Takao Nishioka

Bio: Takao Nishioka is an academic researcher from Sumitomo Electric Industries. The author has contributed to research in topics: Silicon nitride & Ceramic. The author has an hindex of 14, co-authored 92 publications receiving 766 citations.

Soft magnetic material and dust core

Abstract: Disclosed is a soft magnetic material comprising a plurality of composite magnetic particles (30) respectively having a metal magnetic particle (10) and an insulating coating film (20) covering the surface of the metal magnetic particle (10) and containing at least one of a metal phosphate and an oxide, and a particulate lubricant which is added in an amount of not less than 0.001 mass% and not more than 0.1 mass% relative to the composite magnetic particles (30). By having such a constitution, the soft magnetic material exhibits excellent lubricity during pressing and desired magnetic characteristics can be attained after pressing.

Silicon nitride sintered body

Abstract: A silicon nitride sintered body comprising α-silicon nitride including α'-sialon and β'-sialon including β-silicon nitride in which the content of the α-silicon nitride including α'-sialon in the surface part thereof is less than its content in the inner part thereof. The silicon nitride sintered body is excellent in mechanical strength at ordinary temperature, productivity and cost efficiency.

Silicon nitride sintered body and process for producing the same

Abstract: Disclosed is a silicon nitride sintered body produced by subjecting a green compact of a mixed powder composed of 1) a silicon nitride powder having a percentage a crystallization of 93% or more and a mean grain diameter of 0.7 µm or less and 2) 5 to 15% by weight in total of a first sintering aid selected from among rare earth element, yttrium oxide and lanthanide oxides and a second sintering aid consisting of aluminum oxide or nitride and at least one selected from among oxides and nitrides of Mg, Ca and Li, to primary sintering in a nitrogen gas atmosphere under a pressure of 1.1 atm or less at 1500 to 1700 °C; and subjecting the sintered body to secondary sintering in a nitrogen gas atmosphere under a pressure of 10 atm or more at the primary sintering temperature or below, thereby giving a sintered body wherein the relative density of the sintered body is 99% or more and the precipitation ratio of an .alpha.-Si3N4 (including .alpha.'-sialon) crystal phase to a .beta.-Si3N4 (including .beta.'-sialon) crystal phase ranges from 1 : 3 to 1 : 8 in terms of the peak intensity ratio in X-ray diffraction.

Soft magnetism material and powder magnetic core

Abstract: A soft magnetic material includes: a plurality of composite magnetic particles formed from a metal magnetic particle and an insulative coating surrounding a surface of the metal magnetic particle and containing metallic salt phosphate and/or oxide; and a lubricant formed as fine particles added at a proportion of at least 0.001 percent by mass and no more than 0.1 percent by mass relative to the plurality of composite magnetic particles. With this structure, superior lubrication is provided during compacting and desired magnetic characteristics can be obtained after compacting.

Combination of shim and cam

Abstract: A combination of a shim and a cam used for, especially, a part of a reciprocating mechanical mechanism exposed to severe sliding conditions, not only capable of obtaining excellent sliding characteristics by reducing frictional work during a sliding operation of the part but also having a high abrasion resistance and high fatigue characteristics. A combination of a shim and a cam, wherein a surface roughness of a sliding surface of the shim with respect to the cam is 0.08 to 0.4 νm in terms of ten-point average surface roughness (Rz), a surface hardness of a shim sliding portion being high as compared with that of the cam, the cam comprising a cam having a plurality of cam edges.

Silicon Nitride Ceramics

Abstract: Silicon nitride ceramics is a generic term for a variety of alloys of Si3N4 with additional compounds necessary for a complete densification of the Si3N4 starting powder. They are heterogeneous, multicomponent materials characterised by the inherent properties of the crystalline modifications α and β of Si3N4 and the significant influence of the densification additives. With a view to ability of the α and β modification to form solid solutions α-Si3N4 (αss) and β-Si3N4 (βss) solid solutions can be distinguished. Each group contains engineered materials with interesting properties for special applications. Phase relations and micro-structures determine the properties decisively. Composition of the phases, the distribution of the grains, their aspect ratio and the grain boundary phase are pronounced microstructural features. The formation of the microstructure strongly depends on the one hand on the quality of the Si3N4 starting powders, which closely is related to the chemistry of the production process, and on the other on the liquid phase sintering as the most important step in the densification route. The interrelation between pure Si3N4, the densification of the powder including the role of sintering additives, microstructural engineering, physicochemical properties of the sintered Si3N4 ceramics (SSN, GPSN, HPSN, HIP-SSN, HIP-SN) are described in more detail and compared to reaction bonded Si3N4 ceramics (RBSN), which are produced by nitridation of silicon powders.

Magnetostrictive actuator of a medical ultrasound transducer assembly, and a medical ultrasound handpiece and a medical ultrasound system having such actuator

Abstract: Apparatus includes a magnetostrictive actuator of a medical ultrasound transducer assembly. The actuator comprises a magnetostrictive alloy chosen from a list. A medical ultrasound handpiece includes an ultrasound transducer assembly adapted to attachingly receive an end effector. The transducer assembly includes a magnetostrictive actuator having a magnetostrictive alloy, and includes a first coil surrounding the actuator and adapted to excite the actuator to substantially a desired medical resonant frequency and substantially a desired medical amplitude. A medical ultrasound system includes a handpiece housing, a first medical ultrasound transducer assembly, and a first medical end effector attachable to the first transducer assembly. The first transducer assembly includes a magnetostrictive first actuator having a first magnetostrictive alloy. At least a portion of the first transducer assembly is attachingly insertable in the handpiece housing without the use of tools, without damaging the handpiece housing, and without damaging the first transducer assembly.

Experimental Investigation of Thermo-Mechanical Characteristics in Laser-Assisted Machining of Silicon Nitride Ceramics

Abstract: Laser-assisted machining (LAM) of silicon nitride (Si 3 N 4 ) is evaluated for its potential to become an economically viable process in fabricating precision ceramic parts. On-line measurements of cutting force and workpiece temperature are performed, and tool wear and surface integrity are examined. Tool wear characteristics are determined as a function of workpiece temperature, which is measured on-line using a laser pyrometer Tool wear/failure mechanisms are characterized using optical microscopy while application of scanning electron microscopy to heated and machined surfaces, as well as to chips, is used to infer material removal mechanisms and the extent of damage caused by LAM. The sub-surface damage of parts produced by LAM is compared with that of typical ground parts.

Dual stage instrument for scanning a specimen

Abstract: A dual stage scanning instrument includes a sensor for sensing a parameter of a sample and coarse and fine stages for causing relative motion between the sensor and the sample. The coarse stage has a resolution of about 1 micrometer and the fine stage has a resolution of 1 nanometer or better. The sensor is used to sense the parameter when both stages cause relative motion between the sensor assembly and the sample. The sensor may be used to sense height variations of the sample surface as well as thermal variations, electrostatic, magnetic, light reflectivity or light transmission parameters at the same time when height variation is sensed. By performing along scan at a coarser resolution and short scans a high resolution using the same probe tip or two probe tips at fixed relative positions, data obtained from the long and short scans can be correlated accurately.

Low-friction sliding mechanism

Abstract: A low-friction sliding mechanism includes first and second sliding members having respective sliding surfaces slidable relative to each other and a lubricant applied to the sliding surfaces of the first and second sliding members. At least the sliding surface of the first sliding member is made of a diamond-like carbon material, and at least the sliding surface of the second sliding member is made of either an aluminum-based alloy material, a magnesium-based alloy material or a diamond-like carbon material. The lubricant contains a base oil and at least one of an ashless fatty-ester friction modifier and an ashless aliphatic-amine friction modifier.