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US 6,685,850 B2Granted
Piezoelectric ceramic material
AssigneeTDK Corporation
InventorsMasaru Nanao, Masakazu Hirose, Takeo Tsukada
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AssigneeTDK Corporation
InventorsMasaru Nanao, Masakazu Hirose, Takeo Tsukada
Estimating the term…
The invention provides a piezoelectric ceramic material comprising a Bi3TiNbO9 crystal and/or an MBi2Nb2O9 crystal which are each a bismuth layer compound, where M represents at least one element selected from Sr, Ba and Ca. The ceramic material contains Bi, Ti, M and Nb as main component elements. The molar ratio as oxides of the main component elements is given by (Bi3−xMx)z (Nb1+yTi1−y)O9 provided that 0<x, y≦0.8 and 0.95≦z≦1.05. When the molar ratio of Ba/(M+Bi) is given by xB/3 and the molar ratio of Ca/(M+Bi) is given by xC/3, it is required that 0≦xB≦0.5 and 0≦xC<0.4. This piezoelectric ceramic material, free from any lead whatsoever, has a sufficiently high Curie point, and exhibits ever more improved piezoelectric properties.
A piezoelectric ceramic material comprising a solid solution comprising Bi, Ti, M and Nb as main component elements, wherein M represents at least one element selected from the group consisting of Sr, Ba and Ca, wherein the molar ratio as oxides of said main component elements is given (Bi3−xMx)z(Nb1+yTi1−y)O9 provided that 0<x, y≦0.8, and 0.95≦z≦1.05, and 0≦xB≦0.5 and 0≦xC≦0.4, wherein the molar ratio of Ba/(M+Bi) is given by xB/3 and a molar ratio of Ca/(M+Bi) is given by xC/3, wherein said solution further includes a bismuth layer compound selected from the group consisting of Bi3TiNbO9 crystal, MBi2Nb2O9 crystal and mixtures thereof.
Dependencies are inferred from the claim text.