Abstract: In various embodiments, metallic alloy powders are formed at least in part by spray drying to form agglomerate particles and/or plasma densification to form composite particles.

Abstract: A tungsten wire according one aspect of the present disclosure includes: a metal wire containing one of tungsten and a tungsten alloy; and a plating layer which covers a surface of the metal wire. The plating layer contains copper.

Abstract: In various embodiments, joined sputtering targets are formed at least in part by spray deposition of the sputtering material and/or welding.

Abstract: A refractory metal matrix-ceramic compound multi-component composite material with the super-high melting point is disclosed. At least one ceramic compound A and at least one refractory bonding metal B are fused together by the smelting process to make the multi-component composite material. The fused ingredients of the multi-component composite material are mAnB, and (m+n)max=13. The positive integer m is the number of the kinds of the ceramic components A, and the positive integer n is the number of the kinds of the refractory bonding metals B. The absolute value of the combining enthalpy of the ceramic compound A is larger than the absolute value of the combining enthalpy between the ceramic compound A and the refractory bonding metal B. The multi-component composite material has the properties including over 3000° C. melting point, high stability, hardness, ductility, and fusibility in high or low temperature, fast production, and low cost.

Abstract: There is provided a flat plate-like sintered tungsten alloy that can be molded into a complex shape by press working or forge processing. The flat plate-like sintered tungsten alloy contains 85% by mass or more and 98% by mass or less of W, 1.4% by mass or more and 11% by mass or less of Ni, and 0.6% by mass or more and 6% by mass or less of at least one substance selected from the group consisting of Fe, Cu and Co, wherein an elongation percentage of the flat plate-like sintered tungsten alloy in a planar direction is 20% or more.

Abstract: Process for the production of a powdered spherical tungstic acid by acidification of an aqueous alkaline tungstate solution with mineral acid at elevated temperature, preferably in a continuous stirred tank or a cascade of at least 2 continuous stirred tanks, and tungstic acid obtainable in this way, which is characterized by a high bulk density and spherical morphology.

Abstract: Provided are an ancillary material, used for shape processing, which is capable of shortening a processing time, avoiding a reduction in quality of a shape provided to a workpiece material, and allowing a relatively low manufacturing cost; a processing method using the ancillary material; and a method of manufacturing the ancillary material. The tungsten alloy grains (1) comprise: tungsten of greater than or equal to 80% by mass and less than or equal to 98% by mass; nickel; at least one kind of metal selected from the group consisting of iron, copper, and cobalt; and an inevitable impurity, a maximum diameter thereof is greater than or equal to 0.1 mm and less than or equal to 5.00 mm, and a specific surface area thereof is less than or equal to 0.02 m2/g. The tungsten alloy grains (1, 10), the workpiece material (30), an abrasive (20) are blended in a container (100) and the container is rotated, thereby processing the shape of the workpiece material (30).

Abstract: A discontinuously reinforced metal matrix composite wherein the reinforcing material is a particulate binary intermetallic compound is described along with methods for preparing the same. The binary intermetallic compound includes the same type of metal as is the principal matrix metal in combination with one other metal. The particle size of the particulate binary intermetallic compound may be less than about 20 ?m and may be between about 1 ?m and about 10 ?m. The intermetallic particles may be present in the discontinuously reinforced metal matrix composites in an amount ranging from about 10% to about 70% by volume. The discontinuous reinforced metal matrix composites of the invention may be used in structures requiring greater strength and stiffness than can be provided by matrix metal alone. The materials of the invention may be used for vehicle parts, structural materials, and the like.

Abstract: An improved composite material, and method of manufacture thereof, comprising varying amounts tungsten powder, or metal/alloy powder of similar density, and clay or silicone is disclosed. The improved composite material may be useful as a replacement for lead and lead-based composites where similar densities are required but the use of lead is undesirable. The disclosed composite material permits a large variety of tungsten powder particle sizes to be utilized and results in improved ductility over known tungsten powder composites.

Abstract: A first tungsten-based sintered material of the present invention comprises Ni in a range from 0.2 to 1.5% by mass, Y2O3 in a range from 0.1 to 1% by mass, and optionally, (a) VC in a range from 0.05 to 0.5% by mass and/or (b) Co and/or Fe in a range from 0.01 to 5% by mass, the balance being tungsten (W); W phases are sinter-bonded; Ni phase or Ni—Co/Fe alloy phase which has the largest particle diameter of 5 ?m or less and Y2O3 having the largest particle diameter of 5 ?m or less are distributed at boundaries of the W phases; and the largest particle diameter of the W phase is 30 ?m or less. The first tungsten-based sintered material is preferably used for a hot press mold for optical glass lenses.

Abstract: Systems and methods for refining or otherwise processing tungsten alloys, including ferrotungsten powder and articles formed therefrom, and methods for detecting the presence of the same. The methods include at least one of magnetically-separating and particle-size-separating ferrotungsten or ferrotungsten-containing powder. In some embodiments, powder may be separated to remove fine particles, and optionally to separate the remaining particles into fractions containing selected particle size distributions. The powder additionally or alternatively may be separated into at least magnetic and non-magnetic fractions. In some embodiments, portions of two or more size and/or magnetism fractions are mixed to provide a ferrotungsten-containing feedstock. Selected fractions resulting from the size and magnetism separation steps may be utilized to provide a ferrotungsten-containing feedstock from which articles are produced and which may include additional components.

Abstract: The invention includes a method for producing high-density composites of metallic glass alloy powders in combination with a refractory metal powder, and includes related methods for producing metallic glass alloys. The invention, in one aspect, employs a system of monitoring the temperature and hot isostatic pressing conditions during the consolidation of metallic compositions in order to produce higher densities and materials of a larger diameter, for example. In another aspect, the invention involves method whereby a third interfacial phase at a metallic glass alloy/refractory metal interface is effectively controlled to produce composites with advantageous properties.

Abstract: Tungsten-based alloy material sintered at a high sintering power that may contain additive elements soluble in the nickel and selected from the group constituted, for example, by rhenium, molybdenum, tantalum, niobium, vanadium or a mixture of these, wherein, after sintering in liquid phase at a temperature of around 1500° C., it has: a two-phased ?-? microstructure that is fully densified, has no porosities or has negligible porosities of a low mean grain size (L?) and a contiguity (C??) that is very low with respect to the size of the tungsten crystals, and a dispersion of micro-oxides with no loss of ductility properties.

Abstract: Tungsten-containing articles and manufacturing processes for tungsten-containing articles. The articles may include firearms projectiles, such as shot, shot slugs, bullets, big game bullets, lead-equivalent bullets, black powder bullets, etc.; radiation shields; and weights, such as fishing weights, dart weights, golf club weights, wheel weights, stabilizers, etc. The projectiles may be at least one of non-toxic, lead-free, ferromagnetic, frangible, sintered, sealed, plated, and/or jacketed. The manufacturing processes include various powder-metallurgy and molten metal processes, and sealing, reforming, intermediate structure, reshaping, plating, working, and jacketing steps which may be selectively utilized. The processes may include forming an intermediate structure and reshaping the structure under different pressure or process to a desired shape.

Abstract: A tungsten-tin composite for green (lead-free) ammunition is provided wherein the composite is made with a spheroidized tungsten powder and has mechanical properties similar to those of lead. The composite may be fully densified at pressures less than about 250 MPa and is suitable for pressing complex projectile shapes to near net size.

Abstract: Disclosed is a flow-softening tungsten alloy having the general formula: W100-pAiBjCkDe wherein W is tungsten; A is one or more elements selected from the group consisting of nickel, iron, chromium and cobalt; B is in or more elements selected from the group consisting of molybdenum, niobium and tantalum; C is one or more of the elements selected from the groups consisting of titanium and aluminum; D is one or more elements selected from the group consisting of boron, carbon, and silicon; i is from about 5 to about 8 weight percent; j is from 0 to about 4 weight percent; k is from about 0.1 to about 4 weight percent; 1 is from 0 to about 0.1 weight percent; and p is greater than or equal to about 7 weight percent and less than or equal to about 20 weight percent. In this alloy p is approximately equal to the sum of i, j, k and 1. A method of preparing this alloy and a kinetic energy penetrator manufactured from it are also disclosed.

Abstract: Methods for producing medium-density articles from recovered high-density tungsten alloy (WHA) material, and especially from recovered WHA scrap. In one embodiment of the invention, the method includes forming a medium-density alloy from WHA material and one or more medium- to low-density metals or metal alloys. In another embodiment, medium-density grinding media, such as formed from the above method, is used to mill WHA scrap and one or more matrix metals into particulate that may be pressed and, in some embodiments, sintered to form medium-density articles therefrom.

Abstract: A large-diameter tungsten-lanthana rod having an elongated grain structure substantially parallel to the longitudinal axis of the rod is described. The large diameter rod is produced by rolling at a temperature greater than 1400° C. and less than 1700° C. to achieve at least about a 40% reduction in cross-sectional area. The high strength of the longitudinally elongated grain structure is desirable for applications such as rocket nozzles.

Abstract: Disclosed are a tungsten material for a penetrating splinter shell and forming method thereof enabling a penetrator to perforate a hard target on high-speed impact as well as having the following splinter cause a severe damage on an inner component by changing a breakage characteristic of the material into brittle fracture from ductile fracture in a manner that a mechanical characteristic of the material is adjusted by controlling a sintering condition and a composition ratio of a tungsten heavy alloy material having Mo added thereto. The present invention includes the steps of mixing 90˜95 wt % W powder, 3.0˜8.0 wt % Mo powder, 0.5˜3.0 wt % Ni powder, and 1.0˜4.0 wt % Fe powder with each other, molding the mixed powders, and sintering the molded powders.

Abstract: A tungsten-tin composite for green (lead-free) ammunition is provided wherein the composite is made with a spheroidized tungsten powder and has mechanical properties similar to those of lead. The composite may be fully densified at pressures less than about 250 MPa and is suitable for pressing complex projectile shapes to near net size.

Abstract: A manufacturing process for articles that are formed from powders containing tungsten and at least one binder. The manufacturing process includes compacting the mixture of powders under a first pressure to yield a desired intermediate structure, then reshaping the structure under a second pressure that is lower than the first pressure to yield the desired article. The binder utilized in the manufacturing process may include a metallic binder or a non-metallic binder, or both. The process is particularly suited for the manufacture of lead substitutes, including firearms projectiles, such as a bullet or shot. Such projectiles may be ferromagnetic or non-ferromagnetic, frangible or infrangible, and jacketed or unjacketed.

Abstract: The thermal conductivity, thermal conductivity, of a sintered copper/refractory metal composite having a maximum porosity of about 1% is greatly improved when the composite contains phosphorus and sintering aid in a specified weight ratio, “phosphorus/sintering aid ratio.” The copper/refractory matrix composite herein comprises, by weight, from about 5% to about 30% copper, from about 0.2% to about 0.6% sintering aid, from about 0.08% to about 0.3% phosphorus, the remaining metal is refractory metal. The phosphorus to sintering aid ratio ranges from about 0.25 to about 0.55. In one embodiment of the invention the sintering aid contains cobalt and the refractory metal is tungsten.

Abstract: The invention concerns a pre-alloyed metal powder consisting essentially of tungsten and/or molybdenum, at least one transition metal selected among iron, cobalt, nickel and copper, and optionally at least one additive, the iron content being less than 50 wt. % and the total additive content being less than 3 wt. %, relative to the total weight of metals, said pre-alloyed metal powder having elementary grain size measured with scanning electron microscope, greater than 200 nm and less than 5 micrometers. The invention also concerns a sintered part obtained with such a powder. The invention is particularly applicable for producing sintered parts to be used as electric contacts, heat sinks, spark machining electrodes, mechanical balance weights, inertial units, tool-holders, anti-radiation screen, armament components, sintered steel or diamond charged cutting or grinding tools or with titanium carbide.

Abstract: Tungsten powder is mixed with a second powder metal and a binder to be used as small arms projectiles and shot pellets for use in shot guns which is cost effective to produce and which can perform ballistically. Ballistic performance equal to or superior to that of lead would be offered by a material having a specific gravity equal to or greater than lead. The non-toxic projectiles are manufactured in a cost-effective process; yet still produces projectiles and shot pellets that can perform ballistically. This projectile composition can perform substantially as well as lead and lead alloys or better without the need to fabricate the composition from a high temperature molten state which requires large amounts of energy input. In one particular embodiment of the invention, the tungsten powder is blended with iron powder and Portland Cement for constructing projectiles. The tungsten, iron and Portland Cement (W/Fe Portland cement) shot provides a satisfactory substitute for lead shot.

Abstract: Tungsten powder is mixed with a second powder metal and a binder to be used as small arms projectiles and shot pellets for use in shot guns which is cost effective to produce and which can perform ballistically. Ballistic performance equal to or superior to that of lead would be offered by a material having a specific gravity equal to or greater than lead. The non-toxic projectiles are manufactured in a cost-effective process; yet still produces projectiles and shot pellets that can perform ballistically. This projectile composition can perform substantially as well as lead and lead alloys or better without the need to fabricate the composition from a high temperature molten state which requires large amounts of energy input. In one particular embodiment of the invention, the tungsten powder is blended with iron powder and Portland Cement for constructing projectiles. The tungsten, iron and Portland Cement (W/Fe Portland cement) shot provides a satisfactory substitute for lead shot.

Abstract: A method of producing a high-density article is presented comprising selecting one or more primary tungsten-containing constituents with densities greater than 10.0 g/cc and one or more secondary constituents with densities less than 10.0 g/cc, co-milling the mixture of constituents in a high-energy mill to obtain mechanical alloying effects, then processing the resulting powder product by conventional powder metallurgy to produce an article with bulk density greater than 9.0 g/cc.

Abstract: A process for preparation of molded articles, such as golf club heads, by metal injection molding and the resulting product.

Abstract: Methods for producing medium-density articles from recovered high-density tungsten alloy (WHA) material, and especially from recovered WHA scrap. In one embodiment of the invention, the method includes forming a medium-density alloy from WHA material and one or more medium- to low-density metals or metal alloys. In another embodiment, medium-density grinding media, such as formed from the above method, is used to mill WHA scrap and one or more matrix metals into particulate that may be pressed and, in some embodiments, sintered to form medium-density articles therefrom.

Abstract: A liner (18) for a shaped charge (10) that utilizes a high performance powered metal mixture to achieve improved penetration depths during the perforation of a wellbore is disclosed. The high performance powdered metal mixture includes powdered tungsten and powdered metal binder. The powered metal binder may be selected from the group consisting of tantalum, molybdenum, lead, cooper and combination thereof. This mixture is compressively formed into a substantially conically shaped liner (18).

Abstract: A highly reliable sintered compact which can be readily and safely produced, and a method for producing such sintered compact are provided. The sintered compact is preferably formed into a heat sink 1 which comprises a heat sink main body 2. The heat sink main body 2 comprises a substrate 3, a plurality of projections 4 integrally formed with the substrate 3 on its heat dissipation surface, and a molded frame 5 integrally formed with the substrate 3 to surround the projections 4. On each corner of the substrate 3 is formed a circular molded hole 6. The opposite surface of the substrate 3 is formed into a contacting surface which is adapted to be in contact with the heat generating semiconductor chip, and this contacting surface is surface treated, for example, by plating. The sintered compact is produced from metal powders, and it comprises at least one metal selected from tungsten and molybdenum and 2 to 50% by weight of silver.

Abstract: A method of imparting high strength, high ductility, and high fracture toughness to a refractory metal alloy workpiece includes: (i) subjecting the workpiece to at least one pass that reduces the initial cross-sectional area of said workpiece, (ii) annealing the workpiece subsequent to the at least one pass, and (iii) subjecting the workpiece to a final working step comprising at least one pass conducted at a temperature between ambient and 300° C., the final working step further reducing the cross-sectional area of the workpiece such that the total reduction in the initial cross-sectional area of the workpiece is approximately 40%-75% and the final cold working is 0.30 to 0.75 of the total reduction in cross-sectional area. The resulting article has a tensile yield strength of approximately 170-200 Ksi, a tensile elongation of approximately 12%-17%, and a Charpy 10 mm Smooth Bar impact toughness of approximately 100 ft.-lb. to 240 ft.-lb.

Abstract: A W—Cu—Ni alloy having thermophysical properties suitable for use in electrical contacts and electrodes is described. The alloy is formed by direct sintering of a powder blend comprising a tungsten-copper composite powder and a nickel powder. The tungsten-copper composite powder component of the blend comprises individual dual phase particles having a copper phase and a tungsten phase wherein the tungsten phase substantially encapsulates the copper phase. The method for direct sintering the W—Cu—Ni alloy substantially eliminates the formation of brittle intermetallics and slumping during sintering.

Abstract: Disclosed is a process for making an oxide dispersion-strengthened tungsten heavy alloy by mechanical alloying that includes the steps of: adding 0.1 to 5 wt. % of Y2O3 powder to a mixed powder comprising more than 90 wt. % of tungsten powder, and nickel and iron powders for the rest; and subjecting the resulting mixture to a mechanical alloying to prepare an oxide dispersion-strengthened tungsten heavy alloy powder. The oxide dispersion-strengthened tungsten heavy alloy prepared by the mechanical alloying is characterized in that fine Y2O3 particles are uniformly dispersed in the matrix which are stable at high temperatures results in enhanced high-temperature strength and a reduction of the shearing strain of the fraction during high strain rate deformation.

Abstract: A method of producing a high-density article is presented comprising selecting one or more primary tungsten-containing constituents with densities greater than 10.0 g/cc and one or more secondary constituents with densities less than 10.0 g/cc, co-milling the mixture of constituents in a high-energy mill to obtain mechanical alloying effects, then processing the resulting powder product by conventional powder metallurgy to produce an article with bulk density greater than 9.0 g/cc.

Abstract: Disclosed is a process for making an oxide dispersion-strengthened tungsten heavy alloy by mechanical alloying that includes the steps of: adding 0.1 to 5 wt. % of Y2O3 powder to a mixed powder comprising more than 90 wt. % of tungsten powder, and nickel and iron powders for the rest; and subjecting the resulting mixture to a mechanical alloying to prepare an oxide dispersion-strengthened tungsten heavy alloy powder. The oxide dispersion-strengthened tungsten heavy alloy prepared by the mechanical alloying is characterized in that fine Y2O3 particles are uniformly dispersed in the matrix which are stable at high temperatures results in enhanced high-temperature strength and a reduction of the shearing strain of the fracture during high-speed shear deformation.

Abstract: The present invention relates to a powder-metallurgically produced composite material comprising a matrix and a granular additive comprising at least one fine-grained refractory metal with an average grain size of at most 2 &mgr;m uniformly distributed in the matrix, so that the composite exhibits a residual porosity of <0.5%. Furthermore, the invention relates to a method for the production of the composite and its use as an electrical contact material.

Abstract: Ductile, high-density, non-toxic W—Ni—Mn—Fe alloy compositions and methods of manufacture by which they may be converted to shot (for use in shotshells) and other useful products traditionally made of lead alloys are presented. Product of the present invention is softer than gun barrel steels and may be hand-loaded (and recycled/reloaded) into shotshells using conventional powders, primers, casings and wads. If desired for game law enforcement, shot of the present invention may be formulated to be ferromagnetic while retaining all other desirable attributes.

Abstract: A highly reliable sintered compact which can be readily and safely produced, and a method for producing such sintered compact are provided. The sintered compact is preferably formed into a heat sink 1 which comprises a heat sink main body 2. The heat sink main body 2 comprises a substrate 3, a plurality of projections 4 integrally formed with the substrate 3 on its heat dissipation surface, and a molded frame 5 integrally formed with the substrate 3 to surround the projections 4. On each corner of the substrate 3 is formed a circular molded hole 6. The opposite surface of the substrate 3 is formed into a contacting surface which is adapted to be in contact with the heat generating semiconductor chip, and this contacting surface is surface treated, for example, by plating. The sintered compact is produced from metal powders, and it comprises at least one metal selected from tungsten and molybdenum and 2 to 50% by weight of silver.

Abstract: A composition for forming molded metal containing articles having improved stability. More particularly, a corrosion resistant composition for forming injection molded articles having a sodium silicate corrosion inhibiting additive. The corrosion inhibitor prevents metal oxidation when a metal containing powder is mixed with a water based binder, providing stability to the article and preventing generation of hydrogen gas. This significantly enhances the shelf life of the moldable composition prior to molding.

Abstract: A method of producing a high-density article is presented comprising selecting one or more primary tungsten-containing constituents with densities greater than 10.0 g/cc and one or more secondary constituents with densities less than 10.0 g/cc, co-milling the mixture of constituents in a high-energy mill to obtain mechanical alloying effects, then processing the resulting powder product by conventional powder metallurgy to produce an article with bulk density greater than 9.0 g/cc.

Abstract: A sintered electrode of high-melting metal (for example tungsten) is produced from spherical metal powder having a well defined particle size. The mean particle size is from 5 to 70 &mgr;m. The particle size distribution covers a range from at most 20% below to at most 20% above the mean particle size.

Abstract: A method of imparting high strength, high ductility, and high fracture toughness to a refractory metal alloy workpiece includes: (i) subjecting the workpiece to at least one pass that reduces the initial cross-sectional area of said workpiece, (ii) annealing the workpiece subsequent to the at least one pass, and (iii) subjecting the workpiece to a final working step comprising at least one pass conducted at a temperature between ambient and 300.degree. C., the final working step further reducing the cross-sectional area of the workpiece such that the total reduction in the initial cross-sectional area of the workpiece is approximately 40%-75% and the final cold working is 0.30 to 0.75 of the total reduction in cross-sectional area. The resulting article has a tensile yield strength of approximately 170-200 Ksi, a tensile elongation of approximately 12%-17%, and a Charpy 10 mm Smooth Bar impact toughness of approximately 100 ft.-lb. to 240 ft.-lb.

Abstract: A projectile, such as a bullet, is made by combining two different metals in proportions calculated to achieve a desired density, without using lead. A base constituent, made of a material having density greater than lead, is combined with a binder constituent having less density. The binder constituent is malleable and ductile metallic phase material that forms projectile shapes when subjected to a consolidation force, such as compression. The metal constituents can be selected, rationed, and consolidated to achieve desired frangibility characteristics.

Abstract: Structural units which come into contact with glass melts and ceramic melts are exposed to strong corrosive attack. Molybdenum is a known material for glass melt electrodes but it is not usable for the majority of highly corrosive glass and ceramic melts. The use of a special molybdenum and/or tungsten alloy as the material for the structural unit reduces corrosion even in the case of contact with highly corrosive glass and ceramic melts.

Abstract: The present invention is related to a family of materials that may act as a replacement for lead in applications where the high density of lead is important, but where the toxicity of lead is undesirable. The present invention more particularly provides a high density material comprising tungsten, fiber and binder. Methods and compositions of such materials and applications thereof are disclosed herein.

Abstract: A high density, non-magnetic alloy is described along with a process for manufacturing it. The preferred composition for the alloy is approximately 95% by weight of tungsten and 5% of austenitic stainless steel. The process for manufacturing the alloy begins with blending tungsten and stainless steel powders which are then mixed with an organic binder to form a feedstock. The latter is then molded into the form of compacted items, such as a hard drive counterweight balance, and then sintered in either vacuum or a hydrogen atmosphere. The tungsten heavy alloys of the present invention can be easily manufactured in large volume economically in many intricate shapes with excellent control of weight and dimensions.

Abstract: The invention relates to the manufacture of sputtering targets of tungsten-titanium alloy using high purity tungsten and titanium hydride powders. The powders are blended and placed in a containment vessel holding a die. The die is heated to a temperature of about 700.degree. C. to about 1000.degree. C. in an argon atmosphere while under pressure. The combination of temperature and pressure is high enough to dehydrate the titanium hydride and to remove the gases. The die is then heated to a higher temperature, in the range of about 1250.degree. C. to 1350.degree. C. while the pressure is increased so as to compact and alloy the powders. The pressure and temperature are held constant until there is no further movement of the ram. The resulting compacted alloy material is then machined to provide a sputtering target with a density between 96% and 100% of theoretical and a gas content less than 850 p.p.m.

Abstract: The process for producing net shape or near net shape metal parts is improved by sintering a compact in a reducing atmosphere where the compact contains a metal and chemically-bound oxygen in the form of a metal oxide, for example, and the chemically-bound oxygen is in an amount sufficient to improve the sintering of the compact. Improved sintering is facilitated when the metal oxide forms a metal/metal oxide eutectic during reduction of the chemically-bound oxygen in a reducing atmosphere during the sintering process. The compact can contain a metal oxide and a solution compound to produce an alloy part, provided the chemically-bound oxygen is present in an amount sufficient to improve sintering. In a preferred embodiment, the compact also contains a reinforcement compound and is sintered to make a metal matrix composite. The resultant density of the near net shape metal parts made by the improved sintering process is preferably about 97% or more of the theoretical density.

Abstract: A new family of transition metal boride coatings having excellent wear and corrosion resistance is disclosed. The coatings comprise hard, ultrafine, transition metal boride particles dispersed in a metal matrix, the particles constituting from about 30 to about 90 volume percent of the coating, the balance being metal matrix. The average size of the particles ranges from about 0.5 to about 3.0 microns. The metal matrix contains at least one metal selected from the group consisting of nickel, cobalt and iron. The coatings may be prepared by a process which comprises depositing a mechanically blended powder mixture of a transition metal and a boron-containing alloy onto a substrate and then heat treating the as-deposited coating. The heat treatment effects a diffusion reaction between the deposited elements resulting in the formation of ultrafine particles of a transition metal boride dispersed in the metal matrix. The coating can be deposited onto the substrate using any of the known deposition techniques.

Abstract: The vacuum valve contact material of the present invention is manufactured by a step of mixing an anti-arc constituent powder and a conductive constituent powder, a step of forming, and a step of sintering the formed body below the melting point of the conductive constituent, and has improved arc interruption performance.