US 12,283,429 B2
Dielectric ceramic and multilayer ceramic capacitor
Taku Mizuno, Nagaokakyo (JP); Keisuke Araki, Nagaokakyo (JP); and Hiroyuki Wada, Nagaokakyo (JP)
Assigned to MURATA MANUFACTURING CO., LTD., Nagaokakyo (JP)
Filed by Murata Manufacturing Co., Ltd., Nagaokakyo (JP)
Filed on Oct. 7, 2021, as Appl. No. 17/496,044.
Claims priority of application No. 2020-179755 (JP), filed on Oct. 27, 2020.
Prior Publication US 2022/0130608 A1, Apr. 28, 2022
Int. Cl. H01G 4/12 (2006.01); C04B 35/46 (2006.01); C04B 35/468 (2006.01); H01G 4/30 (2006.01)
CPC H01G 4/1227 (2013.01) [C04B 35/4682 (2013.01); H01G 4/30 (2013.01); C04B 2235/3224 (2013.01); C04B 2235/3236 (2013.01); C04B 2235/3418 (2013.01); C04B 2235/442 (2013.01); C04B 2235/75 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A dielectric ceramic comprising:
a plurality of first crystal grains, each of the plurality of first crystal grains having an interface, a barium titanate (BaTiO3)-based compound as a main component thereof, and a rare earth element,
wherein, in a cross-section of the dielectric ceramic, each of the plurality of first crystal grains have a concentration varying region, a high concentration region, and a low concentration region,
the concentration varying region comprising a first segment between two points having RE/Ti ratios differing by 3% or more, wherein RE/Ti ratios are a molar ratio of a concentration of the rare earth element to a concentration of titanium,
the two points being along a cross-sectional straight line passing through an inner portion of a respective first crystal grain of the plurality of first crystal grains from the interface around the respective first crystal grain,
the high concentration region comprising a second segment between the interface and an interface-side point of the two points along the cross-sectional straight line and having an RE/Ti ratio of 5% to 20%,
the low concentration region comprising a third segment that extends from a second of the two points toward the inner portion of the respective first crystal grain along the cross-sectional straight line and having an RE/Ti ratio of 0% to 2%.