An alumina sintered body having a low dielectric loss tangent and a method for manufacturing the alumina sintered body are provided. An alumina sintered body contains Al.sub.2O.sub.3 99.50 mass % or more, and 99.95 mass % or less and sodium and silicon, wherein at a surface layer A in any given cross-section and a central portion B of the cross-section in a depth direction from the surface layer A, a concentration ratio of sodium to silicon in the surface layer A is smaller than the concentration ratio of sodium to silicon at the central portion B.

The invention relates to α/β-sialon-based materials. The invention particularly relates to α/β-sialon-based materials that have an improved sintering activity and impart high edge strength to the sintered molded articles made of said materials.

Techniques of additive deposition for producing articles of manufacture are disclosed herein. In one embodiment, an article of manufacture can include a substrate having a surface and composed of a metal or metal alloy and multiple layers of composite materials deposited on the surface of the substrate. The composite materials is composed of the metal or metal alloy and a ceramic material. The individual composite materials at each of the multiple layers has a composition with a corresponding ratio between the metal or metal alloy material and the ceramic material. The ratios between the metal or metal alloy material and the ceramic material change along at least one dimension of the article of manufacture.

An aluminium oxide ceramic material containing the following components:

TABLE-US-00001 component wt.-% Al.sub.2O.sub.3  95.0 to 99.989 MgO 0.001 to 0.1 Eu, calculated as Eu.sub.2O.sub.3  0.01 to 1.0.

Provided is a solid oxide fuel cell having a service life of approximately 90,000 hours, a level required to encourage the widespread use of SOFC. The solid oxide fuel cell is provided with a solid electrolyte layer, an oxygen electrode layer provided on one side of the solid electrolyte layer, and a fuel electrode layer provided on the other side of the solid electrolyte layer. The oxygen electrode layer is made from a material containing iron or manganese, and the solid electrolyte layer contains an yttria-stabilized zirconia solid electrolyte material having a lanthanoid oxide dissolved therein.

A method for manufacturing a positive active material is provided. The method includes forming a positive active material precursor including nickel, mixing and firing the positive active material precursor and lithium salt to form a preliminary positive active material particle, forming a coating material including fluorine on the preliminary positive active material particle by dry-mixing the preliminary positive active material particle with a coating source including fluorine, and manufacturing a positive active material particle by thermally treating the preliminary positive active material particle on which the coating material is formed.

A ceramic brush seal for a gas turbine engine, and a process for manufacturing the seal are provided. In one example, the process includes deinfiltrating an edge of a plurality of plies having a preimpregnated configuration. The edge is defined by a plurality of ceramic fibers extending away from a portion edge of a matrix infiltrated portion of each of the plies. In another example, the process includes masking an edge of a plurality of plies, the edge being defined by a plurality of ceramic fibers extending away from a portion edge of a body portion of each of the plies, and infiltrating the body portion of the plurality of plies with a ceramic matrix slurry. The plies are stacked, formed into a green body and then fired to form the component. The plies may include oxide/oxide woven ceramic fiber plies.

A dielectric ceramic composition has good characteristics even under the high electric field intensity, and particularly good IR characteristic and the high temperature accelerated lifetime. The dielectric ceramic composition has a main component having a perovskite type compound shown by a compositional formula (Ba.sub.1-x-ySr.sub.xCa.sub.y).sub.m(Ti.sub.1-zZr.sub.z)O.sub.3, a first sub component having oxides of a rare earth element R, a second sub component as a sintering agent, wherein the dielectric particles has dielectric particles having high diffusion rate of the rare earth element, preferably of a complete solid solution particle, and when a concentration of Ti atom in the diffusion phase is 100 atom %, then an average concentration of the rare earth element R in the diffusion phase is 5 atom % or more, and an average concentration of Zr in the diffusion phase is 10 atom % or more.

A piezoelectric element includes a piezoelectric body having a main phase configured by lead zirconate titanate and a heterogenous phase configured by a different component to lead zirconate titanate, and a pair of electrodes provided on the piezoelectric body. The piezoelectric body has a surface region within 10 μm of a surface, and an inner region more than 10 μm from the surface. A surface area coverage of the heterogenous phase in a cross section of the surface region is at least 0.75% greater than a surface area coverage of the heterogenous phase in a cross section of the inner region.

A voltage-nonlinear resistor element 10 includes a voltage-nonlinear resistor (referred simply as “resistor”) 20 and a pair of electrodes 14 and 16 between which the resistor 20 is interposed. The resistor 20 has a multilayer structure including a first layer 21 composed primarily of zinc oxide, a second layer 22 composed primarily of zinc oxide, and a third layer 23 composed primarily of a metal oxide other than zinc oxide. The second layer 22 is adjacent to the first layer 21 and has a smaller thickness and a higher volume resistivity than the first layer 21. The third layer 23 is adjacent to the second layer 22.