Abstract: In an exemplary embodiment, a piezoelectric ceramic composition is an alkali niobate-based piezoelectric ceramic composition whose primary component is a compound expressed by the general formula LixNayK1-x-yNbO3 (where 0<x<1, 0<y<1, and x+y<1), and which contains 100 ppm or more but less than 1000 ppm of fluorine by mass. The alkali niobate-based piezoelectric ceramic composition demonstrates good properties even when sintered at low temperature.

Abstract: A polymer flocculant mixing and dissolving system comprising: a mixing tank (2) in which a solid polymer flocculant is mixed with water used as a solvent; a liquid feed unit (3) for feeding an aqueous solution containing the polymer flocculant from the mixing tank; a regenerative mixer (4A,4B) used to mix and dissolve the polymer flocculant by applying pressure to the aqueous solution containing the polymer flocculant fed from the liquid feed unit while forming a vortex flow; a process channel (61) through which the aqueous solution that has passed through the regenerative mixer is fed to a downstream process; a circulation channel (62) through which the aqueous solution is returned to a position on an upstream side of the liquid feed unit; and a flow rate adjusting unit (6) for adjusting a balance between a flow rate of the aqueous solution flowing through the process channel and a flow rate of the aqueous solution flowing through the circulation channel.

Abstract: Form internal electrodes with a metal whose silver content is 80 percent by mass or higher, and also constitute piezoelectric ceramic layers with a piezoelectric ceramic whose primary component is an alkaline niobate having a perovskite structure and which contains at least one type of alkaline earth metal selected from calcium and barium, as well as silver, wherein the total content of the alkaline earth metal is 0.2 percent by mol or higher but lower than 2.0 percent by mol when the element content in the B sites of the alkaline niobate represents 100 percent by mol, and wherein the piezoelectric ceramic layers each contain at least one sintered grain 41 that has silver-segregated regions 42 inside and the silver-segregated regions 42 have a long diameter of 10 nm or smaller.

Abstract: In an exemplary embodiment, a piezoelectric ceramic composition is an alkali niobate-based piezoelectric ceramic composition whose primary component is a compound expressed by the general formula LixNayK1?x?yNbO3 (where 0<x<1, 0<y<1, and x+y<1), and which contains 100 ppm or more but less than 1000 ppm of fluorine by mass. The alkali niobate-based piezoelectric ceramic composition demonstrates good properties even when sintered at low temperature.

Abstract: A piezoelectric element which is a single-layer or laminated piezoelectric element has a first electrode, a second electrode, and a piezoelectric ceramic layer. The first electrode and second electrode contain silver by 50 percent by weight or more. The piezoelectric ceramic layer is placed between the first electrode and second electrode, and constituted by a polycrystalline substance of alkali niobate piezoelectric ceramic containing at least one alkali earth metal being calcium, strontium, or barium, and silver. According to this constitution, the electrical resistance and piezoelectric property can be improved, and consequently high reliability and good piezoelectric characteristics can be achieved.

Abstract: A piezoelectric ceramic speaker includes a piezoelectric element using a vibration sheet formed with piezoelectric ceramic having a primary phase constituted by ceramic grains of perovskite crystal structure containing Pb, Nb, Zn, Ti, and Zr, and a secondary phase constituted by ZnO grains, wherein the primary phase is constituted by ceramic grains expressed by a composition formula Pb {(Zr(1-a)Tia)x·(Ni1/3Nb2/3)y·(Zn1/3Nb2/3)z}O3 (where 0<x?0.85, 0?y<1, 0<z<1, x+y+z=1, and 0.45?a?0.60); and an enclosure which encloses the piezoelectric element.

Abstract: A piezoelectric ceramic speaker includes a piezoelectric element using a vibration sheet formed with piezoelectric ceramic having a primary phase constituted by ceramic grains of perovskite crystal structure containing Pb, Nb, Zn, Ti, and Zr, and a secondary phase constituted by ZnO grains, wherein the primary phase is constituted by ceramic grains expressed by a composition formula Pb {(Zr(1-a)Tia)x.(Ni1/3Nb2/3)y.(Zn1/3Nb2/3)z}O3 (where 0<x?0.85, 0?y<1, 0<z<1, x+y+z=1, and 0.45?a?0.60); and an enclosure which encloses the piezoelectric element.

Abstract: A piezoelectric ceramic has a primary phase constituted by ceramic grains of perovskite crystal structure containing Pb, Nb, Zn, Ti, and Zr, and a secondary phase constituted by ZnO grains present sporadically in the primary phase. The piezoelectric ceramic of high kr and high specific dielectric constant can be sintered at low temperature and exhibit minimal characteristics variations.

Abstract: A piezoelectric element which is a single-layer or laminated piezoelectric element has a first electrode, a second electrode, and a piezoelectric ceramic layer. The first electrode and second electrode contain silver by 50 percent by weight or more. The piezoelectric ceramic layer is placed between the first electrode and second electrode, and constituted by a polycrystalline substance of alkali niobate piezoelectric ceramic containing at least one alkali earth metal being calcium, strontium, or barium, and silver. According to this constitution, the electrical resistance and piezoelectric property can be improved, and consequently high reliability and good piezoelectric characteristics can be achieved.

Abstract: In a piezoelectric ceramic which has an alkali-containing niobate-based perovskite structure in which constituent elements are Li, Na, K, Nb, and O, a Li3NbO4 crystal phase is intentionally deposited on a piezoelectric ceramic having an alkali-containing niobate-based perovskite structure, whereby sintering becomes possible at about 1000° C. rather than at the normally required sintering temperature of 1050° C. or greater.

Abstract: A piezoelectric ceramic is constituted by a polycrystal whose main phase is an alkali-containing niobate perovskite structure, where both elemental nickel and elemental manganese are present at the grain boundary of the polycrystal. The piezoelectric ceramic is such that drop in piezoelectric characteristics due to application of high electric field is suppressed.

Abstract: A piezoelectric element includes first internal electrodes and second electrodes, as well as piezoelectric ceramic layers that are made of ceramics and arranged between the first internal electrodes and second internal electrodes. Manganese is present relatively more abundantly in the areas of the piezoelectric ceramic layers adjacent to the first internal electrodes and second internal electrodes, compared to at the centers of the piezoelectric ceramic layers. Insulation performance of the piezoelectric element is kept from dropping over the course of use.

Abstract: A piezoelectric ceramic has a primary phase constituted by ceramic grains of perovskite crystal structure containing Pb, Nb, Zn, Ti, and Zr, and a secondary phase constituted by ZnO grains present sporadically in the primary phase. The piezoelectric ceramic of high kr and high specific dielectric constant can be sintered at low temperature and exhibit minimal characteristics variations.

Abstract: A piezoelectric ceramic comprising as a main component an alkali-containing niobate-based perovskite structure expressed by a compositional formula (LixNayK1-x-y)a(Nb1-zTaz)O3 (provided: 0.04<x?0.1, 0?y?1, 0?z?0.4, and 0.95?a?1.005); wherein a crystal phase or an amorphous phase containing Si and K is made present at a grain boundary or a grain boundary triple point of a plurality of crystal grains constituting the piezoelectric ceramic.

Abstract: A piezoelectric ceramic is constituted by a polycrystal whose main phase is an alkali-containing niobate perovskite structure, where both elemental nickel and elemental manganese are present at the grain boundary of the polycrystal. The piezoelectric ceramic is such that drop in piezoelectric characteristics due to application of high electric field is suppressed.

Abstract: A piezoelectric element includes first internal electrodes and second electrodes, as well as piezoelectric ceramic layers that are made of ceramics and arranged between the first internal electrodes and second internal electrodes. Manganese is present relatively more abundantly in the areas of the piezoelectric ceramic layers adjacent to the first internal electrodes and second internal electrodes, compared to at the centers of the piezoelectric ceramic layers. Insulation performance of the piezoelectric element is kept from dropping over the course of use.

Abstract: In a piezoelectric ceramic which has an alkali-containing niobate-based perovskite structure in which constituent elements are Li, Na, K, Nb, and O, a Li3NbO4 crystal phase is intentionally deposited on a piezoelectric ceramic having an alkali-containing niobate-based perovskite structure, whereby sintering becomes possible at about 1000° C. rather than at the normally required sintering temperature of 1050° C. or greater.

Abstract: [Problems] To provide a ceramic composition that retains a high insulation resistance after being fired in a reductive atmosphere to form a laminated body. [Means for Solving the Problem] A novel ceramic composition according to an embodiment of the invention include: (NaxK1-x)(NbyTa1-y)O3 (0?x?1.0, 0.3<y?1.0) as main ingredient and Li and F in an amount ranging from 0.1 to 10.0 mol, calculated on lithium fluoride basis, relative to 100 mol of the main ingredient.

Abstract: As a piezoelectric ceramic having an alkaline-containing niobic acid-perovskite structure contains [K1-xNax]1-yLi[Nb1-z-wTazSbw]O3 (x, y, z, and w each indicate a molar ratio, and 0?x<1, 0?y<1, 0?z<1, and 0?w<1 hold) as a primary phase and K3Nb3O6Si2O7 as a subphase.

Abstract: A piezoelectric ceramic comprising as a main component an alkali-containing niobate-based perovskite structure expressed by a compositional formula (LixNayK1-x-y)a(Nb1-zTaz)O3 (provided: 0.04<x?0.1, 0?y?1, 0?z?0.4, and 0.95?a?1.005); wherein a crystal phase or an amorphous phase containing Si and K is made present at a grain boundary or a grain boundary triple point of a plurality of crystal grains constituting the piezoelectric ceramic.