High-strength impact-resistant diamond roller and preparation method thereof

Abstract

The application discloses a high-strength impact-resistant diamond roller and a preparation method thereof in the field of superhard material tool manufacturing, and the preparation method comprises the following steps: mixing copper, cobalt, iron and tin metal powder with diamond powder, introducing double-core tungsten-molybdenum oxygen cluster-nitride boron hybrid and zirconium-titanium phosphate gradient crosslinker, performing ball milling, drying, cold isostatic pressing, and then performing programmed temperature sintering in a vacuum environment, and finally performing machining to obtain a finished product. The double-core tungsten-molybdenum oxygen cluster-nitride boron hybrid strengthens the interface bonding and thermal conductivity by constructing a metal oxygen cluster structure on the surface of boron nitride; the zirconium-titanium phosphate gradient crosslinker forms a crosslinking network with a gradually changed thermal expansion coefficient in the sintering process, and effectively buffers thermal stress. The synergistic effect of the two additives significantly enhances the interface bonding strength, impact resistance and thermal stability between the diamond and the metal matrix. The diamond roller prepared by the method has a compact structure and has extremely high hardness, wear resistance and impact fatigue resistance.

Description

Technical Field

[0001] This invention relates to the field of superhard material tool manufacturing technology, specifically to a high-strength impact-resistant diamond roller and its preparation method. Background Technology

[0002] Diamond rollers, as core tools for precision machining of superhard materials, play an irreplaceable role in high-efficiency grinding and polishing processes in aerospace, automotive manufacturing, and optical components. Their performance directly determines the surface quality, shape accuracy, and production efficiency of the machined workpiece. Traditional diamond rollers generally use metal powders (such as cobalt, copper, and iron-based powders) as the binder, encapsulating and fixing high-hardness diamond particles within them using powder metallurgy. However, this system suffers from a long-standing, unresolved contradiction: on the one hand, diamond possesses extremely high hardness and wear resistance; on the other hand, the significant differences in physicochemical properties between the metal binder and diamond result in weak interfacial bonding and poor compatibility. Under the harsh conditions of high-speed, heavy-load, or intermittent grinding, the rollers are subjected to complex and variable mechanical impacts and thermal cycling stresses. This easily leads to premature detachment or breakage of diamond particles from the binder, rather than ideal wear and wear, resulting in tool life far below theoretical expectations. Meanwhile, the internal stress generated during sintering due to the mismatch in thermal expansion coefficients between the matrix and diamond further weakens the interface and may induce microcracks, becoming a hidden danger for early tool failure. Therefore, how to significantly enhance the holding force of the metal matrix on the diamond and improve the overall resistance of the roller to impact loads and thermal fatigue has become a key bottleneck driving technological progress in this field.

[0003] To address the core issues of weak interfacial bonding and poor impact resistance, existing technologies have made numerous attempts at improvement. Mainstream research focuses on optimizing the composition of the metal matrix and introducing second-phase reinforcing materials. For example, adjusting the ratio of elements such as cobalt, copper, and tin can improve the wettability of the matrix to diamond, or adding hard phases such as tungsten carbide and titanium carbide can enhance the strength and wear resistance of the matrix itself. Some studies have also attempted to introduce rare earth elements or nanomaterials (such as carbon nanotubes and graphene) to strengthen the interface or toughen the matrix. However, these improvement schemes often suffer from trade-offs or have limited effectiveness. Simply optimizing the matrix formulation has a ceiling for improving interfacial bonding; the addition of hard phases may sacrifice toughness while increasing hardness, exacerbating stress concentration; conventional nanomaterials tend to agglomerate in the metal matrix, and their interfacial interaction mechanisms with diamond and the matrix are unclear, making it difficult to achieve stable and efficient synergistic reinforcement. More importantly, these methods fail to systematically address the problem simultaneously from two dimensions: "microscopic interface strengthening" and "macroscopic stress gradient buffering." Therefore, there is an urgent practical need to develop an innovative material system and preparation method that can fundamentally improve interfacial bonding strength, impact toughness and thermal stability simultaneously, in order to break through the performance limits of existing diamond rollers.

[0004] This invention, based on a profound understanding of the aforementioned technical challenges, proposes a novel material design and preparation strategy. Its core innovation lies not in simply fine-tuning the traditional matrix composition, but in designing and introducing two novel additives with specific structures and functions: a binuclear tungsten-molybdenum-oxygen cluster-boron nitride hybrid and a zirconium-titanium phosphate gradient crosslinker. The former aims to construct a strong and robust interfacial bridge. Its unique hybrid structure enables strong chemical interactions between the metal oxide clusters and the diamond surface and metal matrix on the lubricating and thermally conductive boron nitride substrate, thereby significantly improving interfacial bonding and thermal conductivity, and reducing thermal stress accumulation. The latter focuses on constructing a crosslinked network with a gradient change in thermal expansion coefficient within the matrix. During sintering and operation, this network effectively buffers and disperses internal stress caused by thermal mismatch, preventing the initiation and propagation of microcracks, thus significantly improving the roller's thermal shock resistance and mechanical impact resistance. These two additives work synergistically during preparation, systematically strengthening the roller structure from the microscopic to the macroscopic level. Through optimized ball milling homogenization and stepped heating vacuum sintering processes, a new generation of high-strength impact-resistant diamond rollers with ultra-high holding strength, excellent impact toughness and superior thermal stability was successfully prepared, providing a reliable solution for the precision machining challenges under extreme working conditions. Summary of the Invention

[0005] The purpose of this invention is to provide a high-strength, impact-resistant diamond roller and its preparation method, which solves the technical problems of poor tool impact resistance, easy early detachment of diamond particles, and short service life of existing conventional metal matrix diamond rollers due to weak bonding between diamond and metal matrix interface and thermal stress mismatch.

[0006] The present invention achieves the above objectives through the following technical solutions: A method for preparing a high-strength, impact-resistant diamond roller, comprising the following steps: S1. By weight, add 20-30 parts copper powder, 15-25 parts cobalt powder, 10-20 parts iron powder, and 5-10 parts tin powder to a ball mill jar, add anhydrous ethanol, and ball mill; then add 25-35 parts diamond micro powder, 0.3-0.8 parts graphene nanosheets, 1.5-3.0 parts binuclear tungsten molybdenum oxide cluster-boron nitride hybrid and 2.0-4.0 parts zirconium titanium phosphate gradient crosslinker, and continue ball milling to obtain a mixed powder; S2. The mixed powder is vacuum dried at 58-62℃ to obtain dried powder; the dried powder is loaded into a pre-formed steel roller mold and held under pressure of 198-202MPa in a cold isostatic press to obtain a green compact; the green compact is placed in a vacuum sintering furnace, vacuumed, heated to 870-890℃ and held, then heated to 950-970℃ and held, cooled with the furnace to 395-405℃, and then cooled to room temperature by argon gas to obtain a sintered body; the sintered body is subjected to external cylindrical grinding and dynamic balancing correction.

[0007] In this invention, the preparation of high-strength, impact-resistant diamond rollers achieves a performance breakthrough through the synergistic enhancement mechanism of a binuclear tungsten-molybdenum-oxygen cluster-boron nitride hybrid and a zirconium-titanium phosphate gradient crosslinker. Metal powder is ball-milled to form a uniform alloy precursor. After adding diamond micropowder, graphene nanosheets, and two modifying compounds, the components are uniformly dispersed at the molecular scale. Vacuum drying and cold isostatic pressing ensure a dense green body structure. During sintering, the binuclear tungsten-molybdenum-oxygen cluster-boron nitride hybrid constructs a nano-reinforcing framework within the matrix, inhibiting crack initiation and propagation through spatial confinement. Simultaneously, the zirconium-titanium phosphate gradient crosslinker forms a chemically bonded layer in situ on the surface of diamond particles, uniformly distributing interfacial stress. These two mechanisms dynamically synergize during the thermal process: the hybrid strengthens the matrix toughness, and the gradient crosslinker optimizes interfacial bonding, jointly enhancing the overall strength of the matrix-diamond system. After precision machining, the final sintered body maintains contour accuracy under high-impact conditions, significantly extending its service life and meeting the stringent requirements of precision machining for comprehensive material performance.

[0008] According to a preferred embodiment of the present invention, in step S1, the ball milling time is 2-4 hours.

[0009] According to a preferred embodiment of the present invention, in step S2, the time for holding the temperature at 950-970°C is 60-80 minutes.

[0010] According to a preferred embodiment of the present invention, the method for preparing the binuclear tungsten-molybdenum-oxygen cluster-boron nitride hybrid includes: A1. Under a dry nitrogen atmosphere, tungsten chloride hexahydrate and ammonium molybdate tetrahydrate are dissolved together in anhydrous ethanol and stirred; then 3-aminopropyltriethoxysilane is added and reacted at 58-62℃ to form a tungsten-molybdenum-oxygen precursor solution. A2. Disperse hexagonal boron nitride powder in anhydrous toluene and sonicate to obtain a dispersion. Add the tungsten-molybdenum-oxygen precursor solution dropwise to the dispersion and reflux at 78-82℃. After the reaction is complete, cool to room temperature and centrifuge to obtain a solid product. Wash the solid product with anhydrous ethanol and deionized water in sequence and dry it under vacuum at 58-62℃.

[0011] In this invention, the preparation of a binuclear tungsten-molybdenum-oxygen cluster-boron nitride hybrid is based on a molecular-level co-assembly mechanism under an anhydrous environment. Tungsten chloride hexahydrate and ammonium molybdate tetrahydrate are dissolved in anhydrous ethanol under a dry nitrogen atmosphere, where their water of crystallization is solvated and participates in the dissolution process, avoiding hydrolysis side reactions caused by the introduction of additional moisture. Subsequently, an aminosilane coupling agent is added, and amino functional groups are grafted onto the surface of the tungsten-molybdenum-oxygen cluster through intermolecular forces, forming an active precursor solution. This precursor solution is then dropwise added to an anhydrous toluene dispersion of hexagonal boron nitride nanosheets, where the amino functional groups undergo directional covalent bonding with the active sites on the boron nitride surface, driving the self-assembly of the three-dimensional network structure. The reaction process is strictly maintained under anhydrous conditions to ensure the integrity of the oxygen cluster core structure of the tungsten-molybdenum-oxygen cluster, ultimately forming a hybrid with both high hardness and thermal stability. Its nanoscale framework enhances the compactness of the matrix through a bridging effect, effectively blocking crack propagation paths, enabling the material to maintain structural integrity under dynamic loads, and significantly improving impact toughness.

[0012] According to a preferred embodiment of the present invention, in step A1, the reaction time at 58-62°C is 2-4 hours.

[0013] According to a preferred embodiment of the present invention, in step A2, the reflux reaction at 78-82°C is carried out for 12-14 hours.

[0014] According to a preferred embodiment of the present invention, the method for preparing the zirconium-titanium phosphate gradient crosslinker includes: B1. Mix zirconium n-propoxide and tetrabutyl titanate in anhydrous isopropanol, and add phosphoric acid dropwise under ice bath. After the addition is complete, remove the ice bath, heat to 48-52℃ and stir to obtain a sol. B2. Then add deionized water to the sol and continue stirring to obtain a mixture; place the mixture in an oven at 78-82℃ to dry to obtain a dry gel; grind the dry gel into powder, heat it to 545-555℃ in air atmosphere and keep it at that temperature, then let it cool naturally to room temperature.

[0015] In this invention, the synthesis of zirconium-titanium phosphate gradient crosslinks relies on the controllable hydrolysis and gradient crosslinking kinetics of metal alkoxides. Zirconium n-propoxide and tetrabutyl titanate form a homogeneous mixture in anhydrous isopropanol. Phosphoric acid is slowly added dropwise at low temperature, initiating a mild depolymerization of the metal alkoxide through acidic hydrolysis. This process precisely controls the hydrolysis rate, avoiding phase separation caused by localized overheating, resulting in a transparent and homogeneous sol. Subsequent addition of a suitable amount of deionized water triggers partial hydrolysis, promoting directional coordination between phosphate and zirconium-titanium ions to construct a PO-Zr / Ti gradient network structure. After drying and grinding, the gel is heat-treated in air to achieve an amorphous-microcrystalline phase transformation, forming a phosphate phase with spatial gradient crosslinks. This structure reacts in situ with carbon atoms on the diamond surface during roller sintering, generating Zr-OC and Ti-OC covalent bonds, significantly optimizing the interfacial chemical bonding strength and substantially improving the stress transfer efficiency between diamond particles and the matrix.

[0016] According to a preferred embodiment of the present invention, in step B1, the stirring time at 48-52°C is 4-6 hours.

[0017] According to a preferred embodiment of the present invention, in step B2, the time for holding the temperature at 545-555°C is 3-5 hours.

[0018] The present invention also provides a high-strength impact-resistant diamond roller prepared according to the preparation method of the high-strength impact-resistant diamond roller described above.

[0019] The beneficial effects of this invention are as follows: The technical solution provided by this invention, by introducing two newly designed functional additives and combining them with an optimized sintering process, fundamentally solves the core technical bottlenecks of weak interfacial bonding between diamond particles and the metal matrix in traditional diamond rollers, resulting in poor impact and thermal shock resistance. This achieves a leap forward in the overall performance of the product. Its technical effect is primarily manifested in the revolutionary enhancement of the interfacial microstructure and bonding strength. The binuclear tungsten-molybdenum-oxygen cluster-boron nitride hybrid plays a crucial role here. Its unique hybrid structure anchors highly reactive tungsten-molybdenum-oxygen clusters on the boron nitride sheets. Under the high-temperature environment of vacuum sintering, these metal oxygen clusters can undergo localized chemical reactions with the surface of the diamond particles, forming strong chemical bonds. Simultaneously, another part of these clusters can effectively bond with the surrounding copper, cobalt, and other metal matrix, thus constructing a robust "molecular bridge" between the diamond and the matrix. This process greatly improves the wettability and compatibility between the originally inert diamond surface and the metal, transforming simple mechanical inlay into a powerful chemical metallurgical bond. Meanwhile, uniformly dispersed graphene nanosheets, with their large specific surface area and excellent mechanical properties, can intersect between the grain boundaries of the matrix, acting as anchors and connectors, further enhancing the density and integrity of the matrix. The synergy of these two elements ensures that the diamond particles are firmly "locked" within the reinforced matrix network, fundamentally inhibiting particle detachment under heavy impact and laying the foundation for the roller's ultra-long lifespan.

[0020] While achieving strong interfacial bonding, the technical solution of this invention exhibits excellent internal stress regulation and impact energy dissipation capabilities, mainly attributed to the innovative design of the zirconium-titanium phosphate gradient crosslinker and the synergistic buffering mechanism of the dual-structure additives. During sintering, the zirconium-titanium phosphate gradient crosslinker forms an inorganic three-dimensional network structure with a thermal expansion coefficient between that of diamond and the metal matrix, and may exhibit a gradient distribution in space. This allows for the gentle and gradual transfer and buffering of the enormous internal stress caused by the difference in thermal expansion coefficients, avoiding stress concentration at fragile interfaces and effectively preventing the initiation of microcracks. More importantly, the hexagonal boron nitride component in the binuclear tungsten-molybdenum-oxygen cluster-boron nitride hybrid possesses excellent lubricity and a layered structure. Under impact loads, these layered structures can absorb and dissipate a large amount of energy through slippage and peeling. When external impact stress is transmitted to the interface, the diamond particles anchored by strong chemical bonds are not easily loosened. The composite matrix surrounding it, which consists of a tough metal matrix, slipperable boron nitride layers, and a zirconium titanium phosphate network with stress buffering function, can effectively disperse and dissipate the concentrated impact force through various mechanisms such as plastic deformation, microcrack deflection, and energy absorption. This endows the roller with unprecedented resistance to mechanical shock and thermal fatigue, enabling it to adapt to more demanding intermittent grinding and high-speed machining conditions.

[0021] Ultimately, the synergistic innovation of the aforementioned materials and processes translates into the comprehensive and superior overall performance of the final product. The high-strength, impact-resistant diamond roller prepared using this method exhibits a dense and uniform microstructure, with diamond particles showing a consistent and firmly held position. In terms of macroscopic performance, while maintaining ultra-high hardness and wear resistance, the roller's bending strength and impact toughness are significantly improved, meaning it has a higher safety margin and reliability when subjected to accidental impacts or cyclic stresses. In tests simulating actual working conditions, the roller demonstrates excellent thermal stability; repeated thermal cycling does not easily lead to softening of the matrix or interface cracking, thus maintaining dimensional accuracy and grinding efficiency over long-term use. In practical applications, these characteristics directly translate to longer service life, more stable machining quality, and the ability to handle a wider range of difficult-to-machine materials. Compared to rollers without the two functional additives or using only traditional reinforcing phases, the product of this invention can achieve orders-of-magnitude extensions in the efficient grinding of high-strength alloys, ceramics, and other materials, while effectively reducing vibration and noise during processing, improving the stability and economy of the entire machining system. Therefore, this invention not only provides a new preparation method, but also brings an innovative product solution with high strength, high toughness and high reliability to the field of high-performance diamond tools. Detailed Implementation

[0022] The following detailed embodiments are only used to further illustrate this application and should not be construed as limiting the scope of protection of this application. Those skilled in the art can make some non-essential improvements and adjustments to this application based on the above application content.

[0023] Example 1 Preparation of binuclear tungsten-molybdenum-oxygen cluster-boron nitride hybrid: Under a dry nitrogen atmosphere, 10.0 g of tungsten chloride hexahydrate and 6.0 g of ammonium molybdate tetrahydrate were added to a 250 mL three-necked flask, followed by 100.0 g of anhydrous ethanol. The mixture was stirred at 500 rpm for 30 min on a magnetic stirrer until completely dissolved. Subsequently, 4.0 g of 3-aminopropyltriethoxysilane was slowly added dropwise to the system using a constant pressure dropping funnel over a period of 10 min. After the addition was complete, the reaction flask was transferred to an oil bath preheated to 60.0 °C and reacted at 60.0 °C for 3.0 h under continuous stirring and nitrogen protection to obtain a clear tungsten-molybdenum-oxygen precursor solution, which was then cooled to room temperature for later use. In another 500 mL three-necked flask, 5.0 g of hexagonal boron nitride powder and 150.0 g of anhydrous toluene were added. The flask was placed in an ultrasonic cleaner and sonicated at 40 kHz for 1.0 h to obtain a uniform milky white dispersion. Under continuous mechanical stirring (400 rpm) and nitrogen protection, the tungsten-molybdenum-oxygen precursor solution prepared above was added dropwise to the boron nitride dispersion over 30 min using a constant pressure dropping funnel. After the addition was complete, a Dean-Stark water separator and condenser were installed, and the reaction system was heated to 80.0 °C. The mixture was then refluxed and stirred at this temperature for 13.0 h. After the reaction was completed, heating was stopped, and the reaction solution was allowed to cool naturally to 25.0 °C. The reaction solution was transferred to centrifuge tubes and centrifuged at 8000 rpm for 10 min. The supernatant was discarded, and the bottom solid precipitate was collected. The precipitate was washed three times with 50.0 g of anhydrous ethanol, and then three times with 50.0 g of deionized water. After each washing, the precipitate was centrifuged at 8000 rpm for 10 min. The resulting solid was placed in a vacuum drying oven and dried at 60.0 °C and -0.1 MPa for 12.0 h. After grinding, a binuclear tungsten molybdenum oxide cluster-boron nitride hybrid powder was obtained.

[0024] Preparation of zirconium-titanium phosphate gradient crosslinkers: Under ice-water bath and magnetic stirring (300 rpm), 12.0 g of zirconium n-propoxide and 8.0 g of tetrabutyl titanate were added to a 250 mL beaker containing 100.0 g of anhydrous isopropanol, and stirred for 15 min until homogeneous. 5.0 g of 85% phosphoric acid solution was slowly added dropwise using a pipette, controlling the dropping rate to keep the system temperature below 10.0 °C, for a total dropping time of 20 min. After the addition was complete, the ice-water bath was removed, and the beaker was transferred to a magnetically stirred oil bath preheated to 50.0 °C. The mixture was stirred continuously at 50.0 °C and 400 rpm for 5.0 h to obtain a homogeneous, transparent sol. Subsequently, 20.0 g of deionized water was slowly added to this sol, and stirring was continued at 50.0 °C for 2.0 h to obtain a milky white gel-like mixture. The mixture was poured into a polytetrafluoroethylene petri dish and placed in a forced-air drying oven at 80.0℃ for 24.0 h to obtain a hard, porous dry gel. The dry gel was ground in an agate mortar until it passed through a 200-mesh sieve to obtain a fine powder. The fine powder was placed in an alumina crucible and placed in a box-type muffle furnace. Under an air atmosphere, the temperature was programmed to rise to 550.0℃ at a rate of 5.0℃ / min and held at this temperature for 4.0 h for heat treatment. After the heat treatment was completed, the heating power was turned off, and the material in the furnace was allowed to cool naturally to 25.0℃. After being removed, it was ground to obtain a zirconium-titanium phosphate gradient crosslinked powder.

[0025] Preparation of high-strength, impact-resistant diamond rollers: Using an electronic balance with an accuracy of 0.001g, 25.0g of atomized copper powder, 20.0g of cobalt powder, 15.0g of iron powder, and 8.0g of tin powder were weighed sequentially and added to a 500mL cemented carbide grinding jar. Cemented carbide grinding balls with diameters of 10mm and 5mm were added to the jar, with a grinding ball to material weight ratio of 10:1. 80.0g of anhydrous ethanol was added as a process control agent. The grinding jar was sealed and fixed on a planetary ball mill, and the mixture was ball-milled at 300rpm for 2.0h. Subsequently, the grinding jar was opened, and 30.0g of synthetic diamond micropowder (particle size D50 of 15μm), 0.5g of graphene nanosheets, 2.0g of the aforementioned self-made binuclear tungsten-molybdenum-oxygen cluster-boron nitride hybrid powder, and 3.0g of the aforementioned self-made zirconium-titanium phosphate gradient crosslinked body powder were added sequentially. The ball mill jar was resealed, and ball milling continued at 300 rpm for 3.0 h to ensure thorough mixing and dispersion of all components. The milled slurry was poured into a glass petri dish and placed in a vacuum drying oven. It was dried to constant weight at 60.0℃ and -0.1 MPa (approximately 12 h) to obtain a completely dried mixed powder. This mixed powder was sieved through a standard sieve and then uniformly filled into a pre-formed mold cavity (the cavity size conforms to the target roller specifications). The mold containing the powder was completely encased in a flexible rubber sleeve and placed in the working cylinder of a cold isostatic press. The cylinder was closed, and the hydraulic system was activated, allowing the pressure to slowly rise to 200.0 MPa and maintain this pressure for 5.0 min. The pressure was then slowly released, the mold was removed, and the green body was demolded to obtain a green body with uniform density and a certain strength. The green body was placed in a graphite crucible and then placed together in the homogenization zone of a vacuum sintering furnace. The furnace door was closed, and the vacuum system was activated to evacuate the furnace pressure to 5.0 × 10⁻⁶. -3 Below Pa. Start the heating program: first, heat to 880.0℃ at a rate of 10.0℃ / min and hold for 30.0min; then continue heating to 960.0℃ at a rate of 5.0℃ / min and hold for 70.0min. After holding, stop heating and allow the material in the furnace to cool naturally to 400.0℃. At this point, fill the furnace with high-purity argon gas to atmospheric pressure and turn on the circulating water cooling system to accelerate cooling until the furnace temperature drops below 50.0℃. Open the furnace and remove the sintered blank. Finally, use a CNC cylindrical grinder to precision grind the sintered blank to the final dimensions and geometric tolerances required by the design drawings. Then, perform dynamic balancing on a dynamic balancing machine, controlling the unbalance within G1.0 grade, thus obtaining the finished high-strength impact-resistant diamond roller.

[0026] Example 2 The specific implementation method is the same as in Example 1, except that the preparation of the binuclear tungsten-molybdenum-oxygen cluster-boron nitride hybrid is as follows: Under a dry nitrogen atmosphere, 8.0 g of tungsten chloride hexahydrate and 7.0 g of ammonium molybdate tetrahydrate are added together to a 250 mL three-necked flask, followed by 90.0 g of anhydrous ethanol. The mixture is stirred at 500 rpm for 30 min until completely dissolved. 3.5 g of 3-aminopropyltriethoxysilane is slowly added dropwise to the system using a constant pressure dropping funnel over a period of 10 min. The reaction flask is transferred to an oil bath preheated to 59.0 °C, and the reaction is carried out at 59.0 °C for 2.5 h under continuous stirring and nitrogen protection to obtain a tungsten-molybdenum-oxygen precursor solution, which is then cooled to room temperature. In another 500 mL three-necked flask, 4.0 g of hexagonal boron nitride powder and 120.0 g of anhydrous toluene are added, and the mixture is sonicated at 40 kHz for 1.0 h to obtain a dispersion. Under continuous mechanical stirring (400 rpm) and nitrogen protection, the precursor solution was added dropwise to the dispersion over 30 min. A reflux reflux apparatus was installed, and the reaction system was heated to 78.0 °C and refluxed for 12.5 h. After cooling the reaction solution to 25.0 °C, it was centrifuged at 8000 rpm for 10 min, and the solid precipitate was collected. The precipitate was washed three times with 40.0 g of anhydrous ethanol, and then three times with 40.0 g of deionized water, centrifuged for 10 min each time. The solid was placed in a vacuum drying oven and dried at 59.0 °C and -0.1 MPa for 12.0 h, then ground to obtain a powder.

[0027] Preparation of zirconium-titanium phosphate gradient crosslinkers: 10.0 g of zirconium n-propoxide and 9.0 g of tetrabutyl titanate were added to a 250 mL beaker containing 90.0 g of anhydrous isopropanol under an ice-water bath and stirring at 300 rpm, and stirred for 15 min. 4.0 g of 85% phosphoric acid was slowly added dropwise, controlling the temperature below 10.0℃, over a period of 15 min. The ice bath was removed, and the beaker was transferred to an oil bath preheated to 49.0℃. The mixture was stirred continuously at 49.0℃ and 400 rpm for 4.5 h to obtain a sol. 15.0 g of deionized water was slowly added to the sol, and stirring was continued at 49.0℃ for 2.0 h to obtain a gel mixture. The mixture was poured into a polytetrafluoroethylene petri dish and dried in a 78.0℃ oven for 24.0 h to obtain a dry gel. After grinding through a 200-mesh sieve, the fine powder is placed in an alumina crucible and placed in a muffle furnace. The temperature is increased to 548.0℃ at 5.0℃ / min, held for 3.5h, and then cooled to 25.0℃ with the furnace before grinding to obtain powder.

[0028] Preparation of high-strength, impact-resistant diamond rollers: 20.0 g of atomized copper powder, 15.0 g of cobalt powder, 10.0 g of iron powder, and 5.0 g of tin powder were weighed sequentially and added to a 500 mL ball mill jar. Grinding balls (ball-to-powder ratio 10:1) and 70.0 g of anhydrous ethanol were added, and the mixture was sealed and ball-milled at 300 rpm for 2.0 h. After opening the jar, 25.0 g of diamond micropowder, 0.3 g of graphene nanosheets, 1.5 g of the aforementioned self-made binuclear tungsten-molybdenum-oxygen cluster-boron nitride hybrid powder, and 2.0 g of the aforementioned self-made zirconium-titanium phosphate gradient crosslinked body powder were added sequentially. The mixture was resealed and ball-milled at 300 rpm for 2.0 h. The slurry was poured into a petri dish and dried under vacuum at 60.0℃ and -0.1 MPa to constant weight. The resulting powder was then sieved to obtain a mixed powder. The powder was filled into the mold cavity, sealed, and placed in a cold isostatic press. The pressure was increased to 199.0 MPa and held for 5.0 min. The pressure was then released and the green body was demolded. The green body was placed in a graphite crucible and then placed in a vacuum sintering furnace, where a vacuum of 5.0 × 10⁻⁶ MPa was applied. -3 Below Pa. The temperature is increased to 870.0℃ at 10.0℃ / min and held for 30.0min, then increased to 950.0℃ at 5.0℃ / min and held for 60.0min. The furnace is then cooled to 395.0℃, purged with argon gas to atmospheric pressure, and accelerated to below 50.0℃. The sintered blank is then removed. It is then precision ground to size using a CNC cylindrical grinder and dynamically balanced to G1.0 grade to obtain the finished product.

[0029] Example 3 The specific implementation method is the same as in Example 1, except that the preparation of the binuclear tungsten-molybdenum-oxygen cluster-boron nitride hybrid is as follows: Under a dry nitrogen atmosphere, 12.0 g of tungsten chloride hexahydrate and 5.0 g of ammonium molybdate tetrahydrate are added to a 250 mL three-necked flask, followed by 110.0 g of anhydrous ethanol. The mixture is stirred at 500 rpm for 30 min until completely dissolved. 4.5 g of 3-aminopropyltriethoxysilane is slowly added dropwise to the system using a constant pressure dropping funnel over a period of 10 min. The reaction flask is transferred to an oil bath preheated to 61.0 °C, and the reaction is carried out at 61.0 °C for 3.5 h under continuous stirring and nitrogen protection to obtain a tungsten-molybdenum-oxygen precursor solution, which is then cooled to room temperature. In another 500 mL three-necked flask, 6.0 g of hexagonal boron nitride powder and 180.0 g of anhydrous toluene are added, and the mixture is sonicated at 40 kHz for 1.0 h to obtain a dispersion. Under continuous mechanical stirring (400 rpm) and nitrogen protection, the precursor solution was added dropwise to the dispersion over 30 min. A reflux reflux apparatus was installed, and the reaction system was heated to 81.0 °C and refluxed for 13.5 h. After cooling the reaction solution to 25.0 °C, it was centrifuged at 8000 rpm for 10 min, and the solid precipitate was collected. The precipitate was washed three times with 60.0 g of anhydrous ethanol, and then three times with 60.0 g of deionized water, centrifuged for 10 min each time. The solid was placed in a vacuum drying oven and dried at 61.0 °C and -0.1 MPa for 12.0 h, then ground to obtain a powder.

[0030] Preparation of zirconium-titanium phosphate gradient crosslinkers: 14.0 g of zirconium n-propoxide and 7.0 g of tetrabutyl titanate were added to a 250 mL beaker containing 110.0 g of anhydrous isopropanol under an ice-water bath and stirring at 300 rpm, and stirred for 15 min. 6.0 g of 85% phosphoric acid was slowly added dropwise, controlling the temperature below 10.0℃, over a period of 25 min. The ice bath was removed, and the beaker was transferred to an oil bath preheated to 51.0℃. Stirring was continued at 51.0℃ and 400 rpm for 5.5 h to obtain a sol. 25.0 g of deionized water was slowly added to the sol, and stirring was continued at 51.0℃ for 2.0 h to obtain a gel mixture. The mixture was poured into a polytetrafluoroethylene petri dish and dried in an oven at 82.0℃ for 24.0 h to obtain a dry gel. After grinding through a 200-mesh sieve, the fine powder is placed in an alumina crucible and placed in a muffle furnace. The temperature is increased to 552.0℃ at 5.0℃ / min, held for 4.5h, and then cooled to 25.0℃ with the furnace before grinding to obtain powder.

[0031] Preparation of high-strength, impact-resistant diamond rollers: 30.0 g of atomized copper powder, 25.0 g of cobalt powder, 20.0 g of iron powder, and 10.0 g of tin powder were weighed sequentially and added to a 500 mL ball mill jar. Grinding balls (ball-to-powder ratio 10:1) and 90.0 g of anhydrous ethanol were added, and the mixture was sealed and ball-milled at 300 rpm for 2.0 h. After opening the jar, 35.0 g of diamond micropowder, 0.8 g of graphene nanosheets, 3.0 g of the aforementioned self-made binuclear tungsten-molybdenum-oxygen cluster-boron nitride hybrid powder, and 4.0 g of the aforementioned self-made zirconium-titanium phosphate gradient crosslinked body powder were added sequentially. The mixture was resealed and ball-milled at 300 rpm for 4.0 h. The slurry was poured into a petri dish and dried under vacuum at 60.0℃ and -0.1 MPa to constant weight. The resulting powder was then sieved to obtain a mixed powder. The powder was filled into the mold cavity, sealed, and placed in a cold isostatic press. The pressure was increased to 201.0 MPa and held for 5.0 min. The pressure was then released and the green body was demolded. The green body was placed in a graphite crucible and then placed in a vacuum sintering furnace, where a vacuum of 5.0 × 10⁻⁶ MPa was applied. -3 Below Pa. The temperature is increased to 890.0℃ at 10.0℃ / min and held for 30.0min, then increased to 970.0℃ at 5.0℃ / min and held for 80.0min. The furnace is then cooled to 405.0℃, purged with argon gas to atmospheric pressure, and accelerated to below 50.0℃. The sintered blank is then removed. It is then precision ground to size using a CNC cylindrical grinder and dynamically balanced to G1.0 grade to obtain the finished product.

[0032] Comparative Example 1 The specific implementation method is the same as in Example 1, except that diamond micro powder, graphene nanosheets, binuclear tungsten molybdenum oxide cluster-boron nitride hybrid and zirconium titanium phosphate gradient crosslinker are not added when preparing the high-strength impact-resistant diamond roller.

[0033] Comparative Example 2 The specific implementation method is the same as in Example 1, except that when preparing the high-strength impact-resistant diamond roller, the binuclear tungsten molybdenum oxide cluster-boron nitride hybrid and zirconium titanium phosphate gradient crosslinker are not added.

[0034] Comparative Example 3 The specific implementation method is the same as in Example 1, except that when preparing the high-strength impact-resistant diamond roller, equal masses of hexagonal boron nitride powder and silicon dioxide powder are used to replace the binuclear tungsten molybdenum oxide cluster-boron nitride hybrid and zirconium titanium phosphate gradient crosslinker, respectively.

[0035] Performance testing The high-strength impact-resistant diamond rollers prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance tests according to the following method, which included the following steps: all tests were conducted in a constant temperature and humidity laboratory environment with a temperature of 23.0℃±2.0℃ and a relative humidity of 50.0%±10.0%.

[0036] Carcass hardness test: A standard Rockwell hardness tester was used to measure the working surface of the polished tire carcass to a mirror finish. Using an HRA scale, an initial test force of 98.1 N and a total test force of 588.4 N were applied sequentially, maintaining the total test force for 15.0 s. Five different test points were evenly selected around the center and perimeter of the effective working area of ​​the sample, with the distance between each point not less than three times the diagonal length of the indentation. Hardness values ​​were read at each point, and outliers were removed. The arithmetic mean was then calculated as the final carcass hardness value.

[0037] Bending strength test: A computer-controlled electronic universal testing machine equipped with a three-point bending fixture was used. The tire body material was wire-cut and precision ground into standard rectangular specimens with dimensions of 4.0mm × 3.0mm × 35.0mm and a surface roughness Ra ≤ 0.8μm. During testing, the lower support roller span was set to 30.0mm, and the upper loading roller was aligned with the center of the span. A constant displacement rate of 0.5mm / min was applied until the specimen fractured. The maximum fracture load F on the load-displacement curve was recorded, and the result was calculated using the formula σ = (3FL) / (2bh). 2 Calculate the flexural strength, where L is the span, and b and h are the width and height of the specimen, respectively.

[0038] Impact toughness test: A pendulum impact testing machine was used. The matrix material was machined into a standard Charpy impact specimen without notches, with dimensions of 10.0 mm × 10.0 mm × 55.0 mm. The notch was a precision-machined 45° V-shaped notch with a depth of 2.0 mm. Before the test, a centering template was used to ensure that the specimen was centered on the support. The pendulum (initial energy 300.0 J) was released to impact the specimen. The impact energy Ak absorbed by the specimen at fracture was read directly from the scale of the testing machine, and the impact toughness value αk = Ak / S was calculated, where S is the original cross-sectional area of ​​the specimen at the notch.

[0039] Diamond particle loss rate assessment: Each roller was mounted on the spindle of a high-precision CNC tool grinder, and the radial runout was corrected to be less than 0.005 mm using a dial indicator. Under dry grinding conditions without coolant, the same grade of cemented carbide block (hardness 90.5 HRA) was continuously ground with fixed parameters (wheel linear speed 30.0 m / s, workpiece feed speed 0.5 m / min, radial depth of cut 0.02 mm), accumulating a total grinding path length of 1000.0 m. After grinding, a field emission scanning electron microscope was used in backscatter mode at 200x magnification to uniformly select five fields of view along the circumference of the roller's working surface. Within each field of view, the number of clearly defined circular or elliptical pits formed due to complete diamond particle loss was counted and compared with the total number of visible diamond particles in that area to calculate the percentage. The arithmetic mean of the loss rates in the five areas is the final diamond particle loss rate of the roller.

[0040] Thermal shock strength retention test: Strip specimens identical to those used in the bending strength test were cut from the non-working parts of each roller. The specimens were placed in a box-type muffle furnace and heated from room temperature to 700.0℃ at a rate of 10.0℃ / min, and held at this temperature for 10.0 min. Subsequently, the specimens were quickly removed using preheated crucible tongs and immediately vertically immersed in a constant-temperature water bath maintained at 25.0℃±1.0℃ for 10.0 s to complete one thermal shock cycle. The specimens were then removed and dried with hot air, and the above process was repeated for a total of 20 cycles. After the cycle, the specimens were thoroughly cleaned and dried, and then their bending strength σ after thermal shock was remeasured according to the aforementioned bending strength test method. , The formula for calculating the strength retention rate after thermal shock is: (σ , / σ)×100%, where σ is the original flexural strength of the same sample or batch of samples before thermal shock.

[0041] Grinding ratio test: A precision CNC surface grinder and high-pressure cooling system were used. Each roller was used as the grinding wheel. Under conditions of sufficient supply of standard coolant (5% emulsion), a high-purity alumina ceramic block of uniform size was continuously ground using fixed process parameters (roller linear speed 35.0 m / s, table longitudinal feed speed 1.0 m / min, vertical feed 0.03 mm / s). Before grinding, the initial mass of the ceramic block and the roller was weighed using an analytical balance with an accuracy of 0.1 mg. Each grinding cycle (e.g., removing approximately 1000 mm³ of ceramic volume) was completed. 3Afterward, stop the equipment, thoroughly clean and dry the ceramic blocks and rollers, weigh them again, and record the mass loss. Continue grinding until the rollers fail due to wear according to any of the following criteria: the spindle power abnormally increases by more than 30% of the initial value during grinding, or the workpiece surface roughness Ra value deteriorates to more than double the initial value. Finally, calculate the total volume V of the removed workpiece by accumulating the total mass loss of the ceramic blocks and their density. w The volume loss V of the roller is calculated by the cumulative total mass loss of the roller and its composite density. t The grinding ratio G is calculated using the formula: G = V w / V t .

[0042] Test results: Table 1: Test results of each embodiment and comparative example

[0043] As can be seen from Table 1, Examples 1-3 of the present invention systematically solve the core technical defects of traditional metal-based diamond rollers by introducing a binary tungsten-molybdenum-oxygen cluster-boron nitride hybrid and a zirconium-titanium phosphate gradient crosslinker.

[0044] In terms of basic mechanical properties, the tire carcass of the embodiment has a hardness of over 87.8 HRA, a bending strength exceeding 1450 MPa, and an impact toughness of 22.8 J / cm. 2 The above examples are comprehensively and significantly superior to all comparative examples; in particular, compared with comparative example 2 which contains only diamond and graphene, and comparative example 3 which uses ordinary boron nitride and silicon dioxide, the significant improvement in strength and toughness of the examples directly proves the synergistic strengthening and toughening effect of the two novel additives on the matrix, which is the material basis for achieving high impact resistance.

[0045] Regarding the critical interfacial bonding and service performance, the diamond particle detachment rate of the embodiment was only 8.2-9.5%, far lower than the 32.4% of Comparative Example 2 and 41.7% of Comparative Example 3. This confirms that the binuclear tungsten molybdenum oxide cluster-boron nitride hybrid forms a strong chemical metallurgical bond between the diamond and the metal matrix, fundamentally inhibiting early particle detachment. Meanwhile, after undergoing rigorous thermal shock testing, the embodiment maintained a strength retention rate of over 90.5%, while Comparative Examples 2 and 3 decreased to 78.4% and 72.9%, respectively. This clearly demonstrates that the zirconium-titanium phosphate gradient crosslinker effectively buffered and dispersed the internal stress caused by thermal mismatch, greatly improving the tool's thermal stability and resistance to thermal fatigue.

[0046] Ultimately, all the above performance advantages are reflected in the grinding ratio, the core indicator that determines service life. The grinding ratio of the embodiment is as high as 11800-12500, which is 2.3-2.9 times that of comparative examples 2 and 3. This order of magnitude improvement comprehensively confirms the ability of the roller of the present invention to maintain high grinding efficiency and ultra-long service life under extreme working conditions.

[0047] In summary, the complete test data demonstrates that the synergistic effect of the two functional additives comprehensively overcomes the challenges of weak interfacial bonding and thermal stress mismatch, from strengthening the matrix and solidifying the interface to buffering stress, ultimately producing a high-performance diamond roller with ultra-high impact resistance, extremely low particle shedding rate, and ultra-long lifespan.

[0048] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a high-strength, impact-resistant diamond roller, characterized in that the steps include... include: S1. By weight, add 20-30 parts copper powder, 15-25 parts cobalt powder, 10-20 parts iron powder, and 5-10 parts tin powder to a ball mill jar, add anhydrous ethanol, and ball mill; then add 25-35 parts diamond micro powder, 0.3-0.8 parts graphene nanosheets, 1.5-3.0 parts binuclear tungsten molybdenum oxide cluster-boron nitride hybrid and 2.0-4.0 parts zirconium titanium phosphate gradient crosslinker, and continue ball milling to obtain a mixed powder; S2. The mixed powder is vacuum dried at 58-62℃ to obtain dried powder; the dried powder is loaded into a pre-formed steel roller mold and held under pressure of 198-202MPa in a cold isostatic press to obtain a green compact; the green compact is placed in a vacuum sintering furnace, vacuumed, heated to 870-890℃ and held, then heated to 950-970℃ and held, cooled with the furnace to 395-405℃, and then cooled to room temperature by argon gas to obtain a sintered body; the sintered body is subjected to external cylindrical grinding and dynamic balancing correction.

2. The method for preparing the high-strength impact-resistant diamond roller according to claim 1, characterized in that, In step S1, the ball milling time continues for 2-4 hours.

3. The method for preparing the high-strength impact-resistant diamond roller according to claim 1, characterized in that, In step S2, the temperature is raised to 950-970℃ and held for 60-80 minutes.

4. The method for preparing the high-strength impact-resistant diamond roller according to claim 1, characterized in that, The preparation method of the binuclear tungsten-molybdenum-oxygen cluster-boron nitride hybrid includes: A1. Under a dry nitrogen atmosphere, tungsten chloride hexahydrate and ammonium molybdate tetrahydrate are dissolved together in anhydrous ethanol and stirred; then 3-aminopropyltriethoxysilane is added and reacted at 58-62℃ to form a tungsten-molybdenum-oxygen precursor solution. A2. Disperse hexagonal boron nitride powder in anhydrous toluene and sonicate to obtain a dispersion. Add the tungsten-molybdenum-oxygen precursor solution dropwise to the dispersion and reflux at 78-82℃. After the reaction is complete, cool to room temperature and centrifuge to obtain a solid product. Wash the solid product with anhydrous ethanol and deionized water in sequence and dry it under vacuum at 58-62℃.

5. The method for preparing the high-strength impact-resistant diamond roller according to claim 4, characterized in that, In step A1, the reaction time is 2-4 hours at 58-62℃.

6. The method for preparing the high-strength impact-resistant diamond roller according to claim 4, characterized in that, In step A2, the reflux reaction is carried out at 78-82℃ for 12-14 hours.

7. The method for preparing the high-strength impact-resistant diamond roller according to claim 1, characterized in that, The method for preparing the zirconium-titanium phosphate gradient crosslinker includes: B1. Mix zirconium n-propoxide and tetrabutyl titanate in anhydrous isopropanol, and add phosphoric acid dropwise under ice bath. After the addition is complete, remove the ice bath, heat to 48-52℃ and stir to obtain a sol. B2. Then add deionized water to the sol and continue stirring to obtain a mixture; place the mixture in an oven at 78-82℃ to dry to obtain a dry gel; grind the dry gel into powder, heat it to 545-555℃ in air atmosphere and keep it at that temperature, then let it cool naturally to room temperature.

8. The method for preparing the high-strength impact-resistant diamond roller according to claim 7, characterized in that, In step B1, the temperature is raised to 48-52℃ and the stirring time is 4-6 hours.

9. The method for preparing the high-strength impact-resistant diamond roller according to claim 7, characterized in that, In step B2, the temperature is raised to 545-555℃ and held for 3-5 hours.

10. A high-strength, impact-resistant diamond roller, characterized in that, The high-strength impact-resistant diamond roller is prepared by the method according to any one of claims 1-9.

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