Abstract: A submount can mount on it a semiconductor light-emitting device with high bonding strength, and a semiconductor unit incorporates the submount. The submount comprises (a) a submount substrate, (b) a solder layer formed at the top surface of the submount substrate, and (c) a solder intimate-contact layer that is formed between the submount substrate and the solder layer and that has a structure in which a transition element layer consisting mainly of at least one type of transition element and a precious metal layer consisting mainly of at least one type of precious metal are piled up. In the above structure, the transition element layer is formed at the submount-substrate side. The semiconductor unit is provided with a semiconductor light-emitting device mounted on the solder layer of the submount.

Abstract: An object of the present invention is to provide a wear-resistant sliding part with a wear-resistant member to reduce wear of contacting portions of two parts which moves in linkage with each other such as a valve bridge and a rocker arm in a valve train system of a diesel engine, wherein the wear-resistant member is held in a recess of a receiving part securely not to fall off and allowed in the recess to rotate and move in the parallel direction to its bottom surface. Also the wear-resistant member is arranged with at least one of the following: a chamfer provided at the perimeter of bottom surface; the bottom surface with the flatness from 0.05 to 0.20 ?m and a convex shape of a raised-up outer side; and at least one of the bottom, side, and top surfaces having surface roughness (Ra) of 0.2 ?m or less.

Abstract: Provided is an aluminum nitride sintered body having a larger area and a smaller thickness as compared to the conventional art, wherein the aluminum nitride sintered body has flatness with controlled warpage and/or waviness height. Methods of producing such sintered body, and further a metallized substrate and a heater using such sintered body are also provided. An aluminum nitride substrate 1 has a maximum length of 320 mm or more, a thickness of more than 0 mm and 2 mm or less, a warpage of 0 ?m/mm or more and less than 2 ?m/mm, and a local waviness height of 0 ?m or more and 100 ?m or less.

Abstract: The present invention provides a submount that allows a semiconductor light-emitting element to be attached with a high bonding strength. A submount 3 is equipped with a substrate 3 and a solder layer 8 formed on a primary surface 4f of the substrate 4. The density of the solder layer 8 is at least 50% and no more than 99.9% of the theoretical density of the material used in the solder layer 8. The solder layer 8 contains at least one of the following list: gold-tin alloy; silver-tin alloy; and lead-tin alloy. The solder layer 8 before it is melted is formed on the substrate 4 and includes an Ag film 8b and an Sn film 8a formed on the Ag film 8b. The submount 3 further includes an Au film 6 formed between the substrate 4 and the solder layer 8.

Abstract: A submount can mount on it a semiconductor light-emitting device with high bonding strength, and a semiconductor unit incorporates the submount. The submount comprises (a) a submount substrate, (b) a solder layer formed at the top surface of the submount substrate, and (c) a solder intimate-contact layer that is formed between the submount substrate and the solder layer and that has a structure in which a transition element layer consisting mainly of at least one type of transition element and a precious metal layer consisting mainly of at least one type of precious metal are piled up. In the above structure, the transition element layer is formed at the submount-substrate side. The semiconductor unit is provided with a semiconductor light-emitting device mounted on the solder layer of the submount.

Abstract: A submount that enables the reliable mounting of a semiconductor light-emitting device on it, and a semiconductor unit incorporating the submount. A submount 3 comprises (a) a substrate 4; and (b) a solder layer 8 formed on the top surface 4f of the substrate 4. The solder layer 8 before melting has a surface roughness, Ra, of at most 0.18 ?m. It is more desirable that the solder layer 8 before melting have a surface roughness, Ra, of at most 0.15 ?m, yet more desirably at most 0.10 ?m. A semiconductor unit 1 comprises the submount 3 and a laser diode 2 mounted on the solder layer 8 of the submount 3.

Abstract: A wet molding method in which a ceramic slurry is charged into a cavity and uniaxially pressed by a punch to remove excess liquid from a portion of the slurry facing the punch to effect molding, the method being improved by maintaining at least one of the following conditions; (a) the pressing of the slurry is stopped at a time between T and 1.5 T, T being defined as the pressing time necessary to remove sufficient excess liquid from the slurry in the mold to produce a molded mass; or (b) the punch displacement position at a time at which sufficient excess liquid is removed from the slurry in the mold to produce a molded mass is less than 17% of the total mold length.

Abstract: A device for producing a ceramic sintered body consisting essentially of a mixing trough for mixing ceramic powder with water to form a slurry, the mixing trough having stirring blades, a separate slurry circulation conduit and a slurry mixing deflocculating unit, said separate slurry circulation conduit connecting said mixing trough and said deflocculating unit, said slurry mixing unit deflocculating said powder which has been flocculated with no grinding of powder by means of causing a high-speed shear flow and a high-speed contraction flow in the slurry, said slurry being repeatedly circulated form said slurry mixing unit to said mixing trough through said separate slurry circulation conduit.

Abstract: A silicon nitride powder with which a highly reliable silicon nitride with high strength and small strength and dimensional variances is obtainable is disclosed. By setting the amount of their surface acidic groups per B.E.T. surface area to not less than 0.2 .mu.eq/m.sup.2, their dispersibility in a mixing solvent is drastically improved. By using them, moldings with high density and homogeneity can be obtained, thereby enabling in turn a highly reliable sintered product of silicon nitride with high strength and small strength and dimensional variances to be easily manufactured. Besides, in the silicon nitride powder, the proportion of the silicon [Si*] belonging to SiO.sub.2, of the surface silicon [Si], which is determined by the X-ray photoelectron spectroscopy (XPS), should be not less than 0.07 in its atomic ratio [Si*/Si] and that to silicon of the surface carbon [C] which is determined by XPS in the same way should be not more than 0.20 in its atomic ratio [C/Si].

Abstract: Provided is an apparatus for producing a silicon nitride sintering body made of a furnace including a heater source. The furnace includes a furnace core chamber defined by at least one partition inside the furnace to prevent an atmosphere containing more than about 30 ppm of carbon monoxide from contacting said silicon nitride sintered body. At least an inner surface of the partition is made of a carbon-free heat-proof material which prevents formation of carbon monoxide gas in an atmosphere in contact with the silicon nitride sintered body during sintering. The furnace also includes a gas supply pipe for supplying an N.sub.2 gas or an inactive gas including an N.sub.2 gas into the furnace core. Also provided is a sintering case made of a vessel defining a sintering atmosphere. The vessel has an opening for loading an object to be sintered into the vessel.

Abstract: The invention provides a method of producing sintered silicon nitrides having such strength characteristics as are sufficient to insure satisfactory reliability of the sintered silicon nitride for use in applications such as automotive engine parts and bearings. The method comprises preparing a sintering aid by blending yttrium oxide, spinel, and aluminum oxide and/or aluminum nitride together in such proportions in terms of molar ratios of metal elements that Y/(Al+Mg) is 0.23 to 0.85 and Al/Mg is 2.1 to 5.2, mixing 5.0 to 13.0% by weight of the sintering aid with 87.0 to 95.0% by weight of a silicon nitride powder having an .alpha. crystallinity of not less than 60%, and, after the resulting powder mixture is molded into shape, sintering the molded piece at temperatures of 1400 to 1650.degree. C. in a nitrogen gas atmosphere or in an inert gas atmosphere containing nitrogen gas.

Abstract: Disclosed herein are a method for molding a high density and homogeneous silicon nitride ceramics within a short time and an apparatus used for the method. A gel-like slurry mixture which is a mixture of ceramic powders consisting mainly of Si.sub.3 N.sub.4 and a liquid and has a powder content of from 45 vol % to 60 vol % is fluidized by imparting thereto a strain by vibration, and the mixture under the fluidized state is filled into, and molded by, a mold. Preferably, the entire part or a part of the mold is made of a liquid permeable material. The vibration preferably has an acceleration of from 0.1 G to 150 G and an amplitude of 1 .mu.m to 1 cm. Furthermore, the viscosity of the slurry filled into the mold is preferably from 2,000 to 20,000 cps.

Abstract: A material is provided for a polarizable electrode. The material comprises a porous carbon material of activated carbon, activated carbon fibers, carbon fibers or powdery carbon as a raw material, wherein the total amount of acid groups of said porous carbon materials is 0.45 to 4.0 .mu.eq/m.sup.2 based on the BET surface area of said carbon material. The material is produced by subjecting the porous carbon raw material to dry oxidation treatment in an oxygen atmosphere whereby the total amount of acid groups introduced into said porous carbon material is 0.45 to 4.0 .mu.eq/m.sup.2 based on the BET surface area of said material.