A method for preparing polycrystalline fluoride ceramics using powder of fluoride ceramics nanocrystallites as starting material, wherein the method includes: (a) Optionally, a pre-processing step at a temperature ranging from 100 C. to 300 C. at vacuum of 10-5 mbar (10-3 Pa) to 10-8 mbar (10-6 Pa) for 30 minutes to 10 hours, (b) Applying a uniaxial pressure in the range from 1 to 200 MPa, at or around ambient temperature, to obtain a pre-compacted sample, (c) Applying to the pre-compacted of step b) a hydrostatic pressure by Cold Isostatic Pressing, to obtain a pre-compacted sample, (d) Loading the pre-compacted sample from step (c) into a die and submitting the sample to a uniaxial compression in combination with electric field-assisted sintering, under vacuum equal to or higher than 5 Pa. Polycrystalline fluoride ceramics obtained by this method find use in IR devices.

A Co.sub.2Z hexaferrite composition is provided containing molybdenum and one or both of barium and strontium, having the formula (Ba.sub.2Sr.sub.(3-Z)Co.sub.(2+X))Mo.sub.xFe.sub.(y-2x)O.sub.41 where x=0.01 to 0.20; y=20 to 24; and z=0 to 3. The composition can exhibit high permeabilities and equal or substantially equal values of permeability and permittivity while retaining low magnetic and dielectric loss tangents and loss factors. The composition is suitable for high frequency applications such as ultrahigh frequency and microwave antennas and other devices.

The durability of a ceramic sintered body is improved, and a reduction in its light emission intensity and the occurrence of a chromaticity variation are suppressed. The ceramic sintered body contains alumina and a compound represented by M1.sub.3-XM2.sub.XM3.sub.5O.sub.12. The volume percent of the compound in the ceramic sintered body is from 3% to 70% inclusive. The ratio of the intensity of XRD from a complex oxide of aluminum and M2 to the intensity of XRD from the compound in the ceramic sintered body is less than 0.05. The average grain diameter of the alumina contained in the ceramic sintered body is from 0.30 (m) to 3.00 (m) inclusive. M1 is at least one selected from Sc, Y, and lanthanoid elements, and M2 is at least one selected from lanthanoid elements except any lanthanoid element selected for M1. M3 is at least one of Al and Ga, and X is from 0.003 to 0.500 inclusive.

The present invention relates to an alumina sintered body and a manufacturing method therefor; for example, the present invention relates to an alumina sintered body that is suitably utilized for a member or similar used in a plasma processing device, an etcher for semiconductor/liquid crystal display device manufacturing, a CVD device, or similar, or that is suitably utilized for a substrate or similar of a plasma-resistant member which is to be coated, as well as a manufacturing method for said alumina sintered body.

A tire stud according to the present invention is manufactured from ceramic, and thus has characteristics of causing the strength of ceramics to recover through crack healing while lowering residual stress by improving a sintering process. In addition, abrasion resistance is improved by further adding a sintering aid and an organic oxide during sintering, and thus friction with a road surface can always be maintained to be constant and life span can be greatly increased.

Setter plates are fabricated from Li-stuffed garnet materials having the same, or substantially similar, compositions as a garnet Li-stuffed solid electrolyte. The Li-stuffed garnet setter plates, set forth herein, reduce the evaporation of Li during a sintering treatment step and/or reduce the loss of Li caused by diffusion out of the sintering electrolyte. Li-stuffed garnet setter plates, set forth herein, maintain compositional control over the solid electrolyte during sintering when, upon heating, lithium is prone to diffuse out of the solid electrolyte.

A solid electrolyte includes partially stabilized zirconia in which a stabilizer forms a solid solution in zirconia. The partially stabilized zirconia includes at least monoclinic phase particles and cubic phase particles as crystal particles that configure the partially stabilized zirconia, and an abundance ratio of the monoclinic phase particle is 5 to 25% by volume. The partially stabilized zirconia includes stabilizer low-concentration phase particles of which concentration of the stabilizer at a particle center is equal to or less than 1 mol %, as the crystal particles. The stabilizer low-concentration phase particles have a particle-size distribution of number frequency thereof having a peak at which an average particle size is 0.6 to 1.0 m, and a particle size at 10% of a cumulative number is 0.5 m or greater, and of the overall low-concentration phase particles, 50% by volume or greater belong to the peak.

A semiconductor manufacturing device member according to the present invention includes a ceramic disc with an internal electrode and a ceramic shaft that supports the disc. The disc and the shaft are integrated without having a bonding interface.

The invention relates to a solid electrolyte including partially stabilized zirconia, a producing method thereof, and a gas sensor including a solid electrolyte. The partially stabilized zirconia includes crystal particles, the crystal particles include mixed phase particles each having a high-concentration phase and a low-concentration phase, the high-concentration phase being defined such that a concentration of the stabilizer is 4.7 mol % or more, the low-concentration phase being defined as a concentration of the stabilizer is less than 4.7 mol %.

The invention relates to a solid electrolyte comprised of partially stabilized zirconia, and a gas sensor including the solid electrolyte. The partially stabilized zirconia includes crystal particles, the crystal particles include at least stabilizer low-concentration phase particles, and the partially stabilized zirconia further includes voids. Among the stabilizer low-concentration phase particles, the presence rate of the stabilizer low-concentration phase particles where each distance from a void is 5 m or less is 65 volume percent or more. The stabilizer low-concentration phase particles include specific stabilizer low-concentration phase particles each having a distance of 5 m or less from an adjacent void in the voids, a presence rate of the specific stabilizer low-concentration phase particles having 65 volume percent or more.