A hydrophobic ZrO2 ceramic for ceramic cutting tools and its preparation method

Abstract

This invention discloses a hydrophobic ZrO2 ceramic for ceramic knives and its preparation method, belonging to the field of ceramic materials technology. The preparation method of this invention includes the following steps: (1) raw material mixing; (2) two-step sintering; (3) annealing treatment; (4) laser surface treatment. This invention uses a pressureless two-step slow sintering process combining nano- and micro-scale ZrO2 powder gradation with multi-component additives to prepare a highly dense and strong ceramic matrix. On this basis, annealing treatment under an oxygen atmosphere is introduced to form an oxygen-saturated surface layer, and laser scanning with specific parameters is used to construct a micro-scale mesh-like protrusion structure with high mechanical strength. This structure gives the ceramic material surface durable hydrophobicity, with a water contact angle of 140-150°, effectively preventing food adhesion and easy cleaning, and the fracture toughness of the material is 6.94-7.56 MPa·m. 1 / 2 With a flexural strength of 683–746 MPa, it achieves long-term stability of surface hydrophobicity while maintaining excellent mechanical properties and durability.

Description

Technical Field

[0001] This invention belongs to the field of ceramic materials technology, specifically relating to a hydrophobic ZrO2 ceramic for ceramic cutting tools and its preparation method. Background Technology

[0002] Zirconia (ZrO2) ceramics have been widely used in cutting tools and other fields in recent years due to their high hardness, high wear resistance, and good chemical stability. ZrO2 ceramic knives are sharp, corrosion-resistant, and odorless, and are gradually becoming an important alternative to stainless steel knives. However, the surface of traditional ZrO2 ceramics is usually hydrophilic, which makes it easy for food to stick when cutting sticky foods (such as dough, meat, fruits, and vegetables). This not only affects cutting efficiency but also increases cleaning difficulty and impacts the user experience.

[0003] To address the adhesion problem on ZrO2 ceramic surfaces, existing technologies primarily employ two methods: surface coating modification and surface texturing. Surface coating methods typically use low surface energy substances such as fluorinated silanes to chemically modify the ceramic, achieving a hydrophobic effect by reducing surface energy. This method is simple and can achieve hydrophobic effects in the short term, but due to the limited adhesion between the coating and the ceramic substrate, the organic coating is prone to peeling or wear during long-term mechanical wear, cutting stress, or repeated cleaning, leading to a rapid decline in hydrophobic properties and insufficient durability. The other method involves constructing micron- or nanometer-scale rough structures on the ceramic surface using physical means such as laser etching and plasma treatment, achieving a hydrophobic state using the Cassie-Baxter model. However, these methods often directly apply to the already sintered, dense ZrO2 ceramic surface. Because ZrO2 ceramics are inherently hard and brittle, the energy parameters are difficult to control precisely during laser processing. If the laser power is too low, it will be difficult to effectively etch the surface; if the power is too high, it will easily cause local overheating, leading to phase transformation of the material, microcracks and other defects, affecting the mechanical properties and lifespan of the ceramic. In addition, the surface structures constructed by existing laser processes are mostly simple pits or grooves, which have insufficient structural strength and are easily worn and collapsed by mechanical action during use, resulting in unstable hydrophobic properties or even failure.

[0004] Patent publication number CN 119319601 A discloses a method for electric field-assisted laser additive manufacturing of zirconia-based ceramic cutting tools. This method involves a complex fabrication process and high manufacturing costs. It relies on the precise integration and synchronous control of two complex devices: laser additive manufacturing and a high-intensity electric field system. It requires a high-power supply (current up to 10... 4A) The stringent requirements for electrode plates and process parameter windows lead to high equipment investment and production costs. It focuses on "forming" and "mechanical properties," lacking surface functionalization design: its technical goal is to optimize the bulk mechanical properties (density, hardness, toughness) of the cutting tool, and its technical approach is to "manufacture a high-performance ceramic preform." However, it does not involve, and is not applicable to, constructing specific micro / nano structures on the cutting tool surface to achieve hydrophobic and anti-adhesion functions.

[0005] Based on the above, existing ZrO2 ceramic cutting tools still have significant shortcomings in achieving durable hydrophobic properties: surface coating methods have poor durability, while surface texturing methods easily damage the material's intrinsic properties and have poor structural stability. Therefore, there is an urgent need for a method that can collaboratively design the entire process from the material itself and sintering process to surface treatment, to achieve stable construction and long-term maintenance of the surface hydrophobic structure while ensuring that ZrO2 ceramics possess excellent mechanical properties such as high strength and toughness. Summary of the Invention

[0006] To address the above problems, this invention provides a hydrophobic ZrO2 ceramic for ceramic cutting tools and its preparation method. A highly dense and strong ceramic matrix is ​​prepared by employing a pressureless two-step slow sintering process combining nano- and micro-scale ZrO2 powder gradation with multi-component additives. Based on this, an annealing treatment in an oxygen atmosphere is introduced to form an oxygen-saturated surface layer. Then, laser scanning with specific parameters is used to construct a micro-scale mesh-like protrusion structure with high mechanical strength. This allows the resulting ceramic material to possess excellent mechanical properties such as high strength and toughness while achieving long-term stability of the surface hydrophobic function.

[0007] This invention is achieved through the following technical solution:

[0008] A method for preparing hydrophobic ZrO2 ceramic for ceramic cutting tools includes the following steps:

[0009] (1) Raw material mixing: According to the mass percentage, take 15-25wt% nano ZrO2 powder, 70-80wt% micron ZrO2 powder, and 5-10wt% additives Y2O3, HfO2, Gd2O3, Al2O3, and SiO2. After mixing evenly, place the resulting mixed powder in a ball mill jar for ball milling. After taking it out, dry it and sieve it. Add polyvinyl alcohol solution and mix it. Then granulate it. After drying it again, sieve it. After pressing it into shape, ceramic green body is obtained.

[0010] (2) Two-step sintering: The ceramic green body is placed in a sintering furnace and heated to 600-800℃ at a rate of 0.5-1℃ / min and held for 2-4 hours for pre-sintering. Then, the temperature is increased to 1400-1500℃ at a rate of 2-4℃ / min and sintered for 2-4 hours. After cooling to room temperature, the ceramic matrix is ​​obtained.

[0011] (3) Annealing treatment: After cleaning and polishing the ceramic substrate, it is placed in an annealing furnace and heated to 800-1200℃ at a rate of 2-5℃ / min and kept in an oxygen atmosphere for 2-4 hours. After the holding period, it is cooled to room temperature to obtain the annealed ceramic substrate.

[0012] (4) Laser surface treatment: The surface of the annealed ceramic substrate is scanned with a laser. The laser power is 5 to 30W, the scanning speed is 200 to 500 mm / s, and the scanning distance is 50 to 200 μm. After the treatment, hydrophobic ZrO2 ceramics for ceramic cutting tools are obtained.

[0013] Furthermore, in step (1), the nano ZrO2 powder is composed of a monoclinic phase with a content of 99% and an average particle size of 20-50 nm.

[0014] Further, in step (1), the micron-sized ZrO2 powder is composed of a monoclinic phase and a tetragonal phase, wherein the content of the monoclinic phase is 75-90%, the content of the tetragonal phase is 10-25%, and the average particle size is 1-3 μm.

[0015] Further, in step (1), the molar ratio of the additives Y2O3, HfO2, Gd2O3, Al2O3, and SiO2 is 0.1±X0:0.3±X1:0.05±X2:0.05±X3:0.3±X4, where X0, X1, X2, X3, and X4 are 0.02 to 0.05.

[0016] Further, in step (1), the ball milling speed is 400-600 r / min and the time is 20-24 h.

[0017] Furthermore, in step (1), the pressing pressure is 120-160 MPa and the time is 2-6 min.

[0018] Furthermore, in step (3), the t phase content of the annealed ceramic matrix is ​​82.4-85.2%, and the c phase content is 14.8-17.6%.

[0019] Furthermore, in step (3), before heating, oxygen is introduced into the annealing furnace and kept for 20 to 40 minutes to remove air, and this is repeated three times. After that, oxygen is continuously introduced to maintain an oxygen atmosphere.

[0020] A hydrophobic ZrO2 ceramic for ceramic cutting tools prepared by the method described above.

[0021] Furthermore, the hydrophobic ZrO2 ceramic used in the ceramic cutting tool has a water contact angle of 140–150° and a fracture toughness of 6.94–7.56 MPa·m. 1 / 2Its flexural strength is 683–746 MPa.

[0022] The preparation principle of the hydrophobic ZrO2 ceramic for ceramic cutting tools of the present invention:

[0023] (1) In terms of material composition, nano-sized and micro-sized ZrO2 powders are graded, and various stabilizers (Y2O3, HfO2) and sintering aids (Gd2O3, Al2O3, SiO2) are introduced. The nanoparticles fill the gaps between the micro-particles, effectively reducing the porosity of the green body and increasing the density of the material; the various additives produce a synergistic effect, optimizing the grain boundary phase structure, ensuring the strength and toughness of the material, while regulating its absorption characteristics and thermal response behavior to laser energy, making it more suitable for subsequent laser surface texturing treatment.

[0024] (2) In terms of sintering process, a pressureless two-step slow sintering method is adopted: first, pre-sintering is carried out, with slow heating and holding to fully remove organic matter and reduce stress in the green body; then, high-temperature sintering is carried out to obtain a ceramic matrix with fine and uniform grains and few internal defects. This process provides a material basis with consistent structure and stable performance for subsequent laser processing.

[0025] (3) In order to further improve the laser processing effect, an annealing process is introduced before laser processing to form an oxygen-saturated surface layer in an oxygen atmosphere, which enhances the material surface's response to laser and creates conditions for constructing micro-protrusion structures on the laser scanning surface.

[0026] (4) On the optimized ceramic substrate, laser scanning with specific parameters (laser power 5-30W, scanning speed 200-500mm / s, scanning spacing 50-200μm) is used to construct a mesh-like microstructure mainly composed of micron-level protrusions on the surface. This structure not only has high mechanical strength and can resist wear during use, but also achieves stable hydrophobic properties through the Cassie-Baxter effect, thereby significantly improving the non-stick properties and easy cleaning of the cutting tool.

[0027] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows:

[0028] 1. This invention starts with the material itself, and significantly improves the density and toughness of the ceramic matrix by employing nano- and micro-scale ZrO2 powder gradation, multi-component additives, and a pressureless two-step slow sintering process. This synergistic design not only reduces internal defects and internal stress, but also provides a material basis with uniform structure and stable performance for subsequent laser surface treatment.

[0029] 2. This invention is based on an optimized ceramic substrate, employing laser scanning with specific parameters to construct a mesh-like structure on the surface, primarily composed of micron-level protrusions. This structure possesses high mechanical strength and is not easily worn or collapsed during use, thus achieving a durable hydrophobic effect. Testing shows a surface water contact angle of 140–150°, exhibiting excellent anti-food adhesion and easy-to-clean properties.

[0030] 3. The fracture toughness of the ceramic material of the present invention is 6.94–7.56 MPa·m. 1 / 2 With a bending strength of 683–746 MPa, it possesses excellent mechanical properties. These performance indicators meet the mechanical requirements of everyday cutting tool use, ensuring that the tool, while possessing hydrophobic properties, still maintains sufficient durability and reliability.

[0031] 4. Compared with existing ZrO2 ceramic surface coating or direct laser etching processes, this invention introduces an annealing process before laser treatment to form an oxygen-saturated surface layer, which helps to build a complete and robust micro-protrusion structure during laser scanning and avoids the generation of defects such as micro-cracks. Thus, while achieving hydrophobic function, the mechanical integrity of the substrate is not compromised. Attached Figure Description

[0032] Figure 1 The image shows the XRD pattern of the annealed ceramic matrix in Example 1.

[0033] Figure 2 This is a SEM image of the hydrophobic ZrO2 ceramic used in ceramic cutting tools in Example 1.

[0034] Figure 3 This is a SEM image of the hydrophobic ZrO2 ceramic used in ceramic cutting tools in Example 1 after thermal etching.

[0035] Figure 4 This is a SEM image of the fracture surface of the hydrophobic ZrO2 ceramic used in ceramic cutting tools in Example 1.

[0036] Figure 5 The mechanical properties of the hydrophobic ZrO2 ceramics used in ceramic cutting tools in Examples 1-5 are shown in the diagram. Detailed Implementation

[0037] The present invention will be further described in detail below through embodiments. These embodiments are only used to illustrate the present invention and do not limit the scope of protection of the present invention.

[0038] Example 1

[0039] A method for preparing hydrophobic ZrO2 ceramic for ceramic cutting tools includes the following steps:

[0040] (1) Raw material mixing: 20wt% of nano ZrO2 powder (composed of 99% monoclinic phase with an average particle size of 25nm), 75wt% of micron ZrO2 powder (composed of 79% monoclinic phase and 18% tetragonal phase with an average particle size of 1.5μm) and 5wt% of the remaining powders Y2O3, HfO2, Gd2O3, Al2O3 and SiO2 in a molar ratio of 0.1:0.3:0.05:0.05:0.3 were weighed according to the following mass percentages: After mixing evenly, the resulting mixed powder was placed in a ball mill jar containing solvent and ball milled at 400r / min for 24h. After taking it out, it was dried at 70℃, sieved, and a 4% polyvinyl alcohol solution (added amount was 5wt% of the total mass of the mixed powder) was added. After mixing, it was granulated, dried and sieved. 2g of powder was weighed and pressed at 120MPa for 2min to form rectangular blocks to obtain ceramic green bodies.

[0041] (2) Two-step sintering: The ceramic green body is placed in a sintering furnace and heated to 600°C at a rate of 1°C / min and held for 2 hours for pre-sintering. Then, the temperature is increased to 1400°C at a rate of 2.5°C / min and sintered for 2 hours. After cooling to room temperature with the sintering furnace, the ceramic matrix is ​​obtained.

[0042] (3) Annealing treatment: After cleaning and polishing the ceramic substrate, it is placed in the annealing furnace. Before heating, oxygen is introduced into the annealing furnace and kept for 30 minutes to remove air. This process is repeated three times. After that, oxygen is continuously introduced to maintain the oxygen atmosphere. Then, the temperature is increased to 800℃ at a rate of 5℃ / min and kept in the oxygen atmosphere for 2 hours. After the holding period, the substrate is cooled to room temperature with the annealing furnace to obtain the annealed ceramic substrate.

[0043] (4) Laser surface treatment: The surface of the annealed ceramic substrate is scanned with a laser with a laser power of 5W, a scanning speed of 300mm / s, and a scanning spacing of 60μm. After the treatment, hydrophobic ZrO2 ceramics for ceramic cutting tools are obtained.

[0044] Example 2

[0045] A method for preparing hydrophobic ZrO2 ceramic for ceramic cutting tools includes the following steps:

[0046] (1) Raw material mixing: 25wt% of nano ZrO2 powder (composed of 99% monoclinic phase with an average particle size of 30nm), 70wt% of micron ZrO2 powder (composed of 80% monoclinic phase and 18% tetragonal phase with an average particle size of 2μm) and 5wt% of the remaining powders Y2O3, HfO2, Gd2O3, Al2O3 and SiO2 in a molar ratio of 0.1:0.28:0.05:0.05:0.35 were weighed according to the following mass percentages: After mixing evenly, the resulting mixed powder was placed in a ball mill jar containing solvent and ball milled at 500r / min for 24h. After taking it out, it was dried at 70℃, sieved, and a 4% polyvinyl alcohol solution (the amount added was 7wt% of the total mass of the mixed powder) was added. After mixing, it was granulated, dried and sieved. 2g of powder was weighed and pressed at 120MPa for 2min to form rectangular blocks to obtain ceramic green bodies.

[0047] (2) Two-step sintering: The ceramic green body is placed in a sintering furnace and heated to 800°C at a rate of 1°C / min and held for 4 hours for pre-sintering. Then, the temperature is increased to 1400°C at a rate of 2°C / min and sintered for 2 hours. After cooling to room temperature with the sintering furnace, the ceramic matrix is ​​obtained.

[0048] (3) Annealing treatment: After cleaning and polishing the ceramic substrate, it is placed in the annealing furnace. Before heating, oxygen is introduced into the annealing furnace and kept for 30 minutes to remove air. This process is repeated three times. After that, oxygen is continuously introduced to maintain the oxygen atmosphere. Then, the temperature is increased to 900℃ at a rate of 5℃ / min and kept in the oxygen atmosphere for 2 hours. After the holding period, the substrate is cooled to room temperature with the annealing furnace to obtain the annealed ceramic substrate.

[0049] (4) Laser surface treatment: The surface of the annealed ceramic substrate is scanned with a laser with a laser power of 10W, a scanning speed of 200mm / s, and a scanning interval of 100μm. After the treatment, hydrophobic ZrO2 ceramics for ceramic cutting tools are obtained.

[0050] Example 3

[0051] A method for preparing hydrophobic ZrO2 ceramic for ceramic cutting tools includes the following steps:

[0052] (1) Raw material mixing: 20wt% of nano ZrO2 powder (composed of 99% monoclinic phase with an average particle size of 30nm), 70wt% of micron ZrO2 powder (composed of 83% monoclinic phase and 16% tetragonal phase with an average particle size of 2μm) and 10wt% of the remaining powders Y2O3, HfO2, Gd2O3, Al2O3 and SiO2 in a molar ratio of 0.1:0.3:0.1:0.1:0.3 were weighed according to the following mass percentages: After mixing evenly, the resulting mixed powder was placed in a ball mill jar containing solvent and ball milled at 600r / min for 20h. After taking it out, it was dried at 90℃, sieved, and a 6% polyvinyl alcohol solution (5wt% of the total mass of the mixed powder) was added. After mixing, it was granulated, dried and sieved. 3g of powder was weighed and pressed at 140MPa for 3min to form rectangular blocks to obtain ceramic green bodies.

[0053] (2) Two-step sintering: The ceramic green body is placed in a sintering furnace and heated to 800°C at a rate of 0.8°C / min and held for 4 hours for pre-sintering. Then, the temperature is increased to 1500°C at a rate of 4°C / min and sintered for 4 hours. After cooling to room temperature with the sintering furnace, the ceramic matrix is ​​obtained.

[0054] (3) Annealing treatment: After cleaning and polishing the ceramic substrate, it is placed in the annealing furnace. Before heating, oxygen is introduced into the annealing furnace and kept for 20 minutes to remove air. This process is repeated three times. After that, oxygen is continuously introduced to maintain the oxygen atmosphere. Then, the temperature is increased to 1200℃ at a rate of 2℃ / min and kept in the oxygen atmosphere for 4 hours. After the holding period, the substrate is cooled to room temperature with the annealing furnace to obtain the annealed ceramic substrate.

[0055] (4) Laser surface treatment: The surface of the annealed ceramic substrate is scanned with a laser with a laser power of 10W, a scanning speed of 200mm / s, and a scanning interval of 50μm. After the treatment, hydrophobic ZrO2 ceramics for ceramic cutting tools are obtained.

[0056] Example 4

[0057] A method for preparing hydrophobic ZrO2 ceramic for ceramic cutting tools includes the following steps:

[0058] (1) Raw material mixing: 20wt% of nano ZrO2 powder (composed of 99% monoclinic phase with an average particle size of 40nm), 70wt% of micron ZrO2 powder (composed of 75% monoclinic phase and 20% tetragonal phase with an average particle size of 2.5μm) and 10wt% of the remaining powders Y2O3, HfO2, Gd2O3, Al2O3 and SiO2 in a molar ratio of 0.15:0.3:0.1:0.05:0.3 were weighed according to the following mass percentages: After mixing evenly, the resulting mixed powder was placed in a ball mill jar containing solvent and ball milled at 400r / min for 20h. After taking it out, it was dried at 90℃, sieved, and a 5% polyvinyl alcohol solution (6wt% of the total mass of the mixed powder) was added. After mixing, it was granulated, dried and sieved. 4g of powder was weighed and pressed at 160MPa for 5min to form rectangular blocks to obtain ceramic green bodies.

[0059] (2) Two-step sintering: The ceramic green body is placed in a sintering furnace and heated to 600°C at a rate of 0.5°C / min and held for 2 hours for pre-sintering. Then, the temperature is increased to 1500°C at a rate of 4°C / min and sintered for 3 hours. After cooling to room temperature with the sintering furnace, the ceramic matrix is ​​obtained.

[0060] (3) Annealing treatment: After cleaning and polishing the ceramic substrate, it is placed in an annealing furnace. Before heating, oxygen is introduced into the annealing furnace and kept for 40 minutes to remove air. This process is repeated three times. After that, oxygen is continuously introduced to maintain an oxygen atmosphere. Then, the temperature is increased to 1200℃ at a rate of 4℃ / min and kept in an oxygen atmosphere for 4 hours. After the holding period, the temperature is cooled to room temperature at a rate of 5℃ / min to obtain the annealed ceramic substrate.

[0061] (4) Laser surface treatment: The surface of the annealed ceramic substrate is scanned with a laser with a laser power of 20W, a scanning speed of 400mm / s, and a scanning interval of 100μm. After the treatment, hydrophobic ZrO2 ceramics for ceramic cutting tools are obtained.

[0062] Example 5

[0063] A method for preparing hydrophobic ZrO2 ceramic for ceramic cutting tools includes the following steps:

[0064] (1) Raw material mixing: 15wt% of nano ZrO2 powder (composed of 99% monoclinic phase with an average particle size of 45nm), 80wt% of micron ZrO2 powder (composed of 90% monoclinic phase and 10% tetragonal phase with an average particle size of 3μm) and 5wt% of the remaining powders Y2O3, HfO2, Gd2O3, Al2O3 and SiO2 in a molar ratio of 0.15:0.25:0.05:0.1:0.3 were weighed according to the following mass percentages: After mixing evenly, the resulting mixed powder was placed in a ball mill jar containing solvent and ball milled at 600r / min for 24h. After taking it out, it was dried at 90℃, sieved, and a 5% polyvinyl alcohol solution (6wt% of the total mass of the mixed powder) was added. After mixing, it was granulated, dried and sieved. 4g of powder was weighed and pressed at 160MPa for 6min to form rectangular blocks to obtain ceramic green bodies.

[0065] (2) Two-step sintering: The ceramic green body is placed in a sintering furnace and heated to 600°C at a rate of 1°C / min and held for 3 hours for pre-sintering. Then, the temperature is increased to 1500°C at a rate of 4°C / min and sintered for 3 hours. After cooling to room temperature with the sintering furnace, the ceramic matrix is ​​obtained.

[0066] (3) Annealing treatment: After cleaning and polishing the ceramic substrate, it is placed in an annealing furnace. Before heating, oxygen is introduced into the annealing furnace and kept for 30 minutes to remove air. This process is repeated three times. After that, oxygen is continuously introduced to maintain an oxygen atmosphere. Then, the temperature is increased to 1200℃ at a rate of 5℃ / min and kept in an oxygen atmosphere for 4 hours. After the holding period, the temperature is cooled to room temperature at a rate of 5℃ / min to obtain the annealed ceramic substrate.

[0067] (4) Laser surface treatment: The surface of the annealed ceramic substrate is scanned with a laser with a laser power of 30W, a scanning speed of 500mm / s, and a scanning spacing of 200μm. After the treatment, hydrophobic ZrO2 ceramics for ceramic cutting tools are obtained.

[0068] Material characterization analysis

[0069] (I) XRD Analysis

[0070] The annealed ceramic matrices in Examples 1-5 were characterized and analyzed using X-ray diffraction (XRD), with the results for Example 1 as follows: Figure 1 As shown. By Figure 1 It can be seen that in the phase composition of the annealed ceramic matrix in Example 1, the t phase content is 82.4% and the c phase content is 17.6%. Furthermore, in the phase compositions of the annealed ceramic matrices in Examples 2-5, the t phase contents are 84.1%, 82.9%, 84.4%, and 85.2%, respectively, and the c phase contents are 15.9%, 17.1%, 15.6%, and 14.8%, respectively.

[0071] In the material's phase composition, the C phase itself has high hardness, and its dispersed distribution in the T phase matrix can play a role in second-phase reinforcement. Furthermore, the surface region of the annealed ceramic matrix undergoes a certain phase transformation during and after laser treatment, and the high proportion of initial T phase ensures that even after phase adjustment, the surface still retains sufficient metastable T phase to provide a continuous phase transformation toughening effect during subsequent service.

[0072] (II) SEM Analysis

[0073] Scanning electron microscopy (SEM) was used to characterize and analyze the hydrophobic ZrO2 ceramic used in ceramic cutting tools in Example 1, the hydrophobic ZrO2 ceramic used in ceramic cutting tools after thermal etching, and its fracture surface. The results are as follows: Figure 2 , Figure 3 , Figure 4 As shown.

[0074] Depend on Figure 2 It is evident that the hydrophobic ZrO2 ceramic surface used in ceramic cutting tools is relatively smooth, with fewer defects such as pores, and no obvious macroscopic defects such as cracks or pores, exhibiting a relatively dense structure. This indicates that the material has achieved good results in the densification process. This low-porosity densified structure is a prerequisite for obtaining excellent mechanical properties and can effectively reduce stress concentration points during stress loading.

[0075] Depend on Figure 3 It is evident that the hydrophobic ZrO2 ceramic used in ceramic cutting tools exhibits significantly refined grain size after thermal etching. Most grains have a narrow size distribution range, demonstrating high uniformity and a relatively good microstructure. The grain distribution is also quite uniform, and these favorable microstructures contribute to improved mechanical properties. The formation of this uniform fine-grained structure follows the classic Hall-Petch relation, implying that grain boundaries enhance the resistance to dislocation movement, thus directly contributing to improved material properties. Simultaneously, the uniform microstructure facilitates the even distribution of stress within the material, avoiding localized stress concentration and further ensuring the reliability of mechanical properties.

[0076] Depend on Figure 4 It is evident that the fracture surface of hydrophobic ZrO2 ceramics used in ceramic cutting tools exhibits predominantly transgranular fracture, meaning the crack propagation path directly penetrates the grain interior, accompanied by a small amount of intergranular fracture. The prevalence of transgranular fracture indicates that the grain boundary bonding strength is higher than or close to the cohesive strength of the grain itself. When cracks propagate transgranularly, their path is more tortuous, requiring more energy to fracture the grains, rather than simply separating along relatively weak grain boundaries. This method consumes more crack energy, thereby improving its mechanical properties.

[0077] (III) Analysis of water contact angle test

[0078] The water contact angle of the hydrophobic ZrO2 ceramics used in ceramic cutting tools in Examples 1-5 was tested and analyzed using a water contact angle measuring instrument. The results showed that the water contact angles of the hydrophobic ZrO2 ceramics used in ceramic cutting tools in Examples 1-5 were 143°, 140°, 145°, 150° and 140°, respectively, indicating that the materials have good hydrophobic properties.

[0079] Material performance testing and analysis

[0080] (I) Mechanical property testing and analysis

[0081] The fracture toughness and flexural strength of the hydrophobic ZrO2 ceramics used for ceramic cutting tools in Examples 1-5 before and after laser treatment were tested using a universal testing machine.

[0082] Before laser treatment, the fracture toughness of the hydrophobic ZrO2 ceramics used for ceramic cutting tools in Examples 1-5 were 9.35, 10.13, 10.21, 9.78, and 9.95 MPa·m, respectively. 1 / 2 The bending strengths are 852, 953, 894, 968, and 927 MPa, respectively.

[0083] After laser treatment, the test results of the sample are as follows: Figure 5 As shown, Figure 5 The sample numbers in the examples correspond to the hydrophobic ZrO2 ceramic samples used in ceramic cutting tools in Examples 1-5, respectively. Figure 5 It can be seen that the fracture toughness of the hydrophobic ZrO2 ceramics used for ceramic knives in Examples 1-5 are 6.94, 7.24, 7.56, 7.16, and 7.43 MPa·m, respectively. 1 / 2 The bending strengths are 683, 741, 692, 725, and 746 MPa, respectively.

[0084] The data above shows that after specific laser treatment, the fracture toughness and flexural strength of the material decreased to some extent. This confirms that the laser treatment process successfully introduced the designed microstructural modification into the ceramic surface. This invention, through optimized laser processing of zirconia ceramic surfaces, although its static mechanical properties were adjusted, successfully achieved beneficial effects on surface performance, and the reduced mechanical properties still meet the requirements of everyday use.

[0085] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for the production of a hydrophobic Zr02ceramic for ceramic cutters, characterized in that, The method comprises the following steps: (1) raw material mixing: taking nano ZrO2 powder 15-25wt%, micron ZrO2 powder 70-80wt%, additives Y2O3, HfO2, Gd2O3, Al2O3, SiO2 in total 5-10wt% according to mass percentage, mixing uniformly, then placing the obtained mixed powder in a ball mill tank for ball milling, taking out and drying and sieving, mixing with polyvinyl alcohol solution, granulating, drying again and sieving, and then pressing and forming to obtain a ceramic green body; The molar ratio of the additives Y2O3, HfO2, Gd2O3, Al2O3, SiO2 is 0.1±X0:0.3±X1:0.05±X2:0.05±X3:0.3±X4, wherein X0, X1, X2, X3, X4 are 0.02-0.05; (2) two-step sintering: placing the ceramic green body in a sintering furnace, heating at a rate of 0.5-1 ℃ / min to 600-800 ℃ and keeping for 2-4 h for pre-sintering, then heating at a rate of 2-4 ℃ / min to 1400-1500 ℃ and sintering for 2-4 h, and cooling to room temperature to obtain a ceramic matrix; (3) annealing treatment: placing the ceramic matrix cleaned and polished in an annealing furnace, heating at a rate of 2-5 ℃ / min to 800-1200 ℃ and keeping in an oxygen atmosphere for 2-4 h, and cooling to room temperature after the keeping to obtain an annealed ceramic matrix; (4) laser surface treatment: scanning the surface of the annealed ceramic matrix by using a laser, the laser power is 5-30 W, the scanning speed is 200-500 mm / s, and the scanning interval is 50-200 μm, and the hydrophobic ZrO2 ceramic for ceramic cutters is obtained after the treatment.

2. The method for the preparation of a hydrophobic Zr02ceramic for ceramic cutters according to claim 1, characterized in that, In step (1), the nano ZrO2 powder is composed of monoclinic phase, and the monoclinic phase content is 99%, and the average particle size is 20-50 nm.

3. The method of claim 1, wherein the hydrophobic Zr02 ceramic for ceramic cutters is characterized by, In step (1), the micron ZrO2 powder is composed of monoclinic phase and tetragonal phase, wherein the monoclinic phase content is 75-90%, the tetragonal phase content is 10-25%, and the average particle size is 1-3 μm.

4. The method of claim 1, wherein the hydrophobic Zr02 ceramic for ceramic cutters is characterized by, In step (1), the rotation speed of the ball milling is 400-600 r / min, and the time is 20-24 h.

5. The method of claim 1, wherein the hydrophobic Zr02 ceramic for ceramic cutters is characterized by, In step (1), the pressure of the pressing and forming is 120-160 MPa, and the time is 2-6 min.

6. The method of claim 1, wherein the hydrophobic Zr02 ceramic for ceramic cutters is characterized by, In step (3), in the phase composition of the annealed ceramic matrix, the t-phase content is 82.4-85.2%, and the c-phase content is 14.8-17.6%.

7. The method of claim 1, wherein the hydrophobic Zr02 ceramic for ceramic cutters is characterized by, In step (3), oxygen is introduced into the annealing furnace before heating for 20-40 min to remove air, and the operation is repeated three times, and then oxygen is introduced to maintain an oxygen atmosphere.

8. A hydrophobic ZrO2 ceramic for ceramic cutters prepared by the preparation method in any one of claims 1-7.

9. The hydrophobic Zr02ceramic for ceramic cutters according to claim 8, characterized in that, The hydrophobic ZrO2 ceramic for ceramic cutters has a water contact angle of 140-150°, a fracture toughness of 6.94-7.56 MPa·m, and a bending strength of 683-746 MPa. 1 / 2 , a bending strength of 683-746 MPa.

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