -containing solution, a Ba 2+ -containing solution, and at least one compound containing a metal element, wherein the metal element is selected from the group consisting of Bi, Sb, Co, Mn, Ni, Y, and Cr.

16 . The ceramic material according to claim 15 , wherein a content of the additives in the ceramic material is ≤5 mol %.

17 . The ceramic material according to claim 15 ,
wherein c 1 is the equivalent content of Co in Co 3 O 4 , m is the equivalent content of Mn in Mn 3 O 4 , s is the equivalent content of Sb in Sb 2 O 3 , c 2 is the equivalent content of Cr in Cr 2 O 3 , a is the content of Al 3+ , y is the equivalent content of Y in Y 2 O 3 , b 1 is the equivalent content of Bi in Bi 2 O 3 , n is the equivalent content of Ni in NiO, b 2 is the content of Ba 2+ , and z is the content of ZnO, and wherein 0.4 mol %≤b 1 ≤0.55 mol %, 1.10 mol %≤s≤1.90 mol %, 0.50 mol %≤c 1 ≤0.80 mol %, 0.20 mol %≤m≤0.30 mol %, 0.70 mol %≤n≤1.20 mol %, 0.25 mol %≤y≤0.45 mol %, 0.00 mol %≤c 2 ≤0.10 mol %, 0.003 mol %≤a≤0.006 mol %, and 0.005 mol %≤b 2 ≤0.015 mol %.

18 . The ceramic material according to claim 17 , wherein (c 1 +5c 2 +2s+4y−m−250a)(1−z)/b 1 =F and 0.27≤F≤0.43.

19 . The ceramic material according to claim 15 , wherein the at least one compound is selected from the group consisting of metal oxides, metal carbonates, metal acetates, metal nitrides and mixtures thereof.

20 . The ceramic material according to claim 15 , wherein the at least one compound is selected from the group consisting of Bi 2 O 3 , Sb 2 O 3 , Co 3 O 4 , Mn 3 O 4 , NiO, Y 2 O 3 , and Cr 2 O 3 .

21 . The ceramic material according to claim 15 , wherein the Al 3+ -containing solution and the Ba 2+ -containing solution are solutions selected from the group consisting of nitrides, acetates, hydrates, and mixtures thereof.

22 . The ceramic material according to claim 15 , wherein the ceramic material has a sintering temperature of between 1020° C. inclusive and 1060° C. inclusive.

23 . A varistor comprising:
a ceramic body containing a sintered ceramic material according to claim 15 .

24 . The varistor according to claim 23 , wherein the varistor has a varistor gradient E 1 mA of between 480 V/mm inclusive and 640 V/mm inclusive.

25 . A method for forming the ceramic material according to claim 15 , the method comprising:
weighing, mixing and ball-milling a first part of additives; adding ZnO, and a second part of additives; forming a homogeneous slurry; and spray-drying the slurry to form a granule of the ceramic material.

26 . The method according to claim 25 , wherein the first part of additives is at least one compound containing a metal element, wherein the metal element is selected from the group consisting of Bi, Sb, Co, Mn, Ni, Y, and Cr, and wherein the second part of additives is at least one of an Al 3+ -containing solution or a Ba 2+ -containing solution.

27 . A method for forming a varistor, the method comprising:
forming a ceramic body comprising the ceramic material formed according to claim 25 ; applying electrode layers on the ceramic body, wherein the ceramic material is sintered at a temperature of between 1020° C. inclusive and 1060° C. inclusive to form the ceramic body.

28 . The method according to claim 27 , wherein forming the ceramic body further comprises:
dry-pressing the granule of the ceramic material; and debindering the ceramic material.

29 . A ceramic material comprising
ZnO as a main component; and additives selected from the group consisting of an Al 3+ -containing solution, a Ba 2+ -containing solution, and at least one compound containing a metal element, wherein the metal element is selected from the group consisting of Bi, Sb, Co, Mn, Ni, Y, and Cr, wherein c 1 is the equivalent content of Co in Co 3 O 4 , m is the equivalent content of Mn in Mn 3 O 4 , s is the equivalent content of Sb in Sb 2 O 3 , c 2 is the equivalent content of Cr in Cr 2 O 3 , a is the content of Al 3+ , y is the equivalent content of Y in Y 2 O 3 , b 1 is the equivalent content of Bi in Bi 2 O 3 , n is the equivalent content of Ni in NiO, b 2 is the content of Ba 2+ , and z is the content of ZnO, and wherein 0.4 mol %≤b 1 ≤0.55 mol %, 1.10 mol %≤s≤1.90 mol %, 0.50 mol %≤c 1 ≤0.80 mol %, 0.20 mol %≤m≤0.30 mol %, 0.70 mol %≤n≤1.20 mol %, 0.25 mol %≤y≤0.45 mol %, 0.00 mol %≤c 2 ≤0.10 mol %, 0.003 mol %≤a≤0.006 mol %, and 0.005 mol %≤b 2 ≤0.015 mol %.

Assignees

• Epcos Ag

Inventors

• Wang Yongli
• Wu Jianxin
• Yi Wenbin

Classifications

• H01C7/112 Primary

  ZnO type · CPC title

• C04B2235/3215

  Barium oxides or oxide-forming salts thereof · CPC title

• C04B35/453 Primary

  based on zinc, tin, or bismuth oxides or solid solutions thereof with other oxides, e.g. zincates, stannates or bismuthates · CPC title

• C04B2235/80

  Phases present in the sintered or melt-cast ceramic products other than the main phase · CPC title

• C04B2235/3294

  Antimony oxides, antimonates, antimonites or oxide forming salts thereof, indium antimonate · CPC title