Abstract: Ag-SnO system alloy electrical contact materials. The Ag alloy before internal oxidation thereof contains Sn of an amount of 5-20 weight %, 0.5-15 weight % of which amount is in the powder form of SnO.sub.2. The existence of SnO.sub.2 particles in the alloy accelerates the internal oxidation speed, allowing oxygen to readily pass aside and between the particles, while the internal oxidation per se makes the alloy more dense by eliminating spaces between SnO.sub.2 grain particles on account of the volumeric expansion of Sn which results from the internal oxidation thereof.

Abstract: A tetrafluoroethylene-type fluoroplastic powder is added and mixed with a metal powder and the mixture is shaped. The compact is heated in a nonoxidizing atmosphere and the oxides on the surface of the metal particles are converted and removed as gaseous fluorides. Alternatively, after the oxides are converted to solid or liquid fluorides, the fluorides are reduced by hydrogen and then they are removed as gaseous reaction products. Thereafter, the compact is sintered.

Abstract: A three step process in which a metal alloy selected from a tungsten based alloy and molybdenum based alloys is provided to prevent the decarbonization of the alloys. The process involves a three step sintering process wherein the atmosphere during the initial heating step is a mixture of carbon monoxide and hydrogen, thereafter at a intermediate temperature range the atmosphere is hydrogen and a final heating step at a elevated temperature is employed and the atmosphere is a mixture of inert gas and a source of carbon.

Abstract: There is disclosed a process for forming a wear-resistant, sintered layer on a metallic substrate. The process comprises steps of adhesively attaching to a surface of metallic substrate an alloy particle sheet containing 94 to 99 weight % of ternary eutectic alloy particles and 6 to 1 weight % of acryl binder, heating in a non-oxidating atmosphere to a temperature of 150.degree. to 380.degree. C. and holding at the temperature for at least 5 minutes, and heating a sintering temperature of the alloy particles.

Abstract: A material which is intended for use in sliding surface bearings comprises a metallic backing, a porous metallic substrate layer applied to said backing, and a PTFE-filler mixture, which completely fills the pores of the substrate layer and constitutes an antifriction layer. The bond strength between the antifriction layer and the substrate layer is improved by coating that surface of the substrate layer which faces the antifriction layer with a primer.

Abstract: Cams which meet all strength requirements and can be shrunk on a shaft can be made in a simple manner by sintering from a nickel- and copper-free mixture which comprises iron powder and contains 0.3 to 1.0 weight percent carbon and molybdenum and/or tungsten in such amounts that the sum of the molybdenums content and the tungsten content multiplied with the ratio of the atomic weight of molybdenum to the atomic weight of tungsten lies between 0.5 and 3 weight percent.

Abstract: A method for fabricating ribbed electrodes that accommodates the shrinkage which occurs during thermal cycling reducing the cracks caused by the confining stresses of a mold. A composition comprising a metal selected from the group consisting of nickel, copper and mixtures thereof with chromium onto a ribbed mold. The mold and composition are prefired in a reducing atmosphere forming a ribbed electrode. The ribbed electrode is removed from the mold and sintered in a reducing atmosphere.

Abstract: An improved fabrication process for cobalt-enriched cemented carbide substrates is disclosed, in which an article is generally comprised of tungsten carbide, cobalt, and carbides, nitrides or carbonitrides of titanium, tantalum, and niobium, or mixtures thereof. In one aspect of the invention the article is contacted with nitrogen gas and then sintered in the absence of nitrogen gas to form a cobalt-enriched, B-1 phase-depleted zone. The article is then sintered in nitrogen gas to form a B-1 phase enriched layer on the surface of the article. Additionally, a metal oxide wear layer can be provided on the article.

Abstract: This invention relates to a hard alloy comprising two phases: a hard phase consisting of at least one compound having a crystal structure of simple hexagonal MC type (M: metal; C: carbon) selected from the group consisting of mixed carbides, carbonitrides and carboxynitrides of molybdenum and tungsten, and a binder phase consisting of at least one element selected from the group consisting of iron, cobalt and nickel. The hard phase is prepared by carburizing an (Mo, W) alloy obtained by reducing oxides of molybdenum and tungsten with a particle size of at most 1 micron, is composed of coarse particles with a mean particle size of at least 3 microns, and has a uniform molybdenum to tungsten ratio in the particles. The hard alloy has a gross composition within the range of the shaded portion ABCDEA in FIG. 1.

Abstract: The present invention provides a molybdenum alloy which suitably comprises in the range of from 0.2 to 1.0% by weight of an oxide of a specified metal prepared by adding a salt of the metal in dissolved form to molybdenum and/or a molybdenum oxide or a mixture of different molybdenum components, reducing this mixture at a temperature of up to 1150.degree. C. using hydrogen, pressing the reduced metal without the addition of a binder suitably under a pressure of from 150 to 300 mPA, and sintering the product at a temperature in the range of from 1750.degree. to 2200.degree. C. It is preferable to add salts of zirconium to the molybdenum oxide.

Abstract: A method for forming an iron alloy article having increased toughness comprises compacting and sintering a powder mixture composed of predominantly iron powder and carbon powder and containing a powder of a liquating nickel boride compound. Limited nickel diffusion into the iron structure during sintering produces metastable retained austenite in regions about pores in the product structure that retards crack formation and thereby improves mechanical properties.

Abstract: Powder metallurgy products of high tensile strength are formed in a pore-free state by a novel process which entirely avoids the use of canisters. An open-pore specimen is purged with depurative gas, backfilled with a reactive gas and, while still immersed in the reactive gas, compressed isostatically to an extent necessary to close the pores. The specimen may then be compressed to full density without the need for either high vacuum or a depurative or reactive gas atmosphere.

Abstract: The invention relates to a process for the production of porous products of boron or boron compounds.This process comprises the following stages:(1) suspending the boron powder in a solution of an alkali metal salt, hydroxide and/or oxide,(2) then separating the powder from the suspension liquid by settling,(3) drying the thus separated powder to obtain an agglomerated powder, and(4) subjecting the thus obtained agglomerated powder to at least two heat treatments performed at different temperatures, the final stage of the heat treatment being performed at a temperature of 1500.degree. to 2200.degree. C. and the first stage being performed at a temperature below that of the final stage.The heat treatment can be performed in three stages, as shown in the attached graph.

Abstract: A method for producing a sintered ferrous alloy containing at least one alloying element whose standard free energy for oxide formation at 1,000.degree. C. is 11,000 cal/g mol O.sub.2 or less is described. The method comprises a sintering procedure comprising steps of elevating the temperature of a green compact comprising said at least one alloying element, sintering it in a sintering furnace and cooling it, wherein the pressure in the sintering furnace is maintained at between about 0.2 and 500 Torr by supplying a reducing gas during at least a part of the sintering procedure under reduced pressure.

Abstract: An improvement is disclosed in a method for producing a metal article of high density comprising pressing a metal powder at a sufficient pressure to form a green article and sintering said green article at a sufficient temperature for a sufficient time to form a sintered article, the improvement being pressing the sintered article at a sufficient temperature for a sufficient time at a sufficient pressure of a non-oxidizing atmosphere to produce the final high density article.

Abstract: A process and mold for applying a porous metal coating to a metal substrate or a portion thereof, especially for forming a medical prosthesis. The substrate to be coated is cleaned, then positioned in a rigid mold of ceramic or metal material having a defined mold cavity. The space between the mold cavity surface and the substrate is filled with a metal powder and the mold, powder and substrate assembly is pre-sintered. The pre-sinter conditions are selected such that the powder lightly sinters together and adheres to the substrate, but not to the mold cavity surface. After removal of the mold, the coated substrate is further sintered to obtain the proper desired bond strength and pore volume. Sintering is carried out in a protective atmosphere.

Abstract: The specification discloses a powder process in which metal or ceramic particles are mixed with a binder such as ultra high molecular weight polyethylene powder and are compacted. The compacted shape is heated to a temperature near the melting point of the binder to consolidate the binder and produce a green shape. The green shape is formed and the binder is removed. Thereafter, the shape is sintered to form a final part.

Abstract: The composite according to the invention is prepared by milling an atomized silver, two metal oxide alloy powder dry or wet in a mill in order to reduce its particle size and deform its particle shape. Subsequently an internal oxidation of the powder is carried out in two stages, at a first temperature range between 673.degree. K. and 773.degree. K. for two to six hours and in a second temperature range between 873.degree. K. and 1073.degree. K. for 0.5 to 2 hours. The internally oxidized powder is pressed into molded parts and these are densified by sintering in a temperature range between 973.degree. K. and 1173.degree. K. in air or a neutral atmosphere and by coining.

Abstract: The present invention concerns the manufacture of bars, wires or profiled elements by hot transformation which may be followed by cold transformation. The invention particularly concerns a new process for the manufacture of a composite billet for hot transformation as well as a method for the manufacture of products which are difficult to transform by making use of such a composite billet.

Abstract: A method of producing a high density tungsten alloy sheet product is disclosed which utilizes as a starting material a thin-gage sheet or foil substrate of a first alloy constituent, such as pure iron or an alloy thereof. A prescribed mixture of tungsten metal powder and a second metal alloy constitutent powder, such as nickel, is loaded on the substrate and partially consolidated in a protective atmosphere furnace to form a porous tungsten alloy skeleton which is also partially bonded to the substrate. The product is then preferably cooled in a protective atmosphere and sheared into desired lengths. The sized pieces are then further heated in a protective atmosphere at gradually increasing temperatures to a point above the melting point of the substrate, whereupon the substrate sheet or foil melts and infiltrates the porous tungsten alloy skeleton to complete the densification of the product.

Abstract: A solid electrolytic capacitor is made with an Aluminum-titanium body. Aluminum and titanium powders are press-molded into a body which is then heated sufficiently to provide a porous Al-Ti alloy with an oxide layer. Next, the body is heated in an atmosphere containing at least 0.1% by volume of oxygen at a temperature in the range of about 500.degree.-700.degree. C. Thereafter, a layer of manganese dioxide is formed over the oxide layer and a cathode electrode layer is then formed over the manganese dioxide layer.

Abstract: Permanent magnetic materials of the Fe-B-R type are produced by:preparing an metallic powder having a mean particle size of 0.3-80 microns and a composition of, by atomic percent, 8-30% R (rare earth elements), 2-28% B, and the balance Fe, compacting, sintering at a temperature of 900-1200 degrees C., and aging at a temperature ranging from 350 degrees C. to the temperature for sintering. Co and additional elements M (Ti, Ni, Bi, V, Nb, Ta, Cr, Mo, W, Mn, Al, Sb, Ge, Sn, Zr, Hf) may be present.

Abstract: A metal powder sheet for use for forming a sintered layer on a metal substrate. The sheet includes powders of a metal which provides a required physical property such as wear-resistance and ultra-fine powders of a metal having a powder size finer than 1 micron. These powders are kneaded with an addition of an acryl resin as a binder. The ultra-fine powders make it possible to carry out the sintering process at a lower temperature.

Abstract: A composite camshaft having a plurality of ferrous fitting members, such as cam lobes and journals, firmly bonded to a steel shaft by sintering in the presence of a liquid phase. The fitting members are fabricated as a green compact from metal powders and pre-sintered to axially shrink the compact by one-half a preselected allowance of shrinkage. Thereafter the pre-sintered fitting members are fitted on the shaft and sintered to axially shrink the compact by the remaining allowance of shrinkage and metallurgically join the shaft.

Abstract: A process for making a strip or sheet comprising dispersion strengthened metal or dispersion strengthened metal alloy which comprises rolling directly from dispersion strengthened metal powder to a green strip or sheet density of from at least 90% to 95% of theoretical density, sintering the green strip or sheet in an inert atmosphere at a temperature and for a period of time sufficient to form a rigid body; reducing the thickness of the strip or sheet by at least 25% by cold rolling or hot rolling and resintering at sintering temperature of at least about 1800.degree. F. for 40 to 75 or more minutes.

Abstract: A method of manufacturing a scandate dispenser cathode having a matrix at least the top layer of which at the surface consists substantially of tungsten (W) and scandium oxide (Sc.sub.2 O.sub.3) and with emitter material in or below said matrix. If said method comprises the following steps:(a) compressing a porous plug of tungsten powder(b) heating said plug in a non-reactive atmosphere and in contact with scandium to above the melting temperature of scandium,(c) cooling the plug in a hydrogen (H.sub.2) atmosphere(d) pulverizing the plug to fragments(e) heating said fragments to approximately 800.degree. C. and firing them at this temperature for a few to a few tens of minutes in a hydrogen atmosphere and slowly cooling in said hydrogen atmosphere(f) grinding the fragments to scandium hydride-tungsten powder (ScH.sub.2 /W)(g) compressing a matrix or a top layer on a matrix of pure tungsten from said ScH.sub.

Abstract: A method for sealing porous metals, which comprises applying powder of a eutectic alloy containing an element having a good diffusibility in a porous metal or powder of a mixture of metals capable of forming the eutectic alloy, to the surface of a porous metal member and heating the surface applied with the powder at a temperature higher than the eutectic temperature of the eutectic alloy to thereby cause the molten eutectic alloy to intrude into pores from the surface of the porous metal member, whereby the melting point of the molten alloy in the pores is promptly increased by diffusion of the element in the porous metal member to solidify the molten metal in the pores, sealing only pores present in the vicinity of the surface of the porous metal member.

Abstract: Pressure assisted sintering achieves full densification in short sinter times with low grain growth. This result is enabled by a stage of sintering to a condition of closed porosity (14) followed by a pressure assisted sinter (PAS) stage (16) carried out at a temperature close to, but just below, sinter temperature. Advantageously a small melt formation is induced by a brief temperature spiking (18) during the PAS stage to enable collapse of voids.

Abstract: An article comprising a first portion which is formed porously by sintering of an alloy or cermet material and a second portion which is formed of a metal and intimately bonds to the first portion. For example, the article is a rocker arm for an automotive internal combustion engine, in which first portion is the wear-resistant tip portion and the second portion the body portion. The second portion is formed by molten metal forging, with the sintered first portion set in the mould as an insert, such that the molten metal under pressure is forced to infiltrate into the pores of the sintered first portion at least in a region contiguous to the interface between the first and second portions. This article features very high strength of the bond at the interface between the first and second portions.

Abstract: A process for the preparation of an iron base sintered alloy well suited for use in valve mechanism members or parts of internal combustion engines, which has a porosity of 5 to 15% and throughout the iron matrix of which is dispersed an Fe-Mo intermetallic compound in the form of a phase harder than the said matrix, by using a powder mixture obtained by incorporating into finely divided iron powders having a particle size of not more than 30 microns the given amounts of copper powders, phosphorus-containing alloy powders, carbon powders and Fe-Mo alloy powders, or the given amounts of bronze powders and/or a mixture of copper powders and tin powders, phosphorus-containing alloy powders, carbon powders and Fe-Mo alloy powders.

Abstract: A canless method for hot working a nickel-base gas atomized alloy powder. The powder is blended with nickel powder, consolidated and sintered to a sufficient green strength. The surface of the resultant form is sealed to create an oxygen impervious layer so as to prevent oxidation therein. The sealed surface, in a sense, acts as a can. The form is then reheated and hot worked.

Abstract: The invention relates to a powder metallurgical method for producing high speed steel products, the shape of which is close to the desired final shape of the product, i.e. according to the so called near net shape technique.

Abstract: To increase the creep strength of a titanium-containing alloy which also contains chromium, the alloy powder is heated in the presence of ammonia at a temperature of the order of 700.degree. C. so as to form a layer of chromium nitride(s) on the particles and is then heated further in an inert atmosphere at a temperature between 1000.degree. C. and 1150.degree. C. to dissociate the chromium nitride(s) thereby effecting nitriding of the titanium to titanium nitride which affords dispersion-strengthening of the alloy.

Abstract: A hot isostatic pressing system including a hot isostatic pressing station having a high pressure container constituted by a vertical pressure-resistant cylinder closed at the top end thereof and a lower lid detachably fitted to the bottom of the pressure resistant cylinder and a treating chamber internally provided with a heater and enclosed by a heat insulating wall, and a mechanism for adjusting an atmospheric gas pressure and temperature of the pressing station into a condition suitable for the hot isostatic pressing of a work item accommodated in the treating chamber; a plurality of auxiliary stations each provided with an opening for receiving from beneath thereof the heat insulating wall of the treating chamber accommodating the internal heater and a work item, a support structure for supporting the heat insulating wall, and a mechanism for cooling the work item and internal heater in an inert gas atmosphere; a carriage for transferring the lower lid and work item or the lower lid, work item, heat insu

Abstract: An object is manufactured from a powdered material by isostatic pressing of a body, preformed from the powdered material, with a pressure medium, whereby the preformed body, in which at least the surface layer consists of a ceramic material in the form of a nitride, is surrounded by a casing which is rendered impenetrable to the pressure medium, before the isostatic pressing is carried out and the powder sintered. As the material in the casing there is used boron oxide or a glass containing boron oxide or a material forming glass while being heated, in which the content of boron oxide is sufficiently high for the glass--or the glass formed during heating--to be removable by water. The preformed body surrounded by the casing is subjected to a heat treatment for the formation of boron nitride on the surface of the preformed body, before the isostatic pressing is carried out. The casing is removed from the finished product by means of water or water vapor.

Abstract: The present invention relates to a method for manufacturing a high-strength sintered silicon carbide article and more particularly, to a method for a sintered silicon carbide article having high mechanical strength by mixing a finely divided silicon carbide powder with the definite amounts of a specific carbon-containing material, a boron compound and silicon powder as densification aids, shaping and then sintering said shaped article under an inert atmosphere.

Abstract: A stainless steel powder is mixed with at least a Ni--Mn and a Ni--Cr powder, and the powder mixture is formed by loose packing into a required configuration. The powder mixture is sintered in a non-oxidizing atmosphere at the melting point of the Ni--Mn powder or at a higher temperature thereby to obtain a porous body.

Abstract: The solid cathodes built into reduction cells for aluminum production have at least one workface which can be wet by the precipitated metal. The starting materials, which contain titanium, boron and carbon in powder form, are first intimately mixed in such proportions that the sum of the powdered carbon and any carbon extracted from the substrate is in excess with respect to the amount required by the starting materials to form titanium diboride. This mixture is heated under a neutral or reducing atmosphere to 1600.degree.-2200.degree. C. and held for 5-45 min at this temperature. The reaction product containing pores and channels is then heated further, to 2250.degree.-2600.degree. C., and held there for 10-60 min to form a compact titanium diboride/carbon eutectic. Subsequently, the solid cathode is cooled to room temperature.

Abstract: Process for the preparation of a composite material incorporating an inorganic matrix in which are distributed inclusions of carbon-containing material, where it comprises the following stages:(a) mixing an inorganic powder with a liquid or viscous resin, which can be transformed into vitreous carbon by heat treatment,(b) subjecting the mixture of resin and inorganic powder to a first heat treatment performed under conditions such that the resin is hardened by crosslinking or polycondensation, and(c) subjecting the thus obtained hardened product to a second heat treatment for transforming the resin into vitreous carbon and thus forming said vitreous carbon inclusions.The composite material obtained comprises a copper matrix in which are uniformly and homogeneously dispersed vitreous carbon inclusions, the vitreous carbon content being at the most 8% by weight.The material is used in the production of electric contacts.

Abstract: A method for removal of organic binders from powder compacts is disclosed in which the compact is heated while the weight change is monitored and controlled. The heating is regulated so that the removal rate of the binder is optimized. The removal time can be shortened without creating defects in the powder compact.

Abstract: The solid cathodes built into reduction cells for aluminum production have at least one workface which can be wet by the precipitated metal. The starting materials, which contain titanium, boron and carbon in powder form, are first intimately mixed in such proportions that the sum of the powdered carbon and any carbon extracted from the substrate is in excess with respect to the amount required by the starting materials to form titanium diboride. This mixture is heated under a neutral or reducing atmosphere to 1600.degree.-2200.degree. C. and held for 5-45 min at this temperature. The reaction product containing pores and channels is then heated further, to 2250.degree.-2600.degree. C., and held there for 10-60 min to form a compact titanium diboride/carbon eutectic. Subsequently, the solid cathode is cooled to room temperature.

Abstract: A powder metallurgical method of consolidating iron-based alloy powder, particularly white cast iron, to form a body of high density in which the powder is thermally cycled above and below the alpha-gamma transformation temperature of below 800.degree. C., and a stress of between 1.7 MPa and 34.5 MPa is simultaneously applied to the powder to form a high density consolidated body.

Abstract: A method of manufacturing molded articles of metal alloys, especially of nickel-base alloys, chromium-base alloys, titanium-base alloys, and dispersion-hardened alloys. A powder of the alloy, or a blend of powders of alloy constituents, is mixed with one or more plastics, selected from thermoplastics, duroplastics, and internal lubricants to form an injectionable granulate compound, the plastic content amounting to about 30% to 50% by volume. The compound is prepared by dissolving the plastic in a solvent which will not attack the base material of the alloy, and by blending it with the metal powder, after which the solvent is evaporated. The injectionable granulate compound is then injection molded to form a molded article. By heat treatment at 600.degree. C. or below in inert gas the plastic is eliminated from the molded article. The article is then sintered. To improve its strength, the article may subsequently be subjected to hot isostatic pressing.

Abstract: A high density sintering method for powder molded products by applying preliminary sintering to powder molded products previously molded into a predetermined shape and then applying hot isostatic press process to the sintered products thereby producing high density sintered product which includes the steps of loading the powder molded products into a movable heating furnace equipped with at least one heating means and having a heat insulating structure, introducing the heating furnace into an atmosphere chamber, applying preliminary sintering to the powder molded products in the heating furnace by the heating means while conditioning the inside of the atmosphere chamber to a vacuum or predetermined gas atmosphere, subsequently removing the heating furnace while maintaining the inside thereof at a high temperature from the atmosphere chamber and directly introducing the furnace into a high pressure vessel, thereafter, applying the hot isostatic press process to the sintered products in the furnace while chargi

Abstract: A method for hot-consolidating powder of metallic and nonmetallic composition and combinations thereof to form a densified compact at a predetermined temperature and pressure at which the powder is transformed into a compact comprises the steps of filling the cavity of a container with a powder, such as a superalloy, to be compacted and hermetically sealing the container. The method is characterized by the steps of heating the container within an autoclave having an inert gas therein, such as argon, to an intermediate temperature, then pressurizing the autoclave to an intermediate temperature and thereafter raising the temperature to thereby increase the pressure and, consequently, reach the temperature and pressure to effect compaction or densification of the compact or article.

Abstract: A method of manufacturing metal pieces by casting and sintering of a metal alloy powder of the type that includes two phases, a conforming phase during which a load of powder is heated inside a formal casting to execute a rigid preform which is porous and a compacting and sintering phase during which the preform is heated under isostatic pressure. The method and resulting metal piece is characterized in that the conforming phase is conducted so that the preform has open pores and the isostatic pressure is applied by way of an envelope that distorts and is airtight. The method is applied advantageously in the execution of complex formal pieces made of superalloys or made of a titanium alloy.

Abstract: A hard alloy including at least one hard phase and a binary or multicomponent binder metal alloy, in which the hard substance comprises a finely dispersed, homogeneous distribution in the binder metal. The hard phase comprises a carbide of a Group IVb, Vb or VIb transition metal, and the binder metal alloy comprises a solid alloy of a Group IVb, Vb or VIb transition metal, with Re, Ru, Rh, Pd, Os, Ir, or Pt.

Abstract: The method of the invention relates to powder metallurgy and is intended to be used for making cutting tools, dies as well as vital structural members.The method comprises charging a powder into a capsule, sealing the capsule, heating and then extruding the capsule containing the powder. The sealed capsule is heated up to a temperature of 700.degree. to 1000.degree. C., whereupon the capsule is depressurized and heated up to a temperature of 1050.degree. to 1200.degree. C.

Abstract: The invention is directed to the production of non-fragile shaped members from powders comprising spheroidal metal particles.For this purpose, the invention provides a process for the production of shaped parts from powders comprising spheroidal metal particles which are mixed with from 0.2% to 2% of lubricant, comprising the combination of the following successive steps, performed in the below-indicated order:(a) mixing the powder formed by spheroidal metal particles with an amount of water-soluble cellulose gum between 0.2% and 2%, and with an amount of water which is also between 0.2% and 2%;(b) a cold compacting operation;(c) an optional oven drying operation;(d) a two-phase sintering operation, in an atmosphere which is neutral or reducing with respect to the compacted powder, the first phase being effected at a temperature of from 300.degree. to 500.degree. C. and the second phase being effected at a temperature which is substantially higher and variable with the nature of the powder.