Disclosed is a ceramic sintered shaped body containing Y.sub.2O.sub.3-stabilized zirconia with a sintered density of at least 99% of the theoretical sintered density and having a mean grain size of <180 nm. The zirconia fraction of the sintered shaped body comprises tetragonal and cubic phases. Also disclosed is a process for the production of a ceramic sintered shaped body containing Y.sub.2O.sub.3-stabilized zirconia, which process comprises dispersion of a submicron powder and comminution of the dispersed submicron powder by means of grinding media having a diameter of less than or equal to 100 μm to a particle size d.sub.95 of <0.42 μm; shaping of the dispersion to form a body, and sintering of the body to form the sintered shaped body.

Disclosed is a homogeneous catalyst having a single phase of Perovskite oxide, wherein at least one doping element is substituted at site A, site B or sites A and B in ABO.sub.3 Perovskite type oxide so that the wettability with a liquid molten carbonate electrolyte may be decreased. The catalyst may have high catalytic activity, inhibit catalyst poisoning caused by creepage and evaporation of a liquid molten carbonate electrolyte, maintain high reaction activity for a long time, provide high methane conversion, and allow production of synthetic gas having a high proportion of hydrogen.

A method of making a ceramic matrix composite that exhibits chemical resistance has been developed. The method comprises depositing a compliant layer comprising boron nitride, silicon-doped boron nitride, and/or pyrolytic carbon on silicon carbide fibers, depositing a barrier layer having a high contact angle with molten silicon on the compliant layer, and depositing a wetting layer comprising silicon carbide, boron carbide, and/or pyrolytic carbon on the barrier layer. After depositing the wetting layer, a fiber preform comprising the silicon carbide fibers is infiltrated with a slurry. After slurry infiltration, the fiber preform is infiltrated with a melt comprising silicon, and then the melt is cooled, thereby forming a ceramic matrix composite.

A method of making a ceramic matrix composite that exhibits moisture and environmental resistance has been developed. The method includes depositing a diffusion barrier layer comprising boron nitride on silicon carbide fibers and depositing a moisture-tolerant layer comprising silicon-doped boron nitride on the diffusion barrier layer, where a thickness of the moisture-tolerant layer is from about 3 to about 300 times a thickness of the diffusion barrier layer. Thus, a compliant multilayer including the moisture-tolerant layer and the diffusion barrier layer is formed. A wetting layer comprising silicon carbide, boron carbide, and/or pyrolytic carbon is deposited on the compliant multilayer layer. After depositing the wetting layer, a fiber preform comprising the silicon carbide fibers is infiltrated with a slurry. After slurry infiltration, the fiber preform is infiltrated with a melt comprising silicon and then the melt is cooled, thereby forming a ceramic matrix composite.

A method may include oxidizing a surface of a silicon-containing substrate to form a layer including silica on the surface of the silicon-containing substrate. The method also may include depositing, from a slurry including at least one rare earth oxide, a layer including the at least one rare earth oxide on the layer including silicon. The method additionally may include heating at least the layer including silica and the layer including the at least one rare earth oxide to cause the silica and the at least one rare earth oxide to react and form a layer including at least one rare earth silicate.

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 gas nozzle according to an embodiment of the present invention includes a columnar main body including a ceramic sintered body having a through hole through which gas flows. An outlet of the through hole for the gas is formed on one end face of the main body. An inner wall of the through hole has a first region located in a vicinity of the outlet, and a second region located further inward of the main body than the first region. The first region and the second region each include a sintered surface of the ceramic sintered body. Average crystal grain size in the first region is larger than average crystal grain size in the second region.

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.

A ceramic composite material and a method for producing same. The ceramic composite material has a ceramic matrix comprising zirconium oxide and at least one secondary phase dispersed therein. The matrix is composed of zirconium oxide as at least 51 vol.-% of composite material, and the secondary phase is in a proportion of 1 to 49 vol.-% of composite material, wherein 90 to 99% of the zirconium oxide is present in the tetragonal phase based on the total zirconium oxide portion. The tetragonal phase of the zirconium oxide is stabilized by at least one member selected from the group consisting of chemical stabilization and mechanical stabilization. The ceramic composite is damage-tolerant.

A powdery composition based on silica for ceramic welding, in particular by projection, comprising from 10 to 90% of a phase of siliceous particles comprise at least 80% by weight of cristobalite and at most 15% by weight of tridymite, based on the total weight of the composition, from 90 to 10% by weight of conventional additives forming a binding phase, based on the total weight of the composition, said siliceous particles having a d.sub.50 comprised between 350 and 800 μm, preferably between 400 and 500 μm.