Additive manufacturing methods and applications of metal-ceramic composites

Abstract

This application discloses an additive manufacturing method and application of metal-ceramic composite materials, which belongs to the field of additive manufacturing. By coating ceramic powder twice, a thin first coating layer (i.e., a metal-ceramic layer) is used to improve the surface properties of the ceramic, and a metal element with excellent thermal properties is selected as the second coating layer (i.e., a metal layer), thereby obtaining a ceramic powder with a composite coating. This significantly improves the wettability of the metal powder and the ceramic powder during the additive manufacturing process, greatly improves the density and thermal conductivity of the heat dissipation device printout, and helps to achieve efficient preparation of large-scale, highly complex-shaped heat sink functional devices.

Description

Technical Field

[0001] The present invention relates to the field of additive manufacturing, and in particular to an additive manufacturing method and application of metal-ceramic composite materials. Background Art

[0002] Metal-ceramic composites combine the advantages of metal and ceramic materials, possessing the high hardness, high strength, and high-temperature resistance of ceramic materials, along with the high toughness and plasticity of metal materials. They are widely used in key fields such as machinery, aerospace, electronic communications, and semiconductor devices. Metal-ceramic composites, formed by ceramic phases such as diamond, silicon carbide, and silicon nitride and metal phases such as copper and aluminum, play an irreplaceable role in the application of heat dissipation devices and heat sink materials. Current methods for preparing metal-ceramic composites primarily involve casting, powder metallurgy, and infiltration. These methods present significant difficulties in preparing complex structural devices, limiting their further application and development.

[0003] Additive manufacturing is an advanced manufacturing technology that uses layers of raw materials to form components. Two key components are laser selective melting and binder jetting. The former uses layer-by-layer powder application and a high-energy laser beam to selectively melt the metal powder within the powder layers to directly form components. The latter uses layer-by-layer powder application and the selective injection of liquid adhesives to bond and stack the powders to create a printed body. The components are then formed through curing, degreasing, sintering, or infiltration processes. Both methods offer the advantages of rapid, high-precision molding of large-scale components and hold great promise for the preparation and molding of metal-ceramic composites and their components.

[0004] In the laser selective melting method and binder jet additive manufacturing process, metal powders such as aluminum and copper and ceramic powders such as silicon nitride, silicon carbide, and diamond used for heat dissipation devices and heat sink materials have poor wettability, making it difficult to prepare high-density heat dissipation device prints. In addition, the bonding performance between the ceramic phase and the metal phase is poor, making additive manufacturing difficult to apply to the preparation of heat dissipation devices.

[0005] There are documents in the prior art that disclose improving the bonding between ceramic powder and metal powder by applying a single coating to ceramic powder. The interface distribution of the single coating is: ceramic → metal ceramic layer → metal matrix. Taking diamond as an example, if the ceramic powder is diamond, the thickness of the single coating is too high, and the metal carbide formed by the interface coating has general thermal properties, it will produce a high interface thermal resistance, thereby reducing the thermal conductivity of the composite material after coating; if the coating thickness is too low, the printability will be greatly reduced. Therefore, there is a conflict between the coating thickness and the low thermal resistance property, and the single coating method is not suitable for the preparation of heat dissipation devices. Summary of the Invention

[0006] The purpose of the present invention is to overcome the limitations of the traditional preparation process of metal-ceramic composite materials, and prepare ceramic powder with a composite coating by double coating of ceramic powder, thereby significantly improving the wettability of metal phase and ceramic phase particles in the additive manufacturing process, and significantly improving the bonding performance of the metal phase and the ceramic phase. On this basis, a method for additive manufacturing preparation of metal-ceramic composite materials is provided. The metal-ceramic composite material device obtained by this method has high density and excellent thermo-mechanical properties, and has great development potential in the application field of heat dissipation devices and heat sink materials.

[0007] To achieve the above object, the present invention provides a method for additive manufacturing of a metal-ceramic composite material, comprising the following steps:

[0008] (1) Processing ceramic powder through two coating processes to obtain ceramic powder with a composite coating;

[0009] (2) The ceramic powder with the composite coating and the metal powder are ball-milled to obtain a raw material powder; the raw material powder obtained by mixing the ceramic powder with the composite coating and the metal powder is printed and formed by a selected laser melting method (SLM) to obtain a metal-ceramic composite material molded part;

[0010] (3) Alternatively, the ceramic powder with the composite coating and the metal powder are ball-milled to obtain a raw material powder; the raw material powder obtained by mixing the ceramic powder with the composite coating and the metal powder is printed by binder jetting (BJ), and then the printed part is cured, degreased, and sintered to obtain a metal-ceramic composite material molded part;

[0011] (4) Alternatively, the ceramic powder with the composite coating is directly printed by binder jetting (BJ), and then the printed part is cured and degreased to obtain a ceramic printed original with a large number of through holes. The infiltration metal is then infiltrated into the ceramic printed original by a melt infiltration process to obtain a metal-ceramic composite molded part;

[0012] In the step (1), the two coating processes include at least one of electrocoating, magnetron sputtering, or chemical vapor deposition; the coating process includes surface purification pretreatment of the ceramic powder; the elements of the first coating layer include at least one of titanium, molybdenum, tungsten, and chromium, and the material of the second coating layer includes at least one of copper, nickel, silver, and iron; the thickness of the first coating layer is 10-1000 nm, and the thickness of the second coating layer is 0.01-10 μm.

[0013] The two coatings can not only improve the wettability of ceramic and metal phase powders in the additive manufacturing process, but also significantly enhance the bonding performance between the ceramic and metal phases, which is beneficial to improving the density of metal-ceramic composite materials and the overall performance of the final metal-ceramic composite components.

[0014] The interface distribution of the two coatings is as follows: ceramic → metal ceramic layer → metal layer-metal substrate. The surface properties of the ceramic are improved by the metal ceramic layer (such as metal carbide layer) of the first coating, and the thickness of the first coating is thin; the second coating selects metal elements with excellent thermal properties as the second coating to form a metal layer.

[0015] On the one hand, the two-coating method can effectively control the interface thermal resistance; on the other hand, the one-coating method needs to control the coating thickness in order to reduce the thermal resistance, which leads to unsatisfactory coating bonding and printability. The printability of the two-coating composite material powder is better than that of the one-coating method.

[0016] Preferably, the ceramic phase powder in step (1) comprises at least one of diamond, silicon nitride and silicon carbide, and the average particle size of the powder is in the range of 1 to 200 μm;

[0017] Preferably, the two metal coatings in step (1) both include a coating pretreatment for surface purification of the ceramic powder; the metal coating process includes at least one of electrocoating, chemical coating, magnetron sputtering, or chemical vapor deposition;

[0018] Further preferably, in step (1), the first layer of coating metal elements includes at least one of titanium, molybdenum, tungsten, and chromium, and has a thickness of 10 to 1000 nm, and the second layer of composite coating metal elements includes at least one of copper, nickel, silver, and iron, and has a thickness of 0.01 to 10 μm;

[0019] Compared with the conventional one-time coating method of ceramic powder, the present invention improves the uniformity of the surface coating of the ceramic powder by coating the surface of the ceramic powder twice, further improves the wettability of ceramic powder and metal powder in additive manufacturing, and further improves the bonding performance of the metal phase and ceramic phase in the additive manufacturing print, ensuring the preparation of high-density and high-performance additive manufacturing prints;

[0020] Preferably, the volume percentage of the ceramic powder in steps (2) to (3) is 20 to 70%;

[0021] Further preferably, in steps (2) to (3), the metal powder comprises at least one of aluminum alloy, copper alloy, pure aluminum, and pure copper metal, and the particle size of the metal powder is in the range of 5 to 80 μm;

[0022] The process parameters of the selective laser melting technology in step (2) include a laser spot size of 10-100 μm, a laser power of 10-1200 W, a scanning speed of 100-3500 mm / s, and a scanning spacing of 0.005-0.08 mm;

[0023] The binder jetting process parameters include a print layer thickness of 30-300 μm, a scraper speed of 0.5-7 cm / s, and a binder saturation of 40-100%.

[0024] Preferably, the curing, degreasing, sintering and infiltration process parameters include:

[0025] (a) The curing process parameters of the printed part formed by binder jet printing of the raw material powder of the ceramic powder with a composite coating and the metal powder or the ceramic powder with a composite coating include a curing temperature of 100 to 350° C. and a curing time of 1 to 8 hours;

[0026] or / and (b) degreasing process parameters of the printed part formed by binder jet printing of the raw material powder of the ceramic powder with the composite coating and the metal powder or the ceramic powder with the composite coating include heating to 250-600° C. at 0.5-10° C. / min in an inert atmosphere and holding the temperature for 1-5 hours;

[0027] or / and (c) the sintering process of the printed part formed by binder jet printing of the raw material powder of the ceramic powder with the composite coating and the metal powder (for the printed part formed by binder jet printing of the raw material powder of the ceramic powder with the composite coating and the metal powder) parameters include the following: -1 ~10 -3 Pa) at a temperature of 0.2-5°C / min to 50-100°C below the melting point of the main metal components in the raw material powder, keep warm for 1-5 hours, and finally cool to room temperature;

[0028] Or / and (d) the metal infiltration process of the printed part formed by binder jet printing of the ceramic powder with the composite coating in step (4) includes:

[0029] At a vacuum degree of 10 -1 ~10 -3 Pa vacuum, or in an inert atmosphere or hydrogen atmosphere at normal pressure, or in a high-pressure inert atmosphere of 1-20 MPa, the temperature is raised at 0.1-5°C / min to 50-300°C above the melting point of the infiltration metal, kept at this temperature for 1-12 hours, and finally furnace cooled to room temperature; the infiltration metal includes at least one of a copper alloy, an aluminum alloy, pure aluminum, and pure copper.

[0030] The main metal component refers to the metal component with the largest volume content in the metal powder; if the metal powder contains only a single metal component, then the main metal component is the single metal component in the metal powder; if the metal powder is a mixed metal powder, such as a mixed powder of aluminum alloy and copper alloy with a volume ratio of 6:4, then the main metal component can be understood as the aluminum alloy component with the largest volume content.

[0031] The invention also includes the application of metal-ceramic composite materials. The metal-ceramic composite materials obtained based on the additive manufacturing method according to the present invention include metal-ceramic composite materials components; the metal-ceramic composite materials components include metal-ceramic composite materials heat dissipation components and heat sink materials.

[0032] Beneficial effects of the present invention:

[0033] 1) The one-time coating method is not suitable for the manufacture of heat dissipation devices because the interface thermal resistance of the formed metal-ceramic layer is high, which leads to a decrease in the thermal conductivity of the composite material after coating;

[0034] The double coating method of the present application has a thin metal ceramic layer in the first coating layer and good thermal conductivity in the metal layer in the second coating layer, which significantly reduces the interfacial thermal resistance between the ceramic phase and the metal phase, promotes the improvement of thermal properties such as thermal conductivity of additively manufactured metal-ceramic composite components, and enables additive manufacturing to be used for the efficient manufacture of high-precision and highly complex-shaped metal-ceramic composite heat dissipation components and heat sink materials.

[0035] 2) To reduce interfacial thermal resistance, the one-shot coating method requires controlling the coating thickness, which results in suboptimal coating bonding performance and does not actually improve the printability of the composite material.

[0036] The secondary coating method utilizes the metal ceramic layer of the first coating to provide better adhesion surface properties for the metal layer of the second coating, and at the same time utilizes the combination of the metal layer of the second coating and the metal substrate to significantly improve the bonding performance between the coatings.

[0037] 3) In the one-shot coating method, the coating element is often selected to have a certain wettability with both the metal and the ceramic;

[0038] In the secondary coating method, the first layer of coating is used to improve the interface characteristics, and the second layer of coating avoids direct contact with the ceramic powder. The second layer of coating can be selected from elements with better thermal properties and better wettability with the metal matrix for secondary coating; the secondary coating method can achieve the effect of both improving thermal properties and optimizing printability.

[0039] 4) For single coating, excessive coating thickness will inevitably lead to high interface thermal resistance; however, for double coating, increasing the coating thickness can achieve improved thermal conductivity.

[0040] 5) By applying metal coating twice to the ceramic phase powder, the wettability of the ceramic phase and the metal phase during the additive manufacturing process is effectively improved, significantly enhancing the bonding performance between the ceramic phase and the metal phase. At the same time, the double coating can effectively protect the ceramic phase powder from being damaged by the high-energy laser beam during the selective laser melting process, thereby ensuring the structural integrity of the composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Schematic diagram of ceramic particles with surface metal composite coating according to the present invention. DETAILED DESCRIPTION

[0042] To further clearly express the purpose, technical solutions and advantages of the present invention, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not limit the scope of protection of the present invention.

[0043] Example 1

[0044] (1) Metal composite coating process on ceramic powder surface:

[0045] Silicon carbide ceramic powder with a particle size of 50-100 μm was subjected to surface purification pretreatment; metal coating was applied to the powder surface using an electroplating process; the first coating layer was titanium metal with a coating thickness of 100 nm; the second coating layer was nickel metal with a coating thickness of 800 nm.

[0046] (2) Preparation of raw powders of metal-ceramic composite materials

[0047] Silicon carbide ceramic powder with a titanium-nickel composite coating and AlSi10Mg aluminum alloy with a particle size of 15-50 μm are ball-milled and mixed, and the ceramic phase composition is 55 vol.%, to obtain a raw material powder;

[0048] (3) Selective laser melting of metal-ceramic composite parts:

[0049] The above raw material powders were poured into the powder feeding bin of the selected area laser melting molding printer. The laser spot was set to 80 μm, the powder layer thickness was 100 μm, the laser power was 460 W, the scanning speed was 300 mm / s, and the scanning spacing was 0.03 mm to produce the metal-ceramic composite molding original.

[0050] After testing, the density of the molded sample was 97.9% and the thermal conductivity was 285 W / mK.

[0051] Example 2

[0052] (1) Metal composite coating process on ceramic powder surface:

[0053] Diamond ceramic powder with a particle size of 100-150 μm was pre-treated for surface purification; a metal coating was applied to the powder surface using a magnetron sputtering process; the first coating layer was molybdenum metal with a coating thickness of 80 nm; the second coating layer was copper metal with a coating thickness of 1 μm.

[0054] (2) Preparation of raw powders of metal-ceramic composite materials

[0055] Diamond ceramic powder with a molybdenum-copper composite coating and CuZn12Sn2 copper alloy powder with a particle size of 10-45 μm were ball-milled and mixed, with a ceramic phase content of 45 vol.%, to obtain a raw material powder;

[0056] (3) Selective laser melting of metal-ceramic composite parts:

[0057] The above raw material powders were poured into the powder feeding bin of the selected area laser melting molding printer. The laser spot was set to 60 μm, the powder thickness was 150 μm, the laser power was 480 W, the scanning speed was 500 mm / s, and the scanning spacing was 0.04 mm to produce the metal-ceramic composite molding original.

[0058] After testing, the density of the molded sample was 98.5% and the thermal conductivity was 526 W / mK.

[0059] Example 3

[0060] (1) Metal composite coating process on ceramic powder surface:

[0061] Silicon nitride ceramic powder with a particle size of 100-150 μm was subjected to surface purification pretreatment; a metal coating was applied to the surface of the ceramic powder using a chemical vapor deposition process; the first coating layer was titanium with a coating thickness of 200 nm; the second composite coating layer was nickel with a coating thickness of 900 nm.

[0062] (2) Preparation of raw powders of metal-ceramic composite materials

[0063] Silicon nitride ceramic powder with a titanium-nickel composite coating and 6061 aluminum alloy with a particle size of 10-60 μm were ball-milled and mixed, with a ceramic phase content of 60 vol.%, to obtain a raw material powder;

[0064] (3) Binder injection molding of metal-ceramic composite bodies:

[0065] The above raw material powders were poured into the powder feeding bin of the binder jet molding printer, and the printing layer thickness was set to 150 μm, the scraper speed was 3 cm / s, and the binder saturation was 75% to obtain a composite material molding body.

[0066] (4) Curing, degreasing and sintering process:

[0067] The formed green body was placed in a curing furnace, the curing temperature was set to 180 ° C, and the holding time was 5 hours for curing; the cured green body was placed in a degreasing furnace, set in a nitrogen atmosphere, and heated to 400 ° C at 3 ° C / min, and kept at this temperature for 3 hours, then heated to 600 ° C at 3 ° C / min, and kept at this temperature for 3 hours, and then cooled to room temperature; the degreased green body was placed in a sintering furnace, and a vacuum atmosphere was set, with a vacuum degree of 10 -3 Pa, heating to 800℃ at 5℃ / min, keeping at this temperature for 2 hours, and finally cooling to room temperature to obtain the composite material sintered original part;

[0068] After testing, the density of the molded sample was 96.8% and the thermal conductivity was 149 W / mK.

[0069] Example 4

[0070] (1) Metal composite coating process on ceramic powder surface:

[0071] Silicon carbide ceramic powder with a particle size of 100-150 μm was subjected to surface purification pretreatment; a metal coating was applied to the surface of the silicon carbide ceramic powder using an electroplating coating process; the first coating layer was chromium metal with a coating thickness of 50 nm; the second coating layer was copper metal with a coating thickness of 2 μm.

[0072] (2) Binder injection molding of ceramic green bodies:

[0073] Silicon carbide ceramic powder with a chromium-copper composite coating was poured into the powder feed bin of a binder jet molding printer. The printing layer thickness was set to 200 μm, the scraper speed was 7 cm / s, and the binder saturation was set to 90%. Silicon carbide ceramic formed bodies with a chromium-copper composite coating were produced.

[0074] (3) Curing and degreasing process:

[0075] The silicon carbide ceramic formed body with a chromium-copper composite coating was placed in a curing furnace, the curing temperature was set to 200°C, and the holding time was 2 hours for post-curing; the cured body was placed in a degreasing furnace, set in a nitrogen atmosphere, and the temperature was increased to 400°C at 2°C / min, the holding time was 1 hour, and then the temperature was increased to 600°C at 2°C / min, the holding time was 2 hours, and the furnace was cooled to room temperature to obtain a composite material degreased body.

[0076] (4) Metal infiltration process

[0077] Put the degreased blank and pure aluminum into a crucible, put the crucible into the infiltration furnace, and evacuate to 10 -3 Pa, and then heated to 800 °C at 3 °C / min, and then introduced high-pressure argon gas to 10 MPa, and kept warm for 3 hours. Finally, the furnace was cooled to room temperature to obtain a composite material infiltration part.

[0078] After testing, the ceramic content in the molded sample was 68 vt%, the density was 98.9%, and the thermal conductivity was 325 W / mK.

[0079] Example 5

[0080] (1) Metal composite coating process on ceramic powder surface:

[0081] Diamond ceramic powder with a particle size of 100-200 μm was subjected to surface purification pretreatment; metal coating was applied to the surface of the diamond ceramic powder using a chemical deposition coating process; the first coating layer was molybdenum with a coating thickness of 80 nm; the second coating layer was copper with a coating thickness of 8 μm.

[0082] (2) Binder injection molding of metal-ceramic composites:

[0083] Diamond ceramic powder with a molybdenum-copper composite coating was poured into the powder feed chamber of a binder jet molding printer. The printing layer thickness was set to 250 μm, the scraper speed was set to 4 cm / s, and the binder saturation was set to 98% to produce a ceramic molded body.

[0084] (3) Curing, degreasing and infiltration process:

[0085] The diamond ceramic formed body with a molybdenum-copper composite coating is placed in a curing furnace, the curing temperature is set to 200°C, and the holding time is 2 hours for curing; the cured body and pure copper are placed in a degreasing-infiltration furnace, set in a nitrogen atmosphere, and the temperature is increased to 400°C at 2°C / min, and the holding time is 1 hour, then the temperature is increased to 600°C at 2°C / min, and the holding time is 2 hours; then the temperature is increased to 1200°C at 5°C / min, and the holding time is 3 hours. Finally, the temperature is cooled to room temperature to obtain a composite material infiltration original component.

[0086] After testing, the diamond ceramic content in the molded sample was 70 vol.%, the density was 99.1%, and the thermal conductivity was 621 W / mK.

[0087] Comparative Example 1

[0088] (1) Preparation of raw material powders for metal-ceramic composite materials

[0089] The raw material powder was prepared by ball milling silicon carbide powder with a particle size of 50-100 μm and AlSi10Mg aluminum alloy with a particle size of 15-50 μm. The silicon carbide ceramic content was 55 vol.%;

[0090] (2) Selective laser melting of metal-ceramic composite parts:

[0091] The above raw material powders were poured into the powder feeding bin of the selected area laser melting molding printer. The laser spot was set to 80 μm, the powder layer thickness was 100 μm, the laser power was 460 W, the scanning speed was 300 mm / s, and the scanning spacing was 0.03 mm to produce the metal-ceramic composite molding original.

[0092] After testing, the molded sample has a density of 73.9% and a thermal conductivity of 45 W / mK.

[0093] Comparative Example 2

[0094] (1) Preparation of raw material powders for metal-ceramic composite materials

[0095] Diamond powder with a particle size of 100-150 μm and CuZn12Sn2 copper alloy with a particle size of 10-45 μm were ball-milled to prepare raw material powder, and the diamond ceramic phase composition was 45 vol.%;

[0096] (2) Selective laser melting of metal-ceramic composite parts:

[0097] The above raw material powders were poured into the powder feeding bin of the selected area laser melting molding printer. The laser spot was set to 60 μm, the powder thickness was 150 μm, the laser power was 480 W, the scanning speed was 500 mm / s, and the scanning spacing was 0.04 mm to produce the metal-ceramic composite molding original.

[0098] It was found that the molding could not be carried out and the printing failed.

[0099] Comparative Example 3

[0100] (1) Preparation of raw material powders for metal-ceramic composite materials

[0101] Silicon nitride powder with a particle size of 100-150 μm and 6061 aluminum alloy with a particle size of 10-60 μm were ball-milled and mixed, and the ceramic phase content was 60 vol.%, to obtain a raw material powder;

[0102] (2) Binder injection molding of metal-ceramic composite bodies:

[0103] The above raw material powders were poured into the powder feeding bin of the binder jet molding printer, and the printing layer thickness was set to 150 μm, the scraper speed was 3 cm / s, and the binder saturation was 75% to obtain a composite material molding body.

[0104] (3) Curing, degreasing and sintering process:

[0105] The formed green body was placed in a curing furnace, the curing temperature was set to 180 ° C, and the holding time was 5 hours for curing; the cured green body was placed in a degreasing furnace, set in a nitrogen atmosphere, and heated to 400 ° C at 3 ° C / min, and kept at this temperature for 3 hours, then heated to 600 ° C at 3 ° C / min, and kept at this temperature for 3 hours, and then cooled to room temperature; the degreased green body was placed in a sintering furnace, and a vacuum atmosphere was set, with a vacuum degree of 10 -3 Pa, heating to 800℃ at 5℃ / min, keeping at this temperature for 2 hours, and finally cooling to room temperature to obtain the composite material sintered original part;

[0106] After testing, the density of the molded sample was 72.5% and the thermal conductivity was 35 W / mK.

[0107] Comparative Example 4

[0108] (1) Metal single-layer coating process on ceramic powder surface:

[0109] Silicon nitride ceramic powder with a particle size of 100-150 μm was subjected to surface purification pretreatment; a single layer of metal coating was applied to the surface of the ceramic powder using a chemical vapor deposition process; the coating was titanium with a thickness of 200 nm;

[0110] (2) Preparation of raw powders of metal-ceramic composite materials

[0111] Silicon nitride ceramic powder with a titanium monolayer coating and 6061 aluminum alloy with a particle size of 10-60 μm were ball-milled to obtain a raw material powder with a ceramic phase content of 60 vol.%;

[0112] (3) Binder injection molding of metal-ceramic composite bodies:

[0113] The above raw material powders were poured into the powder feeding bin of the binder jet molding printer, and the printing layer thickness was set to 150 μm, the scraper speed was 3 cm / s, and the binder saturation was 75% to obtain a composite material molding body.

[0114] (4) Curing, degreasing and sintering process:

[0115] The formed green body was placed in a curing furnace, the curing temperature was set to 180 ° C, and the holding time was 5 hours for curing; the cured green body was placed in a degreasing furnace, set in a nitrogen atmosphere, and heated to 400 ° C at 3 ° C / min, and kept at this temperature for 3 hours, then heated to 600 ° C at 3 ° C / min, and kept at this temperature for 3 hours, and then cooled to room temperature; the degreased green body was placed in a sintering furnace, and a vacuum atmosphere was set, with a vacuum degree of 10 -3 Pa, heating to 800℃ at 5℃ / min, keeping at this temperature for 2 hours, and finally cooling to room temperature to obtain the composite material sintered original part;

[0116] After testing, the density of the molded sample was 81.2% and the thermal conductivity was 68 W / mK.

[0117] Comparative Example 5

[0118] (1) Binder injection molding of metal-ceramic composites:

[0119] Silicon carbide ceramic powder with a particle size of 100-150 μm was poured into the powder feed bin of a binder jet molding printer. The printing layer thickness was set to 200 μm, the scraper speed was set to 7 cm / s, and the binder saturation was set to 90% to produce a ceramic molded body.

[0120] (2) Post-curing, degreasing and sintering process:

[0121] The ceramic formed green body was placed in a curing furnace, the curing temperature was set to 200°C, and the holding time was 2 hours for post-curing; the cured green body was placed in a degreasing furnace, set in a nitrogen atmosphere, and the temperature was increased to 400°C at 2°C / min, the holding time was 1 hour, and then the temperature was increased to 600°C at 2°C / min, the holding time was 2 hours, and the furnace was cooled to room temperature to obtain a sintered original part;

[0122] (3) Metal infiltration process

[0123] Place the sintered original and pure aluminum into a crucible, place the crucible into an infiltration furnace, and evacuate to 10 -3 The temperature was raised to 800°C at a rate of 3°C / min, and then high-pressure argon was introduced to 10 MPa, and the temperature was kept at this temperature for 3 hours. Finally, the temperature was cooled to room temperature.

[0124] It was found that the molding could not be carried out and the printing failed.

[0125] Comparative Example 6

[0126] (1) Binder injection molding of metal-ceramic composites:

[0127] Diamond ceramic powder with a particle size of 100-200 μm was poured into the powder feed bin of a binder jet molding printer. The printing layer thickness was set to 250 μm, the scraper speed was set to 4 cm / s, and the binder saturation was set to 98% to produce a ceramic molded body.

[0128] (2) Post-curing, degreasing and sintering process:

[0129] The ceramic formed body is placed in a curing furnace, the curing temperature is set to 200°C, and the holding time is 2 hours for post-curing; the cured body is placed in a degreasing furnace, set in a nitrogen atmosphere, and the temperature is increased by 2°C / minute to 400°C, and the holding time is 2 hours; the cured body and pure copper are placed in a degreasing-infiltration furnace, set in a nitrogen atmosphere, and the temperature is increased by 2°C / minute to 400°C, and the holding time is 1 hour, then the temperature is increased by 2°C / minute to 600°C, and the holding time is 2 hours; then the temperature is increased by 5°C / minute to 1200°C, and the holding time is 3 hours, and finally the furnace is cooled to room temperature;

[0130] It was found that the molding could not be carried out and the printing failed.

[0131] Comparative Example 7

[0132] (1) Metal single-layer coating process on ceramic powder surface:

[0133] Diamond ceramic powder with a particle size of 100-200 μm was subjected to surface purification pretreatment; a single-layer metal coating was applied on the surface of the diamond ceramic powder using a chemical deposition coating process. The coating material was molybdenum and the coating thickness was 80 nm.

[0134] (2) Binder injection molding of metal-ceramic composites:

[0135] Diamond ceramic powder with a molybdenum single-layer coating was poured into the powder feed chamber of a binder jet molding printer. The printing layer thickness was set to 250 μm, the scraper speed was set to 4 cm / s, and the binder saturation was set to 98% to produce a ceramic molded body.

[0136] (3) Curing, degreasing and infiltration process:

[0137] The diamond ceramic formed body with a molybdenum-copper composite coating is placed in a curing furnace, the curing temperature is set to 200°C, and the holding time is 2 hours for curing; the cured body and pure copper are placed in a degreasing-infiltration furnace, set in a nitrogen atmosphere, and the temperature is increased to 400°C at 2°C / min, and the holding time is 1 hour, then the temperature is increased to 600°C at 2°C / min, and the holding time is 2 hours; then the temperature is increased to 1200°C at 5°C / min, and the holding time is 3 hours. Finally, the temperature is cooled to room temperature to obtain a composite material infiltration original component.

[0138] After testing, the diamond ceramic content in the molded sample was 70 vol.%, the density was 89.9%, and the thermal conductivity was 205 W / mK.

[0139] The density of the metal-ceramic composite material obtained in the embodiment / comparative example was measured by the Archimedes drainage method, and the thermal conductivity of the metal-ceramic composite material was measured at room temperature using a thermal conductivity meter. The test sample size was 10 mm × 10 mm × 2 mm (length × width × height).

[0140] Table 1 Performance parameters and comparison parameters of samples prepared in Example

[0141]

[0142] Table 1 Performance parameters and comparative parameters of samples prepared in the embodiment, where SLM is selective laser melting technology and BJ is binder jet molding technology; it can be seen from the table that the method for performing metal composite coating on the surface of ceramic powder described in the present invention is effectively applicable to the additive manufacturing of metal-ceramic composite materials and has high molding density, especially the selective laser melting and binder jet molding technologies; while the additive manufacturing of metal-ceramic mixed powders using direct uncoated ceramic powders is difficult to achieve high-density molding, or even no molding; the additive manufacturing of metal-ceramic mixed powders using single-layer coated ceramic powders is also difficult to achieve high-density molding.

[0143] In particular, when the present invention is used to perform BJ printing on diamonds with a molybdenum-copper metal composite coating and then infiltrate pure copper, when the volume content of diamond ceramic is 70%, the density of the obtained metal-ceramic composite material can reach 99.1% and the thermal conductivity can reach 621W / mK; however, when uncoated diamonds are subjected to BJ printing, they cannot be formed.

[0144] By comparing the double coating of Example 3 with the single coating of Comparative Example 4, and comparing the double coating of Example 5 with the single coating of Comparative Example 7, it can be seen that: compared with the single coating, the sintered parts obtained by the double coating method have excellent density and thermal conductivity; according to general reports in the literature, for single coating, excessive coating thickness will inevitably lead to high interface thermal resistance, that is, reduced thermal conductivity.

[0145] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for additive manufacturing of metal-ceramic composite materials, characterized in that: The steps include: (1) Processing ceramic powder through two coating processes to obtain ceramic powder with a composite coating; (2) The ceramic powder with the composite coating and the metal powder are ball-milled to obtain a raw material powder; the raw material powder obtained by mixing the ceramic powder with the composite coating and the metal powder is printed and formed by a selective laser melting method to obtain a metal-ceramic composite material molded part; Alternatively, the ceramic powder with the composite coating and the metal powder are ball-milled to obtain a raw material powder; the raw material powder obtained by mixing the ceramic powder with the composite coating and the metal powder is printed by a binder jet, and then the printed part is cured, degreased, and sintered to obtain a metal-ceramic composite material molded part; Alternatively, the ceramic powder with the composite coating is directly printed by binder jet printing, and then the printed part is cured and degreased to obtain a ceramic printed original with a large number of through holes. The infiltration metal is then infiltrated into the ceramic printed original by the melt infiltration process to obtain a metal-ceramic composite molded part; In step (1), the two coating processes include at least one of electrocoating, magnetron sputtering, or chemical vapor deposition; the coating process includes surface purification pretreatment of the ceramic powder; the elements of the first coating layer include at least one of titanium, molybdenum, tungsten, and chromium, and the material of the second coating layer includes at least one of copper, nickel, silver, and iron; The thickness of the first coating layer is 10~1000 nm, and the thickness of the second coating layer is 0.01-10 μm.

2. The method according to claim 1, characterized in that The ceramic powder in step (1) includes at least one of silicon nitride, silicon carbide, and diamond; the average particle size of the ceramic powder is in the range of 1 to 200 μm.

3. The method according to claim 1, characterized in that In the step (2), the metal powder includes at least one of aluminum alloy, copper alloy, pure aluminum, and pure copper; and the particle size of the metal powder is in the range of 5 to 80 μm.

4. The method according to claim 1, wherein In the step (2), the volume percentage of ceramic powder in the raw material powder is 20-70%.

5. The method according to claim 1, wherein the selective laser melting printing process parameters include a laser spot size of 10-100 μm, a laser power of 10-1200 W, a scanning speed of 100-3500 mm / s, and a scanning pitch of 0.005-0.08 mm.

6. The method according to claim 1, wherein the binder jet printing process parameters include a print layer thickness of 30-300 μm, a scraper speed of 0.5-7 cm / s, and a binder saturation of 40-100%; The curing process parameters include a curing temperature of 100 to 350° C. and a curing time of 1 to 8 hours; Or / and the degreasing process parameters include heating to 250-600° C. at 0.5-10° C. / min in an inert atmosphere and holding the temperature for 1-5 hours; Or / and the sintering process parameters include hydrogen atmosphere, inert atmosphere or 10 -1 ~10 -3 Heat the powder at 0.2-5°C / min in a Pa vacuum to 50-100°C below the melting point of the main metal components in the raw material powder, keep it warm for 1-5 hours, and finally cool it down to room temperature; Or / and the infiltration process parameters include a vacuum degree of 10 -1 ~10 -3 Pa vacuum, or in an inert atmosphere or hydrogen atmosphere at normal pressure, or in a high-pressure inert atmosphere of 1-20 MPa, the temperature is raised at 0.1-5°C / min to 50-300°C above the melting point of the infiltration metal, kept at this temperature for 1-12 hours, and finally furnace cooled to room temperature; the infiltration metal includes at least one of a copper alloy, an aluminum alloy, pure aluminum, and pure copper.

7. Application of metal-ceramic composite materials, characterized by: Application of the additive manufacturing method of metal-ceramic composite materials according to any one of claims 1 to 6 in metal-ceramic composite materials components.

8. The use of the metal-ceramic composite material according to claim 7, characterized in that: The metal-ceramic composite material component includes a heat dissipation component and a heat sink material.

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