RU2366539C2 - Method of compacting solid powders with hard coating - Google Patents

Abstract

FIELD: metallurgy. ^ SUBSTANCE: intermediary layer out of compound different in contents from material of particles of core is applied on particles of core consisting from at least one compound chosen from nitrides of metal and metalloid, metal carbides and metalloid, metal carbonitrides and metalloid, metal borides and metalloid, metal oxides and metalloid, metal sulphides and metalloid, metal silicides and metalloid, and diamond. Compound of intermediary layer is capable to bind with material of particles and with metal chosen from a group: iron, cobalt, nickel, copper, titanium, aluminium, magnesium, lithium, beryllium, silver, gold, platinum and their mixtures. On the intermediary layer there is applied an external layer out of metal chosen from a group: iron, cobalt, nickel, and their mixtures forming component particles. Produced particles are moulded, and liquid phase sintering is performed at temperature sufficient for transforming at least part of the external layer into a liquid state within time facilitating dissolution of part of the intermediary layer in the liquid external layer to produce effective amount of liquid therefore achieving practically absolute density without applying considerable external compacting pressure. ^ EFFECT: producing item of high density, hardness and wear resistance. ^ 44 cl, 7 dwg

Description

Field of Invention

A method is disclosed for compaction of solid powders with a hard coating (TSNR) to almost absolute density at low pressure or without it, and products obtained using this method. The method is a cost-effective method of manufacturing sintered substrates for materials from TSNR, based on liquid phase sintering, which provides improved performance compared to conventional hard products and materials currently known in the art.

BACKGROUND OF THE INVENTION

Sintering can be defined as the heat treatment of powder or pressed powder parts in order to bind particles to create a solid product.

In some applications where the powder consists of a mixture of powders of at least two different materials with different melting points, the powder mixture is pressed into a porous ("green") base. This base is heated above the melting point of the constituent component with the lowest melting point, and part of the compressed loose powder mixture turns into a liquid state. After the base is held at the sintering temperature for a predetermined time, the material is cooled, and the liquid solidifies and “cementes” the base into a compacted suitable structure. Examples of such structures are copper / tin, iron / copper and tungsten carbide / cobalt.

In such processes, the solidification of the densified base occurs in the presence of a liquid phase, and similar sintering processes are called liquid phase sintering (LPS). In some structures, in particular during compaction of hard alloys such as tungsten carbide and other ceramic particles, liquid phase sintering is sometimes called ordinary sintering. In liquid phase sintering processes, it is advantageous to have a certain minimum amount of the liquid phase present at the sintering temperature to ensure the transfer of the binder phase to achieve uniform distribution and solidification. It is also usually advantageous to limit the amount of liquid phase present in order to avoid partial deformation of the part shape and grain growth.

Transformation into a liquid, for example, allows to increase mass transfer, redistribution of particles, to develop a skeletal structure and to provide solidification. It is generally believed that this is done by rounding the particles as their external irregularities turn into a liquid state, and by flowing this liquid to fill the voids. After cooling, recrystallization occurs and often grain growth. Due to the hardening of the structure, porosity can be reduced as a percentage of the entire volume. The curing rate can be influenced, for example, by sintering temperature, sintering time, sintering pressure, sintering atmosphere and mass fraction of the binder component.

Liquid phase sintering of conventional hard alloys such as pressed tungsten-cobalt carbide (WC-Co) is usually carried out at sintering temperatures in the range from 1325 ° C to 1475 ° C.

As the WC-Co powder part heats up during the sintering of WC-Co solid metals, cobalt will begin to behave like a very viscous liquid fraction at approximately 700 ° C, and diffusion will increase with increasing temperature as it decreases accordingly viscosity Co. It is assumed that the behavior and viscosity of Co metal similar to a thick lubricant creates capillary attractive forces arising from Co's strong tendency to wet the WC surface as much as possible. This leads to a redistribution of WC particles, and the composite material begins to shrink even before the formation of the first liquid phase.

At 1275 ° C, the Co binder metal begins to dissolve the WC particles, and the triple eutectic reaction begins to form the Co-W-C alloy. In view of the continued increase in temperature, increase in the wetting surface, the formation of a liquid fraction and the presence of capillary forces, the redistribution and shrinkage of the powder mass into the form of the desired products continues, as the grain boundaries move to the interface between the grains of the WC and the binding phase Co.

The high density, uniformity and stoichiometry of WC in a sintered body are the basic requirements for the microstructural integrity and strength of WC-Co. Ensuring an appropriate local carbon balance during liquid phase sintering, eliminating the formation of a brittle carbon-depleted Co ₃ W ₃ C phase and the carbon porosity caused by too high a carbon content, are also of great importance in providing viscosity during the destruction of materials from WC-Co. The elimination of the strength-reducing porosity and grain growth in the microstructure can be achieved by choosing the appropriate sintering temperature and pressure. For example, the temperature should be high enough to convert enough material into the liquid fraction to carry out the mass transfer necessary to fill the pores between the particles, and it should be low enough to avoid excessive dissolution of the WC, causing grain growth. To the extent that capillary forces are insufficient to provide compaction to a density close to theoretical, external pressure may be applied.

In conventional sintering, cobalt is usually mixed with WC in small percentages (3-18 wt.%). Binding cobalt plays a role in compaction, and its uniform distribution is desirable to achieve uniformity in WC-Co microstructures. Microstructural defects are usually found in sintered parts from WC-Co. A common cause is the inherent imperfect homogenization (even over a long period) of WC and Co powders, which have approximately the same diameter. It is desirable that, as a result of this process, each WC particle be encapsulated, encapsulated (or at least bound) with an appropriate amount of cobalt so that the Co to WC ratio is almost uniform throughout the mixture. Statistically, it is highly unlikely that this result could be achieved, because cobalt does not have enough small nanoparticles to uniformly homogenize with WC particles. Barriers for this are cobalt oxidation, explosive pyrophoric (self-igniting) reactions.

The result is a mixture of WC-Co with areas rich in Co and poor Co. The liquid phase first forms in Co-rich zones, and cobalt, unsaturated WC, seeks thermodynamic equilibrium by (a) absorbing smaller WC crystals nearby (the smallest can be completely absorbed) and (b) by mobilizing unsaturated Co over long distances to areas poor in co to dissolve more and more WC until saturation is reached. Thus, a temperature higher than that required to create a liquid phase is required to convert to a liquid fraction and transport cobalt to cobalt-poor zones where it is required for equilibrium and to provide a sufficient amount of liquid Co to wet WC particles.

The effects of this uneven distribution of Co are typically controlled by (a) a very long grinding time in a ball mill, (b) higher sintering temperatures, and (c) a longer sintering time. Ball mill grinding tends to reduce WC particles to fine particles, which preferably dissolve in Co during heating. The last two measures really help to increase the binder phase and normalize the distribution of liquid cobalt during sintering, but they also increase the dissolution of WC. In addition to this, part of Co will penetrate into WC particles along the grain boundaries, because the energy of the WC / WC interfacial interaction is higher (more positive) than the energy of the WC / Co interfacial interaction, at least as long as the grain boundaries have an interface angle of almost perpendicular to the surface. After cooling, a saturated WC-Co solution precipitates WC, preferably serving as a crystallization center and recrystallizing WC on adjacent remaining larger undissolved WC crystals, creating an undesirable Ostwald ripening phenomenon (grain growth) as it solidifies. Grain growth proceeds until the temperature decreases to below the tertiary eutectic temperature of 1275 ° С of the Co-W-C structure. 1 shows a phase diagram of a pseudo-binary WC-Co. For WC-Co materials, almost 100% sintering density is common.

Thus, an increase in sintering temperatures promotes mobility of the binder, but also causes excessive dissolution of the WC, leading to undesirable grain growth. There is an optimal ratio between temperature and sintering time, which must be carefully balanced. The maximum temperature should be high enough to liquidize enough material to carry out the mass transfer necessary to fill the pores between the particles (compromising structural strength), while at the same time trying to avoid too high temperatures for a long time to eliminate grain growth (which also reduces structural strength).

Since sintering temperature control is one of the main aspects for high quality carbide microstructures, alternative sintering techniques have been used. These techniques include studying shorter sintering times (e.g., microwave sintering) and using gas pressure (e.g., hot pressing, hot isostatic pressing (HiP), and Ceracon and Roc-Tec sintering / stamping methods) to achieve densification at lower temperatures.

Another approach used in compaction of conventional hard alloys is to increase the mass fraction of such a binder component as cobalt. This can be in the range of 18-25 wt.%, Which not only increases the amount of liquid present, but can have a positive effect of increasing the strength of the structure. However, this approach has two significant drawbacks and, therefore, is usually avoided. Firstly, an increase in the mass% of the binder component decreases the mass% of the WC (wear-resistant phase) in the structure and, accordingly, reduces the wear resistance. Secondly, an increase in the size of the binder component also leads to the dissolution of more WC, making a significant contribution to grain growth during cooling.

Further, the only way to improve the wear resistance of conventional carbides (while maintaining high viscosity during the destruction of the WC-Co substrate) over the past seventy years was (a) continuous improvement and improvement of conventional powder and processing and compaction methods, (b) the addition of thin wear-resistant coatings and ( c) layering harder materials on a WC-Co substrate. The improvement of conventional WC-Co microstructures is ensured by a delicate balance of time, temperature, grain size and other parameters of the product and process. Over the past fifty years, the improvement of conventional carbides has increased by better controlling the sintering temperature and using more pure, absolutely homogeneous starting powders WC and Co. Over the past thirty years after the introduction of external coatings, the improvement in the wear resistance of materials while maintaining the strength of WC-Co has slowed by almost half.

Although these techniques have reduced the problems encountered in liquid-phase sintering of conventional solid metals, nevertheless, there remains an unmet need for a method of producing particles with properties that ensure the uniformity of all WC powders and a binder component after sintering, and the production of products obtained from them.

In order to avoid the drawbacks described above, the invention provides a method of compacting granular materials with a microstructure of a new class having an unprecedented combination of properties called hard powders with a hard coating (TSNR or EternAloy® alloy) using liquid phase sintering. This new family of sintered granular materials consists of one or more types of class C Geldart superhard particles or larger core particles of a ceramic or heat resistant alloy having extreme wear resistance, surface finish and other properties that are (1) individually coated with nanolayers of a metal compound having relatively more high fracture toughness such as WC or TaC, and (2) are again coated with a second layer comprising a binder metal such as Co or Ni. The combination of alloys with many properties within the sintered structure of TSNR allows us to combine usually conflicting extreme values of characteristics, including, but not limited to, fracture toughness, abrasion resistance, resistance to chemical wear, and light weight at the levels given above to create materials with properties exceeding the existing sintered homogeneous powders. TCHP materials are disclosed in U.S. Patent No. 6372346 issued to Mr. Toth, incorporated by reference.

The process of this invention allows the integration of thermodynamically incompatible varieties of materials and extreme values of characteristics in a single material. Thus, TSNR materials can be created with a hardness approaching that of diamond, with a fracture toughness higher than tungsten carbide fracture toughness, and with a weight approaching that of titanium. As a result, TSNR can significantly exceed the wear resistance of conventional tools for cutting and molding; abrasive materials; friction and wear products and thermal coatings; as well as automotive, aerospace parts and parts of the heavy and defense industries.

Summary of invention

In view of the foregoing, a method for forming an article from a granular material is provided. The method includes providing a plurality of core particles including one core particle material or a plurality of different core particle materials selected from metal nitride and metalloid, metal carbide and metalloid, metal carbonide and metalloid, metal boride and metalloid, metal oxide and metalloid, metal sulfide and metalloid , metal silicides and metalloid and diamond.

On most core particles, an intermediate layer is provided. The intermediate layer includes a second compound that is different in composition from the material of the core particles and has a higher relative fracture toughness. The second compound is able to bind to the material of the core particles and is able to bind to a metal selected from iron, cobalt, nickel, copper, titanium, aluminum, magnesium, lithium, beryllium, silver, gold, platinum, and mixtures thereof. The combination of core particles and the intermediate layer forms coated particles.

The outer layer is applied to the coated particles. The outer layer includes metal selected from iron, cobalt, nickel and mixtures thereof and forms a substantially continuous outer layer on the intermediate layer. The combination of coated particles and the outer layer forms component particles.

Many component particles are formed into an article.

The product is sintered to almost absolute density without significant external seal pressure, at the temperature necessary to turn at least part of the outer layer into a liquid state, and for a time sufficient to dissolve part of the intermediate layer in a liquid formed from the outer layer.

The liquid fractions formed from the outer layer and the intermediate layer solidify until a significant degrading interaction of the liquid fractions with the core particles occurs.

In one embodiment, the core particle material has the formula M _a X _b , where M is an element selected from titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, aluminum, magnesium, copper, and silicon; X is an element selected from nitrogen, carbon, boron, sulfur, and oxygen; and a and b are numbers greater than zero and up to fourteen inclusive.

In another embodiment of the invention, the core particle material is selected from TiN, TiCN, TiC, TiB ₂ , ZrC, ZrN, ZrB ₂ , HfC, HfN, HfB ₂ , TaB ₂ , VC, VN, cBN, hBN, Al ₂ O ₃ , Si ₃ N ₄ , SiB ₆ , SiAlCB, B ₄ C, B ₂ O ₃ , W ₂ B ₅ , WS ₂ , AIN, AlMgB ₁₄ , MoS ₂ , MoSi ₂ , Mo ₂ B ₅ and MoB ₂ .

Metalloid elements are those elements that are placed along the line between metals and non-metals in the periodic table. Metalloids typically include boron, silicon, germanium, arsenic, antimony, and tellurium. Polonium is also often regarded as a metalloid. Non-limiting examples of nitride metalloids include cubic boron nitride (cBN) and Si ₃ N ₄ . An example of a carbide metalloid is B ₄ C. An example of a bimetalloid compound is SiB ₆ .

The present invention also discloses a method of forming a product from a granular material, comprising creating a plurality of core particles consisting of one core particle material or a plurality of different core particle materials selected from such as TiN, TiCN, TiC, TiB ₂ , ZrC, ZrN, ZrB ₂ , HfC, HfN, HfB ₂ , TaB ₂ , VC, VN, cBN, hBN, Al ₂ О ₃ , Si ₃ N ₄ , SiB ₆ , SiAlCB, B ₄ C, В ₂ О ₃ , W ₂ B ₅ , WB ₂ , WS ₂ , AIN, AlMgB ₁₄ , MoS ₂ , MoSi ₂ , Mo ₂ B ₅ , MoB _2, and diamond; and creating an intermediate layer on most of these core particles in an amount ranging from 10% to 80% by weight of the product. The intermediate layer typically includes a second compound that is different in composition from the core particle material and has a higher relative fracture toughness, characterized in that the second compound is selected from WC, TaC, W ₂ C, and mixtures of WC and W ₂ C, thereby forming coated particles.

Coated particles are usually processed as described previously, which involves applying an outer layer to the coated particles, the outer layer comprising a metal selected from iron, cobalt, nickel and mixtures thereof and forms a substantially continuous outer layer on the intermediate layer, thereby forming component particles ; the formation of many component particles in the product; sintering the product at a temperature sufficient to turn into a liquid state at least part of the outer layer and for a time sufficient to dissolve from 5 vol.% to 90 vol.% of the intermediate layer in a liquid formed from the outer layer to provide an effective amount liquid to achieve almost absolute density without significant external seal pressure, while the solid part of the aforementioned intermediate layer prevents the interaction of the liquid with the core particles; and solidification of the liquid fractions formed from the outer layer and the intermediate layer before exerting a significant deteriorating property of the interaction of the liquid fractions with the core particles.

The temperature and sintering time are such that they do not lead to complete dissolution of the intermediate layer, but at best lead to the dissolution of some part of the intermediate layer, such as 5-50% dissolution or 50-99% dissolution of the intermediate layer. Indeed, it is the solid part of the intermediate layer that prevents the chemical interaction of the liquid with the aforementioned core particles.

Brief Description of the Drawings

1 shows a phase diagram of a pseudo-binary WC-Co.

Figure 2 shows a typical sintered product from TSNR.

Figure 3 presents a photograph taken using a scanning electron microscope (SEM), which shows that the structure of TCHP is not affected even when an excess of Co is included.

Figure 4 presents a photograph taken using a scanning electron microscope (SEM), which shows the effective prevention of the dissolution of the WC layer during and after sintering.

Figure 5 presents a model of various materials TSNR at different sintering temperatures. It compares the dissolution of particles under various conditions of liquid phase sintering.

Figure 6 shows a table of calculated compositions of solid and liquid phases of WC-Co at various temperatures and cobalt content.

Figure 7 shows microstructural photographs of a liquid phase sintered TSNR. DETAILED DESCRIPTION OF THE INVENTION

The present disclosure of the subject invention describes methods for enclosing (encapsulating) and sintering fine particles having the required set of properties with grain boundary modifiers having other properties, thereby allowing the construction of previously impossible combinations of material properties. The “building block” of TSNR particles contains such elements as hardness + wear resistance + fracture toughness + binder metal + other properties of the structure being created, and this gives the materials scientist thousands of new grades of material in which the developed properties are simultaneously optimized for nano-, micro-, macro- and functional levels.

The fusion of nano-encapsulation with sintering of small particles creates a pseudo-alloy structure that integrates thermodynamically incompatible phases and material properties. Such integration allows these phases and properties to simultaneously act as complex components and as thermally applied coatings, for example, at work surfaces and tool edges. The combination of many properties, such as, for example, low weight, low coefficient of friction, high / low thermal conductivity, surface cleanliness, lubricity is achieved without traditional restrictions imposed by alloys, coatings, enhanced mechanical properties and heat treatment.

The methods described herein include forming an article from a granular material. For example, a particulate material, or TCHP, includes a plurality of core particles, an intermediate coating on most particles, and an outer coating on the particles.

In embodiments where the materials are presented in powder form, the core particles may be a unique class of composite granular material that includes, for example, one core particle material or a plurality of different core particle materials selected from metals or metalloids nitrides, carbides, carbonitrides, borides , oxides, sulfides and silicides, or diamond. Core particle materials are often a metal compound having the formula M _a X _b , where M is selected from at least one element selected from titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, aluminum, manganese , copper, boron and silicon, where X is selected from at least one element selected from nitrogen, carbon, boron, sulfur, silicon and oxygen.

The letters a and b in the formula M _a X _b are numbers that range from zero to fourteen. Non-limiting examples of such compounds include TiN, TiCN, TiC, ZrC, ZrN, VC, VN, Al ₂ O ₃ , Si ₃ N ₄ , SiB ₆ , SiAlCB, W ₂ B ₅ , AIN, AlMgB ₁₄ , MoS ₂ , MoSi ₂ , Mo ₂ B ₅ and Mo ₂ B. In another embodiment, the plurality of core particles include at least one particle selected from diamond, cubic boron nitride and hexagonal boron nitride, and mixtures thereof with each other or any of the above materials.

The use of the terms “selected from” or “selected from” in this application refers to the selection of individual components or a combination of two (or more) components. For example, X may include only one substance from nitrogen, carbon, boron, sulfur, silicon and oxygen, or it may include a mixture of any or all of these components.

In other embodiments, most of the particles comprise an intermediate layer comprising WC, W ₂ C, tool steel, glassy and devitrified alloys of nano-steel, silicon nitride or tantalum carbide. Such materials have a fracture toughness greater than that of cubic boron nitride. However, it should be understood that the material of the intermediate layer must not only have a higher fracture toughness than the materials constituting the core particles, but also be able to bind to the metal (s) compound (s) or the material (s) forming the particles cores, and also be able to bind to a material selected from iron, cobalt, nickel, copper, titanium, aluminum, magnesium, lithium, beryllium, silver, gold and platinum.

In one non-limiting embodiment, the coated particles have an average particle size of less than about 1000 microns. In another embodiment, the coated particles may have an average particle size of less than 100 microns, for example, less than about 50 microns, even less than 2 microns, and further, for example, less than about 1 micron. In another embodiment, coated particles may have an average particle size in the range of 100-1000 nanometers.

In another non-limiting embodiment, the intermediate layer may have a thickness after sintering in the range of 5% to 50% of the diameter of the core particles. The thickness of the intermediate layer affects the mechanical properties of products made from it. In one embodiment of the invention, when coated particles (a core with an intermediate layer on it) have an average particle diameter measured graphically in a sectional photomicrograph using a mean free path of particles of less than about 2 microns, the resistance to movement movement inside adjacent sintered particles is enhanced, improving the mechanical properties of the sintered product. Even using the classical mechanical approach using finite element analysis, it is obvious that increasing the thickness of the spherical shell of the WC surrounding the TiN sphere from about 0.1 microns to about 0.4 microns can increase the theoretical fracture toughness by more than 40%. As coatings of WC, TaC, W ₂ C or WC and W ₂ C decrease, starting at about 150 nanometers, it is assumed that the reflected loads begin to gradually increase the fracture toughness by significantly higher values than those predicted by finite element analysis. As discussed by N. Lowat in Acta Metallurgica, Volume 33, No. 1, pp. 59-69 (1985), “reflected loads” are defined as Newton’s inherent resistance to microstructural dislocation slip.

Such an intermediate layer may be deposited by at least one method selected from chemical vapor deposition, physical vapor deposition, plasma deposition, laser cladding or the deposition process, plasma cladding, magnetic plasma deposition, electrochemical coating, electrolysis coating , metallization by spraying, synthesis of the solid phase, processes of chemical deposition from solutions; and a combination of these processes.

In some embodiments, depending on the precipitated compound or compounds, various starting materials used for the precipitated compound, the deposition method used from the preceding paragraph, the chemical composition of the core particle, the thickness of the intermediate layer and the desired coating properties, the intermediate layer is deposited at a temperature that may range from 20 ° C to about 8000 ° C, similar to, for example, from 20 ° C to 125 ° C. In another embodiment, the intermediate layer is deposited at a temperature that can range from 125 ° C to about 1800 ° C, from 1800 ° C to about 8000 ° C, and then, for example, from 200 ° C to 800 ° C.

Additionally, in some embodiments, the intermediate layer includes a material selected, for example, from WC, TaC, W ₂ C or WC and W ₂ C in an amount that may range from, for example, 60% to 98% by weight of the product . In another embodiment, the intermediate layer comprises WC, TaC, W ₂ C or WC and W ₂ C in an amount that may range from, for example, 10% to 60% by weight of the article. In another embodiment, the intermediate layer comprises WC, TaC, W ₂ C or WC and W ₂ C in an amount that may range from, for example, 5% to 10% by weight of the article.

In some embodiments, most of the coated TCHP particles can then be coated (encapsulated) with an outer bonding layer, which may, for example, be continuous. This layer may include cobalt, nickel, iron, mixtures thereof, their alloys or their intermetallic compounds deposited on the outer surface of the second layer of the metal compound. The outer layer usually has a thickness after sintering in the range from 3% to 12% of the diameter of the coated particles. Such an outer layer includes at least one layer selected from other metals or ceramics, a binder component, a sintering agent and a polymeric material.

The outer layer can be deposited by at least one of the following methods: chemical vapor deposition, physical vapor deposition, plasma deposition, laser cladding or deposition process, plasma cladding, magnetic plasma deposition, electrochemical deposition, electrolysis deposition, metallization sputtering, solid phase synthesis, chemical precipitation from solutions; and a combination of these processes. In one embodiment of TCHP, the previously mentioned outer layer comprises at least one compound selected from a metal, ceramic, binder, sintering agent, waxes or polymeric materials. In the case of binders, sintering agents, waxes or polymeric materials, the coating can be done by mixing or averaging, with or without adding heat in the range from 50 ° C to 150 ° C.

TSNR coating layers can be deposited over a wide temperature range using various processes, with chemical vapor deposition (CVD) being the most common. The most common temperature range for CVD coating is 200 ° C to 800 ° C. However, significantly higher temperatures (1800 ° C to about 8000 ° C) are typical of processes such as plasma deposition, magnetoplasma deposition, pulsed laser deposition, and electric arc discharge. Further, much lower temperatures (20 ° C to 200 ° C) are typical for processes such as chemical deposition from saturated solutions, electrochemical and electrolysis deposition.

As with the intermediate layer, in various embodiments of the invention, the outer layer is deposited at different temperatures depending on the deposited compound or compounds, various starting materials used for the deposited compound, the deposition method used from the preceding paragraph, the chemical composition of the core particle, the thickness of the intermediate layer and required coating properties, the outer layer is deposited at a temperature that can be in the range from 20 ° C to about 650 ° C. In one embodiment, the outer layer is deposited at a temperature that can range from, for example, 20 ° C to 125 ° C. In another embodiment, the outer layer is deposited at a temperature that can range from, for example, 125 ° C to 650 ° C. In another embodiment, the outer layer is deposited at a temperature in the range of, for example, 200 ° C. to 550 ° C.

As mentioned, the outer layer of particles typically has a thickness after sintering in the range of 3% to 12% of the diameter of the coated particles. The thickness of the outer layer may allow deformation fields associated with displacements in one coated particle, which are transmitted through the outer bonding layer to the immediately next intermediate layer.

In one embodiment, the outer layer comprises, for example, up to 45% by weight of the article, and further, for example, from about 0.5% to 3.0% by weight of the article. In another embodiment, the outer layer comprises an amount in the range of more than 3% to 18% by weight of the product, and in yet another embodiment, the outer layer comprises an amount in the range of more than 18% to 45% by weight of the product.

The combination of particles of the core, the intermediate layer and the outer layer can form a coated particle having an average particle size of, for example, less than about 1 micron.

Using the powders described above, an example of the implementation of sintered TCHP can be developed, including many variants of sintered TCHP coated composite particles having many of the above-described compounds or elements of core particles, which will simultaneously be in the adjacent microstructure with high fracture toughness, consisting of particles of an intermediate coating and a bonding layer. It is these combinations and movements (permutations) of more than 30 different compounds and elements of the core particles that give the TSNR family such a variety of diverse properties, each of which has unique combinations of properties.

In general, TSNR are made for final compaction into finished products or coatings for them. Finished products TSNR are designed for various applications, which require both extreme wear resistance and high strength. In embodiments of the invention, TCHP powders are a unique class of materials, essentially consisting of multiple composite coated TCHP particles, sintered into a single unit. In some embodiments, coated particles of TCHP are agglomerated into articles using liquid phase sintering. In one embodiment, the articles are agglomerated by liquid phase sintering using cobalt as the binder phase. In another embodiment, nickel, or iron, or alloys of cobalt, nickel and iron can be used as binders. During this sintering process, compaction can occur mainly from capillary forces.

Liquid phase sintering of TSNR can be stimulated by several factors. One factor is the almost uniform distribution of the material, including the outer layer, throughout the powder. For the purpose of describing the distribution of a given material, “homogeneous” means that the outer layer on the surface of the intermediate layer of particles is such that the material of the outer layer is evenly distributed over an array of green compacted powder. This can be achieved in some embodiments by adding cobalt (or other material included in the outer layer of the particle) on the atom during the coating process to encapsulate, encapsulate the surface of the highly uniform WV coated TCHP particle with a given Co: WC ratio. This continues until the desired Co: WC ratio is uniformly distributed on the TCHP particles and throughout the powder. This feature of TCHP allows you to adapt the conditions in such a way as to suit the different required TCHP formulations, such as, for example, by (a) protecting the core particles from being dissolved by the binder and (b) providing an adjacent strong supporting structure. The result is higher sintering temperatures than those used for conventional WC-Co materials, while at the same time reducing the requirement for higher external pressure without risking WC grain growth and loss of strength. A more uniform distribution of Co also leads to significantly better microstructural stability and a uniform distribution of core particles of the wear-resistant phase. The resulting homogeneous microstructure of TSNR has a more perfect microstructural integrity. This leads to fewer structural defects and then goes into better, more appropriate material properties with a concomitant increase in performance.

In some embodiments, sintering can occur under conditions such as temperature and / or compaction pressure for a time sufficient to obtain a liquid phase in the outer layer, the intermediate layer, or both together in an amount up to, for example, 99.5% , like 70% by volume of the layers, not including the volume of the core particles and further, for example, up to 45% by volume of the layers, not including the volume of the core particles.

In some embodiments of the invention, the sintering temperature may be in the range, for example, from 600 ° C to about 8000 ° C. In one embodiment, the temperature may range from 600 ° C to 1700 ° C, such as, for example, from 1250 ° C to 1700 ° C. In another embodiment, the sintering temperature may be in the range of, for example, from 1700 ° C. to about 8000 ° C.

In one non-limiting embodiment, the sintering temperature may be in the range of, for example, 600 ° C to 1700 ° C and the liquid phase may be in the range of, for example, 6 to 44% by volume of the layers, not including the volume of core particles.

Typically, TSNR compaction occurs at a certain pressure higher than absolute zero pressure, somehow in the range from absolute zero pressure to atmospheric pressure.

Typically, “vacuum” sintering pressures occur in the range of 1-760 torr (760 torr = 1 atmosphere), and this is commonly referred to as “pressureless sintering”. In this case, the use of pressure below atmospheric usually has two goals - controlling the rates of the chemical reaction and controlling the physical processes during the various temperature ranges used during the sintering process. Gases may include, but are not limited to, nitrogen, argon, helium, hydrogen, neon, krypton, xenon, methane, acetylene, carbon monoxide, carbon dioxide, mixtures thereof and related compounds.

It should be understood that sintering without pressure refers only to sintering or densification at sintering temperatures, and not to the formation of a prebaked (or “green”) article during cold or semi-hot pressing processes such as cold isostatic pressing (CIP). During pressing procedures, the external seal pressure is usually applied in an amount sufficient to form a “green” product. It will be understood by those of ordinary skill in the art that sintering does not occur during semi-hot or cold pressing processes.

Binder components commonly used to add pre-baking strength to products formed from TCHP described herein include paraffin waxes, stearic acid, ethylene bis-stearamide (EBS), plasticizers (such as polyvinyl alcohol, polyethylene glycol or synthetic resins) and similar organic compounds, but not limited to them.

Some core TCHP powders, such as nitrides, including, but not limited to TiN, ZrN, and HfN, respond to high sintering temperatures by liberating nitrogen gas. The release of N2 liberates Ti atoms, which can deplete the WC coating with carbon, creating a non-stoichiometric state, which is harmful to the mechanical properties of TSNR. Examples of TCHP chemical reactions that can be prevented or activated by using pressures below atmospheric include oxidation and reduction reactions (such as decarbonization, deoxidation, denitrification, gas evolution, or chemical decomposition of various constituents in a powder of a core or coatings). The control of these oxidation and reduction reactions is desirable for the uniformity of the sintered parts and for stabilization processes, which will further provide additional assistance in hardening.

Some TCHP particles of the core have a very random shape and lubricant additives may be required to help seal them, since they are not rounded by dissolution. In addition to this, thin TSNR coatings from WC and Co require protection against atmospheric oxygen and humidity, and this may require additional polymer protective coatings. Examples of physical TSNR processes controlled by using pressures below atmospheric include the transfer of polymeric materials (for example, the rate of removal of the binder component or lubricant), the rate of evaporation, the rate of thermal conductivity, and possible thermal destruction of the composite materials.

Polymeric materials are used in these examples of application of TSNR as volatile components and lubricants, for coating with a protective coating, and to increase durability / stability, for example, contain the previously mentioned paraffin waxes, stearic acid, ethylene bis-stearamide (EBS), plasticizers (such like polyvinyl alcohol, polyethylene glycol or synthetic resins) and similar organic compounds.

Below atmospheric pressures are not commonly used for compaction processes. One of the goals of absolute pressures above atmospheric is to seal the powder metal part. However, gas pressures above atmospheric can also serve to control the above reactions.

It is clear that the volume of the liquid phase in the outer layer or the intermediate layer can be increased by increasing at least one parameter selected, for example, from the sintering temperature, sintering pressure and the content of the binder component material. A non-limiting example of a binder component is cobalt.

A very uniform distribution of Co, both locally and throughout the entire TSNR, reduces the requirement of high external pressure by allowing the sintering temperature to be increased to the required temperature exceeding the aforementioned eutectic point at 1275 ° C to obtain the amount of liquid phase necessary for mass transfer and solidification of the TSNR.

During sintering of TSNR even at sub-eutectic temperatures, the wetting angle of the cobalt layer on the WC coating can, for example, be small and, further, for example, can be zero. In one embodiment of the invention, cobalt in TSNR applied directly to the WC layers needs to travel extremely short distances to wet and coat the WC coatings. During TCHP heating, the outer layers of atoms in each WC layer first diffuse and then dissolve into the outer Co layer. The WC layer uniformly dissolves from the outside to the inside. In TSNR, these layers achieve thermodynamic equilibrium and the liquid phase with significantly reduced necessary cobalt mobility.

In some embodiments, cobalt does not penetrate the core particle through the coating. For example, an extremely continuous WC _(1-x) coating surface structure, typical of vapor deposition (CVD) coatings, may be present on tool inserts and other products. WC _(1-x) polycrystals obtained by vapor deposition (CVD) at deposition temperatures can be up to two orders of magnitude smaller and denser packed than those found in ordinary fragmented WC-Co particles. During the carburization of the WC _(1-x) coating prior to stoichiometry, there is grain growth inside the coating polycrystals (depending on the carburizing temperature). However, the significant proximity of cobalt to these fields and crystals is such that the polycrystals of the coating will be uniformly dissolved around the WC coating, and equilibrium can limit grain growth. Figure 3 and Figure 4 on the structures of the WC coating after sintering, you can see that the polycrystals can be one order of magnitude smaller than with conventional fragmented WC-Co polycrystals. In another embodiment, in zones where significant Co accumulation occurs, grain growth of up to about 1 micron can be seen.

The impermeability of TSNR coatings from WC to Co penetration can be at least partially explained by the following. It is axiomatic that WC and Co in TSNR chemically behave almost like WC and Co in ordinary mixtures of hard alloys.

By evaluating the WC-Co phase diagram (see FIG. 5), it can be determined (see FIG. 6) that, during sintering, a typical TSNR design matrix consisting of 50 vol.% Particles (75 wt.%) Of the WC coating with the composition coatings of 94 wt.% WC - 6 wt.% Co at 1500 ° C, 87.1 wt.% of the WC coating (or 92.7% of the initial WC coating in 50 vol.%) remains as a protective solid WC in the TSNR coating on the particles of the core TSNR. As the WC coating dissolves from the outside to the inside, the remaining solid WC can only be present as the intended core-protecting structural coating.

As cobalt softens and approaches the liquid phase, some particle transfer is expected, but only the transfer will be insufficient to ensure complete solidification, so it is necessary to turn an additional WC into a liquid state. Solidification can be obtained even with very low volumes of the liquid phase. Since Co of the liquid phase is uniformly distributed in TSNR, almost completely along all WC surfaces, without groupings or gradients, a very low volume of Co liquid binder can provide the bulk of liquid phase sintering. It is assumed that the dissolution of the WC should provide the rest of the liquid phase sintering.

As mentioned, WC coatings of TCHP particles usually dissolve from the outside to the inside, leaving the protective and structural layer around the core particles undissolved, and re-precipitate and form crystallization centers to enhance the existing particle coating or serve as a kinetically transported pore filler and intercrystalline space. When used in this work, “intercrystalline aggregate" means a material that fills the internodes (small spaces) between adjacent particles. Only partial dissolution of the WC coating layer in Co binder is necessary for the solidification, reprecipitation / recrystallization of the WC and the creation of continuous integrity of the microstructure matrix of TSNR. The only mobility required by Co and WC is the mobility required to transfer material to fill the diminishing adjacent interstices between the coated core particles.

Theoretically, there are at least three ways to increase the dissolution of a solute in a solvent: (1) an increase in the amount of solvent present (in one embodiment, the Co: WC ratio in wt.%), (2) an increase in the temperature of the solvent and solute , and (3) reducing pressure on the solvent and the solute. In reality, there are only two ways to increase the amount of liquid phase present during sintering of TSNR. The first two ways are considered.

A certain number of core particles, for example, transition metal carbides and nitrides, will chemically interact with cobalt, nickel and other binding components. These core particles are called a soluble core group of particles. As for the temperature increase, even if the sintering temperature of TSNR would be significantly increased to a value sufficient to provide the necessary amount of liquid phase for LPS (liquid phase sintering) - a thick layer of WC will still be present to protect the group of particles with the “soluble core” from the effects of cobalt . Perhaps it is necessary to increase the temperature so strongly to the value required to obtain any additional amount of the liquid phase (“lubricant + interstitial aggregate + capillary attractor), necessary for absolute density with minimal attention to grain growth.

For example, in one embodiment using a TiN particle with a 1 micron TCHP core with equal WC and TiN in vol.%, The initial WC coating (spherical model) will have a thickness of almost 129 nm and will include about 75 wt.% Of the whole particle . Dissolving WC at 1500 ° C will remove only 7.9 nm or about 6% of the coating thickness, leaving about 121 nm or about 94% of the original coating thickness to protect the core particles to ensure equal particle spacing and structural strength.

Due to the similar property of TCHP, an increase in the amount of solvent of the binding phase present, for example, an increase in the thickness of the cobalt layer, is another possible sintering method that can be used in accordance with the methods described here. For example, an increase in the mass% of cobalt above the values typical for WC-Co sintering becomes feasible as a means to provide the required dissolution, capillarity, WC kinetics and hardening for TSNR. It should be remembered that in TSNR, WC is present primarily as a solid matrix material due to the fact that real wear resistance is provided by core particles. Therefore, the added cobalt will increase the amount of liquid phase during sintering, and at the same time increase the viscosity upon failure after cooling.

Sintering can take place by a method selected from the following processes: extrusion sintering, vacuum sintering, injection molding, plastic extrusion, hot pressing, hot isostatic pressing (HIP), hot isostatic pressing sintering, agglomeration electric furnace, laser cladding, plasma cladding , high-speed oxygen-fuel (HVOF) process, spark plasma sintering, plasma sintering under pressure, method in a pressure transmission medium , Dynamic / explosive compaction, sinter forging press and forging, rapid prototyping, electron beam method and the arc method.

In TCHP, a WC coating protects core particles. Firstly, during sintering, especially in the “soluble core” group, the WC coating can protect the core particles from being dissolved by the binder metal and can also protect the matrix from harmful impurities, such as, for example, TiN, ZrN, NbC. During use, the extremely wear-resistant particles of the TSNP core can protect the support matrix from wear after sintering, while the support matrix protects the brittle phases from cracking and stress. Figure 2 shows the sintered microstructure of a typical TCHP material.

The structure of TSNR with a small size of solid particles of the core and viscous shells of nanoscale, separated by thin cobalt bonds of less than one micrometer in size between grains, improves, for example, elasticity, hardness, fracture toughness and strength. In one non-limiting example embodiment of the invention, even when using a material with low hardness (like cobalt), reflected loads from dislocation (displacement) near the surface (and all of them occur near the surface with grains smaller than a micrometer), the properties of the composite are higher than the possible abrasive composites.

In accordance with the method described here, TSNR provides a sintering suitable metallic granular material that can be designed to provide an optimal balance of properties, such as, for example, fracture toughness, strength, low friction coefficient and stiffness. In one non-limiting embodiment of the invention, operational improvements that can be observed in molds and other tools made from TSNR are, for example: (a) a low coefficient of friction at the interface between the workpiece and the tool, which reduces heat and wear and the formation of craters and requires less energy during processing and additional use of external lubricants, which ultimately leads to a longer tool life and better control Applicants' process; (b) low chemical activity with iron, which reduces sticking and diffusion, flanking or wear of the mold and which, in turn, extends the life of the extrusion mold; and (c) the microstructure of the sintered tool material, in which a strong, strong coating material (e.g., WC) on the particles forms a cellular support macrostructure on the tool, at the same time providing a tight fit of the surface and a tightly adjacent protective layer for solid core particles (from, for example, TiN), which keeps them in the desired position and allows optimal exposure to external influences and the preservation of the solid phase at the wear-resistant surface of the tool. This contrasts with products made by conventional methods in which Ti-Co-WC fusion significantly reduces the strength of the binder existing between the particles, and the binder itself decreases the fracture toughness and bending strength, or in which the sintered product is completely coated casing for hardness, while the thin coating has a limited service life or cracks.

Placing the solid phase alloys inside as a core particle, instead of placing it outside, distributes the solid phase alloys (exposed on the external surfaces after final grinding) over the sintered microstructure in much larger proportions and thickness than is possible in any known conventional material. This in itself can, for example, increase wear resistance, reduce chemical interaction with the workpiece and significantly reduce the friction coefficient. Tool life can be increased by constantly updating surface grains that are worn and removed by an opposing sliding surface.

Also, the wear and adhesion characteristics of many possible core materials are known for their behavior in conventional materials, so that their performance as core materials is predicted in light of the present disclosure. Since, in some non-limiting embodiments, the core particles are coated with known materials (e.g., WC), mixing and sintering together coated particles having several different core materials will simplify the amplification of many characteristics. Accordingly, development and testing costs are reduced, while at the same time providing the final material with unique properties. Thus, the construction of a sintered microstructure in which each particle has a dense shell (intermediate layer), which can very strongly attach to its neighboring particles and form a strong cellular support system over the entire substrate of the sintered product, produces a sintered product with a high combination of strength, high modulus elasticity, fracture toughness and carbide content.

In some embodiments of the invention, the resulting microstructure of the product is a cellular microstructure skeleton consisting of strong, strong, interconnected coated particles, each of which contains and supports at least one material selected from mechanically and chemically bonded core particles, crystals, fibers and whiskers. This principle of optimizing the combination of different materials for core particles and the surrounding intermediate layer allows you to combine commonly conflicting product characteristics, such as strength and brittleness, at levels unattainable in conventional materials.

This concept can give the material designer many tools that can be used individually or in combination and an exhaustive way to provide simple and complete control when adapting the structure of the TCHP particle (intermediate layer thickness, core size and material) and mixing (integrating various powders into the tool zones and products) to meet various unique, combined and specially required conditions for an individual product or tool.

Moreover, the use of a standard durable material (such as WC, for example) as a solid outer shell of a particle significantly reduces research, development and industrial deployment efforts, because only one source gas reagent of a material (for example, tungsten carbide) should be used to coat powder particles , instead of many tens of complex source gases and chemically active gases used in multiple external coating of the substrate. Such granular materials will sinter as if they were made of tungsten carbide particles, for example, which, as is already known, are very strongly bonded to adjacent tungsten carbide particles and a cobalt-like binder. The thickness of the tungsten carbide coating on the particle can be increased, for example, to meet more complex strength requirements, or can be reduced, for example, in applications with more critical wear, to solve most design problems. For example, the particle size of the core can be easily increased to meet more stringent requirements for wear resistance or reduced for applications with higher strength. The use of various materials of the core particles with characteristics such as stiffness and coefficient of friction, known or proven to be the best in specific applications, such as when wearing along the edge (cutting tool) or ulcerative wear, can also be done by choosing the core material . You can also combine the aforementioned thickness, diameter and powder parameters of the core material to solve most applications with many criteria.

Products made from TSNR particles combine the best mechanical properties, such as strength, hardness, high elastic modulus, fracture toughness, low interaction with the workpiece and low friction coefficient, which exist separately in conventional materials and form products with incomparable combined properties. TSNR have almost unlimited applications in the production, surface modification, or repair of components, assemblies and machines. One group of components includes cutting, forming, grinding, measuring, oil, as well as mining and construction tools. Non-instrumental components include biomedical, military, electronic, sports, thermal management, and space applications. Extensive industrial applications can be found in the agricultural, civilian, woodworking and pulp and paper, petrochemical, rubber and plastic industries, transport, aviation / aerospace, maritime, architectural and energy sectors. Thus, this material is well suited for use in a wide range of products, including, for example:

tools such as wire drawing dies, extrusion dies, forging dies, cutting and embossing dies, molds, forming rollers, injection molds, scissors, drills, milling cutters and milling cutters for lathes, saws, master punches , bits, reamers, taps and dies;

individual mechanical parts such as gears, cam, trunnions, nozzles, seals, valve seats, pump impellers, drums, guide rollers, bearings and wearing surfaces;

integrated co-sintered components for replacing mating parts of an internal combustion engine, connecting rods, bearings and / or providing solid surface areas in mechanical parts made of powder metal, replacing forged or machine-made steel parts with heat treatment zones, such as camshaft, transmission parts, parts printer / copy machine;

products for heavy industry, such as drill heads for drilling deep wells, tines for mining and earth moving equipment, hot rolls for steel mills; and

electromechanical components such as memory drives, read heads, specialized magnets.

The fact that the manufactured TSNR products are macroscopically homogeneous and not coated with an external shell can offer users or suppliers the option of cost-effective grinding and reuse of originally worn products. This is especially important for tools such as wire drawing dies, twist drills, cones and water jets.

Those skilled in the art will understand that changes can be made to the above-described embodiments of the invention without deviating from its broad inventive concept. Therefore, it is understood that the invention is not limited to the specific disclosed embodiments, but include modifications that are within the spirit and scope of the invention defined by the appended claims.

Unless otherwise specified, all numbers expressing the amounts of ingredients, reaction conditions, and so on, used in the description and formula, are understood as in all cases modified by the term “approximately”, which should mean +/- 5% of the expressed number.

Accordingly, unless indicated to the contrary, the numerical parameters set forth in this description and the accompanying formula are approximations that may vary depending on the desired properties that are expected to be obtained using the present invention.

Claims (44)

1. The method of forming the product, including
preparing a plurality of core particles containing one core particle material or a plurality of different core particle materials, wherein the aforementioned core particle material is selected from the group consisting of metal nitrides and metalloid, metal carbides and metalloid, metal carbonitrides and metalloid, metal borides and metalloid, oxides metal and metalloid, sulfides of metal and metalloid and silicides of metal and metalloid, and diamond;
creating an intermediate layer on most of the aforementioned core particles, wherein the aforementioned intermediate layer comprises a second compound that is different in composition from the aforementioned core particle material and has a higher relative fracture toughness, the second compound being able to bind to the aforementioned core particle material and is able to bind with a metal selected from the group consisting of iron, cobalt, nickel, copper, titanium, aluminum, magnesium, lithium, beryllium, silver, gold, platinum and mixtures thereof, thereby forming coated particles;
applying an outer layer to the aforementioned coated particles, wherein the aforementioned outer layer includes a metal selected from the group consisting of iron, cobalt, nickel and mixtures thereof, to form a substantially continuous outer layer on the aforementioned intermediate layer, thereby forming component particles;
molding a plurality of the aforementioned component particles into an article;
sintering the aforementioned product at a temperature sufficient to liquidize at least a portion of the aforementioned outer layer, and for a time sufficient to dissolve a portion of the aforementioned intermediate layer in a liquid fraction formed from the aforementioned outer layer to provide an effective amount of liquid for achieving almost absolute density without the application of significant external seal pressure; and
solidification of the liquid fractions formed from the aforementioned outer layer and the aforementioned intermediate layer, until the aforementioned significant harmful effects of the aforementioned liquid fractions on the aforementioned core particles. 2. The method according to claim 1, characterized in that the aforementioned material of the core particles has the formula M _a X _b , where M is an element selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, aluminum, magnesium, copper and silicon; X is an element selected from nitrogen, carbon, boron, sulfur, and oxygen; a and b are numbers greater than zero to fourteen inclusive. 3. The method according to claim 1, characterized in that the aforementioned material of the core particles is selected from the group consisting of TiN, TiCN, TiC, TiB ₂ , ZrC, ZrN, ZrB ₂ , HfC, HfN, HfB ₂ , TaB ₂ , VC, VN, cBN, hBN, Al ₂ O ₃ , Si ₃ N ₄ , SiB ₆ , SiAlCB, B ₄ C, B ₂ O ₃ , W ₂ B ₅ , WB ₂ , WS ₂ , AlN, AlMgB ₁₄ , MoS ₂ , MoSi ₂ , Mo ₂ B ₅ , MoB ₂ and mixtures thereof. 4. The method of forming the product, including
preparing a plurality of core particles containing one core particle material or a plurality of different core particle materials, wherein the aforementioned core particle material is selected from the group consisting of TiN, TiCN, TiC, TiB ₂ , ZrC, ZrN, ZrB ₂ , HfC, HfN, HfB ₂ , TaB ₂ , VC, VN, cBN, hBN, Al ₂ O ₃ , Si ₃ N ₄ , SiB ₆ , SiAlCB, B ₄ C, B ₂ O ₃ , W ₂ B ₅ , WB ₂ , WS ₂ , AlN, AlMgB ₁₄ , MoS ₂ , MoSi ₂ , Mo ₂ B ₅ , MoB _2, and diamond;
creating an intermediate layer on most of the aforementioned core particles in the range of 10 to 80% by weight of the aforementioned product, wherein the aforementioned intermediate layer comprises a second compound that is different in composition from the aforementioned core particle material and has a higher relative fracture toughness, while the second compound is selected from the group consisting of WC, TaC, W ₂ C and a mixture of WC and W ₂ C, thereby forming coated particles;
applying an outer layer to the aforementioned coated particles, wherein the aforementioned outer layer includes a metal selected from the group consisting of iron, cobalt, nickel and mixtures thereof, and forms a substantially continuous outer layer on the aforementioned intermediate layer, thereby forming component particles;
molding a plurality of the aforementioned component particles into an article;
sintering the aforementioned product at a temperature sufficient to liquidize at least part of the aforementioned outer layer, and for a time sufficient to dissolve from 5 to 90 vol.% of the aforementioned intermediate layer in a liquid fraction formed from the aforementioned outer layer, to provide an effective amount of fluid to achieve near absolute density without significant external seal pressure; however, the solid part of the aforementioned intermediate layer prevents the chemical interaction of the aforementioned liquid fraction with the aforementioned core particles; and
solidification of the liquid fractions formed from the aforementioned outer layer and the aforementioned intermediate layer, until the aforementioned significant harmful effects of the aforementioned liquid fractions on the aforementioned core particles. 5. The method according to any one of claims 1 to 3, characterized in that the aforementioned sintering temperature and time do not completely dissolve the aforementioned intermediate layer. 6. The method according to any one of claims 1 to 3, characterized in that the aforementioned temperature and sintering time lead to 5-50% dissolution of the aforementioned intermediate layer. 7. The method according to any one of claims 1 to 3, characterized in that the aforementioned temperature and sintering time lead to 50-99% dissolution of the aforementioned intermediate layer. 8. The method according to any one of claims 1 to 3, characterized in that the solid part of the aforementioned intermediate layer prevents the chemical interaction of the aforementioned liquid fraction with the aforementioned core particles. 9. The method according to any one of claims 1 to 3, characterized in that the aforementioned intermediate layer includes a material selected from the group consisting of WC, W ₂ C, tool steel, glassy and devitrified alloys of nanosteel, silicon nitride and tantalum carbide. 10. The method according to any one of claims 1 to 4, characterized in that the aforementioned coated particles have an average particle size of less than about 1000 microns. 11. The method according to any one of claims 1 to 4, characterized in that the aforementioned coated particles have an average particle size of less than about 100 microns. 12. The method according to any one of claims 1 to 4, characterized in that the aforementioned coated particles have an average particle size of less than about 50 microns. 13. The method according to any one of claims 1 to 4, characterized in that the aforementioned coated particles have an average particle size of less than about 2 microns. 14. The method according to any one of claims 1 to 4, characterized in that the aforementioned coated particles have an average particle size of less than about 1 μm. 15. The method according to any one of claims 1 to 4, characterized in that the aforementioned coated particles have an average size in the range of 100-1000 nm. 16. The method according to any one of claims 1 to 4, characterized in that the aforementioned intermediate layer has a thickness after sintering in the range from 5 to 50% of the diameter of the aforementioned core particles. 17. The method according to any one of claims 1 to 4, characterized in that the aforementioned outer layer has a thickness after sintering in the range from 3 to 12% of the diameter of the aforementioned core particles. 18. The method according to any one of claims 1 to 4, characterized in that the aforementioned outer layer further comprises one or more layers of material selected from the group consisting of metal, ceramics, a binder component, a sintering agent and a polymeric material. 19. The method according to any one of claims 1 to 4, characterized in that the aforementioned intermediate layer is deposited by at least one of the methods selected from chemical vapor deposition, physical vapor deposition, plasma deposition, laser cladding or a process deposition, plasma cladding, magnetic plasma deposition, electrochemical coating, electrolysis coating, spray metallization, solid phase synthesis, chemical deposition processes from solutions, and a combination of these ess. 20. The method according to any one of claims 1 to 4, characterized in that the aforementioned outer layer is deposited by at least one of the methods selected from chemical vapor deposition, physical vapor deposition, plasma deposition, laser cladding or a process deposition, plasma cladding, magnetic plasma deposition, electrochemical coating, electrolysis coating, spray metallization, solid phase synthesis, chemical deposition from solutions and a combination of these processes . 21. The method according to any one of claims 1 to 4, characterized in that the aforementioned intermediate layer is deposited at a temperature in the range from 125 to 1800 ° C. 22. The method according to any one of claims 1 to 4, characterized in that the aforementioned intermediate layer is deposited at a temperature in the range from 20 to 125 ° C. 23. The method according to any one of claims 1 to 4, characterized in that the aforementioned intermediate layer is deposited at a temperature in the range from 1800 to 8000 ° C. 24. The method according to any one of claims 1 to 4, characterized in that the aforementioned intermediate layer is precipitated at a temperature in the range from 200 to 800 ° C. 25. The method according to any one of claims 1 to 4, characterized in that the aforementioned outer layer is deposited at a temperature in the range from 20 to 125 ° C. 26. The method according to any one of claims 1 to 4, characterized in that the aforementioned outer layer is deposited at a temperature in the range from 125 to 650 ° C. 27. The method according to any one of claims 1 to 4, characterized in that the aforementioned outer layer is deposited at a temperature in the range from 200 to 550 ° C. 28. The method according to any one of claims 1 to 4, characterized in that the aforementioned sintering temperature is in the range from 600 to 1700 ° C. 29. The method according to any one of claims 1 to 4, characterized in that the aforementioned sintering temperature is in the range from 1700 to 8000 ° C. 30. The method according to any one of claims 1 to 4, characterized in that the aforementioned outer layer is contained in an amount of from 0.5 to 3% by weight of the aforementioned product. 31. The method according to any one of claims 1 to 4, characterized in that the aforementioned outer layer is contained in an amount of from 3 to 18% by weight of the aforementioned product. 32. The method according to any one of claims 1 to 4, characterized in that the aforementioned outer layer is contained in an amount of from 18 to 45% by weight of the aforementioned product. 33. The method according to any one of claims 1 to 3, characterized in that the aforementioned intermediate layer comprises a material selected from WC, TaC and W ₂ C in an amount of from 60 to 98% by weight of the aforementioned product. 34. The method according to any one of claims 1 to 3, characterized in that the aforementioned intermediate layer comprises a material selected from the group consisting of WC, TaC and W ₂ C in an amount of from 10 to 60% by weight of the aforementioned product. 35. The method according to any one of claims 1 to 3, characterized in that the aforementioned intermediate layer comprises a material selected from the group consisting of WC, TaC and W ₂ C in an amount of from 5 to 10% by weight of the aforementioned product. 36. The method according to any one of claims 1 to 4, characterized in that the sintering occurs at a compaction pressure and a temperature sufficient to obtain a liquid phase containing an outer layer, an intermediate layer, or both in an amount of up to 45% of the volume of component particles, not including the volume of the core particle. 37. The method according to any one of claims 1 to 4, characterized in that the sintering occurs at a compaction pressure and a temperature sufficient to obtain a liquid phase in the outer layer, the intermediate layer or both in an amount of up to 99.5% of the volume of component particles, not including the volume of the core particle. 38. The method according to any one of claims 1 to 4, characterized in that the sintering compaction is primarily due to capillary forces. 39. The method according to any one of claims 1 to 4, characterized in that the sintering temperature is in the range from 600 to 1700 ° C, and the amount of liquid phase is in the range from 6 to 44% of the volume of the component particles, not including the volume of the core particle. 40. The method according to any one of claims 1 to 4, characterized in that the volume of the liquid phase increases by increasing at least one parameter selected from the sintering temperature and the cobalt content. 41. The method according to any one of claims 1 to 4, characterized in that the compaction occurs in an atmosphere of a gas selected from nitrogen, argon, helium, hydrogen, neon, krypton, xenon, methane, acetylene, carbon monoxide, carbon dioxide and mixtures thereof and connections. 42. The method according to paragraph 41, wherein the aforementioned process gases are supplied in the range from zero absolute pressure to atmospheric pressure. 43. The method according to any one of claims 1 to 4, further comprising mixing at least one additive selected from paraffin waxes, stearic acid, ethylene bis-stearamide (EBS), polyvinyl alcohol and polyethylene glycol, with many of the above component particles to or simultaneously with the aforementioned molding. 44. The product formed by the method according to any one of claims 1 to 4.

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