The present application discloses a dense lead metaniobate piezoelectric ceramic and a preparation method therefor. The chemical composition of the lead metaniobate piezoelectric ceramic is Pb.sub.1-xNb.sub.2O.sub.6, wherein x represents the Pb vacancy concentration of A sites in a tungsten bronze crystal structure, and x is greater than 0.00 and smaller than or equal to 0.20.

The present application discloses a dense lead metaniobate piezoelectric ceramic and a preparation method therefor. The chemical composition of the lead metaniobate piezoelectric ceramic is Pb.sub.1-xNb.sub.2O.sub.6, wherein x represents the Pb vacancy concentration of A sites in a tungsten bronze crystal structure, and x is greater than 0.00 and smaller than or equal to 0.20.

An electrocaloric effect element includes a laminate including an electrode layer mainly including Pt and a ceramic layer that are stacked, in which the ceramic layer has a perovskite structure and mainly includes a ceramic including Pb, Sc, and Ta, where a content ratio of Sc is y, a content ratio of Ta is 1−y, and a range of the y is about 0.450≤y≤about 0.495.

A transparent optical element may include a layer of an electroactive ceramic disposed between transparent electrodes, such that the electrodes are each oriented perpendicular to a non-polar direction of the ceramic layer. Optical properties of the optical element, including transmissivity, haze, and clarity may be improved by the application of a voltage to the electroactive ceramic, and an associated phase transformation.

Provided are a dielectric material including a compound represented by Formula 1, a device including the same, and a method of preparing the dielectric material:
(1−x)K.sub.aNa.sub.bNbO.sub.3.xM(A.sub.cSb.sub.d)O.sub.3  [Formula 1] wherein, in Formula 1, M is a Group 2 element, A is a trivalent element, and 0<x<1, 0<a<1, 0<b<1, 0<c<1, 0<d<1, a+b=1, and c+d=1.

Provided are a dielectric material including a compound represented by Formula 1, a device including the same, and a method of preparing the dielectric material:
(1−x)K.sub.aNa.sub.bNbO.sub.3.xM(A.sub.cSb.sub.d)O.sub.3  [Formula 1] wherein, in Formula 1, M is a Group 2 element, A is a trivalent element, and 0<x<1, 0<a<1, 0<b<1, 0<c<1, 0<d<1, a+b=1, and c+d=1.

Provided are a dielectric material including a compound represented by Formula 1, a device including the same, and a method of preparing the dielectric material:

(1−x)K.sub.aNa.sub.bNbO.sub.3.xM(A.sub.cSb.sub.d)O.sub.3  [Formula 1] wherein, in Formula 1, M is a Group 2 element, A is a trivalent element, and 0<x<1, 0<a<1, 0<b<1, 0<c<1, 0<d<1, a+b=1, and c+d=1.

Provided are a dielectric material including a compound represented by Formula 1, a device including the same, and a method of preparing the dielectric material:

(1−x)K.sub.aNa.sub.bNbO.sub.3.xM(A.sub.cSb.sub.d)O.sub.3  [Formula 1] wherein, in Formula 1, M is a Group 2 element, A is a trivalent element, and 0<x<1, 0<a<1, 0<b<1, 0<c<1, 0<d<1, a+b=1, and c+d=1.

A process for preparing a porous ceramic body includes forming a green body with a mixture of ceramic material powder, binder material, and pore-forming particles. The process further includes extracting the binder material, decomposing the pore-forming particles, and removing residual organic materials from the green body at respective, progressively higher pre-firing temperatures. After these three stages, the green body is sintered at a still-higher temperature to form the porous ceramic body. Embodiments facilitate manufacturing and can render most or all surface grinding unnecessary, allowing electrode deposition directly onto substantially non-porous surfaces of the porous ceramic body that are naturally formed during sintering. Advantageously, the green body may be formed into net shape by injection molding the mixture that includes the pore-forming particles, and embodiments can result in porous ceramic bodies that are much thicker than currently available, with better structural integrity.

A process for preparing a porous ceramic body includes forming a green body with a mixture of ceramic material powder, binder material, and pore-forming particles. The process further includes extracting the binder material, decomposing the pore-forming particles, and removing residual organic materials from the green body at respective, progressively higher pre-firing temperatures. After these three stages, the green body is sintered at a still-higher temperature to form the porous ceramic body. Embodiments facilitate manufacturing and can render most or all surface grinding unnecessary, allowing electrode deposition directly onto substantially non-porous surfaces of the porous ceramic body that are naturally formed during sintering. Advantageously, the green body may be formed into net shape by injection molding the mixture that includes the pore-forming particles, and embodiments can result in porous ceramic bodies that are much thicker than currently available, with better structural integrity.