US 12,283,430 B2
Ceramic electronic device having a copper-containing baked electrode layer
Toshihiro Iguchi, Tokyo (JP); Tetsuhiro Takahashi, Tokyo (JP); and Tomohisa Fukuoka, Tokyo (JP)
Assigned to TDK CORPORATION, Tokyo (JP)
Filed by TDK CORPORATION, Tokyo (JP)
Filed on Aug. 24, 2022, as Appl. No. 17/894,293.
Claims priority of application No. 2021-164078 (JP), filed on Oct. 5, 2021.
Prior Publication US 2023/0107429 A1, Apr. 6, 2023
Int. Cl. H01G 4/232 (2006.01); H01G 4/30 (2006.01)
CPC H01G 4/2325 (2013.01) [H01G 4/30 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A ceramic electronic device comprising:
an element body including a ceramic layer and an internal electrode layer; and
an external electrode formed on an end surface of the element body and electrically connected to at least one end of the internal electrode layer, wherein
the external electrode includes a baked electrode layer,
the baked electrode layer includes a main component comprising copper and/or a copper alloy,
the baked electrode layer includes a void,
an inner wall surface defining the void is at least partly covered by a film comprising nickel and/or a nickel alloy,
the baked electrode layer comprises a first region and a second region,
the first region is in contact with the end surface of the element body and is located near a joint boundary between the baked electrode layer and the element body,
the second region is located at an outer side of the first region and constitutes an external surface of the baked electrode layer, and
a value of [(a second ratio of Ni/Cu)−(a first ratio of Ni/Cu)] is 0.02 or more based on the premise that the first ratio of Ni/Cu denotes an atomic ratio of nickel atoms to copper atoms in the first region and the second ratio of Ni/Cu denotes an atomic ratio of nickel atoms to copper atoms in the second region.