A structural ceramic material, a method of manufacture, applications and a nozzle

Abstract

The application discloses a structural ceramic material, a preparation method and application and a nozzle, and belongs to the technical field of the nozzle for the Yellow River water sprinkling irrigation. The structural ceramic material comprises a base and an added phase, wherein the base is (Ti, W)C, and the added phase is Ti3SiC2, and the structural ceramic material is prepared by adopting discharge plasma coupling high-frequency induction sintering. Ti3SiC2 uniformly dispersed in the (Ti, W)C base is used as a sintering aid, the good electric conductivity and high thermal conductivity of the Ti3SiC2 are utilized, the discharge sintering effect is strengthened and the heat conduction is accelerated, the sintering performance of the (Ti, W)C ceramic material is improved, sintering is completed at a lower sintering temperature, and the defect of poor high-temperature mechanical property caused by the traditional addition of a metal bonding phase as a sintering aid is overcome; the addition of the Ti3SiC2 can also improve the tribological property of the (Ti, W)C ceramic material, and the obtained structural ceramic material has excellent friction-reducing and wear-resistant properties, and is an excellent nozzle material for the Yellow River water sprinkling irrigation.

Description

Technical Field

[0001] This invention belongs to the technical field of nozzles for Yellow River water sprinkler irrigation, specifically relating to a structural ceramic material, its preparation method, its application, and the nozzle itself. Background Technology

[0002] The Yellow River, as an important source of water for agricultural irrigation, places multiple demands on sprinkler irrigation nozzles due to its high sediment content and alkaline nature. On the one hand, the water contains a high concentration of calcium ions (Ca). 2+ ), magnesium ions (Mg 2+ ) and bicarbonate ions (HCO3) - When the flow rate or pressure changes, insoluble precipitates such as calcium carbonate and magnesium hydroxide are easily formed, depositing inside the nozzles to form scale, leading to flow channel blockage and reduced spraying efficiency. On the other hand, hard sediment particles in the water continuously erode the inner wall of the nozzles during high-speed flow, requiring materials with high wear resistance to resist long-term abrasion. Simultaneously, alkaline water (pH often above 7.5) easily undergoes electrochemical corrosion with metallic materials or aging reactions with engineering plastics, requiring nozzle materials with excellent chemical corrosion resistance. Furthermore, sprinkler irrigation systems need to adapt to field vibrations, soil pressure, and seasonal temperature variations, requiring materials with sufficient strength and thermal shock resistance. Existing copper and stainless steel nozzles are prone to scaling and clogging, while engineering plastic nozzles, although corrosion-resistant, lack sufficient erosion resistance; neither can fully meet the complex operating conditions required for Yellow River water sprinkler irrigation.

[0003] While structural ceramic materials possess high hardness and chemical stability, they also face significant limitations in practical applications. Firstly, oxide ceramics (such as Al2O3 and ZrO2) have relatively low hardness and limited wear resistance, while non-oxide ceramics (such as SiC and B4C), although hard, are brittle and prone to crack propagation or even fracture under the impact of Yellow River sand particles. Secondly, the inherently high coefficient of friction of ceramic materials easily adsorbs sediment particles. If sintering density is insufficient (e.g., the presence of pores or grain boundary defects), it exacerbates particle deposition and scale buildup, creating a vicious cycle of reduced flow rate, intensified sedimentation, and worsened blockage. In terms of manufacturing processes, high hot-pressing sintering temperatures (often exceeding 1700℃) and high pressure conditions not only consume a lot of energy but also make it difficult to form complex flow channel structures, limiting the optimization space for nozzle design. Furthermore, ceramic materials lack ductility, are sensitive to impact loads, and are easily damaged during installation or transportation; their high hardness also leads to increased processing costs, especially for porous, microporous, or irregularly shaped nozzles, where the precision machining difficulty is significantly higher than for metal or plastic materials. Currently, ceramic nozzles are mostly focused on industrial applications such as sandblasting and desulfurization. Their material systems (such as Al2O3-based and SiC-based) and structural designs have not fully considered the actual working conditions such as periodic start-stop and water quality fluctuations in agricultural irrigation, resulting in insufficient long-term reliability in the Yellow River water environment. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a structural ceramic material, preparation method, application, and nozzle. The structural ceramic material provided by the present invention has high relative density, good mechanical properties, and excellent self-lubricating properties, reducing the friction coefficient between mud and the pipe wall, making it less prone to ion adsorption and mud deposition, thus meeting the requirements for long-term use.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: In a first aspect, the present invention provides a structural ceramic material comprising a matrix and an additive phase, wherein the matrix is ​​(Ti,W)C and the additive phase is Ti3SiC2; The mass percentage of each component is: (Ti,W)C 80%~99.9%, Ti3SiC 20.1%~20%, and the sum of the masses of each component is 100%.

[0006] This invention uses (Ti,W)C as the matrix and Ti3SiC2 as the additive phase and sintering aid. It is prepared by high-frequency induction sintering via discharge plasma coupling. By utilizing the good electrical and thermal conductivity of Ti3SiC2, the discharge sintering effect is enhanced and the heat conduction is accelerated, thereby achieving high-density sintering.

[0007] In some embodiments of the present invention, the mass percentage of each component is: (Ti,W)C 80%~95%, Ti3SiC 25%~20%.

[0008] In some embodiments of the present invention, the mass percentage of each component is: (Ti,W)C 90%~95%, Ti3SiC 25%~10%.

[0009] In some embodiments of the present invention, the mass percentage of each component is: (Ti,W)C 80%~85%, Ti3SiC2 15%~20%, and the sum of the mass of each component is 100%.

[0010] In some embodiments of the present invention, the mass percentage of each component is: (Ti,W)C 80%, Ti3SiC2 20%.

[0011] In some embodiments of the present invention, the mass percentage of each component is: (Ti,W)C 85%, Ti3SiC2 15%.

[0012] In some embodiments of the present invention, the mass percentage of each component is: (Ti,W)C 90%, Ti3SiC2 10%.

[0013] In some embodiments of the present invention, the mass percentage of each component is: (Ti,W)C 95%, Ti3SiC 25%.

[0014] In some embodiments of the present invention, the relative density of the structural ceramic material is 97%~98%, and the coefficient of friction is 0.17~0.21.

[0015] A second aspect of the present invention provides a method for preparing the above-mentioned structural ceramic material, comprising: (Ti,W)C powder and Ti3SiC2 powder were dispersed in a polyethylene glycol-anhydrous ethanol dispersion, wet ball milled, dried, and sieved to obtain a sintering precursor. The sintering precursor is obtained by high-frequency induction sintering with discharge plasma coupling under vacuum conditions.

[0016] In some embodiments of the present invention, the average particle size of the (Ti,W)C powder is 1~3 μm, and the average particle size of the Ti3SiC2 powder is 1~3 μm.

[0017] In some embodiments of the present invention, the concentration of polyethylene glycol in the polyethylene glycol-anhydrous ethanol dispersion is 2-4 g / L. The mass of polyethylene glycol is 0.09% to 1.1% of the total mass of (Ti,W)C powder and Ti3SiC2 powder.

[0018] In some embodiments of the present invention, the sintering temperature is 1290~1310℃, the sintering pressure is 25~35MPa, and the holding time is 10~20 min.

[0019] In some embodiments of the present invention, the heating process during sintering is as follows: preheating to 560~580℃ and heating to 600℃ within 1 minute; heating to 890~910℃ at 90~110℃ / min; heating to 1250℃ at 70~80℃ / min; and heating to the target temperature at 50℃ / min.

[0020] A third aspect of the present invention provides the application of the structural ceramic material described in the first aspect or the structural ceramic material prepared by the preparation method described in the second aspect in a nozzle.

[0021] In some embodiments of the present invention, the nozzle is used for spraying irrigation with a sand content greater than 3 kg / m³. 3 Water with a pH of 7-8.5 and an ion concentration of 100-350 mg / L.

[0022] A fourth aspect of the present invention provides a nozzle comprising the structural ceramic material described in the first aspect or the structural ceramic material prepared by the preparation method described in the second aspect.

[0023] In some embodiments of the present invention, the nozzle is used for spraying irrigation with a sand content greater than 3 kg / m³. 3Water with a pH of 7-8.5 and an ion concentration of 100-350 mg / L.

[0024] The beneficial effects of this invention are as follows: This invention provides a structural ceramic material with (Ti,W)C as the matrix and Ti3SiC2, which possesses self-lubricating properties, good electrical conductivity, and high thermal conductivity, as the additive phase. The (Ti,W)C ceramic exhibits high hardness, high wear resistance, and high-temperature stability, and is not easily oxidized or decomposed during sintering, contributing to a denser structure. The addition of Ti3SiC2 endows the structural ceramic material with not only excellent mechanical properties but also superior friction-reducing and wear-resistant properties, while also allowing for a reduction in sintering temperature. By incorporating Ti3SiC2 with a lamellar microstructure into (Ti,W)C, this invention imparts excellent self-lubricating properties to the structural ceramic material, thereby reducing the friction coefficient between sediment and the pipe wall, making it less prone to ion adsorption and sediment deposition, thus meeting the requirements for long-term use. Therefore, this structural ceramic material can serve as an ideal material for Yellow River water sprinkler irrigation nozzles.

[0025] This invention also provides a method for preparing structural ceramic materials. Ti3SiC2 powder is mixed with (Ti,W)C powder as an additive phase, ball-milled, and dried to obtain a sintering precursor for the structural ceramic material. Then, spark plasma coupling high-frequency induction sintering is performed at a low sintering temperature (1300℃) to obtain a structural ceramic material with good density, high mechanical properties, and a low coefficient of friction. Specifically, Ti3SiC2, uniformly dispersed in the (Ti,W)C matrix, acts as a sintering aid. Its good electrical and thermal conductivity enhances the spark sintering effect and accelerates heat conduction, improving the sintering performance of the (Ti,W)C ceramic material. Sintering is completed at a lower sintering temperature, overcoming the defect of poor high-temperature mechanical properties caused by traditional methods of adding metal binder phases as sintering aids. Attached Figure Description

[0026] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0027] Figure 1 This is an electron microscope image and elemental analysis diagram of the structural ceramic material prepared in Example 3 of the present invention. Detailed Implementation

[0028] Given the shortcomings of existing technologies, there is an urgent need to develop a structural ceramic material with excellent mechanical properties, wear-reducing and wear-resistant properties, as well as its preparation method and applications. This invention uses (Ti,W)C as the matrix and Ti3SiC2 as the additive phase, and is prepared by high-frequency induction sintering via spark plasma coupling. By utilizing the good electrical conductivity, high thermal conductivity, and self-lubricating properties of Ti3SiC2, the spark sintering effect is enhanced and heat conduction is accelerated, achieving high-density sintering.

[0029] Ti3SiC2 is a unique ternary layered ceramic material that cleverly combines the excellent properties of both metals and ceramics. Ti3SiC2 has a nanoscale layered structure, consisting of alternating layers of covalently bonded Ti6C octahedra and weakly bonded Si atoms. This layered structure is the source of its self-lubricating and high toughness. Its hexagonal crystal structure and low interlayer shear strength reduce the friction coefficient of the structural ceramic material, minimizing sediment adhesion and fundamentally preventing clogging. The weak interlayer bonding of Si atoms in its structure allows for easy slippage between layers when the material is subjected to shear forces (such as the friction from sediment carried by water flow). This forms a complete, uniform, and dense oxide film of TiO2, SiO2, and Fe2O3 on the friction surface, preventing further wear and significantly reducing its wear rate. Furthermore, when cracks propagate within the material, this layered structure uses mechanisms such as crack deflection and particle pull-out to make the crack propagation path tortuous, consuming a large amount of energy, rather than resulting in brittle fracture like traditional ceramics. This gives the material a damage tolerance similar to that of metals, meaning it is not easily broken under high loads.

[0030] Furthermore, Ti3SiC2, uniformly dispersed in the (Ti,W)C matrix, serves as a sintering aid. Its excellent electrical and thermal conductivity enhances the discharge sintering effect and accelerates heat conduction, thereby improving the sintering performance of (Ti,W)C ceramic materials. Sintering can be completed at a lower sintering temperature, overcoming the defect of poor high-temperature mechanical properties caused by the traditional addition of metal binder phases as sintering aids.

[0031] (Ti,W)C ceramics possess high conductivity, high hardness, high wear resistance, and high-temperature stability. Under spark plasma coupled high-frequency induction sintering, the conductivity of (Ti,W)C ceramics and Ti3SiC2 is not simply superimposed, but rather exhibits a significant synergistic coupling effect, which is key to achieving low-temperature sintering. The introduction of Ti3SiC2, forming a three-dimensional conductive network with the (Ti,W)C matrix, further optimizes the pulse current distribution through its unique layered structure, enhances Joule heating efficiency, and activates the particle surface, thereby significantly reducing the sintering activation energy of the material. This synergistic effect jointly promotes particle rearrangement and mass migration during sintering, enabling the ceramic body to achieve high densification at temperatures far below those required for (Ti,W)C material alone (1300℃), while effectively suppressing abnormal grain growth.

[0032] Ti3SiC2 belongs to the MAX phase ceramics. Ti and C form a strong, well-bonded octahedral framework, while Si atoms are arranged like "sandwich layers" in the middle of the Ti-C framework. This structure decomposes at high temperatures, around 1400°C. If metals or other sintering aids are present in the material system, this decomposition temperature may be lower than 1300°C. The coupling characteristics of (Ti,W)C and Ti3SiC2 in this invention allow for preparation at a lower sintering temperature (1300°C). Since both are carbides, the phase composition is simple and pure. Without the need for sintering aids, the decomposition of Ti3SiC2 at high temperatures is avoided from the outset, maintaining its self-lubricating crystal structure. Furthermore, this sintering temperature also avoids the potential chemical reaction between Si and C to form SiC (reaction temperature approximately 1700°C). Without the need to introduce other sintering aids, it can avoid grain boundary impurities caused by sintering aids, resulting in a very clean phase interface and strong bonding between the two, laying a solid foundation for improving macroscopic performance; it can also avoid the corrosive effect of Yellow River water on sintering aids with low chemical stability, which helps to extend service life.

[0033] The technical effects of adding Ti3SiC2 vary depending on the matrix. If Ti3SiC2 is added to a Ti(C,N) cermet matrix, which is similar to traditional (Ti,W)C cermets, not all the technical effects of this invention can be achieved simultaneously. The specific reasons are as follows: The performance advantages of components can only be transformed into synergistic breakthroughs within a suitable system. The success of Ti3SiC2 in a (Ti,W)C matrix is ​​fundamentally due to its quadruple coupling of complementary conductivity, structural compatibility, thermal matching, and functional synergy. However, when using a Ti(C,N) matrix, its conductivity is weaker than that of (Ti,W)C, leading to a reduced coupling sintering effect between the matrix and Ti3SiC2. Si and C, and N respectively have the potential to form SiC and Si3N4 through chemical reactions, and the reaction temperature of Si3N4 (approximately 1300℃) is lower than that of SiC (approximately 1700℃). Therefore, under the rapid sintering conditions of high-frequency induction coupled with spark plasma coupling, Ti3SiC2 exhibits good chemical compatibility with (Ti,W)C, but poor chemical compatibility with Ti(C,N) containing N. The coefficient of thermal expansion of Ti3SiC2 is 8.5-9.5 × 10⁻⁶. -6 / K is higher than 7.0-7.8×10 for Ti(C,N). -6 / K and (Ti,W)C 6.8-7.4×10 -6 The difference in temperature is small, so there is no significant thermal expansion mismatch. Furthermore, the residual stress formed with (Ti,W)C as the matrix is ​​slightly greater than that with Ti(C,N) as the matrix, which is beneficial for residual stress toughening. In summary, the same synergistic chains cannot be constructed using the Ti(C,N) matrix, resulting in no synergistic effect between the sintering aids, self-lubricating phase, and toughening phase of Ti3SiC2. Therefore, using (Ti,W)C as the matrix and Ti3SiC2 as the matrix are unique characteristics.

[0034] A first typical embodiment of the present invention provides a structural ceramic material, comprising a matrix and an additive phase, wherein the matrix is ​​(Ti,W)C and the additive phase is Ti3SiC2; The mass percentage of each component is: (Ti,W)C 80%~99.9%, Ti3SiC 20.1%~20%, and the sum of the masses of each component is 100%.

[0035] To achieve even better technical results, the mass percentage of each component is 80%~95% for (Ti,W)C and 25%~20% for Ti3SiC, with the sum of the masses of all components being 100%. Alternatively, the mass percentage of each component is 90%~95% for (Ti,W)C and 25%~10% for Ti3SiC, with the sum of the masses of all components being 100%. Or, the mass percentage of each component is 80%~85% for (Ti,W)C and 15%~20% for Ti3SiC, with the sum of the masses of all components being 100%.

[0036] The specific addition amount of Ti3SiC2 can be 5%, 7%, 8%, 10%, 11%, 13%, 15%, 16%, 17%, 18%, 19%, or 20%.

[0037] The multiple synergistic effects of Ti3SiC2 cannot be fully established due to insufficient content. At too low a content, the self-lubricating film formation is discontinuous. During friction, insufficient Ti3SiC2 cannot form a complete, uniform, and continuously replenishable oxide lubricating film on the friction surface. The lubricating film is easily depleted locally, leading to unstable friction reduction and insignificant wear rate reduction. At too low a content, the toughening effect is limited. As a toughening phase, its particle count is too small to effectively achieve toughening mechanisms such as crack deflection and crack bridging. The crack propagation path remains largely unchanged, and the material tends towards brittleness. At too low a content, the sintering-promoting effect is weak, contributing little to the reduction of the conductive network and sintering activation energy, requiring higher temperatures for densification, and resulting in poor grain control.

[0038] The multiple synergistic effects of Ti3SiC2 become more beneficial than harmful when its content is too high. Excessive content leads to an excessive decrease in hardness. According to Arcard's wear law, reduced hardness results in decreased wear resistance. The hardness of Ti3SiC2 itself (4 GPa) is much lower than that of the (Ti,W)C matrix (20 GPa). Excessive addition significantly reduces the overall hardness of the composite material. Excessive content also damages structural integrity. Too many layered phases become weak bonding interfaces in the material. Under shear force, these dense weak bonding interfaces become channels for crack initiation and propagation, thus reducing the material's fracture toughness. Excessive content also impairs high-temperature stability. During sintering, excessive Ti3SiC2 easily decomposes and undergoes unfavorable interfacial reactions with the matrix, generating brittle phases and damaging the material's high-temperature mechanical properties. Furthermore, excessive content weakens the adhesion between the lubricating film and the matrix. An excessively thick lubricating film on the surface weakens its adhesion to the matrix, making it prone to large-scale peeling during friction, forming abrasive particles and exacerbating wear.

[0039] Therefore, this invention limits the amount of Ti3SiC2 added to between 5% and 20%, while ensuring that the material has significant self-lubricating properties (anti-clogging), excellent comprehensive mechanical properties (wear resistance), high density (anti-permeability), and stability of microstructure (reliability), thereby meeting the demanding working conditions of Yellow River water sprinkler nozzles.

[0040] To further achieve better technical results, the mass percentage of each component is: (Ti,W)C 80%, Ti3SiC2 20%.

[0041] To further achieve better technical results, the mass percentage of each component is: (Ti,W)C 85%, Ti3SiC2 15%.

[0042] To further achieve better technical results, the mass percentage of each component is: (Ti,W)C 90%, Ti3SiC2 10%.

[0043] To achieve even better technical results, the mass percentage of each component is: (Ti,W)C 95%, Ti3SiC 25%.

[0044] In some embodiments of the present invention, the relative density of the structural ceramic material is 97% to 98%, and the coefficient of friction is 0.17 to 0.21.

[0045] A second typical embodiment of the present invention provides a method for preparing the above-mentioned structural ceramic material, comprising: (Ti,W)C powder and Ti3SiC2 powder were dispersed in a polyethylene glycol-anhydrous ethanol dispersion, wet ball milled, dried, and sieved to obtain a sintering precursor. The sintering precursor is obtained by high-frequency induction sintering with discharge plasma coupling under vacuum conditions.

[0046] In some embodiments of the present invention, the average particle size of the (Ti,W)C powder is 1~3 μm, preferably 1~1.5 μm; the average particle size of the Ti3SiC2 powder is 1~3 μm, preferably 3 μm.

[0047] Understandably, smaller particle size implies higher specific surface area and surface energy, which significantly enhances the diffusion kinetics of the powder during sintering, promotes mass transport and densification, and thus helps obtain high-density structural ceramic materials at relatively lower sintering temperatures. Simultaneously, controlling the particle size of the two-phase powders within a similar range facilitates their uniform distribution during mixing, reduces agglomeration and segregation caused by particle size differences, and ensures that the Ti3SiC2 self-lubricating phase can be uniformly dispersed in the (Ti,W)C matrix, effectively exerting its role in reducing the coefficient of friction and improving toughness. Furthermore, fine and uniform powder particle size helps suppress abnormal grain growth during sintering, resulting in a finer microstructure, which is crucial for improving the material's mechanical properties and wear resistance. Further optimizing the powder particle size to 1~1.5 μm or 3 μm allows for the utilization of its higher sintering activity, which is significant for achieving better overall performance and further optimizing the sintering process.

[0048] In some embodiments of the present invention, polyethylene glycol is added to anhydrous ethanol and stirred in a water bath at a constant temperature, then cooled to room temperature to obtain a polyethylene glycol-anhydrous ethanol dispersion. The water bath temperature is 55-65°C, and magnetic stirring is used for 10-15 minutes. The concentration of polyethylene glycol in the polyethylene glycol-anhydrous ethanol dispersion is 2-4 g / L.

[0049] The average molecular weight of the polyethylene glycol (PEG) is 4000-8000, more preferably 6000, i.e., the polyethylene glycol is preferably PEG6000.

[0050] In some embodiments of the present invention, the mass of polyethylene glycol in the polyethylene glycol-anhydrous ethanol dispersion is 0.09% to 1.1% of the total mass of (Ti,W)C powder and Ti3SiC2 powder. Specifically, it can be 0.09%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, or 1.1%.

[0051] In some embodiments of the present invention, (Ti,W)C powder and Ti3SiC2 powder can be added sequentially to the polyethylene glycol-anhydrous ethanol dispersion, or the two powders can be mixed before being added to the polyethylene glycol-anhydrous ethanol dispersion. To ensure thorough dispersion, ultrasonic dispersion and stirring are performed after addition. The ultrasonic dispersion time is preferably 30-45 minutes, and mechanical stirring is used.

[0052] In some embodiments of the present invention, the grinding balls used in the ball mill are cemented carbide grinding balls with diameters of 5 mm and 10 mm, the mass ratio of the 5 mm and 10 mm cemented carbide grinding balls is (1-2):(1-5), the ball-to-material mass ratio is (10-20):1, preferably 15:1, and the ball milling is carried out under a protective atmosphere for 70-94 h.

[0053] In some embodiments of the present invention, the ball milling is a planetary ball milling process, employing a stirred high-energy ball mill, carried out under a protective atmosphere, cooled by circulating water, and at a rotation speed of 300 rpm-500 rpm. Preferably, the protective atmosphere is nitrogen or argon.

[0054] In some embodiments of the present invention, the drying is vacuum drying at a temperature of 100~120°C for 24~48 hours, preferably 36 hours.

[0055] In some embodiments of the present invention, the sieving process uses a sieve with a mesh size of 50-150, preferably 100 mesh.

[0056] In some embodiments of the present invention, the sintering is spark plasma coupled high-frequency induction sintering, and the sintering temperature is 1290~1310℃, specifically 1290℃, 1291℃, 1292℃, 1293℃, 1294℃, 1295℃, 1296℃, 1297℃, 1298℃, 1299℃, 1300℃, 1301℃, 1302℃, 1303℃, 1304℃, 1305℃, 1306℃, 1307℃, 1308℃, 1309℃, 1310℃, etc., preferably 1295~1305℃, more preferably 1298~1302℃, and most preferably 1300℃. If the temperature is too low, sintering cannot be formed; if the temperature is too high, abnormal grain growth will occur and a large number of pores will exist on the cross-section of the material.

[0057] In spark plasma coupled high-frequency induction sintering, the sintering pressure is 25~35 MPa, specifically 25 MPa, 26 MPa, 27 MPa, 28 MPa, 29 MPa, 30 MPa, 31 MPa, 32 MPa, 33 MPa, 34 MPa, 35 MPa, etc., preferably 30 MPa.

[0058] In spark plasma coupling high-frequency induction sintering, the sintering holding time is 10~20 min, specifically 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min, 20 min, preferably 10 min.

[0059] In some embodiments of the present invention, the specific heating process in spark plasma coupling high-frequency induction sintering is as follows: preheating to 560~580℃ (e.g., 570℃), and heating to 600℃ within 1 min; heating to 890~910℃ (e.g., 900℃) at 90~110℃ / min (e.g., 100℃ / min); heating to 1250℃ at 70~80℃ / min (e.g., 75℃ / min); and heating to the target temperature at 50℃ / min.

[0060] In the process of preparing structural ceramic materials according to this invention, a high-frequency induction sintering process coupled with spark plasma coupling is required. Other sintering methods (traditional hot pressing or atmospheric pressure sintering) cannot achieve the technical effects of this invention for the following reasons: (1) The essential difference between activation energy and sintering kinetics In the process of spark plasma coupled high-frequency induction sintering, the high-energy pulsed current introduced between powder particles not only rapidly heats the material from the inside through the Joule heating effect, but more importantly, it generates spark plasma between the particles. This plasma can effectively remove impurities and gas adsorption layers from the surface of the powder particles, activating the particle surface and generating a large number of defects, significantly reducing the activation energy of atomic diffusion, thereby greatly promoting the densification process thermodynamically and kinetically. In contrast, traditional sintering methods mainly rely on slow external heating and solid-state diffusion, which have high energy barriers for atomic migration, making densification difficult.

[0061] (2) The unique advantages of the material system of the present invention The (Ti,W)C-Ti3SiC2 composite material system of this invention is extremely sensitive to the sintering process. Utilizing the high electrical conductivity of Ti3SiC2, high-frequency induction sintering via discharge plasma coupling (SPCC) reduces the sintering current, thereby lowering the sintering temperature, reducing energy consumption and production costs. Traditional hot-pressing or atmospheric pressure sintering, lacking an electric field, cannot take advantage of Ti3SiC2's high electrical conductivity. The rapid heating and short holding time of SPCC effectively suppress the decomposition of the Ti3SiC2 phase and the abnormal growth of (Ti,W)C grains. This is crucial for obtaining a microstructure with fine grains, uniform composition, and good interfacial bonding between the two phases. In contrast, traditional hot-pressing or atmospheric pressure sintering, due to prolonged high temperatures, easily leads to unstable decomposition or grain coarsening of Ti3SiC2, damaging its self-lubricating properties and impairing the material's mechanical properties. High-frequency induction sintering via spark plasma coupling can be performed at a relatively low sintering temperature (1300℃). Furthermore, since both (Ti,W)C and Ti3SiC2 are carbides, their phase composition is simple and pure, avoiding the decomposition of Ti3SiC2 at high temperatures and maintaining its self-lubricating crystal structure. No other sintering aids need to be introduced, thus avoiding grain boundary impurities caused by sintering aids and the erosion of chemically unstable sintering aids by Yellow River water, which helps extend the material's service life.

[0062] (3) Synergistic coupling effect achieves low-temperature and high-efficiency densification The significance of "coupling" lies in the synergy between pulsed current heating (discharge plasma) and induction coil heating. The auxiliary heating field provided by the induction coil significantly improves the uniformity of the thermal field within the sintered body, reducing the temperature difference between the sample center and edges. This uniform temperature field avoids cracks and density inhomogeneity caused by thermal stress. The synergy of these two processes enables the structural ceramic material obtained in this invention—high-hardness (Ti,W)C-based ceramics—to achieve near-theoretical density in a very short time at temperatures far below its conventional sintering temperature (e.g., 1300℃). A single sintering method or traditional process cannot achieve sufficient densification at such low temperatures.

[0063] As a preferred embodiment, the method for preparing structural ceramic materials includes the following steps: (1) Polyethylene glycol was added to anhydrous ethanol and stirred in a water bath at a constant temperature to dissolve it. The mixture was then cooled to room temperature to obtain a polyethylene glycol-anhydrous ethanol dispersion. (2) Add (Ti,W)C powder and Ti3SiC2 powder to polyethylene glycol-anhydrous ethanol dispersion in sequence according to the mass ratio, disperse by ultrasonication and stir to obtain a mixed solution; (3) Pour the prepared mixed solution and grinding balls into a tank. The ratio of the total amount of raw materials to the weight of the grinding balls is 1:15. Grind under a protective atmosphere for 70-94 h. (4) Vacuum dry and sieve the ball mill slurry to obtain a mixed powder, and seal it for later use; (5) The mixed powder was placed in a graphite mold and subjected to high-frequency induction sintering by discharge plasma coupling under a vacuum atmosphere to obtain a Ti3SiC2 modified (Ti,W)C self-lubricating ceramic material.

[0064] A third typical embodiment of the present invention provides an application of the above-described structural ceramic material or the structural ceramic material prepared by the above-described preparation method in a nozzle.

[0065] In some embodiments of the present invention, the nozzle is used for spraying irrigation with a sand content greater than 3 kg / m³. 3 Water with a pH of 7-8.5 and an ion concentration of 100-350 mg / L.

[0066] The ions include Na + Ca 2+ Mg 2+ HCO3 - SO4 2- , Cl - Any one or more of them.

[0067] In some embodiments of the present invention, the nozzle is used for spraying water from the Yellow River.

[0068] The structural ceramic material prepared by this invention has excellent friction reduction and wear resistance properties, making it an excellent nozzle material for Yellow River water sprinkler irrigation.

[0069] A fourth typical embodiment of the present invention provides a nozzle comprising the above-described structural ceramic material or the structural ceramic material prepared by the above-described preparation method.

[0070] In some embodiments of the present invention, the nozzle is used for spraying irrigation with a sand content greater than 3 kg / m³. 3 Water with a pH of 7-8.5 and an ion concentration of 100-350 mg / L.

[0071] The ions include Na + Ca 2+ Mg 2+ HCO3 - SO4 2- , Cl - Any one or more of them.

[0072] In some embodiments of the present invention, the nozzle is used for spraying water from the Yellow River.

[0073] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0074] In the examples and comparative examples, the average particle size of (Ti,W)C powder was 1-3 μm, and the average diameter of Ti3SiC2 powder was 3 μm; both were commercially available products. The polyethylene glycol used was PEG6000.

[0075] Example 1 This embodiment provides a structural ceramic material with the following mass percentage content of each component: (Ti,W)C 95%, Ti3SiC 25%.

[0076] The preparation method of the structural ceramic material includes the following steps: (1) Place anhydrous ethanol in a beaker, weigh and add polyethylene glycol, place the beaker in a water bath, and stir magnetically at 55°C for 10 min until the polyethylene glycol is completely dissolved. Cool to room temperature to obtain a polyethylene glycol-anhydrous ethanol dispersion with a dispersion amount of 2 g / L.

[0077] (2) According to the mass percentage of each component, mix (Ti,W)C powder and Ti3SiC2 powder, add them to the polyethylene glycol-anhydrous ethanol dispersion prepared in step (1), ultrasonically disperse for 30 min and mechanically stir to obtain a mixed solution; the mass of polyethylene glycol in the polyethylene glycol-anhydrous ethanol dispersion is 0.09% of the total mass of (Ti,W)C powder and Ti3SiC2 powder.

[0078] (3) The prepared mixed solution is placed in a ball milling jar. The grinding balls used in the ball milling are mixed cemented carbide grinding balls with diameters of 5 mm and 10 mm. The mass ratio of the cemented carbide grinding balls with diameters of 5 mm and 10 mm is 2:3, and the mass ratio of the ball to the material is 15:1. The ball milling is carried out for 84 h under nitrogen protection.

[0079] (4) The ball mill slurry was vacuum dried at 120 °C for 24 h and passed through a 200-mesh sieve to obtain Ti3SiC2 modified (Ti,W)C self-lubricating ceramic powder (i.e. sintering precursor), which was then sealed for later use.

[0080] (5) The Ti3SiC2 modified (Ti,W)C self-lubricating ceramic powder was placed in a graphite mold and subjected to high-frequency induction sintering by discharge plasma coupling under a vacuum atmosphere. The sintering temperature was 1300℃, the sintering pressure was 30 MPa, and the heating rate was as follows: preheating to 570℃ and then heating to 600℃ within 1 min; heating to 900℃ at 100℃ / min; heating to 1250℃ at 75℃ / min; and heating to the target temperature at 50℃ / min. The holding time was 10 min, and the Ti3SiC2 modified (Ti,W)C self-lubricating ceramic material, i.e., structural ceramic material, was obtained.

[0081] The prepared structural ceramic material sample was cut and processed, and its relative density was measured to be 97.2%. Its mechanical properties were: flexural strength 548 MPa and fracture toughness 4.2 MPa. m 1 / 2 Its Vickers hardness is 6.79 GPa and its coefficient of friction is 0.21.

[0082] Example 2 This embodiment provides a structural ceramic material with the following mass percentage content of each component: (Ti,W)C 90%, Ti3SiC2 10%.

[0083] The preparation method of the structural ceramic material is completely consistent with the preparation method in Example 1.

[0084] The prepared structural ceramic material sample was cut and processed, and its relative density was measured to be 97.5%. Its mechanical properties were: flexural strength 555 MPa, fracture toughness 4.1 MPa. m 1 / 2 Vickers hardness 7.56 GPa, coefficient of friction 0.20.

[0085] Example 3 This embodiment provides a structural ceramic material with the following mass percentage content of each component: (Ti,W)C 85%, Ti3SiC2 15%.

[0086] The preparation method of the structural ceramic material is completely consistent with the preparation method in Example 1.

[0087] The prepared structural ceramic material sample was cut and processed, and its relative density was measured to be 97.8%. Its mechanical properties were: flexural strength 619 MPa, fracture toughness 4.0 MPa. m 1 / 2 Vickers hardness 9.71 GPa, coefficient of friction 0.17.

[0088] The electron microscope and elemental analysis diagram of the structural ceramic material prepared in Example 3 are shown below. Figure 1 As shown. From Figure 1It can be clearly seen that Ti3SiC2 and (Ti,W)C can form a strong interfacial bond with a thin layer of TiC as the transition. EDS line scanning or area scanning reveals a diffusion region of Ti, W, and C elements at the interface, with a compositional gradient. This indicates that atomic diffusion occurred during sintering.

[0089] Example 4 This embodiment provides a structural ceramic material with the following mass percentage content of each component: (Ti,W)C 80%, Ti3SiC2 20%.

[0090] The preparation method of the structural ceramic material is completely consistent with the preparation method in Example 1.

[0091] The prepared structural ceramic material sample was cut and processed, and its relative density was measured to be 97.7%. Its mechanical properties were: flexural strength 280 MPa, fracture toughness 2.3 MPa. m 1 / 2 Vickers hardness 3.74 GP, coefficient of friction 0.18.

[0092] A comparison of Examples 1-4 shows that increasing the Ti3SiC2 content leads to a decrease in the friction coefficient but a comprehensive decline in mechanical properties, essentially a dual competition between its lubrication function and structural weakening. As a soft layered phase, increased Ti3SiC2 provides a slip interface and promotes the formation of a lubricating film, thus significantly reducing the friction coefficient; however, its hardness and strength, far lower than that of the (Ti,W)C matrix, directly reduce the overall hardness and load-bearing capacity of the composite material. Excessive Ti3SiC2 forms a connected network in the matrix, and its weak bonding interfaces easily become crack initiation sources and low-resistance propagation channels under stress, causing the flexural strength and fracture toughness to decrease rather than increase. The improved self-lubricating properties of Ti3SiC2-reinforced (Ti,W)C ceramics come at the cost of sacrificing the overall mechanical properties of the ceramic structure; a balance between the two can only be achieved by controlling the content.

[0093] Comparative Example 1 This comparative example provides a structural ceramic material, the mass percentage of each component being (Ti,W)C 100%.

[0094] The preparation method of the structural ceramic material includes the following steps: (1) Place anhydrous ethanol in a beaker, weigh and add polyethylene glycol, place the beaker in a water bath, and stir magnetically at 55°C for 10 min until the polyethylene glycol is completely dissolved. Cool to room temperature to obtain a polyethylene glycol-anhydrous ethanol dispersion with a dispersion amount of 2 g / L.

[0095] (2) Add (Ti,W)C powder to the polyethylene glycol-anhydrous ethanol dispersion obtained in step (1), ultrasonically disperse for 30 min and mechanically stir to obtain a mixed solution; the mass of polyethylene glycol in the polyethylene glycol-anhydrous ethanol dispersion is 0.09% of the mass of (Ti,W)C powder.

[0096] (3) The prepared mixed solution is placed in a ball milling jar. The grinding balls used in the ball milling are mixed cemented carbide grinding balls with diameters of 5 mm and 10 mm. The mass ratio of the cemented carbide grinding balls with diameters of 5 mm and 10 mm is 2:3, and the mass ratio of the ball to the material is 15:1. The ball milling is carried out for 84 h under nitrogen protection.

[0097] (4) The ball mill slurry was vacuum dried at 120 °C for 24 h and passed through a 200-mesh sieve to obtain (Ti,W)C ceramic powder (i.e., sintering precursor), which was then sealed for later use.

[0098] (5) The (Ti,W)C ceramic powder was placed in a graphite mold and subjected to high-frequency induction sintering via discharge plasma coupling under a vacuum atmosphere. The sintering temperature was 1300℃, the sintering pressure was 30 MPa, and the heating rate was as follows: preheating to 570℃ and then heating to 600℃ within 1 min; heating to 900℃ at 100℃ / min; heating to 1250℃ at 75℃ / min; and heating to the target temperature at 50℃ / min. The holding time was 10 min, and the (Ti,W)C ceramic material, i.e., the structural ceramic material, was obtained.

[0099] The prepared structural ceramic material sample was cut and processed, and its relative density was measured to be 96.3%. Its mechanical properties were: flexural strength 705 MPa, fracture toughness 5.1 MPa. m 1 / 2 Vickers hardness 14.33 GPa, coefficient of friction 0.49.

[0100] Comparative Example 2 This comparative example provides a structural ceramic material with the following mass percentage content of each component: (Ti,W)C 75%, Ti3SiC2 25%.

[0101] The preparation method of the structural ceramic material is completely consistent with the preparation method in Example 1.

[0102] The prepared structural ceramic material sample was cut and processed, and its relative density was measured to be 97.5%. Its mechanical properties were: flexural strength 165 MPa, fracture toughness 2.2 MPa. m 1 / 2 Vickers hardness 2.9 GPa, coefficient of friction 0.17.

[0103] Comparative Example 3 This comparative example provides a structural ceramic material with the following mass percentage content of each component: (Ti,W)C 98%, Ti3SiC 22%.

[0104] The preparation method of the structural ceramic material is completely consistent with the preparation method in Example 1.

[0105] The prepared structural ceramic material sample was cut and processed, and its relative density was measured to be 96.8%. Its mechanical properties were: flexural strength 496 MPa, fracture toughness 3.6 MPa. m 1 / 2 Vickers hardness 8.95 GP, coefficient of friction 0.33.

[0106] Comparative Example 4 This comparative example provides a structural ceramic material with the following mass percentage content of each component: (Ti,W)C 95%, Ti3SiC 25%.

[0107] The difference between the preparation method of the structural ceramic material and the preparation method in Example 1 is that the high-frequency induction sintering coupled with spark plasma coupling is not used; only spark plasma sintering is used. The remaining steps are exactly the same as those in Example 1.

[0108] The prepared structural ceramic material sample was cut and processed, and its relative density was measured to be 97.0%. Its mechanical properties were: flexural strength 505 MPa, fracture toughness 3.9 MPa. m 1 / 2 Vickers hardness 6.43 GP, coefficient of friction 0.22.

[0109] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A structural ceramic material, characterized in that, It includes a matrix and an additive phase, wherein the matrix is ​​(Ti,W)C and the additive phase is Ti3SiC2; The mass percentage of each component is: (Ti,W)C 80%~99.9%, Ti3SiC 20.1%~20%.

2. The structural ceramic material as described in claim 1, characterized in that, The mass percentage of each component is: (Ti,W)C 80%~95%, Ti3SiC 25%~20%.

3. The structural ceramic material as described in claim 1, characterized in that, The mass percentage content of each component is: (Ti,W)C 90%~95%, Ti3SiC 25%~10%; Alternatively, the mass percentage of each component is: (Ti,W)C 80%~85%, Ti3SiC2 15%~20%.

4. The structural ceramic material as described in claim 1, characterized in that, The mass percentage of each component is: (Ti,W)C 80%, Ti3SiC2 20%; Alternatively, the mass percentage of each component is: (Ti,W)C 85%, Ti3SiC2 15%; Alternatively, the mass percentage of each component is: (Ti,W)C 90%, Ti3SiC2 10%; Alternatively, the mass percentage of each component is: (Ti,W)C 95%, Ti3SiC 25%.

5. The structural ceramic material as described in claim 1, characterized in that, The relative density of the structural ceramic material is 97%~98%, and the coefficient of friction is 0.17~0.

21.

6. A method for preparing the structural ceramic material according to claim 1, characterized in that, include: (Ti,W)C powder and Ti3SiC2 powder were dispersed in a polyethylene glycol-anhydrous ethanol dispersion, wet ball milled, dried, and sieved to obtain a sintering precursor. The sintering precursor is obtained by high-frequency induction sintering with discharge plasma coupling under vacuum conditions.

7. The preparation method according to claim 6, characterized in that, The average particle size of the (Ti,W)C powder is 1~3 μm, and the average particle size of the Ti3SiC2 powder is 1~3 μm; In the polyethylene glycol-anhydrous ethanol dispersion, the concentration of polyethylene glycol is 2~4 g / L; The mass of polyethylene glycol is 0.09% to 1.1% of the total mass of (Ti,W)C powder and Ti3SiC2 powder.

8. The preparation method according to claim 6, characterized in that, The sintering temperature is 1290~1310℃, the sintering pressure is 25~35 MPa, and the holding time is 10~20 min; The heating process during sintering is as follows: preheat to 560~580℃, and then heat to 600℃ within 1 min; heat to 890~910℃ at 90~110℃ / min; heat to 1250℃ at 70~80℃ / min; and heat to the target temperature at 45~55℃ / min.

9. The application of a structural ceramic material according to any one of claims 1-5 or a structural ceramic material prepared by the preparation method according to any one of claims 6-8 in a nozzle; The nozzle is used for sprinkling the water with sand content more than 3 Kg / m 3 water with pH 7-8.5 and ion concentration 100-350 mg / L.

10. A nozzle, characterized in that, Includes the structural ceramic material according to any one of claims 1-5 or the structural ceramic material prepared by the preparation method according to any one of claims 6-8; The nozzle is used for sprinkling the water with sand content more than 3 Kg / m 3 water with pH 7-8.5 and ion concentration 100-350 mg / L.

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