Provided is a piezoelectric ceramics including crystal grains each including: a first region that is formed of a perovskite-type metal oxide having a crystal structure in which a central element of a unit cell is located at an asymmetrical position; and a second region that is formed of a perovskite-type metal oxide having a crystal structure in which a central element of a unit cell is located at a symmetrical position, and that is present inside the first region, wherein a ratio of a cross-sectional area of the second region to a cross-sectional area of the piezoelectric ceramics is 0.1% or less.

A method for making a fuel rod cladding tube and a cladding tube are described. The method includes wrapping ceramic fibers, for example, SiC fibers in a SiC matrix, around a tube formed from a metal alloy, such as a zirconium alloy. The interstices of the SiC wrappings on the tube are at least partially filled with SiC nano-sized particles. The surface of the filled tube is exposed by atomic layer deposition, at temperatures ranging from 25° C. to 600° C., to at least one cycle of alternating, non-overlapping pulses of gaseous precursors containing carbon and silicon to form a SiC monolayer. The step of filling the interstices of the SiC wrappings on the tube with SiC nano-sized particles fills large voids in the SiC wrapping. The step of exposing the surface of the particle filled SiC windings to at least one cycle of gaseous pulses fills small voids in the SiC wrapping.

Provided is a thermoelectric material satisfying (MX).sub.1+a(TX.sub.2).sub.n and having a superlattice structure, wherein M is at least one element selected from the group consisting of Group 13, Group 14, and Group 15, T is at least one element selected from Group 5, X is a chalcogenide element, a is a real number satisfying 0<a<1, and n is a natural number of 1 to 3.

A polycrystalline ceramic solid and a method for producing a polycrystalline ceramic solid are disclosed. In an embodiment a polycrystalline ceramic solid includes a main phase with a composition of the general formula: (1-y)Pb.sub.a(Mg.sub.bNb.sub.c)O.sub.3-e+yPb.sub.aTi.sub.dO.sub.3 with 0.055≤y≤0.065, 0.95≤a≤1.02, 0.29≤b≤0.36, 0.63≤c≤0.69, 0.9≤d≤1.1, and 0≤e≤0.1, and optionally one or more secondary phases, wherein, in each section through the solid, a proportion of the secondary phases relative to any given cross-sectional area through the solid is less than or equal to 0.5 percent, or wherein the solid is free of the secondary phases.

An alumina/titanium silicon carbide composite material is prepared by making titanium aluminum carbide (Ti.sub.3AlC.sub.2) in uniform contact with silicon monoxide (SiO), and carrying out vacuum sintering. The composite material is obtained through mutual diffusion of aluminum and silicon and has high compactness and stable performance. In the composite material, the alumina is generated by means of a reaction between the titanium aluminum carbide and the silicon monoxide, and can be uniformly wrapped around surfaces of titanium silicon carbide crystals to form a relatively compact oxide film, such that substance exchange between a matrix and the outside is hindered, and overall antioxidation of the composite material is improved. Toughness of the composite material is enhanced by means of the titanium silicon carbide. The prepared composite material has relatively high purity, relatively low sintering temperature, and relatively high bending strength. The process is simple and convenient for industrial production.

A lead-free piezoelectric ceramic composition mainly includes a first crystal phase (KNN phase) and a second crystal phase (NTK phase). In the first crystal phase (KNN phase), a plurality of crystal grains formed of an alkali niobate/tantalate perovskite oxide having piezoelectric characteristics is bound to each other in a deposited state. The second crystal phase (NTK phase) is formed of a compound containing titanium (Ti) and fills spaces between the crystal grains in the first crystal phase.

A composite ceramic including: a lithium garnet major phase; and a grain growth inhibitor minor phase, as defined herein. Also disclosed is a method of making composite ceramic, pellets and tapes thereof, a solid electrolyte, and an electrochemical device including the solid electrolyte, as defined herein.

A ferroelectric perovskite composition, comprising a perovskite oxide ABO.sub.3, and a doping agent selected from perovskites of Ba(Ni,Nb)O.sub.3 and Ba(Ni,Nb)O.sub.3-δ. The ferroelectric perovskite composition may be represented by the formula: xBa(Ni,Nb)O.sub.3.(1-x)ABO.sub.3 or xBa(Ni,Nb)O.sub.3-δ.(1-x)ABO.sub.3. A method of producing the ferroelectric perovskite composition in thin film form is also provided.

A multilayer ceramic capacitor that includes a ceramic body including a stack of a plurality of dielectric layers and a plurality of first and second internal electrodes; and first and second external electrodes provided at each of both end faces of the ceramic body. Each of the plurality of dielectric layers contain Ba, Ti, P and Si. The plurality of dielectric layers include an outer dielectric layer located on an outermost side in the stacking direction; an inner dielectric layer located between the first and second internal electrodes; and a side margin portion in a region where the first and second internal electrodes do not exist. In at least one of the outer dielectric layer, the inner dielectric layer and the side margin portion, the P and the Si segregate in at least one of grain-boundary triple points of three ceramic particles.

The invention relates to a material for storing and releasing oxygen, consisting of a reactive ceramic made of copper, manganese and iron oxides, wherein, subject to the oxygen partial pressure of a surrounding atmosphere and/or an ambient temperature, the reactive ceramic has a transition region that can be passed through any number of times, said transition region being between a discharge threshold state of a three-phase crednerite/cuprite/hausmannite mixed ceramic and a charge threshold state of a two-phase spinel/tenorite mixed ceramic. A passing through of the transition region from the discharge threshold state towards the charging threshold state is associated with oxygen uptake and a passing through of the transition region from the charge threshold state towards the discharge threshold state is associated with oxygen release.