A phosphor plate including: a complex containing an α-sialon phosphor and a sintered body containing spinel represented by a general formula M.sub.2xAl.sub.4-4xO.sub.6-4x (where M represents at least one of Mg, Mn, and Zn, and 0.2<x<0.6). In addition, there is provided a light emitting device including: a group III nitride semiconductor light emitting element; and the phosphor plate provided on one surface of the group III nitride semiconductor light emitting element. Further, there is provided a method for manufacturing the phosphor plate.

The present invention relates to parts of transparent corundum ceramics and the production and use of said parts.

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.

A Ca—SiAlON ceramic with enhanced mechanical properties and a method employing micron-sized and submicron precursors to form the Ca—SiAlON ceramic. The Ca—SiAlON ceramic comprises not more than 42 wt % silicon, relative to the total weight of the Ca—SiAlON ceramic. The method employs submicron particles and also allows for substituting a portion of aluminum nitride with aluminum to form the Ca—SiAlON ceramic with enhanced mechanical properties.

The present invention relates to a method of preparing a solid solution ceramic material having increased electromechanical strain, as well as ceramic materials obtainable therefrom and uses thereof. In one aspect, the present invention provides a method A method of increasing electromechanical strain in a solid solution ceramic material which exhibits an electric field induced strain derived from a reversible transition from a non-polar state to a polar state; i) determining a molar ratio of at least one polar perovskite compound having a polar crystallographic point group to at least one non-polar perovskite compound having a non-polar crystallographic point group which, when combined to form a solid solution, forms a ceramic material with a major portion of a non-polar state; ii) determining the maximum polarization, P.sub.max, remanent polarisation, P.sub.r, and the difference, P.sub.max−P.sub.r, for the solid solution formed in step i); and either: iii)a) modifying the molar ratio determined in step i) to form a different solid solution of the same perovskite compounds which exhibits an electric field induced strain and which has a greater difference, P.sub.max−P.sub.r, between maximum polarization, P.sub.max, and remanent polarisation, P.sub.r, than for the solid solution from step i), or; iii)b) adjusting the processing conditions used for preparing the solid solution formed in step i) to increase the difference, P.sub.max−P.sub.r, in maximum polarization, P.sub.max, and remanent polarisation, P.sub.r, of the solid solution.

Provided is a method for producing a silicon nitride sintered body including: a step of molding and firing a raw material powder containing silicon nitride, in which an α-conversion rate of the silicon nitride contained in the raw material powder is less than or equal to 30 mass %. A thermal conductivity (at 20° C.) of the silicon nitride sintered body exceeds 100 W/m.Math.K and a fracture toughness (K.sub.IC) is greater than or equal to 7.4 MPa.Math.m.sup.1/2.

Provided are a transparent fluorescent sialon ceramic having fluorescence and optical transparency; and a method of producing the same. Such a transparent fluorescent sialon ceramic includes a sialon phosphor which contains a matrix formed of a silicon nitride compound represented by the formula M.sub.x(Si,Al).sub.y(N,O).sub.z (here, M represents at least one selected from the group consisting of Li, alkaline earth metals, and rare earth metals, 0≤x/z<3, and 0<y/z<1) and a luminescent center element.

A method for producing a composite of cubic boron nitride dispersed in a SiAlON ceramic. This method involves mixing silicon nitride nanoparticles, aluminum nitride nanoparticles, silica nanoparticles, calcium oxide nanoparticles, and cubic boron nitride microparticles to produce a mixture. The cubic boron nitride may be coated with nickel. The mixture is sintered to produce the composite, and this sintering may involve spark plasma sintering and/or sintering at a relatively low temperature. The composite may comprise a mixture of Ca--SiAlON and -SiAlON ceramic reinforced by boron nitride in either or both cubic and hexagonal phases.

A method for producing a composite of cubic boron nitride dispersed in a SiAlON ceramic. This method involves mixing silicon nitride nanoparticles, aluminum nitride nanoparticles, silica nanoparticles, calcium oxide nanoparticles, and cubic boron nitride microparticles to produce a mixture. The cubic boron nitride may be coated with nickel. The mixture is sintered to produce the composite, and this sintering may involve spark plasma sintering and/or sintering at a relatively low temperature. The composite may comprise a mixture of Ca--SiAlON and -SiAlON ceramic reinforced by boron nitride in either or both cubic and hexagonal phases.

A CaSiAlON ceramic with enhanced mechanical properties and a method employing micron-sized and submicron precursors to form the CaSiAlON ceramic. The CaSiAlON ceramic comprises not more than 42 wt % silicon, relative to the total weight of the CaSiAlON ceramic. The method employs submicron particles and also allows for substituting a portion of aluminum nitride with aluminum to form the CaSiAlON ceramic with enhanced mechanical properties.