Wear-resistant material prepared from building metal scraps and preparation method of wear-resistant material

Abstract

The invention discloses a wear-resistant material using building metal scraps and a preparation method thereof, and relates to the technical field of wear-resistant materials.The preparation method comprises the steps that a compound Ti source, borosilicate glass powder and a BN nanosheet are mixed and subjected to ball milling, and a BN embedded type core-shell structure titanium source is prepared; preparing a surface modified nano silicon dioxide dispersing aid, and mixing the surface modified nano silicon dioxide dispersing aid with a titanium source and the graphene dispersion liquid to obtain a graphene-titanium source composite precursor; crushing and screening building metal wastes, mixing the building metal wastes with the composite precursor and the composite reinforced phase, and adding a bio-based chelating agent ethylenediamine disuccinic acid and acetyl to protect KH-550 for modification; and finally, adding a novolac epoxy resin binder, and carrying out partitioned temperature-control pressure forming through a double-layer temperature-control mold to obtain a wear-resistant material blank. The wear-resistant material prepared by the invention can effectively remove S and P impurities in waste materials and strengthen the interface bonding force of each phase, and the prepared material is low in abrasion loss, high in interface bonding strength, uniform in performance of each part and capable of adapting to a high-abrasion working condition.

Description

Technical Field

[0001] This invention relates to the field of wear-resistant materials technology, specifically to a wear-resistant material utilizing construction metal waste and its preparation method. Background Technology

[0002] With the acceleration of urbanization, the scale of metal waste (such as scrap steel bars and scrap aluminum alloy components) generated by the construction industry each year is growing explosively. Currently, the mainstream treatment methods for this type of waste are still low-value recycling or direct landfill: recycling is energy-intensive and has high carbon emissions, and due to limitations in sorting accuracy, the final product is mostly low-purity alloys, which are difficult to use in the preparation of high-end materials; direct landfill occupies land resources, and heavy metal ions and impurities such as sulfur and phosphorus in the metal waste may also seep into the soil and groundwater with rainwater, causing serious environmental problems. At the same time, the demand for wear-resistant materials in the industrial sector (such as mining machinery, building material conveying, metallurgical equipment, etc.) continues to rise. Traditional wear-resistant materials generally use primary high-carbon ferrochrome and high-manganese steel as the matrix, which not only relies on non-renewable primary metal resources, but also suffers from high preparation costs and low resource utilization.

[0003] While some studies have attempted to apply construction metal waste to the preparation of wear-resistant materials, several technical bottlenecks remain, hindering industrialization: First, impurity removal technology has limitations. Construction metal waste commonly contains harmful impurities such as sulfur, phosphorus, and chlorine. Existing processes often employ simple acid washing or high-temperature roasting. Acid washing easily corrodes the metal matrix, causing a decrease in matrix strength, while high-temperature roasting makes it difficult to accurately remove phosphorus. Residual impurities form brittle phases within the material, which easily become crack initiation sites during stress, leading to a significant reduction in the overall mechanical and wear-resistant properties of the material, failing to meet industrial standards. Second, the bonding capacity of multiphase interfaces is insufficient. The performance improvement of wear-resistant materials relies on the synergistic effect of multi-phase components such as reinforcing phase, matrix, and binder. However, the surface of the matrix of construction metal scrap is prone to oxide layer and oil stains, and the chemical compatibility of each phase component varies greatly. Existing processes lack effective interface control methods, resulting in only physical bonding between the phases. During service, problems such as reinforcing phase detachment and binder peeling off from the matrix are very likely to occur, significantly shortening the service life of the material. Thirdly, the molding process lacks precision. The performance uniformity of wear-resistant materials is closely related to the conversion efficiency of precursors. Existing molding processes mostly adopt an overall temperature control mode, which cannot achieve differentiated temperature control according to the functional requirements of different parts of the material. This often results in incomplete conversion of the surface precursor and excessive carbonization of the core binder, ultimately leading to an unbalanced performance state in which the material exhibits insufficient surface wear resistance and lack of core toughness, making it difficult to adapt to the stringent requirements of high wear conditions for the overall performance of the material.

[0004] Therefore, it is necessary to provide a wear-resistant material utilizing construction metal waste and its preparation method to solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide a wear-resistant material using construction metal waste and its preparation method, so as to solve the problems of difficult removal of impurities, weak interfacial bonding, incomplete precursor conversion, and poor overall wear resistance of existing wear-resistant materials based on construction metal waste.

[0006] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, this invention provides a wear-resistant material utilizing construction metal waste, comprising, by weight: 65-75 parts of construction metal waste, 8-12 parts of a graphene-titanium source composite precursor derived phase, and... 6-10 parts of composite reinforcing phase and 12-18 parts of phenolic epoxy resin binder.

[0007] In a second aspect, the present invention provides a method for utilizing wear-resistant materials from construction metal waste, comprising the following steps: Step 1: Mix Ti source, borosilicate glass powder and BN nanosheets at a mass ratio of 100:(4-6):(1-2), and after ball milling, screen to obtain BN embedded core-shell structured titanium source; Step 2: Mix nano-SiO2 and silane coupling agent solution at a mass ratio of 1:(8-12) and react them. After drying, surface-modified nano-silica dispersant is obtained. Step 3: Mix BN-embedded core-shell titanium source, surface-modified nano-silica dispersant and graphene dispersion at a mass ratio of 100:(6-10):(12-18), and obtain graphene-titanium source composite precursor by wet ball milling, solid-liquid separation and drying. Step 4: Crush and screen the construction metal waste, and collect metal particles with a diameter of 2-15mm; Step 5: Combine the metal particles, the graphene-titanium source composite precursor obtained in Step 3, and... The composite reinforcing phase is mixed at a mass ratio of (65-75):(8-12):(6-10), and 0.5-0.7% of the bio-based chelating agent ethylenediamine disuccinic acid and 0.8-1.2% of the acetyl-protected KH-550 are added. The pH value is adjusted to 4.0-4.5, and the mixture is ball-milled to obtain the modified raw material mixture. Step 6: Add 12-18% of phenolic epoxy resin binder by weight of total material to the raw material modification mixture, stir evenly to obtain the molding mixture; Step 7: Pour the molding mixture into a double-layer temperature-controlled mold, and after zoned temperature control and pressurization, keep it at temperature and pressure for 12-18 minutes to convert the graphene-titanium source composite precursor into a graphene-titanium source composite precursor derivative phase; after the mold cools down to 20-30℃, open the mold, take out the molding material, and obtain the green body.

[0008] This invention utilizes the bio-based chelating agent ethylenediamine disuccinic acid to first purify impurities in construction metal waste, directionally complexing harmful impurities within the waste and eliminating the formation of brittle phases at the source, thus clearing obstacles for the stable bonding of subsequent phases. Based on this, acetyl-protected KH-550 can effectively bind metal particles, composite precursors, and... A robust chemical bond interface is established between the composite reinforcing phases, strengthening the interfacial bonding of the multiphase system and preventing delamination of components during molding and service. The composite reinforcing phase can rely on its own hard support and toughness to bridge the micro-nano structure, and work synergistically with the TiC hard phase and graphene lubricating phase formed by the transformation of the precursor to form a multi-phase synergistic system with wear resistance, lubrication properties and crack resistance. The three types of materials successively complete the progressive functions of impurity purification, interface strengthening and performance complementarity, realizing the transformation of waste matrix from low-value recycling to high-performance wear-resistant materials, while ensuring the structural stability and long-term performance of the material under high wear conditions.

[0009] Preferably, in step 1, the Ti source is a mixture of ferrotitanium powder and tetrabutyl titanate in a mass ratio of (2-4):1; the ball milling speed is 550-650 r / min, the ball-to-material ratio is (8-12):1, and the time is 25-35 min.

[0010] Preferably, in step 2, the nano-SiO2 particle size is 50-100 nm, the silane coupling agent is KH-560, the silane coupling agent solution is a KH-560 ethanol solution with a mass concentration of 0.8-1.2%, and the volume ratio of ethanol to water is (8-10):1; the stirring reaction temperature is 55-65℃, the stirring rate is 280-320 r / min, and the time is 25-35 min; the drying treatment temperature is 75-85℃, and the drying time is 1.5-2.5 h.

[0011] Preferably, in step 3, the graphene dispersion contains 0.6-1.0% graphene, 0.1-0.3% polyvinylpyrrolidone, and 0.05-0.15% sodium dodecyl sulfate; the wet ball milling speed is 700-800 r / min, the ball-to-material ratio is (8-12):1, and the time is 65-75 min; the solid-liquid separation is carried out by centrifugation, the centrifugation speed is 4500-5500 r / min, and the time is 8-12 min; the drying temperature is 55-65℃, and the time is 1-2 h.

[0012] Preferably, in step 4, the crushing process is carried out in two steps: coarse crushing and fine crushing. The gap between coarse crushing and fine crushing is 5-10 mm, and the gap between fine crushing and fine crushing is 1-3 mm. The screening process uses a grading screen with a pore size of 2-15 mm to collect metal particles with a particle size of 2-15 mm.

[0013] Preferably, in step 5 The preparation steps of the composite reinforcing phase include: a1) Mix SiC powder with The powders are mixed at a mass ratio of 1.5:1 to 2.5:1, and anhydrous ethanol, accounting for 3-5% of the total mass of the mixed powders, is added as a dispersant. The mixture is stirred at 300-400 r / min for 15-25 min to obtain a premixed powder. a2) Ball mill the premixed powder at a ball-to-material ratio of 8:1-10:1 and a speed of 450-550 r / min for 2-3 hours, and collect the composite powder with a particle size of 1-3 μm. a3) Add 2-4% (by mass) of KH-550 ethanol solution to the composite powder, stir at 200-300 r / min for 1.5-2.5 h at 70-90℃, and then dry at 80-90℃ for 1-2 h to obtain... Composite reinforced phase.

[0014] The preparation of the present invention Composite reinforcing phase, achieved by mixing SiC and... Powder can both build a hard, wear-resistant framework based on SiC and utilize... The toughness of SiC inhibits crack propagation between SiC particles. The addition of anhydrous ethanol and low-speed stirring can prevent powder agglomeration, balancing the wear resistance and crack resistance of the reinforcing phase from the source. Subsequent ball milling refines the powder to a specific particle size range, which not only facilitates the uniform dispersion of the reinforcing phase in the metal matrix and maximizes the contact area with the matrix, but also allows SiC to bond with the matrix through mechanical force. The particles are tightly interlocked, which improves the defects of single reinforcing phases being prone to brittleness or insufficient wear resistance. Finally, the grafting treatment with KH-550 ethanol solution can introduce active functional groups on the surface of the composite powder, which not only improves the compatibility between the reinforcing phase and the phenolic epoxy resin binder, but also forms chemical bonds with the surface of metal particles, strengthens the interfacial bonding force between the reinforcing phase and the waste matrix, and prevents the reinforcing phase from falling off during service. The final reinforcing phase can work synergistically with the TiC hard phase and the graphene lubricating phase to significantly improve the wear resistance and structural stability of the material.

[0015] Preferably, the preparation step of the bio-based chelating agent ethylenediamine disuccinic acid in step 5 includes: b1) Add maleic anhydride and ethylenediamine to the reactor in a molar ratio of 2:1-2.2:1, add 8-10% deionized water by mass of the total materials, purge with nitrogen for protection, heat to 80-90℃, stir at 150-200 r / min for 3-4 h to obtain intermediate solution. b2) Add 20-25% sodium hydroxide solution to the intermediate solution, adjust the pH to 9.0-10.0, raise the temperature to 100-110℃, and keep the reaction at this temperature for 4-5 hours to obtain EDDS sodium salt solution. b3) Add 15-20% hydrochloric acid solution to the sodium salt solution of EDDS dropwise to adjust the pH value to 2.0-3.0. White crystals will precipitate. After filtration, wash with deionized water 3-5 times and vacuum dry at 60-70℃ for 2-3 hours to obtain ethylenediamine bis(succinic acid) with a purity ≥98%.

[0016] The bio-based chelating agent prepared in this invention is mixed with maleic anhydride and ethylenediamine in a specific ratio, along with an appropriate amount of deionized water, and heated and stirred under nitrogen protection. This ensures that the two react fully to form the target intermediate, while preventing the raw materials from being oxidized and destroying the subsequent formation of chelating groups. Adding an alkaline solution to the intermediate solution to adjust the pH and raising the temperature to maintain the reaction promotes the hydrolysis and ring-closing reaction of the intermediate, generating EDDS sodium salt with strong chelating ability. The alkaline environment and high temperature provide a suitable kinetic environment for this conversion reaction, ensuring the integrity of the chelating active sites. Subsequent addition of an acid solution to adjust the pH allows for the crystallization of EDDS by utilizing the difference in solubility. After multiple water washings and low-temperature vacuum drying, residual salts and impurities are removed, yielding high-purity ethylenediamine disuccinic acid, which can directionally complex S, P, and other impurity ions in construction metal waste, preventing the formation of brittle phases inside the material. Finally, combined with pH adjustment of the system, the impurity removal efficiency can be maximized, solving the performance degradation problem caused by impurity residues in traditional waste-based materials.

[0017] Preferably, step 5, the preparation step of acetyl-protected KH-550, includes: c1) Mix KH-550 with acetic anhydride at a molar ratio of 1:1-1:1.2, then add 10-15% anhydrous toluene as a solvent and 0.5-1.0% pyridine as a catalyst. c2) Under nitrogen protection, the temperature is raised to 60-70℃ and the reaction is stirred at 120-150r / min for 2-3h to obtain the acetylation reaction solution; c3) Distill the reaction solution under reduced pressure at a temperature of 50-60℃ and a vacuum degree of 0.08-0.09MPa to remove the solvent and unreacted acetic anhydride. Wash the remaining product 2-3 times with anhydrous diethyl ether and dry it under vacuum at 50-60℃ for 1-2 hours to obtain acetyl-protected KH-550.

[0018] The acetyl-protected KH-550 prepared in this invention, when mixed with acetic anhydride in a specific ratio, along with anhydrous toluene solvent and a pyridine catalyst, provides a stable non-aqueous reaction environment for the acetylation reaction. The catalyst also lowers the activation energy, ensuring precise coating of the active amino groups in the KH-550 molecule by the acetyl groups. Heating and stirring under nitrogen protection prevents oxidation of the reactants and allows the acetyl groups to stably bind with KH-550, forming a sterically hindered protective structure. This prevents premature hydrolysis and deactivation of KH-550 during subsequent raw material mixing, preserving the activity of its silane groups. Subsequent vacuum distillation removes the solvent and unreacted raw materials, followed by washing with diethyl ether and low-temperature vacuum drying for purification, yielding high-purity acetyl-protected KH-550. In the raw material modification stage, the steric hindrance of the acetyl groups maintains its stability, while the silane groups can react with metal particles, composite precursors, and other components. It enhances the formation of chemical bonds on the phase surface, builds a stable interface transition layer, strengthens the bonding force between phases, avoids interface delamination during service, and works synergistically with the impurity purification effect of bio-based chelating agents to jointly solve the problem of weak interface bonding in traditional waste-based wear-resistant materials, ensuring the overall structural stability and wear resistance of the material.

[0019] Preferably, in step 5, the pH value is adjusted using a 4-6% hydrochloric acid solution or a 4-6% sodium hydroxide solution; the ball milling speed is 850-950 r / min, the ball-to-material ratio is (10-14):1, and the time is 110-130 min; In step 7, the temperature rise rate of the zoned temperature control is 4-6℃ / min, the surface temperature control range is 210-230℃, the core temperature control range is 170-190℃, and the pressure of the pressurization process is 20-24MPa.

[0020] Compared with the prior art, the beneficial effects of the present invention are: 1. The preparation method provided by this invention realizes the high-value utilization of construction metal waste, transforming low-value construction metal waste into wear-resistant material matrix, which not only reduces the preparation cost of wear-resistant materials and reduces the consumption of primary metal resources, but also reduces the resource waste and environmental problems caused by landfilling or low-value recycling of construction metal waste.

[0021] 2. The preparation method provided by this invention effectively solves the problem of difficult removal of impurities in construction metal waste. Through the action of bio-based chelating agents, harmful impurities in the waste can be removed in a targeted manner, avoiding the formation of brittle phases inside the material from the root, ensuring the basic mechanical properties of the material, and solving the defect of performance degradation caused by impurity residue in traditional waste-based wear-resistant materials.

[0022] 3. The preparation method provided by this invention enhances the interfacial bonding ability of multiphase systems. Acetyl-protected KH-550 can construct a stable chemical bonding interface between the metal matrix, composite precursor and composite reinforcing phase, improve the bonding force between phases, avoid component delamination during the molding and service process, and ensure the stability of the material structure.

[0023] 4. The preparation method provided by this invention improves the overall wear resistance of the material. The composite reinforcing phase can work synergistically with the hard phase and graphene lubricating phase formed by the conversion of the precursor, giving the material excellent wear resistance, crack resistance and friction reduction properties. At the same time, the zoned temperature-controlled molding process ensures uniform performance of all parts of the material, which can be adapted to high wear conditions and extend the service life of the material. Attached Figure Description

[0024] Figure 1 This is a bar chart comparing the wear amount of the materials prepared in Examples 1-3 and Comparative Examples 1-6 of the present invention; Figure 2 This is a bar chart comparing the interfacial bonding strength of the materials prepared in Examples 1-3 and Comparative Examples 1-6 of the present invention; Figure 3 This is a bar chart comparing the S and P impurity removal rates of the materials prepared in Examples 1-3 and Comparative Examples 1-6 of the present invention. Detailed Implementation

[0025] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. 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.

[0026] Example 1: This embodiment provides a wear-resistant material made from construction metal waste and its preparation method. The specific steps are as follows: Step 1: Titanium iron powder and tetrabutyl titanate were compounded at a mass ratio of 3:1 to form a Ti source, and borosilicate glass powder and BN nanosheets were mixed at a mass ratio of 100:5:1.5. The mixture was ball-milled for 30 minutes at a speed of 600 r / min and a ball-to-material ratio of 10:1. After screening through a 200-mesh sieve, a BN embedded core-shell structure titanium source with a particle size of 10 μm was obtained.

[0027] Step 2: Take 80nm nano-SiO2 particles and mix them with 1.0% KH-560 ethanol solution (ethanol to water volume ratio 9:1) at a mass ratio of 1:10. Stir the mixture at 60℃ and 300r / min for 30min and dry it at 80℃ for 2h to obtain surface-modified nano-silica dispersant.

[0028] Step 3: Preparation of graphene-titanium source composite precursor. BN-intercalated core-shell structured titanium source, surface-modified nano-silica dispersant, and graphene dispersion (containing 0.8% graphene, 0.2% polyvinylpyrrolidone, and 0.1% sodium dodecyl sulfate) were mixed at a mass ratio of 100:8:15. The mixture was wet ball-milled for 70 min at a speed of 750 r / min and a ball-to-material ratio of 10:1. After centrifugation at 5000 r / min for 10 min, the mixture was dried at 60℃ for 1.5 h to obtain a graphene-titanium source composite precursor with a particle size of 8 μm and an agglomeration rate of 3%.

[0029] Step 4: The construction metal waste with an Fe content of 88% is subjected to coarse crushing (8mm gap) and fine crushing (2mm gap) in sequence, and then screened with a 2-15mm aperture grading screen to collect metal particles with a particle size of 2-15mm.

[0030] Step 5: First prepare Composite reinforcing phase: SiC and The powders were mixed at a mass ratio of 2:1, and 4% anhydrous ethanol was added. The mixture was stirred at 350 r / min for 20 min to obtain a premixed powder. The powder was then ball-milled at a ball-to-powder ratio of 9:1 and a speed of 500 r / min for 2.5 h to collect composite powder with a particle size of 2 μm. Finally, 3% KH-550 ethanol solution was added, and the mixture was stirred at 80℃ and 250 r / min for 2 h. The mixture was then dried at 85℃ for 1.5 h to obtain the reinforcing phase.

[0031] Preparation of ethylenediamine disuccinic acid: Maleic anhydride and ethylenediamine were mixed at a molar ratio of 2.1:1, and 9% deionized water was added. The mixture was stirred at 85°C and 180 r / min for 3.5 h under nitrogen protection to obtain an intermediate. 22% sodium hydroxide solution was added dropwise to adjust the pH to 9.5, and the reaction was carried out at 105°C for 4.5 h to obtain sodium EDDS. 18% hydrochloric acid was added dropwise to adjust the pH to 2.5. After filtration and washing, the mixture was dried under vacuum at 65°C for 2.5 h to obtain ethylenediamine disuccinic acid with a purity of 98.5%.

[0032] Preparation of acetyl-protected KH-550: KH-550 and acetic anhydride were mixed at a ratio of 1:1.1, and 12% anhydrous toluene and 0.8% pyridine were added. The mixture was stirred at 65°C and 135 r / min for 2.5 h under nitrogen protection. The mixture was then distilled under reduced pressure at 55°C and 0.085 MPa. After washing with diethyl ether, the product was dried under vacuum at 55°C for 1.5 h to obtain the product.

[0033] Metal particles and graphene-titanium source composite precursor were mixed in a mass ratio of 70:10:8. The reinforcing phase was prepared by adding 0.6% ethylenediamine disuccinic acid and 1.0% acetyl-protected KH-550, adjusting the pH to 4.2 with 5% hydrochloric acid, and ball milling for 120 min at a speed of 900 r / min and a ball-to-material ratio of 12:1 to obtain the raw material modified mixture.

[0034] Step 6: Add 15% phenolic epoxy resin binder to the raw material modification mixture, stir at 1350 r / min for 25 min to obtain the molding mixture.

[0035] Step 7: Pour the mixture into a double-layer temperature-controlled mold, heat it at a rate of 5℃ / min, with the surface temperature controlled at 220℃ and the core at 180℃, and the pressure at 22MPa, and keep it heated and pressured for 15 minutes; cool it down to 25℃ and open the mold to obtain the wear-resistant material blank.

[0036] Example 2: The difference between this embodiment and Embodiment 1 is that: In step 1, the Ti source is a mixture of ferrotitanium powder and tetrabutyl titanate in a mass ratio of 2:1, and the ball milling speed is 550 r / min for 35 min. In step 3, the graphene dispersion contains 0.6% graphene, 0.1% polyvinylpyrrolidone, and 0.05% sodium dodecyl sulfate. The wet ball milling speed is 700 r / min and the time is 75 min. In step 5 SiC with reinforced phase The mass ratio is 1.5:1, and the molar ratio of maleic anhydride to ethylenediamine in the preparation of ethylenediamine disuccinic acid is 2:1; In step 7, the surface temperature is controlled at 210℃, the core temperature at 170℃, the pressure at 20MPa, and the temperature and pressure are maintained for 18 minutes.

[0037] Example 3: The difference between this embodiment and Embodiment 1 is that: In step 1, the Ti source is a mixture of ferrotitanium powder and tetrabutyl titanate at a mass ratio of 4:1, and the ball milling speed is 650 r / min for 25 min. In step 3, the graphene dispersion contains 1.0% graphene, 0.3% polyvinylpyrrolidone, and 0.15% sodium dodecyl sulfate. The wet ball milling speed is 800 r / min and the time is 65 min. In step 5 SiC with reinforced phase The mass ratio is 2.5:1, and the molar ratio of KH-550 to acetic anhydride in the preparation of acetyl-protected KH-550 is 1:1.2. In step 7, the surface temperature is controlled at 230℃, the core temperature at 190℃, the pressure at 24MPa, and the temperature and pressure are maintained for 12 minutes.

[0038] Comparative Example 1: The difference between this comparative example and Example 1 is that the bio-based chelating agent ethylenediamine disuccinic acid was not added, while the remaining steps and parameters were the same as in Example 1.

[0039] Expected performance: Wear will increase significantly, interfacial bonding strength will decrease significantly, removal rate of impurities such as S and P will decrease significantly, and overall density of the blank will also decline considerably, failing to meet the basic requirements for wear-resistant materials.

[0040] Comparative Example 2: The difference between this comparative example and Example 1 is that no acetyl group protection for KH-550 was added; the remaining steps and parameters are the same as in Example 1.

[0041] Expected performance: Wear will increase significantly, interfacial bonding strength will decrease significantly, the impact resistance of the billet will be significantly insufficient, and only the removal rate of S and P impurities will remain basically at the original level. Overall performance is far lower than that of the example.

[0042] Comparative Example 3: The difference between this comparative example and Example 1 is as follows: Composite reinforced phase SiC and The mass ratio is 1:1, and the remaining steps and parameters are the same as in Example 1.

[0043] Expected performance: Wear resistance will decrease significantly, interfacial bonding strength will be reduced, material fracture toughness will be insufficient, and overall wear life will be much shorter than that of the example sample, making it unsuitable for high wear conditions.

[0044] Comparative Example 4: The difference between this comparative example and Example 1 is that step 7 does not use zoned temperature control, and the overall temperature control is 180°C. The remaining steps and parameters are the same as in Example 1.

[0045] Expected performance: Wear amount increases significantly, interfacial bonding strength declines significantly, graphene-titanium source composite precursor conversion efficiency is low, surface hardness of the preform falls far short of design standards, and performance of various parts is severely uneven.

[0046] Comparative Example 5: The difference between this comparative example and Example 1 is that the Ti source is pure titanium iron powder, which is not compounded with tetrabutyl titanate, while the remaining steps and parameters are the same as in Example 1.

[0047] Expected performance: Wear will increase significantly, interfacial bonding strength will decrease, the core-shell structure will have a very poor coating effect, the material's stability under high-temperature conditions will decrease significantly, and the coefficient of friction will increase sharply.

[0048] Comparative Example 6: The difference between this comparative example and Example 1 is that polyvinylpyrrolidone and sodium dodecyl sulfate were not added to the graphene dispersion, while the remaining steps and parameters were the same as in Example 1.

[0049] Expected performance: Wear amount increased significantly, interfacial bonding strength declined significantly, graphene agglomeration was severe, the overall lubrication performance of the preform was greatly reduced, and the coefficient of friction was much higher than that of the example sample.

[0050] To compare the performance differences of the preparation methods provided in Examples 1-3 and Comparative Examples 1-6, the present invention provides the following experimental methods: All examples and comparative samples were pretreated to uniform specifications. The formed blanks were machined into circular specimens with a diameter of 30 mm and a height of 7 mm for wear resistance testing; into cuboid specimens with a length of 50 mm, a width of 10 mm, and a height of 5 mm for interfacial bonding strength testing; and into circular specimens with a diameter of 10 mm and a height of 5 mm for impurity content detection. The specimen surfaces were sequentially polished with 400-grit, 800-grit, and 1200-grit sandpaper until the surface roughness Ra ≤ 0.8 μm. Afterward, they were ultrasonically cleaned with anhydrous ethanol for 15 min and dried for later use.

[0051] I. Wear Resistance Test 1. The testing equipment is a universal friction and wear testing machine; 2. The test parameters were set as follows: the friction pair used GCr15 steel balls with a hardness of 62 to 64 HRC and a diameter of 5 mm; the test load was 200 N; the spindle speed was 200 r / min; the wear time was 1 h; and the test environment was room temperature 25℃±2℃, relative humidity 50%±5%, and no lubrication throughout the process. 3. The test procedure is as follows: Before the test, weigh the initial mass of the sample using an analytical balance with an accuracy of 0.0001g and record it. The sample is fixed on the working table of the testing machine and the contact position between the grinding steel ball and the sample surface is adjusted to the center area of ​​the sample. The equipment is started and the wear test is completed according to the set parameters. After the test, the wear debris on the sample surface is ultrasonically cleaned with anhydrous ethanol for 10 minutes. After drying, the sample mass is weighed again and recorded as m1. The wear amount is calculated by the formula Δm=m0-m1. At the same time, the wear mark width and depth are recorded by the built-in wear mark measurement module of the equipment as an auxiliary evaluation basis for wear resistance performance.

[0052] II. Interface Bonding Strength Test 1. The testing equipment is an electronic universal tensile testing machine with a range of 0 to 100 kN and an accuracy of 0.5 grade; 2. The testing principle is based on the tensile peel method. The interfacial peel force between the composite reinforcing phase and the metal matrix is ​​converted into interfacial bonding strength. 3. The test procedure is as follows: the reinforcing phase enrichment surface of the cuboid specimen is bonded to a special tensile fixture using high-temperature structural adhesive, ensuring a bonding area of ​​20mm × 10mm. After curing at 80℃ for 2 hours, the specimen is cooled to room temperature. The fixture and specimen are fixed in the upper and lower jaws of the tensile testing machine, and the coaxiality is adjusted to avoid additional bending moment during the loading process. The tensile test is carried out at a loading rate of 1mm / min until the reinforcing phase and the matrix peel off at the interface, and the maximum peel load F is recorded. The interfacial bonding strength is calculated using the formula σ = F / S, where S is the bonding area, i.e., the effective bonding area between the reinforcing phase and the matrix.

[0053] III. Impurity Removal Rate Test 1. The testing equipment was an inductively coupled plasma atomic emission spectrometer; 2. The test objects are metal particles from pretreated construction metal waste and metal particles from modified raw material mixtures; 3. The test procedure is as follows: Weigh 0.5g of untreated construction metal waste powder and pretreated metal particle powder respectively, and label them as Sample A (untreated) and Sample B (treated). Place the samples in a polytetrafluoroethylene digestion vessel and add 10mL of aqua regia. The ratio of aqua regia to nitric acid is 3:1. After sealing, place the vessel in a microwave digester and heat it according to the set program. Maintain the temperature at 120℃ for 10min and at 180℃ for 20min to complete the digestion. After cooling, dilute the digest with deionized water to 50mL and filter. Then, import the solution into an inductively coupled plasma atomic emission spectrometer. Set the instrument detection wavelength to 180.7nm for sulfur and 178.3nm for phosphorus. Measure the mass concentrations of sulfur and phosphorus in Sample A and Sample B respectively and record them as ρA and ρB. Calculate the impurity removal rate using the formula η=[(ρA-ρB) / ρA]×100%. Take the average value of 3 parallel samples as the final result.

[0054] The experimental data are as follows:

[0055] Based on the experimental data, the wear amount in Examples 1-3 was all below 15mg, far lower than that in the comparative examples, fully demonstrating that this technical solution can significantly improve the wear resistance of the material. Among them, Example 1 had the lowest wear amount, only 12.5mg, because its process parameters were in the optimal ratio range, and the compounded Ti source could fully generate the TiC hard phase. The composite reinforcing phase can exert a synergistic effect of hard support and toughness bridging. With the combination of zoned temperature control and pressurization process, the precursor can be directionally transformed into a derivative phase with both wear resistance and lubrication properties. The effectiveness of each component is maximized, and the material can effectively resist the cutting and plowing action of abrasive particles during friction.

[0056] The wear amount in Example 2 was 14.2 mg and the wear amount in Example 3 was 13.1 mg, which was slightly higher than that in Example 1. This was because some parameters in the two examples deviated from the optimal range, resulting in insufficient TiC hard phase formation or weakened toughness bridging effect of the reinforcing phase, and a decrease in the integrity of the wear-resistant system. However, the overall wear resistance level was still excellent.

[0057] Comparative Example 1 showed a sharp increase in wear to 28.7 mg, primarily due to the absence of ethylenediamine disuccinic acid. This prevented the effective complexation of S and P impurities in the construction metal scrap, leading to the formation of numerous brittle phases within the material. These brittle phases were prone to fracture and spalling under frictional stress, significantly exacerbating material wear. Comparative Example 4 exhibited a wear of 30.2 mg, more than double that of Example 1. This was because the absence of a zoned temperature control process resulted in incomplete precursor conversion due to the overall low-temperature environment. Consequently, sufficient TiC hard phase could not form on the material surface, making it difficult to resist abrasive impacts and leading to severe wear. The other comparative examples also showed significantly higher wear rates than the example groups due to the lack of core processes or components.

[0058] Regarding interfacial bonding strength, the interfacial bonding strength of the example groups all exceeded 58 MPa, with Example 3 reaching a high level of 65 MPa, indicating that the technical solution can effectively enhance the interfacial bonding force of multiphase systems. This is because acetyl-protected KH-550 can be applied to metal matrices, composite precursors, and... The composite reinforcing phases form a stable chemical bond interface. Combined with ball milling and pressure processing, this reduces interfacial porosity, improves the bonding tightness between phases, and prevents interfacial delamination during service.

[0059] The interfacial bonding strength of Comparative Example 2 was only 38 MPa, far lower than that of the Example Group. This was because no acetyl-protected KH-550 was added, and the phases were bonded solely by physical interactions, resulting in extremely low interfacial bonding energy and easy separation under stress. The interfacial bonding strength of Comparative Example 6 was 40 MPa, also at a low level. This was because no dispersant was added to the graphene dispersion, leading to severe graphene agglomeration and numerous stress concentration points at the interface. These sites cracked first under tensile force, thus reducing the overall interfacial bonding strength. The other comparative examples also showed interfacial bonding strengths generally below 50 MPa due to the lack of core interfacial control methods, verifying the significant impact of acetyl-protected KH-550 and the graphene dispersion system on interfacial properties.

[0060] Regarding the removal rates of S and P impurities, the removal rates of S and P impurities in the example group were all above 95%, which can effectively remove harmful impurities from construction metal waste. This is because the bio-based chelating agent ethylenediamine disuccinic acid can directionally complex S and P ions in the waste, and separate them from the system through subsequent processes, thus avoiding the formation of brittle phases from the source.

[0061] The removal rate of S and P impurities in Comparative Example 1 was only 65.3%, directly demonstrating the core purification effect of ethylenediamine disuccinic acid. Without this chelating agent, impurities cannot be effectively removed, which will have a serious negative impact on the material performance. The other comparative examples, which did not lack ethylenediamine disuccinic acid, all maintained an impurity removal rate of over 92%, which indirectly confirms that the chelating agent is the key to achieving efficient purification of waste impurities. Only by ensuring a high removal rate of impurities can the foundation for the excellent performance of the material be laid.

[0062] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A wear-resistant material utilizing construction metal scrap, characterized in that, By weight, it includes: 65-75 parts of construction metal waste, 8-12 parts of graphene-titanium source composite precursor derived phase, 6-10 parts of composite reinforcing phase and 12-18 parts of phenolic epoxy resin binder.

2. A method for preparing the wear-resistant material using construction metal waste as described in claim 1, characterized in that, Includes the following steps: Step 1: Mix Ti source, borosilicate glass powder and BN nanosheets at a mass ratio of 100:(4-6):(1-2), and after ball milling, screen to obtain BN embedded core-shell structured titanium source; Step 2: Mix nano-SiO2 and silane coupling agent solution at a mass ratio of 1:(8-12) and react. After drying, obtain surface-modified nano-silica dispersant. Step 3: Mix BN-embedded core-shell titanium source, surface-modified nano-silica dispersant and graphene dispersion at a mass ratio of 100:(6-10):(12-18), and obtain graphene-titanium source composite precursor by wet ball milling, solid-liquid separation and drying. Step 4: Crush and screen the construction metal waste, and collect metal particles with a diameter of 2-15mm; Step 5: Combine the metal particles, the graphene-titanium source composite precursor obtained in Step 3, and... The composite reinforcing phase is mixed at a mass ratio of (65-75):(8-12):(6-10), and 0.5-0.7% of the bio-based chelating agent ethylenediamine disuccinic acid and 0.8-1.2% of the acetyl-protected KH-550 are added. The pH value is adjusted to 4.0-4.5, and the mixture is ball-milled to obtain the modified raw material mixture. Step 6: Add 12-18% of phenolic epoxy resin binder by weight of total material to the raw material modification mixture, stir evenly to obtain the molding mixture; Step 7: Pour the molding mixture into a double-layer temperature-controlled mold, and after zoned temperature control and pressurization, keep it at temperature and pressure for 12-18 minutes to convert the graphene-titanium source composite precursor into a graphene-titanium source composite precursor derivative phase; after the mold cools down to 20-30℃, open the mold, take out the molding material, and obtain the green body.

3. The preparation method according to claim 2, characterized in that, In step 1, the Ti source is a mixture of ferrotitanium powder and tetrabutyl titanate in a mass ratio of (2-4):

1. The ball milling process is performed at a speed of 550-650 r / min, a ball-to-material ratio of (8-12):1, and a time of 25-35 min.

4. The preparation method according to claim 2, characterized in that, In step 2, the nano-SiO2 particles have a diameter of 50-100 nm, the silane coupling agent is KH-560, the silane coupling agent solution is a KH-560 ethanol solution with a mass concentration of 0.8-1.2%, and the volume ratio of ethanol to water is (8-10):

1. The stirring reaction was carried out at a temperature of 55-65℃, a rate of 280-320 r / min, and a time of 25-35 min. The drying process is carried out at a temperature of 75-85℃ for 1.5-2.5 hours.

5. The preparation method according to claim 2, characterized in that, The graphene dispersion in step 3 contains 0.6-1.0% graphene, 0.1-0.3% polyvinylpyrrolidone, and 0.05-0.15% sodium dodecyl sulfate; The wet ball milling speed is 700-800 r / min, the ball-to-material ratio is (8-12):1, and the time is 65-75 min; Solid-liquid separation is performed by centrifugation at a speed of 4500-5500 r / min for 8-12 min. The drying process is carried out at a temperature of 55-65℃ for 1-2 hours.

6. The preparation method according to claim 2, characterized in that, In step 4, the crushing process is carried out in two steps: coarse crushing and fine crushing. The gap between coarse crushing and fine crushing is 5-10 mm, and the gap between fine crushing and fine crushing is 1-3 mm. The screening process uses a grading screen with a pore size of 2-15mm to collect metal particles with a particle size of 2-15mm.

7. The preparation method according to claim 2, characterized in that, Step 5 The preparation steps of the composite reinforcing phase include: a1) Mix SiC powder with The powders are mixed at a mass ratio of 1.5:1 to 2.5:1, and 3-5% anhydrous ethanol is added as a dispersant. The mixture is stirred at 300-400 r / min for 15-25 min to obtain a premixed powder. a2) Ball mill the premixed powder at a ball-to-material ratio of 8:1-10:1 and a speed of 450-550 r / min for 2-3 hours, and collect the composite powder with a particle size of 1-3 μm. a3) Add 2-4% (by mass) of KH-550 ethanol solution to the composite powder, stir at 200-300 r / min for 1.5-2.5 h at 70-90℃, and then dry at 80-90℃ for 1-2 h to obtain... Composite reinforced phase.

8. The preparation method according to claim 2, characterized in that, The preparation steps of the bio-based chelating agent ethylenediamine disuccinic acid in step 5 include: b1) Add maleic anhydride and ethylenediamine to the reactor in a molar ratio of 2:1-2.2:1, add 8-10% deionized water by mass of the total materials, purge with nitrogen for protection, heat to 80-90℃, stir at 150-200 r / min for 3-4 h to obtain intermediate solution. b2) Add 20-25% sodium hydroxide solution to the intermediate solution, adjust the pH to 9.0-10.0, raise the temperature to 100-110℃, and keep the reaction at this temperature for 4-5 hours to obtain EDDS sodium salt solution. b3) Add 15-20% hydrochloric acid solution to the sodium salt solution of EDDS dropwise to adjust the pH value to 2.0-3.

0. White crystals will precipitate. After filtration, wash with deionized water 3-5 times and vacuum dry at 60-70℃ for 2-3 hours to obtain ethylenediamine bis(succinic acid) with a purity ≥98%.

9. The preparation method according to claim 2, characterized in that, The preparation steps of acetyl-protected KH-550 in step 5 include: c1) Mix KH-550 with acetic anhydride at a molar ratio of 1:1-1:1.2, then add 10-15% anhydrous toluene as a solvent and 0.5-1.0% pyridine as a catalyst. c2) Under nitrogen protection, the temperature is raised to 60-70℃ and the reaction is stirred at 120-150r / min for 2-3h to obtain the acetylation reaction solution; c3) Distill the reaction solution under reduced pressure at a temperature of 50-60℃ and a vacuum degree of 0.08-0.09MPa to remove the solvent and unreacted acetic anhydride. Wash the remaining product 2-3 times with anhydrous diethyl ether and dry it under vacuum at 50-60℃ for 1-2 hours to obtain acetyl-protected KH-550.

10. The preparation method according to claim 2, characterized in that, In step 5, pH adjustment is performed using a 4-6% hydrochloric acid solution or a 4-6% sodium hydroxide solution. The ball milling process is performed at a speed of 850-950 r / min, a ball-to-material ratio of (10-14):1, and a time of 110-130 min. In step 7, the temperature rise rate of the zoned temperature control is 4-6℃ / min, the surface temperature control range is 210-230℃, the core temperature control range is 170-190℃, and the pressure of the pressurization process is 20-24MPa.

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