Diamond-silicon carbide-titanium composite material and method of making and use

Abstract

The present application belongs to the technical field of ceramic composite material manufacturing, and particularly relates to a diamond-silicon carbide-titanium composite material and a preparation method and application thereof. The present application takes silicon powder as a main body, adds vanadium, chromium and molybdenum elements for modification as a bonding agent, and is segregated at a grain boundary in a sintering process, so that the excessive growth of silicon carbide grains is inhibited by pinning the grain boundary migration, and two-step temperature and pressure sintering is combined, which is beneficial to the densification of the product in the sintering process. The introduction of the titanium grain boundary regulator reduces the content of free silicon in the titanium-free diamond-silicon carbide composite material, so that the prepared diamond-silicon carbide-titanium composite material has excellent mechanical properties and wear resistance. The diamond-silicon carbide-titanium composite material prepared by the present application is applied to wear-resistant parts, such as wear-resistant nozzles or diamond cutting tools, so that the strength and fracture resistance of the product are improved.

Description

Technical Field

[0001] This invention belongs to the field of ceramic composite material manufacturing technology, specifically relating to diamond-silicon carbide-titanium composite materials, their preparation methods, and applications. Background Technology

[0002] In wear-resistant and tool applications, common types of diamond composite materials mainly refer to polycrystalline diamond prepared by the high-temperature, high-pressure (HTHP) method and the subsequently developed ceramic-based diamond composite materials. HTHP-prepared polycrystalline diamond essentially enhances the extreme performance of diamond composite materials by sacrificing the low cost of traditional diamond tools, thus meeting the requirements of high-performance cutting tools and mining drill bits. Diamond particles are sintered in a cobalt binder under high temperature and pressure to form a nearly continuous diamond framework. The cobalt required in the preparation process catalyzes the graphitization of diamond at the high temperatures generated during material use, causing the performance of polycrystalline diamond to degrade and fail above 700°C. Ceramic-based diamond composite materials bond diamond particles together by reacting silicon to form silicon carbide. Although this eliminates the cobalt present in polycrystalline diamond, thus increasing the material's operating temperature by at least 300°C compared to polycrystalline diamond, these materials often contain 5-12 wt% residual silicon, resulting in fracture toughness and strength similar to reaction-sintered silicon carbide, lower than polycrystalline diamond.

[0003] Chinese invention patent CN115338420B discloses polycrystalline diamond precursor materials and their preparation methods, polycrystalline diamond and its preparation methods, and polycrystalline diamond composite materials and their preparation methods, belonging to the field of superhard materials technology. The preparation method of the polycrystalline diamond precursor material of this invention employs a wet mixing process. First, diamond particles, a nonionic surfactant, and a solvent are mixed to obtain a mixture. Then, a powdered binder is added to the mixture, allowing the powdered binder to be uniformly dispersed and adsorbed on the surface of the diamond particles under the action of the nonionic surfactant, forming an encapsulation of diamond particles and powdered binder. After drying, a polycrystalline diamond precursor material with uniform composition is obtained. This invention's preparation method of the polycrystalline diamond precursor material can solve the problem that diamond particles are prone to agglomeration during mixing due to their small particle size, resulting in poor microstructure and uneven component distribution in the prepared polycrystalline diamond. It can improve the wear resistance and toughness of the prepared polycrystalline diamond. To address the limitations in performance, phase characteristics, and production costs of the aforementioned materials, the present invention aims to provide a diamond composite material that balances preparation cost and material performance. Its production cost is significantly lower than that of PCD materials, its maximum service temperature and thermal shock resistance are significantly higher than those of PCD materials, and its material design flexibility, fracture toughness, and strength are superior to ceramic-based diamond / silicon carbide composite materials. This composite material exhibits stable thermal shock resistance, with diamond and ceramic bonded by strong covalent bonds and a tunable grain boundary structure, allowing it to be manufactured using ceramic production processes. Summary of the Invention

[0004] The purpose of this invention is to provide a diamond-silicon carbide-titanium-based composite material prepared by vacuum / atmosphere hot pressing sintering and its preparation method. This material uses a mixture of diamond particles, bonding agent powder, and titanium powder as a grain boundary modifier as raw materials, prepared by hot pressing sintering. During the hot pressing sintering process, the main crystalline phase diamond particles are firmly bonded to silicon carbide generated by the bonding agent through high-temperature reaction sintering. Titanium or a titanium-silicon alloy formed by titanium and silicon bonding agents fills the grain boundaries, improving the mechanical properties of the material. When the product phases are controlled in an appropriate proportion, especially when the residual elemental free silicon decreases sharply due to the presence of titanium, the composite material can achieve 30-50% higher flexural strength and fracture toughness than the corresponding titanium-free diamond-silicon carbide reference system.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: Diamond-silicon carbide-titanium composite material is prepared from the following raw materials in the indicated mass percentages: 61.5-65% diamond particles, 4-7.5% titanium grain boundary modifier, and 28-35% bonding agent; The diamond particles are composed of coarse diamond particles and fine diamond particles in a mass ratio of 50~60:40~50, with the average particle size of the coarse diamond particles being 20~30μm and the average particle size of the fine diamond particles being 7~10μm. The bonding agent is one or more combinations of silicon powder, carbon powder, chromium powder and molybdenum powder; The titanium grain boundary modifier is pure titanium powder with an average particle size of 10~20μm and a purity of 99.99%.

[0006] The preparation method of diamond-silicon carbide-titanium composite material includes the following steps: S1. Add diamond particles to hydrochloric acid and heat to clean, then add sodium hydroxide aqueous solution and heat to clean, filter to remove diamond particles, wash with deionized water until neutral, vacuum dry, and set aside. S2. Mix diamond particles, bonding agent and titanium grain boundary modifier, add polyvinyl butyral binder and mix to obtain a mixture, and load the mixture into a graphite mold. S3. The graphite mold is placed in the sintering furnace, the vacuum is drawn and the air is exhausted. The furnace is heated and pressurized for sintering. The mold is then cooled to room temperature and demolded to obtain the diamond-silicon carbide-titanium composite material.

[0007] Preferably, in step S1, the hydrochloric acid concentration is 30-35 wt%, the temperature is raised to 60-70℃ for 30-40 min, the sodium hydroxide aqueous solution concentration is 25-30 wt%, the temperature is raised to 80-90℃ for 30-40 min, and then vacuum dried at 50-60℃ for 2-4 h.

[0008] Preferably, the amount of polyvinyl butyral binder added in S2 is 1-5% of the total mass of diamond particles, bonding agent and titanium grain boundary modifier. The polyvinyl butyral binder is diluted with ethanol to a concentration of 20-25 wt% in ethanol and mixed at a speed of 300-500 rpm for 20-30 min. After adding the polyvinyl butyral binder, it is mixed at a speed of 1500-2000 rpm for 20-30 min.

[0009] Preferably, in step S3, the vacuum degree is 1~5 Pa, the temperature is increased to 500~550℃ at a heating rate of 5~10℃ / min, the vacuum degree needs to be less than 0.01 Pa, the temperature is held for 20~30 min, then the temperature is increased to 1320~1450℃ at a heating rate of 10~15℃ / min, the pressure is increased to 25~40 MPa, the temperature is held for sintering for 10~30 min, and the temperature is increased to 1540~1660℃ at a heating rate of 20~30℃ / min, the pressure is held for sintering for 30~60 min.

[0010] Diamond-silicon carbide-titanium composite materials are used to manufacture wear-resistant parts.

[0011] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. This invention uses polyvinyl butyral as a binder. During the subsequent vacuum debinding stage, polyvinyl butyral can achieve rapid and complete decomposition and volatilization, leaving almost no residual carbon. This significantly reduces the risk of defects such as blistering and cracking in the green body during the debinding stage, thus ensuring the uniformity and integrity of the green body before sintering. Combined with two-step heating and pressurizing sintering, this facilitates densification of the product during the sintering process. The introduction of a titanium grain boundary regulator reduces the free silicon content in the titanium-free diamond-silicon carbide composite material, giving the resulting diamond-silicon carbide-titanium composite material excellent mechanical properties and wear resistance.

[0012] 2. The bonding agent of the present invention agglomerates at the grain boundaries during sintering, which inhibits the excessive growth of silicon carbide grains by pinning grain boundary migration, thereby improving the strength and toughness of the diamond-silicon carbide-titanium composite material.

[0013] 3. This invention applies high-performance composite materials to wear-resistant parts, matching their coefficient of thermal expansion with that of diamond-silicon carbide-titanium composite materials. This reduces residual stress at the interface caused by the mismatch in thermal expansion between the two materials, improves the wear resistance and toughness of the prepared diamond composite material, and ensures that the high toughness of the composite material itself is not weakened in the tool. Detailed Implementation

[0014] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] Example 1, this example serves as a comparative reference example of titanium-free diamond-silicon carbide composite material. No titanium grain boundary modifier or bonding agent is added; only silicon powder is used to prepare the diamond-silicon carbide composite material. The preparation method includes the following steps: S1. Add diamond particles to 35wt% hydrochloric acid and heat to 60℃ for 30 min, then add to 25wt% sodium hydroxide aqueous solution and heat to 90℃ for 30 min. Filter to remove diamond particles, wash with deionized water until neutral, and vacuum dry at 60℃ for 4 h for later use. The diamond particles are composed of coarse diamond particles and fine diamond particles in a mass ratio of 50:50. The average particle size of the coarse diamond particles is 24 μm, and the average particle size of the fine diamond particles is 7.5 μm. S2. Mix 64.87g of diamond particles and 35.13g of silicon bonding agent at 500rpm for 30min, add 4g of polyvinyl butyral, dilute polyvinyl butyral with ethanol to a concentration of 20wt% in ethanol, wet grind and mix at 2000rpm for 30min to obtain a mixture, and load the mixture into a graphite mold. S3. The graphite mold is placed in a sintering furnace and the vacuum degree is 5 Pa. The temperature is increased to 500°C at a heating rate of 5°C / min, and the vacuum degree is reduced to 0.005 Pa. The temperature is held for 30 min, and then the temperature is increased to 1400°C at a heating rate of 12°C / min. The pressure is increased to 25 MPa and the temperature is held for sintering for 10 min. The temperature is increased to 1600°C at a heating rate of 30°C / min and the pressure is held for sintering for 30 min. The temperature is then cooled to room temperature in the furnace and demolded to obtain the diamond-silicon carbide composite material.

[0016] Example 2, the preparation method of the diamond-silicon carbide-titanium composite material in this example includes the following steps: S1. Add diamond particles to 31wt% hydrochloric acid and heat to 63℃ for 33 min, then add to 26wt% sodium hydroxide aqueous solution and heat to 83℃ for 33 min. Filter to remove diamond particles, wash with deionized water until neutral, and vacuum dry at 53℃ for 2.5 h for later use. The diamond particles are a mixture of coarse diamond particles and fine diamond particles in a mass ratio of 53:47. The average particle size of the coarse diamond particles is 23 μm, and the average particle size of the fine diamond particles is 8 μm. S2. Mix 62.58g of diamond particles, 30.13g of bonding agent and 7.29g of titanium grain boundary modifier at 400rpm for 30min. The titanium grain boundary modifier is pure titanium powder with an average particle size of 13μm and a purity of 99.99%. The bonding agent is silicon powder. Add 2g of polyvinyl butyral. Dilute the polyvinyl butyral with ethanol to a concentration of 21wt% in ethanol. Wet mill and mix at 1650rpm for 23min to obtain a mixture. Load the mixture into a graphite mold. S3. The graphite mold is placed in a sintering furnace and the vacuum degree is 2 Pa. The temperature is increased to 520°C at a heating rate of 7°C / min until the vacuum degree reaches 0.006 Pa. The temperature is held for 20 min, then increased to 1320°C at a heating rate of 12°C / min and pressurized to 28 MPa. The temperature is held for sintering for 16 min, then increased to 1660°C at a heating rate of 30°C / min and held for sintering for 38 min. The mold is then cooled to room temperature in the furnace and demolded to obtain the diamond-silicon carbide-titanium composite material.

[0017] Example 3, the preparation method of the diamond-silicon carbide-titanium composite material in this example includes the following steps: S1. Add diamond particles to 34wt% hydrochloric acid and heat to 68℃ for 38 min, then add to 29wt% sodium hydroxide aqueous solution and heat to 88℃ for 38 min. Filter to remove diamond particles, wash with deionized water until neutral, and vacuum dry at 58℃ for 3.5 h for later use. The diamond particles are a mixture of coarse diamond particles and fine diamond particles in a mass ratio of 58:42. The average particle size of the coarse diamond particles is 28 μm, and the average particle size of the fine diamond particles is 9.5 μm. S2. Mix 61.93g of diamond particles, 31.58g of bonding agent and 6.49g of titanium grain boundary modifier at 300rpm for 20min. The titanium grain boundary modifier is pure titanium powder with an average particle size of 18μm and a purity of 99.99%. The bonding agent is prepared by mixing 29.52g of silicon powder and 2.06g of chromium powder. Add 4g of polyvinyl butyral, which is diluted with ethanol to a concentration of 24wt% in ethanol. Wet mill and mix at 1900rpm for 28min to obtain a mixture. Load the mixture into a graphite mold. S3. The graphite mold is placed in a sintering furnace and the vacuum degree is 4 Pa. The temperature is increased to 540°C at a heating rate of 9°C / min until the vacuum degree reaches 0.004 Pa. The temperature is held for 25 min, then increased to 1440°C at a heating rate of 14°C / min and pressurized to 36 MPa. The temperature is held for sintering for 25 min, then increased to 1590°C at a heating rate of 28°C / min and held for sintering for 55 min. The mold is then cooled to room temperature in the furnace and demolded to obtain the diamond-silicon carbide-titanium composite material.

[0018] Example 4, the preparation method of the diamond-silicon carbide-titanium composite material in this example includes the following steps: S1. Add diamond particles to 35wt% hydrochloric acid and heat to 70℃ for 40 min, then add to 30wt% sodium hydroxide aqueous solution and heat to 90℃ for 40 min. Filter to remove diamond particles, wash with deionized water until neutral, and vacuum dry at 60℃ for 4 h for later use. The diamond particles are a mixture of coarse diamond particles and fine diamond particles in a mass ratio of 60:40. The average particle size of the coarse diamond particles is 30 μm, and the average particle size of the fine diamond particles is 8 μm. S2. Mix 61.93g of diamond particles, 31.58g of bonding agent and 6.49g of titanium grain boundary modifier at 350rpm for 25min. The titanium grain boundary modifier is pure titanium powder with an average particle size of 20μm and a purity of 99.99%. The bonding agent is prepared by mixing 29.52g of silicon powder, 1.06g of molybdenum powder and 1g of chromium powder. Add 5g of polyvinyl butyral, which is diluted with ethanol to a concentration of 25wt% in ethanol. Wet mill and mix at 2000rpm for 30min to obtain a mixture. Load the mixture into a graphite mold. S3. The graphite mold is placed in a sintering furnace and the vacuum degree is 5 Pa. The temperature is increased to 550°C at a heating rate of 10°C / min until the vacuum degree reaches 0.003 Pa. The temperature is then increased to 1450°C at a heating rate of 15°C / min, and the pressure is increased to 40 MPa. The temperature is held for sintering for 30 min. The temperature is then increased to 1600°C at a heating rate of 30°C / min and held for sintering for 60 min. The temperature is then cooled to room temperature in the furnace and demolded to obtain the diamond-silicon carbide-titanium composite material.

[0019] Comparative Example 1 differs from Example 1 in that the bonding agent is replaced with a bonding agent prepared by mixing 25g of graphite powder and 65g of silicon powder.

[0020] Comparative Example 2 differs from Example 1 in that polyvinyl butyral is replaced with phenolic resin.

[0021] Comparative Example 3 differs from Example 2 in that the sintering process in S3 is replaced by a vacuum degree of 0.005 Pa, directly heating to 1660 °C at 10 °C / min, pressurizing to 25 MPa, holding for sintering for 60 min, and then cooling with the furnace.

[0022] Performance testing The diamond-silicon carbide-titanium composite materials prepared in each embodiment and comparative example were cut into 1cm×1cm×1cm samples. The initial mass of the samples was weighed in air using an electronic balance. The samples were then completely immersed in deionized water at 20±0.5℃ and their mass in the deionized water was weighed. The density was calculated according to the following formula. The measurements were taken three times and the average value was taken.

[0023] ; This is the density of the sample, in g / cm³. 3 ; The density of deionized water at 20℃ is 0.9982 g / cm³. 3 ; m1 is the initial mass of the sample in air, in grams; m2 is the mass of the sample in deionized water, in grams.

[0024] The fracture toughness of diamond-silicon carbide-titanium composite materials prepared in each example and comparative example was measured according to GB / T 23806-2025 "Test Method for Fracture Toughness of Fine Ceramics - Single-sided Precracked Beam (SEPB) Method".

[0025] The flexural strength of the diamond-silicon carbide-titanium composite materials prepared in each example and comparative example was measured according to GB / T 6569-2006 "Test Method for Bending Strength of Fine Ceramics".

[0026] The test results are shown in Table 1 below: Table 1 Test Results

[0027] As shown in Table 1 above, the densities of the diamond-silicon carbide-titanium composite materials prepared in Examples 2-4 are 3.38-3.54 g / cm³. 3 The fracture toughness is 4.8~6.0 MPa×m. 0.5 The flexural strength was 450~550MPa, significantly better than the titanium-free diamond-silicon carbide comparative example. In Comparative Example 3, the sintering process in step S3 was replaced with a vacuum of 0.005Pa, directly heating to 1660℃ at 10℃ / min, pressurizing to 25MPa, and holding for 60min. This one-step sintering resulted in insufficient densification of the diamond-silicon carbide-titanium composite material, with a fracture toughness of only 3.9MPa×m. 0.5The bending strength is only 350 MPa, indicating that the diamond-silicon carbide-titanium composite material prepared by the two-step sintering method provided by this invention is beneficial for densification during the sintering process. The introduction of titanium grain boundary modifier reduces the free silicon content in the titanium-free diamond-silicon carbide composite material, thus giving the material excellent bending resistance and crack resistance.

[0028] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0029] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A diamond-silicon carbide-titanium composite material, characterized in that, It is made from the following raw materials in the indicated mass percentages: 61.5-65% diamond particles, 4-7.5% titanium grain boundary modifier, and 28-35% bonding agent.

2. The diamond-silicon carbide-titanium composite material according to claim 1, characterized in that, The diamond particles are composed of coarse diamond particles and fine diamond particles in a mass ratio of 50~60:40~50, with the average particle size of the coarse diamond particles being 20~30μm and the average particle size of the fine diamond particles being 7~10μm. The bonding agent is one or more combinations of silicon powder, carbon powder, chromium powder and molybdenum powder; The titanium grain boundary modifier is pure titanium powder with an average particle size of 10~20μm and a purity of 99.99%.

3. The method for preparing the diamond-silicon carbide-titanium composite material according to claims 1-2, characterized in that, Includes the following steps: S1. Add diamond particles to hydrochloric acid and heat to clean, then add sodium hydroxide aqueous solution and heat to clean, filter to remove diamond particles, wash with deionized water until neutral, vacuum dry, and set aside. S2. Mix diamond particles, bonding agent and titanium grain boundary modifier, add polyvinyl butyral binder and mix to obtain a mixture, and load the mixture into a graphite mold. S3. The graphite mold is placed in the sintering furnace, the vacuum is drawn and the air is exhausted. The furnace is heated and pressurized for sintering. The mold is then cooled to room temperature and demolded to obtain the diamond-silicon carbide-titanium composite material.

4. The diamond-silicon carbide-titanium composite material according to claim 3, characterized in that, The hydrochloric acid concentration in S1 is 30-35 wt%, and the temperature is raised to 60-70℃ for 30-40 min. The sodium hydroxide aqueous solution concentration is 25-30 wt%, and the temperature is raised to 80-90℃ for 30-40 min. Then, it is vacuum dried at 50-60℃ for 2-4 h.

5. The method for preparing the diamond-silicon carbide-titanium composite material according to claim 3, characterized in that, The amount of polyvinyl butyral binder added in S2 is 1-5% of the total mass of diamond particles, bonding agent and titanium grain boundary modifier. The polyvinyl butyral binder is diluted with ethanol to a concentration of 20-25 wt% in ethanol and mixed at a speed of 300-500 rpm for 20-30 min. After adding the polyvinyl butyral binder, it is mixed at a speed of 1500-2000 rpm for 20-30 min.

6. The method for preparing the diamond-silicon carbide-titanium composite material according to claim 3, characterized in that, In step S3, the vacuum degree is 1~5 Pa. After heating to 500~550℃ at a heating rate of 5~10℃ / min, the vacuum degree must be less than 0.01 Pa. Hold at this temperature for 20~30 min, then heat to 1320~1450℃ at a heating rate of 10~15℃ / min, pressurize to 25~40MPa, hold at this temperature for sintering for 10~30 min, and then heat to 1540~1660℃ at a heating rate of 20~30℃ / min and hold at this pressure for sintering for 30~60 min.

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