Dielectric ceramic and laminated ceramic capacitor
AssigneeMurata Manufacturing Co., Ltd.
InventorsTomonori Muraki, Tomoyuki Nakamura, Makoto Matsuda, Akihiro Shiota
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Abstract
A dielectric ceramic (and capacitor containing it) balancing high temperature load characteristics and temperature characteristics of capacitance even when layer thickness is less than 1 μm has a mixture of different crystal grains containing a barium titanate compound as the main constituent. The first crystal grains can contain rare earth element solid solution region 1 at the surface layer section. The second crystal grains have a core-shell structure including a shell section having a rare earth element solid solution present. The first and second crystal grains are 12% to 84% f and 16% to 88%, respectively, of the total number of crystal grains.
Claims10
A dielectric ceramic having main phase grains containing a barium titanate compound as their main constituent,
- the dielectric ceramic comprising 12% to 84% of first crystal grains which are the main phase grains optionally including at least one rare earth element R selected from the group consisting of La, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Tb, Lu, and Y in a minute amount present as a solid solution therein, and 16% to 88% of second crystal grains having a core section comprising the main phase grains and a shell section around the core section and comprising main phase grains having therein at least one rare earth element R present as a solid solution,
- wherein the first crystal grains have an amount of rare earth element R such that its solid solubility distance is 5 nm or less (including 0) in the main phase grain measured from the surface of the main phase grain toward the inside thereof and
- wherein the shell section has a thickness of ⅛ or more and ⅜ or less the diameter of the main phase grain.
A dielectric ceramic having main phase grains containing a barium titanate compound as their main constituent,
- the dielectric ceramic comprising 12% to 84% of first crystal grains which are the main phase grains optionally including at least one rare earth element R selected from the group consisting of La, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Tb, Lu, and Y in a minute amount present as a solid solution therein, and 16% to 88% of second crystal grains having a core section comprising the main phase grains and a shell section around the core section and comprising main phase grains having therein at least one rare earth element R present as a solid solution,
- wherein the first crystal grains have an amount of rare earth element R such that its solid solubility distance is 5 nm or less (including 0) in the main phase grain measured from the surface of the main phase grain toward the inside thereof and
- wherein the shell section has a thickness of ⅛ or more and ⅜ or less the diameter of the main phase grain, and
- wherein the composition formula is represented by {100(Ba1-xCax)mTiO3+aRO3/2+bMgO+cMOy+dSiO2+eLiO1/2} in which formula, M represents at least one of Mn and V, and y represents a positive number determined by the valence of M, and
- 0.960≦m≦1.030;
- 0≦x≦0.20;
- 0.2≦a≦5.0;
- 0≦b≦2.0;
- 0.2≦c≦1.0;
- 0.5≦d≦4.0;
- and
- 0.5≦e≦6.0.
A dielectric ceramic having main phase grains containing a barium titanate compound as their main constituent,
- the dielectric ceramic comprising 12% to 84% of first crystal grains which are the main phase grains optionally including at least one rare earth element R selected from the group consisting of La, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Tb, Lu, and Y in a minute amount present as a solid solution therein, and 16% to 88% of second crystal grains having a core section comprising the main phase grains and a shell section around the core section and comprising main phase grains having therein at least one rare earth element R present as a solid solution, and
- wherein the composition formula is represented by
- {100(Ba1-xCax)mTiO3+aRO3/2+bMgO+cMOy +dSiO2+eLi1/2}
- in which formula, M represents at least one of Mn and V, and y represents a positive number determined by the valence of M, and
- 0.960≦m≦1.030;
- 0≦x≦0.20;
- 0.2≦a≦5.0;
- 0≦b≦2.0;
- 0.2≦c≦1.0;
- 0.5≦d≦4.0;
- and
- 0.5≦e≦6.0.
Dependencies are inferred from the claim text.