22 results about "Sintered alloy" patented technology

The application provides a method suitable for additive manufacturing of high crack sensitivity alloy, and belongs to the technical field of 3D printing. The application utilizes the characteristics of a uniform laser spot diameter, high laser power and uniform energy distribution to pre-sinter metal powder, so that the preheating of a substrate can be realized, and the preheating of the formed material can be realized in the middle and later stages of additive manufacturing. Then, a Gaussian laser is used for processing, so that the temperature difference between the molten pool and the substrate (or the formed material) is reduced, the temperature gradient is reduced, the thermal stress in the cooling process is reduced, the stress concentration is reduced, and thus the formation and expansion of cracks are reduced. The characteristics of a small Gaussian laser spot diameter and energy concentration are used for secondary scanning sintering of the pre-sintered alloy, so that the material is more fine, the problems of uneven material distribution, surface defects and the like that may exist are eliminated, the risk of cracks is further reduced, and the additive manufacturing of high crack sensitivity alloy is suitable.

Provided are a valve seat that is made of an iron-based sintered alloy and has superior wear resistance, and a combination of a valve seat and a valve.　This valve seat that is made of an iron-based sintered alloy has a structure in which the base phase is a fine carbide precipitation phase in which an area ratio of 15-40% pearlite and fine carbides of 10 μm or less are precipitated, hard particles with a Vickers hardness of 650-1300 HV are dispersed in the base phase in an area ratio of 20-40%, the structure further has a high alloy phase in an area ratio of 0-5%, and solid lubricant particles are dispersed in an area ratio of 0-5%. Consequently, there is little valve wear even when a Tribaloy-based alloy-metallized valve with a face surface hardness of 550 HV is used, and a combination of a valve and a valve seat that has superior wear resistance can be achieved.

To provide a valve seat made of an iron-based sintered alloy excellent in wear resistance and falling-off resistance.SOLUTION: The valve seat 1 has a two layer structure in which a functional member side layer 11 and a support member side layer 12 are integrated by sintering. The functional member side layer has a structure in which hard particles or further solid lubricant particles are dispersed in a base matrix phase mainly including 5.87% or less of a fine carbide precipitation phase and a tempered martensite phase, and further including 8.11 to 21.39% of a high alloy phase around the hard particles, the iron-based sintered alloy material has a matrix portion composition containing, by mass%, C:0.5 to 2.0%, Si: 0.1 to 1.0%, Mn: 0.1 to 2.5%, Ni: 1.0 to 7.0%, Cr: 1.0 to 12.0%, Mo: 2.0 to 12.0%, Co: 2.0 to 20.0%, W: 0.1 to 2.0%, and V: 0.01 to 1.0%, and further containing S: 0 to 1.5%, and includes pores filled with Cu by infiltration.SELECTED DRAWING: Figure 1

The objective is to provide an iron-based sintered alloy with excellent surface pressure fatigue strength. [Solution] An iron-based sintered alloy having an overall composition of Cr: 1-5% and C: 0.6-1.5% by mass, with the remainder being Fe and unavoidable impurities, comprising a matrix and metal carbides dispersed in the matrix, with the number of metal carbides having a particle size of 0.2-2.0 μm being 10,000-25,000 in the range of 100 μm × 100 μm.

The invention relates to the field of powder metallurgy, in particular to a powder metallurgy alloy / composite material for improving strength and plasticity based on an interface micro-casting technology and a preparation method of the powder metallurgy alloy / composite material. The material is prepared by taking micron-sized metal or alloy powder as matrix powder, adding low-melting-point metal powder relative to a matrix and carrying out spark plasma sintering. Wherein according to the mass percent, the matrix accounts for 60%-95%, and the low-melting-point metal phase accounts for 5%-40%. According to the method, a low-melting-point metal phase is added, a spark plasma sintering process is combined, a substrate and a second phase form a solid solution firstly, a liquid phase is continuously formed and solidified through a mechanism that the melting point of the solid solution and the sintering real-time temperature compete, and through the process similar to casting, the element diffusion rate is increased, original inter-particle defects are removed; the mechanical property of the composite material is improved, the material has good plasticity on the premise that the strength is guaranteed, and the method can be used for comprehensively improving the mechanical property of the powder metallurgy sintered alloy or the metal-based composite material.

The present invention relates to a method for manufacturing a part in austenitic stainless steel comprising successively the following steps: 1) Provision of a powder and sintering of said powder to form a sintered alloy with an austenitic structure; said alloy having a nitrogen content greater than or equal to 0.1% by weight, 2) Treatment of the sintered alloy to transform the austenitic structure into a ferritic or two-phase ferrite + austenite structure on a layer (2) on the surface of the alloy, 3) Treatment of the sintered alloy to transform the ferritic or two-phase ferrite + austenite structure obtained in step 2) into an austenitic structure and to form after cooling the part (1) having on the layer (2) subjected to the transformations of steps 2) and 3) a density greater than that of the core (3) of the part (1).

The invention discloses an alloy ball sintering method, which belongs to the technical field of tungsten alloy ball production, and comprises the following steps: metal sand is adhered to the peripheral surface of an under-sintered alloy ball, the melting temperature of the metal sand is higher than the re-sintering temperature of the alloy ball, and the alloy ball adhered with the metal sand is re-sintered. And the metal sand with the melting temperature higher than the re-sintering temperature is used as an anti-sticking isolation measure, so that the problems of mutual adhesion, block formation or caking caused by surface diffusion, liquid phase generation or micro-area melting and the like in the high-temperature sintering process of the spheres can be avoided.

The invention discloses a high-specific-gravity high-toughness tungsten-nickel-copper alloy material and a preparation method thereof, and the alloy material comprises the following components in percentage by mass: 91-96% of tungsten, 3-8% of nickel and copper in total, wherein the ratio of Ni to Cu is (1: 1)-(7: 3), and 1% of cobalt. The preparation method comprises the steps that the tungsten powder, the nickel powder, the copper powder and the cobalt powder are firstly put into an acoustic resonance mixer to be premixed and then put into an all-dimensional planetary machine to be subjected to ball milling; pressing the uniformly mixed powder into a biscuit in a cold isostatic pressing manner; the pressed biscuit is introduced into a tubular furnace to be pre-sintered; carrying out hot isostatic pressing sintering on the sintered alloy material in an inert atmosphere; and the alloy in the hot isostatic pressing state is subjected to vacuum oil quenching heat treatment. According to the invention, through the process of combining two-step mixing, two-step sintering and heat treatment, the strength and elongation of the alloy are synergistically improved while the density of the tungsten-nickel-copper alloy is improved, and the problems of coarse grains, low density and poor elongation of the traditional tungsten-nickel-copper alloy are solved.

The invention discloses a preparation method of tungsten heavy alloy strengthened by oxide dispersion in tungsten crystal grains, and belongs to the field of dispersion strengthened tungsten heavy alloy materials. The method comprises the following steps: firstly, obtaining a mixture of a tungsten heavy alloy oxide and a dispersion strengthened second-phase oxide through liquid combustion synthesis, and carrying out hydrogen reduction to obtain in-situ synthesized oxide-doped second-phase dispersion distribution tungsten heavy alloy nano powder; and finally, non-pressure two-step liquid phase sintering is conducted in hydrogen, and the tungsten heavy alloy strengthened by dispersion of the oxide in the tungsten crystal grains is obtained. The process for preparing the alloy powder is simple and rapid, one-step synthesis of in-situ synthesis of the nano tungsten heavy alloy powder doped with the second-phase particles can be achieved, the average particle size of the alloy composite powder is small, and the preparation time of the alloy powder is greatly shortened. Non-pressure two-step liquid phase sintering is adopted, the density of a sintered body can be effectively improved, the liquid phase sintering time is shortened, excessive growth of tungsten crystal grains is prevented, second-phase oxide particles can be dispersed and distributed in the tungsten crystal grains, and meanwhile the sintering period is shortened. The compressive strength of the sintered alloy is not lower than 1500 MPa.

Provided is an iron-based sintered alloy valve seat that has excellent wear resistance and peeling resistance. A valve seat is produced that has a double-layer structure in which a functional component side layer and a support component side layer are integrated by sintering. The functional component side layer is a layer in which a hard particle or a solid lubricant particle is dispersed in a matrix phase mainly composed of an annealed martensite phase, and further, a high alloy phase is present around the hard particle, and further, a matrix portion composition containing C: 0.3 to 2.0% by mass, and further, one or two or more selected from Si, Mn, Ni, Cr, Mo, Co, or further, S, and a layer in which pores are filled with Cu by melting and impregnation. Thus, the wear resistance and peeling resistance are improved, and even when used in a cast iron cylinder head of an internal combustion engine, sufficient durability can be maintained.

Provided is a separation and recovery device for continuously separating and recovering a hydrolysis component a of a hydrolyzable polymer A and a non-hydrolyzable polymer B from a resin mixture containing a resin containing the hydrolyzable polymer and a resin containing the non-hydrolyzable polymer, the separation and recovery device comprising: a crushing unit for crushing the resin mixture; a melting and ejecting unit for melting the crushed product obtained by the crushing unit to form a fluid and ejecting the fluid at high pressure; and a hydrothermal reaction treatment unit for continuously performing a hydrothermal reaction treatment on the fluid ejected from the melting and ejecting unit, in which the hydrolyzable polymer A is hydrolyzed to dissolve and transfer the hydrolysis component a thereof to water impregnated through a sintered alloy diaphragm, thereby separating the non-hydrolyzable polymer B.

This invention provides a cathode electrode for water electrolysis that achieves catalytic performance equivalent to, or even exceeding, that of platinum (Pt), without using any platinum (Pt). [Solution] In a cathode electrode used for hydrogen production by water electrolysis, the spaces between tungsten carbide (WC) nanoparticles are composed of a sintered alloy with nickel (Ni) and chromium (Cr) as binder phases. The sintered alloy constituting the cathode electrode contains 5-25% by weight of Ni and 0.5-3.0% by weight of Cr. By using this sintered alloy as the cathode electrode for water electrolysis, the hydrogen overpotential (ηH(V)) during hydrogen production is reduced, enabling highly efficient and stable hydrogen production.

To provide a valve seat made of an iron sintered alloy excellent in wear resistance and falling resistance.SOLUTION: There is provided a two layer structure valve seat 1 which is obtained by integrating by sintering, a function member layer 11, and a support member layer 12, the function member layer includes in a matrix phase including mainly, 20.0% of a fine carbide precipitation phase, and an annealing martensite phase: dispersed hard particles or solid lubricant particles; and a high allow phase around the hard particles. The iron sintered alloy material includes in mass%, one or two or more kinds selected from: 0.5-2.0% of C; 0.1-1.0% of Si; 0.1-2.5% of Mn; 1.0-7.0% of Ni; 1.0-12.0% of Cr; 2.0-12.0% of Mo; 2.0-20.0% of Co; 0.1-2.0% of W; 0.01-1.0% of V, and further has a matrix part composition including 0-1.5% of S, and includes holes in which Cu is filled by infiltration.SELECTED DRAWING: Figure 1

This invention provides a sputtering apparatus and a sputtering method. The sputtering apparatus includes: a vacuum chamber in which a target and a substrate are arranged opposite each other; a DC power supply electrically connected to the target; a gas supply source for introducing a film-forming gas containing nitrogen into the vacuum chamber; and a pulsed unit for pulsed current flowing from the DC power supply to the target. Using a sintered gold target material with a binary or higher composition as the target, plasma is generated in the vacuum chamber to form a nitride thin film with a ternary or higher composition containing nitrogen on the substrate.

The invention discloses preparation of high-entropy binding phase tungsten heavy alloy nano-powder through one-step hydrogen reduction and a sintering process, and belongs to the field of preparation of high-entropy binding phase tungsten heavy alloy materials. According to the preparation method, an oxide composite precursor substance with uniformly mixed metal elements is obtained through a solution combustion synthesis wet chemical method, reduction is carried out in a hydrogen atmosphere, and atomic-scale uniformly-mixed high-entropy binding phase tungsten heavy alloy nano powder is directly obtained; and finally, the high-entropy binding phase tungsten heavy alloy is prepared through pressureless sintering in a hydrogen environment and one-step hydrogen reduction. The process is simple and rapid, the high-entropy binding phase tungsten heavy alloy nano-powder can be prepared through one-step hydrogen reduction, the average particle size of the alloy composite powder is small, and the preparation time of the alloy powder is greatly shortened. By adopting a pressureless sintering technology, the density of a sintered body can be effectively improved, the liquid-phase sintering time is shortened, meanwhile, the sintering period is shortened, and excessive growth of tungsten crystal grains can be effectively prevented. The relative density of the sintered alloy is not lower than 97%, the tensile strength is not lower than 800 MPa, and the compressive strength is not lower than 1000 MPa.

According to the anti-sticking coating for sintering, TiN or TiC serves as an anti-sticking and blocking material, MgO serves as a shell forming agent, MgO and a TiO2 oxide film formed on the surface of the TiN or TiC form a magnesium titanate (MgTiO3) ceramic phase through a solid-solid diffusion reaction, the magnesium titanate ceramic phase is connected with coarse TiN or TiC particles after high-temperature sintering, and the anti-sticking coating for sintering is obtained. A relatively hard TiN or TiC shell is formed, so that the friction resistance and scratch resistance of the coating are improved, and the service life of the coating is prolonged. According to the sintering tray coated with the anti-sticking coating for sintering, the surface of the coating is free of peeling, cracking and other defects after sintering, the coating is completely reserved, the good and stable barrier effect is achieved, and the problems that impurities are likely to be introduced into an existing sintering anti-sticking coating, the sintering anti-sticking coating reacts with sintered alloy at the high temperature, and the performance of a sinter is deteriorated are solved.

The invention belongs to the field of powder metallurgy, and particularly relates to a cobalt-phase segregated hard alloy and a preparation method thereof. According to the preparation method, low-cobalt aggregates with micro-pores are prefabricated through inflation under-pressure heating sintering, then cobalt powder is added, light grinding and mixing are carried out, and slurry is dried and granulated; and the dried alloy powder is subjected to compression molding and put into a pressure sintering furnace for high-temperature sintering, the cobalt liquid phase is migrated and filled in prefabricated holes through high-temperature sintering, and then a sintered alloy product is obtained after the alloy powder is cooled to the room temperature. Compared with a common hard alloy, the hard alloy provided by the invention has a cobalt phase segregation structure, has a thicker cobalt layer thickness and higher impact resistance on the premise of the same cobalt content and average grain size, and has the advantages of absorbing heat energy and preventing thermal fatigue crack propagation in a high-temperature environment. The method is simple in process, low in equipment investment and suitable for popularization and application.

This invention discloses a high-density, high-elongation tungsten-nickel binary alloy material and its step-hot isostatic pressing (HIP) preparation method, belonging to the field of powder metallurgy binary alloy technology. The alloy material has the following mass percentages: W: 93-98%, Ni: 2-7%. The preparation method includes the following steps: pre-mixing tungsten powder and nickel powder in an acoustic resonance mixer, followed by inert atmosphere ball milling in an omnidirectional planetary ball mill; pressing the uniformly mixed powder into a green blank using cold isostatic pressing; densifying the green blank using a step-hot isostatic pressing sintering process, achieving microstructure optimization through multi-stage temperature-pressure synergistic control; and finally, vacuum oil quenching of the sintered alloy. This invention, by combining binary component ratio optimization with a step-hot isostatic pressing sintering process, solves the problems of coarse grains, insufficient elongation, and uneven density in traditional tungsten-nickel alloys. While ensuring high specific gravity, it achieves simultaneous improvement in strength and elongation. The process is simple and controllable, suitable for industrial mass production.

To provide a sintered alloy bearing that is less prone to wear on the mating component (matting shaft) and can minimize adverse environmental impacts during manufacturing. [Solution] This is a sintered alloy bearing obtained by compressing raw material powder to form a compact, and then sintering this compact. The sintered alloy contains, by weight ratio, Cu: 1.0~5.0 wt%, Sn: 0.4~2.0 wt%, and free carbon C: 0 wt% or 0.6~3.0 wt%, with the remainder being Fe and unavoidable impurities. The iron structure formed from the iron powder has a ferrite structure with an area ratio of 90% or more.

A sintered alloy comprising a compound phase and a Cr3C2 phase, the compound phase containing a solid solution phase comprising at least one metal element selected from Ti, Ta, Nb and V and at least one metal element selected from C and N, and having a NaCl-type structure at least 80 vol% or more, the content of the compound phase being 38 vol% to 95 vol%.

The invention relates to the technical field of 3D printing, in particular to a crack-free alloy for achieving double homogenization through 3D printing and a preparation method and application of the crack-free alloy. The method comprises the steps that a metal salt precursor and a photosensitive resin solution are prepared; uniformly mixing the metal salt precursor with the photosensitive resin solution to form resin ink; a 3D printing structure is obtained based on resin ink and by means of the digital light processing 3D printing technology; sequentially sintering the 3D printing structure according to a preset temperature gradient to obtain a metal oxide; the metal oxide is treated for 4-8 h at the temperature of 800-1200 DEG C, mixed gas of hydrogen and argon is introduced, heat preservation is conducted for 5-10 h at the temperature of 400-800 DEG C, and the crack-free alloy is obtained. According to the method, the cracking phenomenon in the sintering process is reduced, and the sintered alloy structure is smooth and flat in surface and compact in microstructure.

A sintered alloy bearing is obtained by compressing raw material powder into a pressed powder body and then sintering the pressed powder body. The sintered alloy contains, by weight, Cu: 1.0–5.0% by mass, Sn: 0.4–2.0% by mass, C as free carbon: 0% by mass or 0.3–3.0% by mass, with the remainder being Fe and unavoidable impurities. The iron microstructure formed from the iron powder has an area fraction of over 90% ferrite.