Composite structure of carbide ceramic and steel, and preparation method therefor

Abstract

A composite structure of a carbide ceramic and steel, and a preparation method therefor. The method comprises the following steps: 1) preparing a cemented carbide powder slurry; (2) subjecting a carbide ceramic to a cemented carbide treatment by using the cemented carbide powder slurry; (3) mixing the cemented carbide-treated carbide ceramics with a steel powders or a cast iron powder at a certain ratio, pressing same into a blank, and sintering at a preset temperature; or casting molten steel into a mold containing the cemented carbide-treated carbide ceramic, so as to obtain a carbide / steel composite material characterized by an internal structure comprising a carbide ceramic, a cemented carbide, and steel. According to the method, the reaction of a carbide ceramic and steel is blocked by means of the cemented carbide layer, the problem of the difficulty in compounding the carbide ceramics with the steel is solved, and the prepared carbide ceramic / steel composite material has a better hardness, impact toughness and wear resistance.

Description

A composite structure of carbide ceramics and steel and its preparation method

[0001] Related applications

[0002] This application claims priority to Chinese Patent Application No. 202411583908X, filed on November 7, 2024, entitled "A composite structure of carbide ceramics and steel and its preparation method". Technical Field

[0003] This invention belongs to the field of wear-resistant materials, specifically relating to a composite structure of carbide ceramics and steel and its preparation method. Background Technology

[0004] Carbide ceramics possess excellent wear resistance but lack toughness, being hard and brittle. For example, silicon carbide (SiC) ceramics not only exhibit excellent room-temperature mechanical properties, such as high flexural strength, excellent oxidation resistance, good corrosion resistance, high wear resistance, and a low coefficient of friction, but also boast the best high-temperature mechanical properties (strength, creep resistance, etc.) among known ceramic materials. Silicon carbide ceramics also possess good oxidation resistance. However, bulk carbide ceramic materials are excessively brittle, resulting in poor impact resistance and toughness.

[0005] Steel or cast iron materials possess good toughness and impact resistance, but their wear resistance is inferior to that of carbide ceramics. The wear resistance coefficient of ordinary steel is generally between 0.3 and 1, while the wear resistance coefficient of rebar is between 0.8 and 1.2 according to national standards. In contrast, silicon carbide ceramics, a type of carbide ceramic, have a wear resistance more than 200 times that of manganese steel and more than 150 times that of high-chromium cast iron.

[0006] Carbide ceramics and steel are combined to prepare carbide ceramic-steel composite materials, which can take advantage of the advantages of both. In order to obtain wear-resistant materials with better properties, the prior art proposes to prepare composite materials by sintering non-metals and metals together. For example, patent 2007100299437 "Ceramic Particle Reinforced Iron-Based Composite Material and Preparation Method Thereof" discloses a method for preparing ceramic particle reinforced iron-based composite material, which is to (1) place metal ceramic particles with a particle size of 1mm to 7mm in a mold, pour molten steel or cast iron into the mold, and statically solidify and cool to prepare ceramic particle reinforced iron-based composite material. However, the composite material obtained by this mixing and sintering is not firmly bonded. In particular, carbide ceramics are prone to react with steel to form a brittle phase, which affects the bonding between the two and deteriorates the performance. Summary of the Invention

[0007] To address the aforementioned problems, this invention proposes a composite structure of carbide ceramics and steel, and its preparation method. This invention introduces a cemented carbide layer between the carbide ceramics and steel, preventing contact between them. This avoids reaction between the carbide ceramics and steel. Furthermore, since both the carbide ceramics and the cemented carbide layer are carbides, they easily bond together, forming chemical bonds. The carbides in the cemented carbide layer do not readily react with steel or cast iron, but can dissolve into them to form a solid solution. Simultaneously, Co or Ni in the cemented carbide layer can readily dissolve with iron, thus allowing for good bonding between the two materials. This solves the problem of the difficulty in composite carbide ceramics and steel.

[0008] In the process, cemented carbide slurry can be coated onto the surface of carbide ceramic by dip coating or spraying. After degreasing and sintering, cemented carbide ceramic is obtained. Then, the cemented carbide ceramic is combined with steel by powder metallurgy or casting to finally obtain a wear-resistant material with an internal structure of carbide ceramic-cemented carbide layer-steel: carbide ceramic / steel or carbide ceramic / cast iron.

[0009] Specifically, the present invention provides a method for preparing a composite structure of carbide ceramics and steel, the method comprising the following steps:

[0010] 1) Prepare cemented carbide powder slurry, wherein the cemented carbide powder slurry comprises at least: hard phase powder, binder phase powder, solvent, initiator and organic functional monomer matched with the initiator;

[0011] 2) Hard alloying treatment of carbide ceramics using the hard alloy powder slurry. This step includes coating the surface of the carbide ceramics with the hard alloy powder slurry, treating the coated carbide ceramics with UV light irradiation or heating to induce the initiator to initiate the polymerization reaction of the organic functional monomers to form a polymer, thereby coating the surface of the carbide ceramics with a hard alloy slurry solidification layer; then sintering the carbide ceramics coated with hard alloy slurry to solidify the hard alloy powder, thereby achieving hard alloying of the silicon carbide ceramic surface.

[0012] 3) The hard alloyed carbide ceramic obtained in step 2) is mixed with steel powder or cast iron powder in a certain proportion, pressed into a blank, and sintered at a predetermined temperature to obtain a carbide / steel composite material with the internal structure of carbide ceramic-hard alloy layer-steel; or, molten steel is cast into a mold containing the hard alloyed carbide ceramic obtained in step 2), and after solidification, a carbide / steel composite material with the internal structure of carbide ceramic-hard alloy layer-steel is obtained.

[0013] In a preferred embodiment, the mass and volume ratio of the hard phase powder and the binder phase powder are 20% to 80% of the total slurry volume, and the remaining part is a mixture of solvent, initiator and organic functional monomer, wherein the mass ratio of organic functional monomer to solvent in the mixture is 1:99 to 30:70, and the amount of initiator added is 0.01% to 10% of the weight of organic monomer.

[0014] In another preferred embodiment, the mass and proportion of the hard phase powder and the binder phase powder to the total slurry volume are 30% to 50%; the weight ratio of the hard phase powder and the binder phase powder is 1:10 to 100:0.1, preferably 1:10 to 10:1.

[0015] In another preferred embodiment, the hard phase powder includes one or more of WC powder, TiC powder, titanium carbonitride powder, NbC powder or TaC powder, and the binder phase powder includes one or more of Co powder, Ni powder, FeCo powder, FeNi alloy powder.

[0016] In another preferred embodiment, the cemented carbide powder slurry further includes a dispersant and a thickener. The dispersant is one or a mixture of several of ZN-1344, SP-710, and SP-6000, and the dispersant accounts for 0.01% to 10% of the total mass of the hard phase powder and the binder phase powder. The thickener includes one or a mixture of several of carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), polyvinyl butyral (PVB), and polyacrylamide (PAM).

[0017] In another preferred implementation, step 2) involves coating the surface of the cemented carbide powder slurry with the cemented carbide powder slurry, which includes: coating the surface of the carbide ceramic with the cemented carbide slurry by dip coating or spraying, and then obtaining the cemented carbide ceramic after degreasing and sintering. During degreasing and sintering, the temperature is gradually increased to a first temperature and held in a hydrogen atmosphere, then the atmosphere is converted to nitrogen, and then the temperature is gradually increased to a second temperature and held.

[0018] In another preferred embodiment, the organic functional monomer includes one or a mixture of several of the following: 1,6-hexanediol diacrylate, pentaerythritol hexaacrylate, hydroxyethyl acrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, and acrylic acid.

[0019] The initiator is a photoinitiator or a thermal initiator, wherein the thermal initiator includes one or more of benzoic acid peroxide, azobisisobutyronitrile, sodium azobiscyanopentate, sodium azo(2-(2-imidazoline)propane)hydrochloride, and azo(2-amidinylpropane)hydrochloride; or

[0020] The photoinitiator includes one or more of 1-hydroxycyclohexylphenyl ketone, trimethylbenzoyl-diphenylphosphine oxide, and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

[0021] In another preferred embodiment, the carbide ceramic includes one or a mixture of several of silicon carbide, boron carbide, chromium carbide or molybdenum carbide, and the size of the carbide ceramic is greater than or equal to 0.5 mm, and the morphology is granular, lath-shaped, spherical or flake-shaped.

[0022] In another preferred embodiment, when preparing the hard alloy powder slurry in step (1), the hard phase powder, binder phase powder, solvent, and organic functional monomer are first mixed and stirred. 0.01h to 1h before the mixing and stirring is completed, the initiator is added and the mixing and stirring continues.

[0023] On the other hand, the present invention provides a composite structure of carbide ceramics and steel, characterized in that the composite structure includes carbide ceramics, a cemented carbide layer and a steel material matrix, wherein the carbide ceramics are bonded to the steel material matrix through the cemented carbide layer to form a metallurgical alloy, thereby giving it the microstructure characteristics of carbide ceramics-cemented carbide-steel. Preferably, the composite structure is made using the method described above.

[0024] In step 2 of this invention, the first temperature is below 1000 degrees Celsius, and the second temperature is above 1000 degrees Celsius.

[0025] In step 3 of this invention, if pressing and sintering is used, the sintering temperature is higher than 1000 degrees Celsius. If casting is used, the casting temperature is 20-100 degrees Celsius higher than the melting point of steel, preferably 1400-1700 degrees Celsius.

[0026] The carbide ceramics involved in this invention have a size of 0.5 mm or larger and are in the form of granules, plates, spheres, or flakes, but are not limited thereto. The carbide ceramics used in this invention are preferably mixtures of one or more of silicon carbide, boron carbide, chromium carbide, or molybdenum carbide, but are not limited thereto.

[0027] The steel or cast iron materials used in this invention include one or a mixture of several of high-chromium steel, high-manganese steel, low-alloy steel or ductile iron, but are not limited thereto.

[0028] The hard alloy layer used in this invention includes, but is not limited to, WC-Co, WC-Ni, TiC-Fe, and Ti(C,N)-Ni.

[0029] The cemented carbide process of this invention includes: ball milling micron-sized cemented carbide powder in a solution containing organic monomers, then reacting and encapsulating the organic matter dipped or sprayed on the surface of silicon carbide ceramic by thermal initiation or photoinitiation, and then forming a dense cemented carbide layer on the surface of silicon carbide ceramic after degreasing and sintering. Beneficial effects

[0030] This invention encapsulates a cemented carbide layer between carbide ceramics and steel using organic polymerization, thus preventing direct contact between the carbide ceramics and steel. This avoids reactions between the carbide ceramics and steel during sintering. Furthermore, since both carbide ceramics and cemented carbide layers are carbides, they readily bond together to form chemical bonds. Moreover, while the carbides in the cemented carbide layer do not readily react with steel or cast iron, they can dissolve into the steel or cast iron to form a solid solution. Simultaneously, Co or Ni in the cemented carbide layer can readily dissolve with iron, allowing for good bonding between the two materials. This invention thus solves the problem of composite materials between carbide ceramics and steel.

[0031] The composite structure prepared by the method of this invention has a stronger bond and higher hardness, impact toughness and wear resistance compared with the composite structure prepared by the traditional direct powder metallurgy sintering method or melting and casting method. Attached Figure Description

[0032] Figure 1 is a schematic flowchart of the composite structure preparation process according to the method of the present invention.

[0033] Figure 2 is a schematic diagram of the composite structure prepared by the method of the present invention. The upper part of the figure is a schematic diagram of the composite structure of granular or small block carbide ceramics and steel matrix; the lower part is a schematic diagram of the composite structure of plate-shaped carbide ceramics and steel matrix.

[0034] Figure 3 shows the crystal phase diagram of the reaction product in Example 2.

[0035] Figure 4 is a physical image of the reaction products in Example 4. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0037] This invention provides a composite structure of carbide ceramics and steel or cast iron, as well as its preparation method. In general, the method of this invention first coats carbide ceramic particles or blocks using dip-coating or spraying. After coating, a hard alloy layer is solidified onto the surface of the carbide ceramic through a curing reaction, forming a hard alloyed carbide ceramic. Then, it is composited with steel or cast iron using powder metallurgy or casting methods, ultimately producing a wear-resistant material with an internal structure of carbide ceramic-hard alloy layer-steel or cast iron: carbide ceramic / steel or carbide ceramic / cast iron.

[0038] The following section uses carbide ceramics as an example to illustrate in detail the method of combining carbide ceramics with steel. As shown in Figure 1, the method includes the following steps:

[0039] 1. Preparation of cemented carbide powder slurry

[0040] A certain proportion of cemented carbide powder, solvent, organic functional monomer, initiator, dispersant and thickener are added into a ball mill and ball-milled for a certain time to obtain cemented carbide powder slurry.

[0041] The cemented carbide powder comprises a hard phase powder and a binder phase powder. The hard phase powder includes, but is not limited to, one or more of the following: WC powder, TiC powder, titanium carbonitride (Ti(C,N)) powder, NbC powder, or TaC powder. The binder phase powder includes, but is not limited to, one or more of the following: Co powder, Ni powder, FeCo powder, or FeNi alloy powder. The cemented carbide powder accounts for 40% to 99% of the total weight of the slurry; the weight ratio of the hard phase powder to the binder phase powder is 1:10 to 100:0.1, preferably 1:10 to 10:1. Preferably, the combined mass of the hard phase powder and the binder phase powder accounts for 40% to 70% of the total mass of the cemented carbide powder slurry.

[0042] The solvent is alcohol, acetone, toluene, or a mixture thereof.

[0043] The organic functional monomers include, but are not limited to, one or more of the following: 1,6-hexanediol diacrylate, pentaerythritol hexaacrylate, hydroxyethyl acrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, and acrylic acid. The organic functional monomers mentioned in this invention refer to organic compounds capable of forming polymers with an initiator under thermal or photoinitiation conditions.

[0044] The initiator is either a thermal initiator or a photoinitiator. The thermal initiator is one or more of the following, but not limited to: benzoic acid peroxide, azobisisobutyronitrile, sodium azobiscyanopentate, sodium azo(2-(2-imidazoline)propane)hydrochloride, and azo(2-amidinylpropane)hydrochloride. The photoinitiator is one or more of the following, but not limited to: 1-hydroxycyclohexylphenyl ketone, trimethylbenzoyl-diphenylphosphine oxide, and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide. The amount of initiator added is 0.01% to 10% of the weight of the organic monomer. The initiator is added last, 0.01 h to 1 h before discharge.

[0045] The dispersant is one or more of ZN-1344, SP-710, and SP-6000, but is not limited to these. The amount of dispersant added is 0.01% to 10% of the weight of the cemented carbide powder.

[0046] The thickener is one or more of carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), polyvinyl butyral (PVB), and polyacrylamide (PAM), but is not limited to these. The amount of thickener added is 0.01% to 20% of the solvent weight.

[0047] The ball mill may be a drum ball mill or a planetary ball mill, but is not limited to these. The grinding balls are cemented carbide balls. The ball-to-material ratio is 1:10 to 10:1. The ball milling time is 0.1 h to 50 h.

[0048] The carbide ceramic is one or a mixture of several of silicon carbide, boron carbide, chromium carbide or molybdenum carbide, but is not limited thereto.

[0049] The carbide ceramics are in the millimeter scale or larger (0.5 mm or larger) and are in the form of granules, strips, spheres or flakes, but are not limited thereto.

[0050] The cemented carbide layer is WC-Co, WC-Ni, TiC-Fe, or Ti(C,N)-Ni, but is not limited to these. The thickness of the cemented carbide layer is 0.01 mm to 100 mm.

[0051] 2. Preparation of cemented carbide ceramics

[0052] The preparation of cemented carbide ceramics includes: coating the surface of the carbide ceramic with cemented carbide slurry by dip-coating or spraying; then loading the cemented carbide ceramic coated with cemented carbide slurry into a sintering furnace and performing metal debinding and sintering through thermal initiation or photoinitiation to obtain a carbide ceramic coated with a cemented carbide layer: carbide ceramic@cemented carbide. This step can be completed in the following way:

[0053] Method 1

[0054] (1) Immersion method

[0055] (1.1) Thermal Initiation Method: If the initiator added in step 1 is a thermal initiator, the carbide ceramic is immersed in the hard alloy slurry prepared in step 1 for 0.1 min to 60 min, then removed and placed in an oven at 50 to 100°C for baking for 0.01 h to 12 h. The organic matter in the slurry undergoes a polymerization reaction under the action of the initiator, coating the carbide ceramic. The coating thickness is controlled within the range of 0.01 mm to 100 mm. If the coating thickness does not meet the standard, the immersion process is repeated or the spraying method described below is performed.

[0056] (1.2) Photoinitiation method: If the initiator added in step 1 is a photoinitiator, the carbide ceramic is immersed in the hard alloy slurry prepared in step 1 for 0.1 min to 60 min, then removed and placed in an ultraviolet oven for irradiation for 0.01 h to 12 h. The organic matter in the slurry undergoes a polymerization reaction under the action of the initiator, coating the carbide ceramic. The coating thickness is controlled within the range of 0.01 mm to 100 mm. If the coating thickness does not meet the standard, the immersion process is repeated or the spraying method described below is performed.

[0057] Preferably, the hard alloy slurry is subjected to vacuum degassing treatment before impregnation.

[0058] Preferably, the dip-coating method is suitable for small-sized carbide ceramics, such as granular or spherical ones.

[0059] Method 2

[0060] (2) Spraying method

[0061] (2.1) If the initiator added in step 1 is a thermal initiator, the hard alloy slurry is uniformly sprayed onto the surface of the carbide ceramic using a spray bottle, and then placed in an oven at 50–100°C for baking for 0.01 h–12 h. The organic matter in the slurry reacts and coats the carbide ceramic. The coating thickness is controlled within the range of 0.01 mm–100 mm. If the coating thickness does not meet the standard, the dipping process is repeated or the spraying method described below is performed.

[0062] (2.2) If the initiator added in step 1 is a photoinitiator, the hard alloy slurry is uniformly sprayed onto the surface of the carbide ceramic using a spray bottle, and then placed in an ultraviolet oven for irradiation for 0.01 h to 12 h. The organic matter in the slurry reacts and coats the carbide ceramic. The coating thickness is controlled within the range of 0.01 mm to 100 mm. If the coating thickness does not meet the standard, the dipping process is repeated or the spraying method described below is performed.

[0063] Preferably, the hard alloy slurry is subjected to vacuum degassing treatment before spraying.

[0064] Preferably, the spraying method is suitable for larger carbide ceramics, such as strips or sheets.

[0065] 3. Composites of carbide ceramics with cemented carbide and steel or cast iron

[0066] By combining carbide ceramics with cemented carbide and steel or cast iron, wear-resistant materials with an internal structure of carbide ceramics-cemented carbide layer-steel or cast iron are obtained: carbide ceramics / steel or carbide ceramics / cast iron.

[0067] The steel or cast iron is one or a mixture of several of the following: high-chromium steel, high-manganese steel, low-alloy steel, or ductile iron, but is not limited thereto.

[0068] This step can be achieved using the following method:

[0069] (1) The hard alloyed carbide ceramic prepared in step 2 is mixed with steel powder or cast iron powder in a certain weight ratio, then put into a mold and pressed into a blank, and then put into a sintering furnace and sintered into a dense block material at a certain temperature.

[0070] The weight ratio of the carbide ceramic@hard alloy to steel powder or cast iron powder is 0.1:100 to 10:0.1.

[0071] The sintering temperature is 0.65 to 0.95 times the melting point of steel powder or cast iron powder.

[0072] Preferably, the dip-coating method is suitable for small-sized carbide ceramic@hard alloys, for example, granular or spherical.

[0073] (2) Casting method

[0074] The carbide ceramic@hard alloy prepared in step 2 is placed into the bottom of the mold. Steel or cast iron is heated to a certain temperature and melted, then poured onto its surface. At the same time, a vibration pump is used to vibrate the mold so that the liquid steel or cast iron is completely wetted with the carbide ceramic@hard alloy, and finally solidified into shape.

[0075] The melting temperature is 100°C or higher than the melting point of steel powder or cast iron powder.

[0076] Preferably, the casting method is suitable for larger-sized carbide ceramic@hard alloys, for example, in strip or sheet form.

[0077] Figure 2 shows a schematic diagram of the composite material formed by pressing, sintering, or casting. It should be noted that if sheet-like silicon carbide ceramics are used, their size should not be too large. Alternatively, if large sizes are used, large sheet-like materials are suitable for applications where impact resistance is not required.

[0078] Example 1

[0079] D50 The composite material consists of 10mm millimeter-sized silicon carbide ceramic particles and high-chromium cast iron Cr28, with a cemented carbide layer of WC-6Co(YG6).

[0080] In this example, the preparation process of the composite structure is as follows:

[0081] Weigh out 0.94 kg of WC powder (D 50 10μm), 0.06Kg Co powder (D 50 50g of toluene (2μm), 10g of hydroxyethyl methacrylate, 0.5g of methylenebisacrylamide, and 0.01g of dispersant SP-6000 were added to a drum ball mill containing 1kg of cemented carbide balls and ball-milled for 2 hours. Then, 5g of carboxymethyl cellulose was added in three portions and ball-milled for another hour. Finally, 0.1g of azobisisobutyronitrile was added and ball-milled for another hour to obtain a thermally initiated cemented carbide slurry.

[0082] Weigh 3 kg of millimeter-sized SiC ceramic particles (D 50 The particles (10 mm thick) are immersed in the above-mentioned cemented carbide slurry for 2 minutes, then removed and placed in an oven at 80°C for 1 hour (to initiate the polymerization reaction of the organic matter) until the surface slurry hardens. This process is repeated twice. The particles are then placed in a cemented carbide sintering furnace and heated to 600°C at 1°C / min under a hydrogen atmosphere, held for 1 hour, then the atmosphere is changed to nitrogen, and the temperature is increased to 1430°C at 5°C / min and held for 2 hours for degreasing and sintering to obtain particles with a cemented carbide layer on the silicon carbide surface, referred to here as SiC@YG6.

[0083] 2.5 kg of SiC@YG6 particles were weighed and placed into a steel mold placed on a vibration table. High-chromium cast iron Cr28, which was melted at 1500℃, was then placed on the vibration table until the liquid Cr28 completely entered the particle gaps and solidified, thus obtaining the SiC-Cr28 composite material.

[0084] The hardness, impact toughness, and wear resistance of the SiC-Cr28 composite material prepared in Example 1 were tested. The testing standards for hardness were GB / T 230.1-2018, impact toughness was GB / T229-2020, and wear resistance was GB / T 34501-2017. The tested hardness was 71.1 HRC, and the impact toughness was 3.2 J / cm². 2 The abrasive wear was 0.8 g / 10 min. The test results show that the overall performance parameters of the composite material prepared in this example are significantly better than those of using carbide ceramics, cemented carbide, or steel alone.

[0085] Crystal phase analysis of the SiC-Cr28 composite material prepared in Example 1 revealed a hard alloy transition layer of about 1 mm between SiC and Cr28.

[0086] Example 2, D 50 The composite material consists of 20mm-sized silicon carbide ceramic particles and low-carbon steel Q235, with a WC-15Ni cemented carbide layer.

[0087] In this example, the preparation process of the composite structure is as follows:

[0088] Weigh 0.85 kg of WC powder (D) 50 10μm), 0.15Kg Ni powder (D 50 40g of hydroxyethyl methacrylate (2μm), 10g of pentaerythritol triacrylate, and 0.1g of dispersant ZN-1344 were added to a drum ball mill containing 1.2Kg of cemented carbide balls and ball-milled for 1.5h. Then, 6g of polyvinyl alcohol was added in three portions and ball-milled for another 1h. Finally, 0.1g of benzoic acid peroxide was added and ball-milled for another 0.5h to obtain a thermally initiated cemented carbide slurry.

[0089] Weigh 3 kg of millimeter-sized SiC ceramic particles (D 50 The particles (20 mm thick) were immersed in the above-mentioned cemented carbide slurry for 2 minutes, then removed and baked in an oven at 70°C for 2 hours until the surface slurry hardened. This process was repeated three times. The particles were then placed in a cemented carbide sintering furnace and heated to 620°C at 0.5°C / min under a hydrogen atmosphere, held for 1 hour, then the atmosphere was changed to nitrogen, and the temperature was increased to 1470°C at 5°C / min and held for 2 hours for degreasing and sintering to obtain particles with a cemented carbide layer on the silicon carbide surface, referred to here as SiC@WC-15Ni.

[0090] 3 kg of SiC@WC-15Ni particles were weighed and placed into a steel mold placed on a vibrating table. Low-carbon steel Q235, which was melted at 1600℃, was then placed on the vibrating table until the liquid low-carbon steel Q235 completely entered the particle gaps and solidified, thus obtaining the SiC-low-carbon steel Q235 composite material.

[0091] The hardness, impact toughness, and wear resistance of the SiC-Q235 composite material prepared in Example 2 were tested. The testing standards for hardness were GB / T 230.1-2018, impact toughness was GB / T229-2020, and wear resistance was GB / T 34501-2017. The tested hardness was 72.3 HRC, and the impact toughness was 4.8 J / cm². 2 Abrasive wear is 0.7g / 10min.

[0092] Crystal phase analysis of the SiC-Q235 composite material prepared in Example 2 revealed a cemented carbide transition layer of approximately 2 mm between SiC and Q235. The crystal phase diagram is shown in Figure 3, where the left side represents the matrix material, the right side represents the silicon carbide material, and a certain transition region exists in the middle, indicated by blue.

[0093] Example 3, D 50 A composite of 15mm millimeter-sized silicon carbide ceramic particles and ductile cast iron HT, with a TiC-10Co cemented carbide layer.

[0094] In this example, the preparation process of the composite structure is as follows:

[0095] Weigh 0.90 kg TiC(D) 50 10μm), 0.1Kg Co powder (D 50 20g of alcohol, 30g of hydroxyethyl acrylate, 10g of trimethylolpropane triacrylate, and 0.05g of dispersant SP-710 were added to a drum ball mill containing 1kg of cemented carbide balls and ball-milled for 2 hours. Then, 4g of polyacrylamide was added in three portions and ball-milled for another hour. Finally, 0.1g of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide was added and ball-milled for another hour to obtain a photoinitiable cemented carbide slurry.

[0096] Weigh 4 kg of millimeter-sized silicon carbide ceramic particles (D 50 The particles (15 mm thick) were immersed in the above-mentioned cemented carbide slurry for 2 minutes, then removed and placed in an ultraviolet oven for irradiation for 1.5 hours until the surface slurry hardened. This process was repeated twice. The particles were then placed in a cemented carbide sintering furnace and heated to 600°C at 1°C / min under a hydrogen atmosphere and held for 1 hour. The atmosphere was then changed to nitrogen, and the temperature was increased to 1480°C at 5°C / min and held for 2 hours for degreasing and sintering to obtain particles with a cemented carbide layer on the surface of silicon carbide, referred to here as silicon carbide SiC@TiC-10Co.

[0097] 2.5 kg of silicon carbide@TiC-10Co particles and 5 kg of spherical cast iron powder (HT powder) were weighed and mixed evenly, then loaded into a steel mold and pressed into shape under 20 MPa. After sintering at 1100 °C for 2 hours under vacuum, silicon carbide-spherical cast iron (HT) composite material was obtained.

[0098] The hardness, impact toughness, and wear resistance of the SiC-HT composite material prepared in Example 3 were tested. The testing standards for hardness were GB / T 230.1-2018, impact toughness was GB / T229-2020, and wear resistance was GB / T 34501-2017. The tested wear-resistant material had a hardness of 68.3 HRC and an impact toughness of 4.1 J / cm². 2Abrasive wear is 0.85 g / 10 min.

[0099] Crystal phase analysis of the SiC-HT composite material prepared in Example 3 revealed a hard alloy transition layer of about 1.3 mm between SiC and HT.

[0100] Example 4, D 50 The composite of 8mm boron carbide ceramic particles and NM600 manganese steel, with a hard alloy layer of WC-20Co (Co content accounts for 20% of the total mass).

[0101] In this example, the preparation process of the composite structure is as follows:

[0102] Weigh 0.80 kg of WC powder (D 50 10μm), 0.20Kg Co powder (D 50 50g of toluene (10μm), 10g of hydroxyethyl methacrylate, 0.5g of methylenebisacrylamide, and 0.02g of dispersant SP-6000 were added to a drum ball mill containing 1kg of cemented carbide balls and ball-milled for 1 hour. Then, 6g of methylcellulose was added in four portions and ball-milled for another 0.5 hours. Finally, 0.2g of trimethylbenzoyl-diphenylphosphine oxide was added and ball-milled for another hour to obtain a photoinitiable cemented carbide slurry.

[0103] Weigh 3 kg of millimeter-sized boron carbide ceramic particles (D 50 The 8mm particles were immersed in the above-mentioned cemented carbide slurry for 2 minutes, then removed and placed in an ultraviolet oven for irradiation for 1.5 hours until the surface slurry hardened. This process was repeated three times. The particles were then placed in a cemented carbide sintering furnace and heated to 600°C at 0.5°C / min under a hydrogen atmosphere and held for 2 hours. The atmosphere was then changed to nitrogen, and the temperature was increased to 1450°C at 6°C / min and held for 2 hours for degreasing and sintering to obtain particles with a cemented carbide layer on the surface of boron carbide, referred to here as boron carbide@WC-20Co.

[0104] Weigh 2.5 kg of boron carbide@WC-20Co particles and place them in a steel mold on a vibration table. Melt manganese steel NM600 at 1650℃ is then injected into the steel mold. The vibration table is turned on until the liquid manganese steel NM600 completely enters the particle gaps and solidifies, thus obtaining the boron carbide-manganese steel NM600 composite material.

[0105] The hardness, impact toughness, and wear resistance of the boron carbide-NM600 composite material prepared in Example 4 were tested. The testing standards for hardness were GB / T 230.1-2018, impact toughness GB / T 229-2020, and wear resistance GB / T 34501-2017. The tested hardness was 68.6 HRC, and the impact toughness was 2.8 J / cm².2 Abrasive wear is 1.9g / 10min.

[0106] Crystal phase analysis of the boron carbide-NM600 composite material prepared in Example 4 revealed a hard alloy transition layer of about 1.6 mm between boron carbide and HT.

[0107] The test results show that the comprehensive performance parameters of the composite materials prepared in Examples 2-4 of the present invention are significantly better than those of carbide ceramics, cemented carbide or steel materials used alone.

[0108] Example 5

[0109] In this example, silicon carbide particles are directly cast into steel to form a composite. First, silicon carbide particles are placed into a mold, and then molten high-chromium cast iron (Cr28) at 1500℃ is poured into it. When the molten steel comes into direct contact with the silicon carbide, the two react directly, forming complex iron silicides and graphite, significantly deteriorating the interfacial bonding performance. The resulting product is shown in Figure 4; the reaction between silicon carbide and steel leaves numerous defects. Figure 4 shows the pores left by the direct reaction of silicon carbide and steel at high temperature, with almost no silicon carbide remaining.

[0110] Example 6

[0111] In this example, silicon carbide particles and steel powder were composited using powder metallurgy sintering. The silicon carbide particles and Cr28 powder were uniformly mixed and pressed into a billet, which was then gradually heated. When the temperature reached above 800℃, the two materials began to react, forming complex iron silicides and graphite, significantly deteriorating the interfacial bonding performance. The resulting material had numerous defects and poor wear resistance. Normal powder metallurgy sintering temperatures are above 1200℃; however, considering the potential reaction, the temperature was only raised to 800℃, without further increases.

[0112] Although the principles of the present invention have been described in detail above with reference to preferred embodiments, those skilled in the art should understand that the above embodiments are merely illustrative explanations of the implementation of the present invention and are not intended to limit the scope of the present invention. The details in the embodiments do not constitute a limitation on the scope of the present invention. Any obvious changes, such as equivalent transformations or simple substitutions, based on the technical solutions of the present invention without departing from the spirit and scope of the present invention fall within the protection scope of the present invention.

Claims

1. A method for producing a composite structure of a carbide ceramic and a steel, characterized by, The method includes the following steps: 1) Prepare cemented carbide powder slurry, wherein the cemented carbide powder slurry comprises at least: hard phase powder, binder phase powder, solvent, initiator and organic functional monomer matched with the initiator; 2) Hard alloying treatment of carbide ceramics using the hard alloy powder slurry. This step includes coating the surface of the carbide ceramics with the hard alloy powder slurry, treating the coated carbide ceramics with UV light irradiation or heating to induce the initiator to initiate the polymerization reaction of the organic functional monomers to form a polymer, thereby coating the surface of the carbide ceramics with a hard alloy slurry solidification layer; then sintering the carbide ceramics coated with hard alloy slurry to solidify the hard alloy powder, thereby achieving hard alloying of the silicon carbide ceramic surface. 3) The hard alloyed carbide ceramic obtained in step 2) is mixed with steel powder or cast iron powder in a certain proportion, pressed into a blank, and sintered at a predetermined temperature to obtain a carbide / steel composite material with the internal structure of carbide ceramic-hard alloy layer-steel; or, molten steel is cast into a mold containing the hard alloyed carbide ceramic obtained in step 2), and after solidification, a carbide / steel composite material with the internal structure of carbide ceramic-hard alloy layer-steel is obtained.

2. The method of making a composite structure according to claim 1, wherein, The mass and volume ratio of hard phase powder and binder powder to the total slurry are 20% to 80%, and the remaining part is a mixture of solvent, initiator and organic functional monomer. The mass ratio of organic functional monomer to solvent in the mixture is 1:99 to 30:70, and the amount of initiator added is 0.01% to 10% of the weight of organic monomer.

3. The method of making a composite structure of claim 2, wherein, The mass and volume ratio of the hard phase powder and the binder phase powder to the total slurry are 30% to 50%; the weight ratio of the hard phase powder and the binder phase powder is 1:10 to 100:0.

1.

4. The method of making a composite structure of claim 4, wherein, The weight ratio of the hard phase powder to the binder phase powder is 1:10 to 10:

1.

5. The method of making a composite structure of claim 3, wherein, The hard phase powder includes one or more of the following: WC powder, TiC powder, titanium carbonitride powder, NbC powder or TaC powder; the binder phase powder includes one or more of the following: Co powder, Ni powder, FeCo powder, FeNi alloy powder.

6. The method for preparing the composite structure according to claim 1, characterized in that, The hard alloy powder slurry further includes a dispersant and a thickener. The dispersant is one or a mixture of several of ZN-1344, SP-710, and SP-6000. The dispersant accounts for 0.01% to 10% of the total mass of the hard phase powder and the binder phase powder. The thickener includes one or a mixture of several of carboxymethyl cellulose (CMC), polyvinyl alcohol (PVA), polyvinyl butyral (PVB), and polyacrylamide (PAM).

7. The method of making a composite structure of claim 1, wherein, In step 2), the process of coating the cemented carbide powder slurry onto the surface of the cemented carbide powder slurry includes: coating the cemented carbide slurry onto the surface of the carbide ceramic by dip coating or spraying, and obtaining the cemented carbide ceramic after degreasing and sintering. During degreasing and sintering, the temperature is gradually increased to a first temperature under a hydrogen atmosphere and then held at that temperature. The atmosphere is then converted to nitrogen, and the temperature is gradually increased to a second temperature and held at that temperature. The first temperature is below 1000 degrees Celsius, and the second temperature is above 1000 degrees Celsius. In step 3, if a pressing sintering method is used, the sintering temperature is above 1000 degrees Celsius; if a casting method is used, the casting temperature is 20-100 degrees Celsius higher than the melting point of steel.

8. The method of making a composite structure of claim 1, wherein, The organic functional monomers include one or a mixture of several of the following: 1,6-hexanediol diacrylate, pentaerythritol hexaacrylate, hydroxyethyl acrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, and acrylic acid. The initiator is a photoinitiator or a thermal initiator, and the thermal initiator includes one or more of the following: benzoic acid peroxide, azobisisobutyronitrile, sodium azobiscyanopentate, sodium azo(2-(2-imidazoline)propane)hydrochloride, and azo(2-amidinylpropane)hydrochloride. The photoinitiator includes one or more of 1-hydroxycyclohexylphenyl ketone, trimethylbenzoyl-diphenylphosphine oxide, and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

9. The method of making a composite structure of claim 1, wherein, The carbide ceramic includes one or a mixture of several of silicon carbide, boron carbide, chromium carbide or molybdenum carbide, and the size of the carbide ceramic is greater than or equal to 0.5 mm, and the morphology is granular, lath-shaped, spherical or flake-shaped.

10. The method of making a composite structure of claim 1, wherein, In step (1), when preparing the hard alloy powder slurry, the hard phase powder, binder powder, solvent and organic functional monomer are first mixed and stirred. 0.01h to 1h before the mixing and stirring is completed, the initiator is added and the mixing and stirring continues.

11. The method of making a composite structure of claim 7, wherein, The casting temperature is 1400-1700 degrees Celsius.

12. A composite structure of carbide ceramic and steel, characterized by The composite structure includes a carbide ceramic, a cemented carbide layer, and a steel material matrix. The carbide ceramic is bonded to the steel material matrix through the cemented carbide layer to form a metallurgical alloy, giving it the microstructure characteristics of carbide ceramic-cemented carbide-steel. The composite structure is made by the method described in any one of claims 1-9.

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