Abstract: A polycrystalline-diamond cutting element for a drill bit of a downhole tool. The cutting element includes a substrate and a diamond table bonded to the substrate. The diamond table includes a diamond filler with at least one leached polycrystalline diamond segment packed therein along at least one working surface thereof. The cutting element may be formed by positioning the diamond table on the substrate and bonding the diamond table onto the substrate such that the polycrystalline diamond segment is positioned along at least one working surface of the diamond table. A spark plasma sintering or double press operation may be used to bond the diamond table onto the substrate.

Abstract: A coated article system includes a substrate and a surface coating on the substrate. The surface coating is formed by depositing individual particles of a composite metal powder with sufficient energy to cause the composite metal powder to bond with the substrate and form the surface coating. The composite metal powder includes a substantially homogeneous dispersion of molybdenum and molybdenum disulfide sub-particles that are fused together to form the individual particles of the composite metal powder.

Abstract: A silica nanofiber is derived from a crystalline polymer filament of a polymer including straight chain polyethyleneimine backbones, which is capable of forming a water-insoluble crystal in the presence of water molecules at room temperature, and the crystalline polymer filament in the silica concentrates metal ions, thereby realizing a composite nanofiber including metals or metal ions in the silica. Furthermore, the composite nanofiber of the present invention can be easily produced by fixing a polymer structure in the silica as the scaffold for metal ions and concentrating metal ions at the scaffold or reducing the metal ions. Furthermore, a metal-containing silica nanofiber can be easily obtained by removing a polymer component from the composite nanofiber, the composite nanofiber association, and the complex nanofiber structure. These nanofibers can be assembled and integrated, and the assembled or integrated association or structure can realize various shapes.

Abstract: To provide a thermal spray membrane contact material, contact member and contact part and an apparatus to which they are applied, showing excellent seizure resistance and wear resistance even under high surface pressure/low speed sliding, high speed/high temperature sliding, or high surface pressure/high speed sliding.

Abstract: Methods for the use of nanocrystalline or amorphous metals or alloys as coatings with industrial processes are provided. Three, specific, such methods have been detailed. One of the preferred embodiments provides a method for the high volume electrodeposition of many components with a nanocrystalline or amorphous metal or alloy, and the components produced thereby. Another preferred embodiment provides a method for application of a nanocrystalline or amorphous coatings in a continuous electrodeposition process and the product produced thereby. Another of the preferred embodiments of the present invention provides a method for reworking and/or rebuilding components and the components produced thereby.

Abstract: To provide a thermal spray membrane contact material, contact member and contact part and an apparatus to which they are applied, showing excellent seizure resistance and wear resistance even under high surface pressure/low speed sliding, high speed/high temperature sliding, or high surface pressure/high speed sliding.

Abstract: The invention relates to a wear-resistant coating used for bearing surfaces and flanks of piston rings in internal combustion engines. The wear-resistant inventive coating is obtained by mechanically alloying powders which form a metallic matrix with hard material dispersoids and lubricant material dispersoids. The coating is then thermally applied to the workpieces, especially by means of high velocity oxygen fuel spraying (HVOF). The workpieces coated are bearing surfaces and parts of flanks pertaining to piston rings in internal combustion engines.

Abstract: A spray powder to be used for forming a coating, which comprises from 80 to 97 wt %, based on the total weight, of a cermet powder and from 3 to 20 wt %, based on the total weight, of a metal powder, wherein the metal powder comprises Cr and Ni in a total amount of at least 90 wt %, based on the total weight of the metal powder, and the content of Cr is from 0 to 55 wt %, based on the total weight of the metal powder.

Abstract: A wear resistant coating for protecting surfaces undergoing sliding contact is disclosed. The wear resistant coating is applied by high velocity oxygen-fuel (HVOF) deposition of a powdered blend of the coating constituents. The powdered blend includes a nickel-chromium alloy, chromium carbide, and molybdenum. The disclosed coating should find use as a bearing surface on piston rings, cylinder liners, and other components of a power cylinder assembly of an internal combustion engine.

Abstract: A spray powder which has a particle size of from 6 to 63 &mgr;m and which comprises from 75 to 95 wt % of a ceramic phase made of a WC powder and at least one chromium carbide powder selected from the group consisting of Cr3C2, Cr7C3 and Cr23C6, and from 5 to 25 wt % of a metal phase made of a Ni or Ni-based alloy powder, wherein the mean particle size of primary particles of the WC powder constituting the ceramic phase is from 5 to 20 &mgr;m, and the mean particle size of primary particles of the chromium carbide powder is from 1 to 10 &mgr;m.

Abstract: A swash plate for a swash plate compressor, wherein aluminum alloy containing 12 to 60% of Si and, as required, 0.1 to 30% of Sn is sprayed onto the iron or aluminum base plate of the swash plate compressor to form a seizure-resisting and abrasion-resisting surface layer dispersed with granulated Si.

Abstract: The seizure resistance of an Al-based flame-sprayed layer formed on the swash plate of a swash-plate type comressor is increased to such a level comparable to that of a flame-sprayed bronze layer. The Al-based flame-sprayed layer of the present invention contains: from 12 to 60% of Si and granular Si particles dispersed in the matrix thereof, and at least one dispersing phase of graphite carbon, amorphous carbon and carbon, the crystallizing degree of which is between the graphite carbon and amorphous carbon, and MoS2.

Abstract: A discharge electrode comprising a material having solid lubricant effect, such as molybdenum, is used to generate discharge in a pulse form between the discharge electrode and a workpiece, the surface of which is to be treated, in working liquid containing carbon components, such as water. Material consumed or melted from the discharge electrode, generated because of the electric discharge energy based on the pulse form discharge, gets adhered to and deposited onto a surface of the workpiece thereby forming a coat having lubricant effect on the surface of the workpiece.

Abstract: The invention provides for a functionally-graded metal substrate that is made of at least two metal compositions, a functional insert and a surrounding body that surrounds the functional insert. In a preferred embodiment of the invention a functional insert powder composition of loose powder metal is placed in a compact of a surrounding body powder composition and both metal compositions are sintered in a sintering furnace to form a sintered part. The sintered part is infiltrated in part or in whole with a molten metal compound to produce a functionally graded metal substrate having a density of at least 90% of theoretical. A heat-generating component such as a chip can be attached to the metal substrate for use in microelectronic packaging. When the functionally-graded metal substrate has two discrete compositions of copper/tungsten the surrounding body which has a CTE that ranges from about 5.6ppm/.degree. C. to about 7 ppm/.degree. C.

Abstract: A contact material for a vacuum interrupter including, a conductive component including at least Cu, and an arc-proof component including at least one selected from the group consisting of carbides of W, Zr, Hf, V and Ti. An amount of the conductive component in the contact material is 40-50 vol %, an amount of the arc-proof component in the contact material is 50-60 vol %, and a grain size of the arc-proof component is 3 .mu.m or less. A total amount of a sintering activator including at least one selected from the group consisting of Co, Fe and Ni melted in the conductive component is 0.1% or less of the amount of the conductive component.

Abstract: An engine tappet of high abrasion resistance, whose surface is coated with a sintered layer. This sintered layer is prepared from a binder comprising about 50-100 wt % of nickel powder, about 0-45 wt % of Cr, about 0-35 wt % of Mo, about 0-10 wt % of Al, about 0-25 wt % of Co, about 0-10 wt % of Cu and inevitably mixed impurities; and from hard particles selected from the group consisting of carbides, nitrides, borides and the mixtures thereof. Also, there is provided an engine tappet which is coated with an alloy powder composition comprising about 44-88 wt % of WC, about 4-10 wt % of Co, about 15-50 wt % of Ni, about 5-20 wt % of Cr, about 0.5-4 wt % of B, about 2-4 wt % of Fe, about 0.5-4 wt % of Si, about up to 1.0 wt % of C and inevitably mixed impurities.

Abstract: A hard facing alloy is applied to a surface of a substrate by making a mixture of at least two constituents whose net composition is the desired hard facing alloy composition. The constituents have different solidus temperatures, at least one of which is above a processing temperature of the substrate and another of which is below the processing temperature of the substrate. In one preferred approach, the mixture is prepared by pressing and lightly sintering the constituents in the form of powders, so that the mixture retains its shape and can be attached to the substrate surface. Then the substrate is heated to the processing temperature and maintained for a time sufficient to permit interdiffusion of the several different phases toward a homogeneous hard facing alloy composition uniformly through a major portion of the volume.

Abstract: The present invention discloses a WC--Co alloy in which substantially only the WC particles of a surface layer or components other than metals belonging to the iron group and only the WC particles are exposed, and (a) an average particle diameter of the WC particles of the surface layer is larger than that of the WC particles of the interior, and/or (b) a surface hardness is higher than that of the interior. The WC--Co alloy itself is Used as a stock for a cutting tool or an abrasion and sliding resistant tool, or the alloy is used as a substrate and a hard carbon-layer excellent in adhesive strength is coated on the surface of the matrix.

Abstract: A metallized ceramic substrate having a smooth plating layer comprises a ceramic substrate containing aluminum nitride as a main component; a tungsten- and/or molybdenum-based metallized layer formed on at least one face of the ceramic substrate; and a nickel-based plating layer formed on the metallized layer wherein the plating layer has a thickness of not greater than 2 .mu.m and a surface roughness (Ra) of not greater than 2 .mu.m. Alternatively, the plating layer on the ceramic substrate may comprise a first nickel-based plating layer having a thickness of not greater than 2 .mu.m and a second gold-based plating layer having a thickness of not greater than 1 .mu.m wherein the gold-based plating layer has a surface roughness (Ra) of 2 .mu.m or less.

Abstract: A thermal spray powder for producing high hardness, low friction, wear resistant coatings on friction surfaces, comprising a blend of an agglomerated molybdenum/dimolybdenum carbide powder and a self-fluxing NiCrFeBSi alloy powder.

Abstract: A material for friction components made by a process including the steps of providing a first powder consisting of grains of a comparatively harder material with a comparatively higher coefficient of friction and an average grain size of from 60 to 100 microns, and a second powder consisting of grains of comparatively softer material with a comparatively lower coefficient of friction and an average grain size of from 60 to 100 microns; mixing the first powder and the second powder to form a powder mixture having a total volume; and subjecting the powder mixture to a pressure and temperature sufficient for the grains of the first powder to be intermixed with the comparatively softer material of the second powder so that the comparatively harder material substantially fills an intergranular space between the grains of the first powder to form the material for the friction components, the comparatively harder material occupying from 1/3 to 4/5 of the total volume of the powder mixture.

Abstract: A TiCN-based cermet cutting insert superior in toughness with improved wear resistance includes a binding phase and at least two hard dispersion phases. One of the hard dispersion phases includes one of a duplex and triplex structure having a core structure containing at least one of titanium carbonitride and a carbonitride solid solution of Ti and one of a V, Cr, Ti, Nb, Zr, W and Mo (hereinafter referred to as a (Ti,M)CN. The other hard dispersion phase includes a single structure wherein the core structure is composed of at least one of (Ti,M)CN or (Ti,M)CN and TiCN.

Abstract: Fiber-reinforced titanium alloy and intermetallic matrix composites having improved stability and tensile strength properties at elevated temperatures. The base reinforced fibers are pre-coated with a tailorable tri-layer coating, such as Ti--TiN--Ti. Preferably the TiN layer is graded so as to have metal-rich outer surfaces, such as titanium-rich TiN, providing excellent bonding affinity for the base titanium layer, bonded to the surface of the fibers, such as silicon carbide, and for the outer titanium layer, bonded to the titanium aluminum matrix, and a compound core, such as stoichiometric TiN, providing a stable interfacial barrier against chemical reactions, whereby the tensile strength and resistance to cracking of the composite is preserved even at elevated temperatures of 900.degree. C. or higher.

Abstract: A turbine blade including a blade and blade foot. The blade foot is formed by a ductile material and the blade comprises a material which is brittle compared to the ductile material but resistant to high temperature. The two materials are alloys of the same base compositions but differ as to presence and/or quantity of at least one doping element. The alloys can be hot-compacted with the formation of a transition zone joining the blade and blade root wherein fine crystallites of the blade root interpenetrate coarse crystallites of the blade. The two materials can comprise a gamma-titanium aluminide containing 0.5 to 8 atomic percent of a dopant. The turbine blade exhibits outstanding mechanical properties at high temperatures, good ductility at room temperature and a long service life.

Abstract: In this invention, a cutting tool comprises two layers of hard sintered compact of cBN. The first sintered compact layer comprises about 75-98% by volume of cBN and a first binder material. The first binder material comprises from about 1 to out 40% by weight of Al. The second sintered compact layer comprises from about 40 to about 65% by volume of cBN and a second binder material. The second binder material comprises about 2 to about 30% by weight of Al. The first sintered compact layer is bonded to the second sintered compact layer. This composite material is bonded directly or indirectly to a tool holder to form a cutting tool. The first sintered compact layer constitutes a rake face of the cutting tool.

Abstract: A turbine blade including a blade foot and a blade. The blade foot is formed by a ductile material and the blade comprises a material which is brittle compared to the ductile material but resistant to high temperature. The two materials are alloys of different chemical compositions and are hot-compacted with the formation of a boundary layer joining the blade foot and blade to produce a bimetallic composite material. The blade foot predominantly comprises a titanium-base alloy and the blade comprises a gamma-titanium aluminide containing 0.5 to 8 atomic percent of a dopant. The turbine blade exhibits outstanding mechanical properties at high temperatures, good ductility at room temperature and a long service life.

Abstract: An improved welding auxiliary material for producing welded joints between refractory metal parts of high-wattage electric light sources is described. The characteristic feature of the invention is that the welding auxiliary material has a porous structure surface layer sintered from a refractory metal powder having a melting point of above 2000.degree. C.

Abstract: In a hard sintered cutting tool, the tool life can be further increased. In this hard sintered body cutting tool, a rake face of an edge portion is formed by a major surface of a first sintered body layer containing at least 80 percent by volume and less than 98 percent by volume of diamond, while a flank of the edge portion is formed by a second sintered body layer containing at least 30 percent by volume and less than 75 percent by volume of cubic boron nitride (CBN). The first sintered body layer is formed to have a thickness of at least 0.02 mm and less than 0.1 mm, and to be in a thickness ratio of at least 1:5 to the second sintered body layer. Thus, chipping resistance of the rake face is improved by the first sintered body layer, while wear resistance of the flank is improved by the second sintered body layer. As a result, it is possible to suppress progress of local wear and chipping, whereby the life of the cutting tool is increased as compared with the prior art.

Abstract: A field emission type emitter comprises: a conductive substrate; an insulating film formed on the conductive substrate; a cavity formed in the insulating film; a cathode formed on the conductive substrate in the cavity; and a gate electrode formed over the insulating film. The gate electrode is preferably made of refractory metal silicide. A polycrystalline silicon film is preferably formed between the gate electrode and the insulating film. The side walls of the insulating film in the portion of the cavity preferably have an inverse tapered shape.In the case where a glass substrate is used, a conductive film is formed on the glass substrate through an insulating film and the cathode is formed on the conductive film in the cavity. Manufacturing methods of the field emission type emitter are also disclosed.

Abstract: A process for producing a ceramic-metal composite body exhibiting binder enrichment and improved fracture toughness at its surface. The process involves forming a shaped body from a homogeneous mixture of: (a) about 2-15 w/o Co or about 2-12 w/o Ni binder, (b) excess carbon, (c) optionally, 0 to less than 5.0 v/o B-1 carbides, and (d) remainder tungsten carbide. The mixture contains sufficient total carbon to result in an ASTM carbon porosity rating of C06 to C08 at the core of the densified body. The weight ratio of excess carbon to binder is about 0.05:1 to 0.037:1. The shaped body is densified in a vacuum or inert atmosphere at or above about 1300.degree. C. and slow cooled, at least to about 25.degree. below the eutectic temperature. Alternatively, the sintered body may be cooled to a holding temperature at or slightly above the eutectic temperature, isothermally held for at least 1/2 hr, and further cooled to ambient.

Abstract: A titanium-tungsten target material capable of limiting the amount of particles generated during sputtering and a method of manufacturing this titanium-tungsten material. The titanium-tungsten target material has a titanium-tungsten alloy phase which occupies 98% or more of the whole area of the material as observed in a micro-structure thereof. In one example of the manufacturing method, an ingot obtained by melting tungsten and titanium is processde by a solution treatment to form a titanium-tungsten target, or a power obtained by melting the ingot is sintered to form a target. Preferably, the melting may be performed under reduced pressure in an electron beam melting manner. In another example of the manufacturing method, a powder is formed from a molten metal by an atomization method and the obtained powder is sintered to form a titanium-tungsten target. For sintering of the powder, it is preferable to apply hot isostatic pressing or hot pressing.

Abstract: A sintered product useful for abrasion- and impact-resistant tools and the like is provided comprising an iron-group metal binder and refractory metal carbide particles, e.g. tungsten carbide, formed in situ during sintering by the exothermic reaction of a carbide-forming refractory metal powder with a carbon source mixed therewith. The sintering is carried out at an elevated temperature and at a pressure at which diamond is stable in the presence of a liquid phase comprised substantially of an iron-group binder metal, refractory metal, and dissolved carbon. The product may optionally contain diamond, up to about 95% in volume, enabling its properties to be tailored for a wide range of applications.

Abstract: Perforated plates (10) having very small holes (14) with a uniform diameter throughout the plate thickness are prepared by a "wire drawing" process in which a billet of sacrificial metal is disposed in an extrusion can of the plate metal, and the can is extruded and restacked repeatedly, converting the billet to a wire of the desired hole diameter. At final size, the rod is then sliced into wafers, and the wires are removed by selective etching. This process is useful for plate metals of interest for high performance regenerator applications, in particular, copper, niobium, molybdenum, erbium, and other rare earth metals. Er.sub.3 Ni, which has uniquely favorable thermophysical properties for such applications, may be incorporated in regions of the plates by providing extrusion cans (20) containing erbium and nickel metals in a stacked array (53) with extrusion cans of the plate metal, which may be copper. The array is heated to convert the erbium and nickel metals to Er.sub.3 Ni.

Abstract: A titanium-tungsten target material used to form, by sputtering, a barrier metal or the like for use in semiconductor devices. The titanium-tungsten target material is substantially composed of tungsten particles and a titanium-tungsten alloy phase surrounding the tungsten particles. The area ratio at which tungsten grains occupy in a cross section of the titanium-tungsten target material is, preferably, not more than 15%, more preferably, not more than 10%. If the average crystal grain size of the target material is not more greater 15 .mu.m, a uniform thin film can be obtained by sputtering. The target material can be obtained by sintering a titanium powder and a tungsten powder.

Abstract: The present invention provides a multilayer composite sliding material with excellent seizure resistance property having a steel plate or a steel plate having surfaces plated with copper or the like; a bond layer having a thickness of 0.05 to 0.5 mm, formed on the steel plate, and made of a sintered powder material consisting of 5 to 16% Sn, 0 to 15% Pb, 0 to 0.5% P and balance essentially Cu; and an alloy layer having a thickness of 0.1 to 1.0 mm, formed on the bond layer, and made of a sintered powder material consisting of 5 to 16% Sn, 1 to 12% MoS.sub.2 and balance essentially Cu. In a modified form of the alloy layer, not more than 20% Pb, not more than 1% P or not more than 12% Ni may be added. MoS.sub.2 powder may be coated with Cu or Ni.

Abstract: An impregnated thermionic cathode includes a porous matrix of sintered tungsten-alloy particles containing less than six percent iridium and/or other platinum-group metal. The pores of the matrix are impregnated with a temporary process impregnant such as molten copper or an organic monomer, and upon solidification is machined to a desired shape. Thereafter the temporary process impregnant is removed, and the matrix pores again infiltrated with a barium oxide such as molten barium aluminate, or other alkaline earth. A thin, iridium-rich surface activating layer, preferably of about 50% iridium, is then applied to the emitting surface. The diffusion of surface activating iridium is substantially blocked; superior emission and lifetime is provided; and the cathode is relatively low cost and easy to fabricate.

Abstract: A composite material (20) comprises a matrix layer (21) having a plurality of interspersed reinforcing whiskers (23) and a plurality of continuous reinforcing fibers (25) embedded within the matrix layer (21). The preferred embodiment includes a matrix layer (21) which may be a ceramic, intermetallic or metallic material having interspersed reinforcing whiskers (23) upon which a second layer of the matrix (24) having embedded continuous reinforcing fibers (25) is placed, and a third layer (22) of the matrix material having the interspersed reinforcing whiskers (23) on the second layer (24). The composite exhibits improved fracture toughness due to the crack deflection ability of whiskers (23) and crack bridging and fiber pull out due to continuous fibers (25) and minimizes creep associated with known ceramic and intermetallic composites.

Abstract: An improved active metal braze filler material is provided in which the coefficient of thermal expansion of the braze filler is more closely matched with that of the ceramic and metal, or two ceramics, to provide ceramic to metal, or ceramic to ceramic, sealed joints and articles which can withstand both high temperatures and repeated thermal cycling without failing.

Abstract: Contact materials of a vacuum interrupter and producing process therefor are disclosed. The contact materials provide a contact which is much high in relatively large current and small lagging and leading current interrupting capabilities and dielectric strength while a little in an anti-welding capability down. The contact materials are composed of between 20 and 70 weight % copper, between 5 and 70 weight % molybdenum and between 5 and 70 weight % chromium. The contact material is produced by diffusion bonding a mixture of molybdenum powder and chromium powder into a porous matrix and infiltrating the matrix with copper. Alternatively, the contact materials may be produced by sintering a mixture of three metal powders.

Abstract: A precision molded article, such as a die cavity, is made by combining granules of a first metal or alloy and a second metal or alloy, the second metal or alloy having a homogeneous appearance at some temperature below its melting point, and a higher Rockwell Hardness than the first metal or alloy, mixing the granules with a heat fugitive organic binder, molding the granule-binder mixture into a green molded preform, thermally degrading and removing essentially all the binder to form a skeletal preform, and infiltrating the preform with a third metal or alloy which will wet the second metal or alloy and has a lower Rockwell Hardness than the second metal or alloy, thereby forming a molded article having granules of first metal or alloy the majority of which are fully enveloped within a single skeleton of the second metal or alloy, the skeleton of second metal or alloy being surrounded by layers or matrices of softer metals.

Abstract: A ferro-sintered alloy having wear resistance at elevated temperatures comprising a matrix in which, on a weight basis, 25-75% of an alloying base A of the following composition is irregularly dispersed with 75-25% of an alloying base B of the following composition, the matrix having dispersed therein 3-15% of at least one of the following hard phases C and D, and optionally being impregnated in its pores with lead:______________________________________ Base A Base B ______________________________________ Cr 2-4% Co 5.5-7.5% Mo 0.2-0.4% Ni 0.5-3% V 0.2-0.4% Mo 0.5-3% C 0.6-1.2% C 0.6%-1.2% Fe the remainder Fe the remainder Hard phase C: 45-60% Co - 33-36% Mo. - and remainder Si Hard phase D: 45-60% Fe - 33-36% Mo - and remainder Si.

Abstract: AgCdO based contact elements are replaced in contactors and small circuit breakers with CdO-less type elements which exhibit little burn-off in the arc, a low welding force and minimal heating when carrying continuous current. However, known AgSnO.sub.2 contact materials do not have optimum values in all operationally important properties. In these contact materials a more firmly adhering oxide layer occurs as compared with AgCdO. The invention relates to a sintered compound material for electrical contacts, consisting of AgSnO.sub.2 Bi.sub.2 O.sub.3 CuO and containing at least one other metal oxide additive which sublimes below the melting temperature of silver. The SnO.sub.2, Bi.sub.2 O.sub.3 and CuO are globularly precipitated in silver material structure zones having a maximum diameter of 200 .mu.m, and the metal oxide additive is distributed on the surfaces of the boundary regions of these microscopic silver zones.

Abstract: A sintered alloy for a valve seat comprising, in weight percent, 0.5 to 1.7% C, 0.5 to 2.5% Ni, 3.0 to 8.0% Cr, 0.1 to 0.9% Mo, 1.0 to 3.8% W and 4.5 to 8.5% Co, the balance being substantially Fe provided by a base atomized powder; said alloy containing 8 to 14% by volume of 250 mesh or less C-Cr-W-Co-Fe and Fe-Mo hard grains and 6 to 13% by volume of cells, with the continuous cells being infiltrated by a copper alloy.

Abstract: A process for the surface treatment of inorganic fibers for reinforcing titanium or nickel, comprising the steps of coating the surface of inorganic fibers with an aqueous or organic solvent solution containing a titanate, borate, tetralkylammonium hydroxide and, if desired, dextrin and then heat treating the coated fibers at a high temperature in an inert or non-oxidizing atmosphere. In one embodiment, the heat treated inorganic fibers is further subjected to ionic or chemical plating with nickel.

Abstract: This invention provides a vacuum type breaker contact material prepared by infiltrating copper into a sintered tungsten matrix, wherein elementary particle size and the growth of the particle size by heat processing are controlled in such a manner that the ratio of the largest value/the smallest value of tungsten particle size becomes not more than 10, and that the maximum value of tungsten particle size is not larger than 2 .mu.m and the minimum value of tungsten particle size is not smaller than 0.3 .mu.m.

Abstract: The present invention relates to lining units used to protect surfaces exposed to intensive wear by solids, gases and liquids.The lining unit is a metallic shell formed with a pipe of rectangular cross section, containing a metallic plate and a wear-resistant composite material, the shell, the metallic plate and the composite material being diffusion-joined one to another.

Abstract: A precision molded electrical discharge machining electrode is made by shaping a preform from granules of carbon and granules of a refractory material selected from the group consisting of tungsten, molybdenum, carbides thereof, and stoichiometric and hyperstoichiometric carbides of the other elements of the groups IVB, VB, and VIB of the Periodic Table of the Elements, the carbon and refractory granules being interconnected in the form of a skeleton at their contiguous points of contact, and infiltrating the preform with copper, silver, or alloys containing those metals.

Abstract: A contact for a vacuum interrupter has excellent characteristics of high withstand voltage, low melt bonding property, large current durability and low chopping current and is prepared by uniformly distributing, in a copper matrix, two kinds of high melting point metal powders having a melting point of higher than 1450.degree. C. which have different particle diameters of (1) 80-300 .mu.m and (2) less than 30 .mu.m. The low chopping current characteristic is imparted by incorporating more than 10 wt. % of the high melting point metal powder. The high melting point metal powder can be selected from the group consisting of Cr, W, Mo, Ir and Co.

Abstract: A contact for a vacuum interrupter has excellent characteristics of high withstand voltage, large current durability and low chopping current and is prepared by infiltrating copper into a skeleton obtained by sintering a specific tungsten powder having an average diameter of less than 1 .mu.m.The skeleton is preferably prepared by a vacuum sintering process and the copper is infiltrating into the skeleton in hydrogen atmosphere or in vacuum.

Abstract: Molybdenum base composite materials having high tensile strength and oxidon resistance at high temperatures are produced by piling in parallel and embedding silicon carbide fibers containing 0.01-20% by weight of free carbon, which have been produced by the specific method already disclosed in U.S. patent application Ser. No. 677,960, in molybdenum base metallic powders and by compressing and sintering the assembly.