Diamond porous microsphere, grinding wheel abrasive material and preparation method and application of diamond porous microsphere and grinding wheel abrasive material

Abstract

The invention belongs to the technical field of grinding wheel abrasives, and particularly relates to a diamond porous microsphere, a grinding wheel abrasive and a preparation method and application thereof. The preparation raw materials of the diamond porous microspheres comprise mixed powder, a binder and water, the mixed powder comprises a first ceramic bond, diamond and a pore forming agent. The first ceramic bond, the diamond and the pore forming agent are used as raw materials for preparing the diamond porous microspheres, the diamond porous microspheres have natural pores and prefabricated spherical pores, the porosity is high, and the self-sharpening performance of the grinding wheel grinding material can be improved; the grinding wheel abrasive material is prepared through secondary air degreasing sintering of the diamond porous microspheres, a new three-dimensional pore structure is formed among the naturally stacked diamond porous microspheres, the grinding wheel abrasive material with a'natural pore + prefabricated spherical pore + stacked pore 'multi-stage pore structure is obtained, the cooling, lubricating and chip removal effects of a grinding wheel can be greatly improved, and the service life of the grinding wheel is prolonged. Therefore, the grinding performance and the service life of the grinding wheel are improved.

Description

Technical Field

[0001] This invention belongs to the field of abrasive wheel technology, and specifically relates to a porous diamond microsphere, abrasive wheel, its preparation method and application. Background Technology

[0002] Precision and ultra-precision machining technologies are a crucial cornerstone of modern manufacturing, especially in the processing of hard and brittle materials such as semiconductor wafers, optical glass, and advanced ceramics, where extremely high demands are placed on machining accuracy, surface integrity, and processing efficiency. Ceramic-bonded diamond wheels, due to their excellent shape retention, high hardness, and good self-sharpening properties, have become key tools for the precision grinding of these materials. However, the porosity in traditional ceramic-bonded diamond wheel agglomerates mainly relies on pore-forming agents, making porosity difficult to control. Excessive porosity leads to easy wheel wear, resulting in a low grinding ratio and short wheel life; conversely, insufficient porosity results in low wheel sharpness, easy clogging, and a tendency to cause grinding burns.

[0003] Traditional diamond grinding wheels are constructed by randomly binding abrasive grains into clumps using a bonding agent. The main components of these clumps include diamond grains, the bonding agent, and pores. The bonding agent holds the diamond grains in place, maintaining their cutting state during grinding and breaking down under high grinding forces to expose new diamond grains for self-sharpening. The pores primarily contain chips during grinding, preventing them from accumulating on the wheel surface and rubbing against the workpiece. They also hold coolant, reducing the wheel's temperature and, consequently, the workpiece's temperature. However, in traditional ceramic-bonded diamond grinding wheels, the pores are often formed by adding pore-forming agents, resulting in poor control over pore size and distribution, hindering the wheel's grinding performance. Furthermore, the resulting porosity is low, the pore shapes are irregular, and many pores are closed, preventing the formation of interconnected internal pores. This limits the wheel's cooling, lubrication, and chip removal capabilities, ultimately reducing its overall performance and lifespan.

[0004] Therefore, it is of great significance to provide a grinding wheel abrasive that can improve cooling and chip removal during the grinding process and enhance the grinding performance of hard and brittle materials that are difficult to machine. Summary of the Invention

[0005] The present invention aims to solve one or more technical problems existing in the prior art, and at least provide a beneficial alternative. Specifically, the present invention provides a porous diamond microsphere, which can improve cooling and chip removal during the grinding process and has good grinding performance for difficult-to-machine hard and brittle materials.

[0006] Therefore, a first aspect of the present invention provides a diamond porous microsphere.

[0007] Specifically, the raw materials for preparing the diamond porous microspheres include mixed powder, binder, and water; The mixed powder includes a first ceramic binder, diamond, and a pore-forming agent.

[0008] Preferably, the particle size distribution of the diamond porous microspheres satisfies (D90-D10) / D50≤0.25.

[0009] Preferably, the diameter of the diamond porous microspheres is 0.01-0.5 mm.

[0010] Preferably, the diamond porous microspheres have spherical pores and natural pores.

[0011] Preferably, in the diamond porous microspheres, the porosity of the spherical pores is 20-40%, and the porosity of the natural pores is 10-20%.

[0012] Specifically, natural pores are pores formed during vacuum degreasing and air degreasing sintering, while spherical pores are obtained by adding pore-forming agents.

[0013] Preferably, the raw materials for preparing the diamond porous microspheres, by mass percentage, include 40-50% mixed powder, 3-10% binder, and 45-55% water.

[0014] Preferably, by mass percentage, the mixed powder comprises 10-30% of a first ceramic binder, 50-70% of diamond, and 5-30% of a pore-forming agent.

[0015] Preferably, the softening point of the first ceramic binder is 540-560℃ and the refractoriness is 690-710℃; more preferably, the softening point of the first ceramic binder is 550℃ and the refractoriness is 700℃.

[0016] Preferably, the first ceramic binder comprises an aluminosilicate ceramic binder.

[0017] Preferably, the D50 particle size of the first ceramic binder is 0.1-10 μm.

[0018] Specifically, the first ceramic binder has a high sintering temperature to ensure that the prepared diamond porous microspheres have sufficient strength.

[0019] Preferably, the diamond has a mesh size of 800-8000.

[0020] Preferably, the pore-forming agent comprises a spherical pore-forming agent.

[0021] Preferably, the pore-forming agent includes at least one of organic pore-forming agents and hollow spherical pore-forming agents.

[0022] Preferably, the organic pore-forming agent includes at least one of polymethyl methacrylate (PMMA) microspheres, polystyrene (PS) microspheres, corn starch, and urea.

[0023] Preferably, the hollow spherical pore-forming agent includes at least one of hollow glass microspheres and hollow alumina spheres.

[0024] Preferably, the D50 particle size of the pore-forming agent is 5-20 μm.

[0025] Specifically, the present invention does not have any particular limitation on the type of adhesive. Any adhesive with adhesive properties that can be obtained by those skilled in the art can be used as an adhesive. In the present invention, dextrin is preferably used as an adhesive.

[0026] Preferably, the raw materials for preparing the diamond porous microspheres further include a dispersant, and by mass percentage, the raw materials for preparing the diamond porous microspheres include 40-50% mixed powder, 3-10% binder, greater than 0% and less than or equal to 2% dispersant, and 45-55% water.

[0027] Preferably, the dispersant includes at least one of a high molecular weight polymeric dispersant (such as KOS 110 from CERI), oleic acid, and stearic acid.

[0028] A second aspect of the present invention provides a method for preparing the diamond porous microspheres described in the first aspect of the present invention.

[0029] Specifically, the preparation method of the diamond porous microspheres includes the following steps: (1) Mix the raw materials for preparing diamond porous microspheres to obtain a slurry; then perform spray granulation to obtain powder; (2) The powder obtained in step (1) is subjected to vacuum degreasing and air degreasing sintering to obtain the diamond porous microspheres.

[0030] Preferably, in step (1), the temperature of the spray granulation is 100-200℃.

[0031] Preferably, in step (2), the temperature of vacuum degreasing is 400-600℃ and the time of vacuum degreasing is 1.5-2.5h.

[0032] Preferably, in step (2), the temperature of the air degreasing sintering is 650-700℃, and the time of the air degreasing sintering is 1.5-2.5h.

[0033] Preferably, in step (2), the heating rate of the air degreasing sintering is 0.3-2℃ / min.

[0034] Specifically, the binder and pore-forming agent in the spherical blank are carbonized at high temperature through vacuum degreasing, and the residual carbon in the spherical blank after vacuum degreasing is oxidized and removed by air degreasing and sintering. This allows the first ceramic binder to fully coat the diamond, improving the mechanical properties of the subsequently prepared grinding wheel abrasive. Similarly, if a dispersant is added, it will also be removed during the vacuum degreasing and air degreasing sintering process.

[0035] Specifically, porous diamond microspheres consist of four components: diamond, a first ceramic binder, natural pores, and pre-formed spherical pores. A schematic diagram of the composition of porous diamond microspheres is shown below. Figure 1 As shown, natural pores are micropores formed during vacuum degreasing and air degreasing sintering, while spherical pores are micropores obtained by adding spherical pore-forming agents. Through the design of the diamond porous microsphere formulation and the size of the spherical pore-forming agent, and the control of the vacuum degreasing and air degreasing sintering temperatures, the porosity Φ of the natural pores is achieved. 自然 The porosity Φ of spherical pores is 10-20%. 球形 It ranges from 20% to 40%.

[0036] Pre-formed spherical pores are exposed during grinding, thus effectively providing chip containment, cooling, and self-sharpening effects. The microporosity of diamond porous microspheres is Φ. 微观 =Φ 自然+ Φ 球形 .

[0037] Preferably, in step (2), the air degreasing and sintering process further includes a grading and sieving process.

[0038] Preferably, the sieving time for the grading sieve is 10-20 minutes, and the vibration frequency of the grading sieve is 20-100 Hz.

[0039] Specifically, after grading and sieving, microspheres with smaller particle sizes (e.g., 50-60 μm) are collected. Furthermore, by changing the sieve aperture and the vibration frequency of the sieving machine, other target microspheres of uniform size can be obtained. Verification using a laser particle size analyzer shows that the particle size distribution of the target microspheres should meet the requirement of (D90-D10) / D50 ≤ 0.25 to ensure that they can form a regular three-dimensional packed pore structure during the subsequent secondary air degreasing and sintering process of the grinding wheel abrasive.

[0040] A third aspect of the present invention provides a grinding wheel abrasive.

[0041] Specifically, the raw materials for preparing the abrasive wheel include the porous diamond microspheres and slurry described in the first aspect of this invention; The slurry comprises a second ceramic binder, an adhesive, and water.

[0042] Preferably, the porosity of the grinding wheel abrasive is 45-85%.

[0043] Preferably, the softening point of the second ceramic binder is 440-460℃, and the refractoriness of the second ceramic binder is 590-610℃; more preferably, the softening point of the second ceramic binder is 450℃, and the refractoriness of the second ceramic binder is 600℃.

[0044] Preferably, the second ceramic binder comprises a boron aluminosilicate ceramic binder.

[0045] Specifically, the second ceramic binder of the present invention is a low-temperature ceramic binder.

[0046] Preferably, the slurry comprises, by mass percentage, 40-50% second ceramic binder, 3-10% binder, and 40-55% water.

[0047] Preferably, the slurry further includes a dispersant, and by mass percentage, the slurry comprises 40-50% second ceramic binder, 3-10% binder, greater than 0% and less than or equal to 2% dispersant, and 40-55% water.

[0048] Preferably, the type of dispersant is the same as that of diamond porous microspheres.

[0049] Specifically, this invention does not impose any particular limitation on the type of binder in the raw materials for preparing grinding wheel abrasives. Any binder with adhesive properties that can be obtained by those skilled in the art can be used as a binder. This invention preferably uses dextrin as a binder.

[0050] A fourth aspect of the present invention provides a method for preparing the grinding wheel abrasive described in the third aspect of the present invention.

[0051] Specifically, the preparation method of the grinding wheel abrasive includes the following steps: The slurry is sprayed onto the surface of the porous diamond microspheres to obtain microspheres with a coating. The coated microspheres are placed in a mold and subjected to air degreasing and sintering to obtain the grinding wheel abrasive.

[0052] Preferably, the slurry is prepared by mixing the second ceramic binder, adhesive, and water.

[0053] Preferably, the D50 particle size of the second ceramic binder is 0.1-10 μm.

[0054] Preferably, a fluidized bed coating is used to uniformly spray the slurry onto the surface of the porous diamond microspheres.

[0055] Preferably, the atomization pressure when using fluidized bed coating is 0.3-3 MPa.

[0056] Preferably, the inlet air temperature when using fluidized bed coating is 40-80℃.

[0057] Preferably, the airflow velocity when using fluidized bed coating is 0.8-1.5 m / s.

[0058] Preferably, the slurry supply rate when using fluidized bed coating is 5-15 mL / min.

[0059] Preferably, in the coated microspheres, the coating thickness is 10-100 μm.

[0060] Preferably, the mold is a steel mold.

[0061] Preferably, the inner surface of the mold is provided with a graphite coating to prevent the porous diamond microspheres from sticking to the steel mold during the sintering process.

[0062] Preferably, during the preparation of the grinding wheel abrasive, the temperature of the air degreasing sintering is 500-600℃, and the time of the air degreasing sintering is 1.5-2.5h.

[0063] Preferably, during the preparation of the grinding wheel abrasive, the heating rate of the air degreasing sintering is 0.3-2℃ / min.

[0064] Specifically, porous diamond microspheres are naturally deposited in the abrasive wheel mold. After air degreasing and sintering (a second air degreasing and sintering process), the naturally deposited porous diamond microspheres are bonded together by a second ceramic binder, forming abrasive wheel agglomerates. Furthermore, because the air degreasing and sintering temperature during the abrasive wheel preparation process is lower than the air degreasing and sintering temperature during the porous diamond microsphere preparation process (i.e., the second degreasing and sintering temperature is lower than the first degreasing and sintering temperature), it ensures that the porous diamond microspheres are bonded together by the second ceramic binder without affecting the first ceramic binder and the pore structure within the porous diamond microspheres. A schematic diagram of the abrasive wheel structure is shown below. Figure 2 As shown.

[0065] Preferably, the thickness d of the shell of the mold is 0.5-5mm.

[0066] Preferably, the length a of the grinding wheel abrasive is 5-50 mm, the width b is 3-10 mm, and the height c is 5-20 mm.

[0067] Preferably, the grinding wheel abrasive has accumulated pores.

[0068] Preferably, the porosity of the packed pores is 15-25%.

[0069] Specifically, porous diamond microspheres are randomly stacked in a molding die and then sintered at a specific temperature and time. This process solidifies the porous diamond microspheres, forming an abrasive wheel (also known as abrasive wheel agglomerate). The abrasive wheel is made by stacking and sintering a specific amount of porous diamond microspheres, creating spatial pores between them. A three-dimensional structural diagram of the porous diamond microsphere stacking pore structure is shown below. Figure 3 As shown, a schematic diagram of the planar structure of the diamond porous microsphere stacked pore structure is as follows. Figure 4 As shown. Spatial pores are pore structures formed by the stacking of diamond porous microspheres. These pore structures are not regularly spherical; they are gaps formed by stacking. Their porosity is related to the diameter of the diamond porous microspheres, the stacking method, and the spacing between the microspheres. The porosity can be roughly estimated using theoretical calculations, and the estimated porosity approximately satisfies the formula: Φ 堆积 =1-[(π / 6)×D 3 / (D+S) 3 Where D is the diameter of the porous diamond microspheres and S is the spacing between the porous diamond microspheres. This porosity is called the microsphere packing porosity Φ. 堆积 After measurement and calculation, the packing porosity Φ of the microspheres was found to be... 堆积 Approximately 15-25%.

[0070] Therefore, the porosity in the abrasive wheel of the present invention includes the porosity Φ of natural pores. 自然 The porosity Φ of the prefabricated spherical pores 球形 Microsphere packing porosity Φ 堆积 Through optimization of the size and content of the spherical pore-forming agent, control of the air degreasing and sintering temperature and time during the preparation of diamond porous microspheres, and regulation of the air degreasing and sintering temperature and time during the preparation of grinding wheel abrasives, the total porosity of the grinding wheel abrasive can reach 45-85%, as shown in the mathematical formula: Φ 总 =Φ 自然 +Φ 球形 +Φ 堆积 .

[0071] A fifth aspect of the present invention provides a grinding wheel.

[0072] Specifically, the grinding wheel includes the abrasive wheel described in the third aspect of the present invention.

[0073] Compared with the prior art, the beneficial effects of the technical solution provided by the present invention are as follows: This invention achieves the preparation of high-porosity porous diamond microspheres by employing a combination of "natural pores + pre-fabricated spherical pores," significantly improving the self-sharpening properties of diamond abrasives. Simultaneously, through secondary air degreasing and sintering between the porous diamond microspheres, a new three-dimensional pore structure is formed between the naturally stacked microspheres, ensuring the mechanical properties of the grinding wheel while creating a multi-level pore structure of "natural pores + pre-fabricated spherical pores + stacked pores." This greatly reduces the resistance to coolant flow, improves the flushing and cooling effect of the coolant during grinding, and provides excellent chip containment and removal space, thus improving cooling and chip containment and removal during grinding and enhancing grinding performance on difficult-to-machine hard and brittle materials. Compared to traditional ceramic-bonded diamond grinding wheels, the grinding wheel abrasive prepared by this invention exhibits better grinding performance and service life. Attached Figure Description

[0074] Figure 1 This is a schematic diagram of the composition of the porous diamond microspheres of the present invention; Figure 2 This is a schematic diagram of the structure of the grinding wheel abrasive of the present invention; Figure 3 This is a three-dimensional structural diagram of the diamond porous microsphere stacked pore structure of the present invention; Figure 4 This is a schematic diagram of the planar structure of the diamond porous microsphere stacked pore structure of the present invention; Figure 5 This is a schematic diagram of the preparation process of the grinding wheel abrasive in Embodiment 1 of the present invention; Figure 6 This is a schematic diagram of the structure of the ceramic-bonded diamond grinding wheel of the present invention. Detailed Implementation

[0075] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.

[0076] Unless otherwise specified, the raw materials, reagents or devices used in the following examples are available from conventional commercial sources or can be obtained by existing known methods.

[0077] The sources of the first and second ceramic binders in the embodiments and comparative examples of this invention are as follows: First ceramic binder, namely aluminosilicate ceramic binder: Foshan Jinggu Materials Technology Co., Ltd., DZ778; The second ceramic binder, namely boron aluminum silicate ceramic binder, is manufactured by Zhengzhou Qianmo Materials Technology Co., Ltd., and its model number is TD-1.

[0078] Example 1 This embodiment provides a method for preparing porous diamond microspheres, the steps of which are as follows: Preparation of ceramic-bonded diamond particles: Weigh diamond (8000 mesh), first ceramic binder (average particle size D50 of 2 μm, softening point of 550℃, refractoriness of 700℃), and pore-forming agent (PMMA microspheres as pore-forming agent, average particle size D50 of 10 μm) at a mass ratio of 55:25:20. Ball mill and mix for 30 min to obtain a uniformly mixed powder. Mix 45 wt% of the mixed powder, 5 wt% of the binder dextrin, 1 wt% of the dispersant oleic acid (OA), and 49 wt% of deionized water to prepare a ceramic-bonded diamond slurry with a solid content of 35 vol%. Stir magnetically for 15 min to obtain a uniformly mixed slurry. Then, turn on the centrifugal spray granulation dryer, set the atomizer frequency to 50Hz, adjust the inlet air temperature to 200℃ and the outlet air temperature to 120℃, and turn on the blower and induced draft fan switches. Next, turn on the heating switch. When the inlet and outlet temperatures are approximately 200℃ and 100℃ respectively, simultaneously turn on the air hammer switch and the atomizer switch. Pour an appropriate amount of deionized water into the material tank, turn on the peristaltic pump, and after the deionized water has finished flowing, pour the uniformly mixed slurry into the material tank. After the slurry in the material tank has completely flowed out, collect the obtained powder. Pour deionized water into the material tank again, and after a period of time, reverse the peristaltic pump. When bubbles emerge from the material tank, turn off the peristaltic pump. Finally, turn off the atomizer switch, air hammer switch, and heating switch. When the inlet and outlet air temperatures drop below 70℃, turn off the induced draft fan, blower, and power switch. This yields ceramic-bonded diamond particles with a particle size of 90-150μm. Preparation of porous diamond microspheres: The prepared ceramic-bonded diamond particles with a particle size of 90-150 μm were placed in a tube furnace and vacuum degreased at a degreasing temperature of 550℃ for 2 hours. The degreased microspheres and crucible were then placed in a box furnace and air degreased and sintered at a sintering temperature of 650℃ for 2 hours to obtain porous diamond microspheres with a particle size of 70-120 μm. Microspheres of different sizes are graded and screened: standard metal wire mesh screens are used for grading and screening on a vibrating screener for 20 minutes and vibration frequency of 50 Hz. Microspheres with a target particle size range of 70-80 μm are collected, which are diamond porous microspheres.

[0079] This embodiment also provides a method for preparing grinding wheel abrasive, the steps of which are as follows: By mass percentage, 50wt% of the second ceramic binder (average particle size D50 of 2μm, softening point of 450℃, refractoriness of 600℃), 41wt% of deionized water, 8wt% of temporary binder dextrin, and 1wt% of dispersant oleic acid were thoroughly mixed and stirred to form a low-temperature ceramic binder slurry. The slurry was magnetically stirred for 15 minutes to obtain a uniformly mixed slurry. The slurry was then coated onto porous diamond microspheres using a fluidized bed with an atomization pressure of 2MPa, an inlet air temperature of 50℃, an airflow velocity of 1m / s, and a slurry supply rate of 10mL / min. This resulted in a uniform low-temperature ceramic binder coating with a thickness of 20μm on the surface of the porous diamond microspheres, thus obtaining coated porous diamond microspheres. Coated porous diamond microspheres are added to a designed grinding wheel abrasive mold. The grinding wheel abrasive mold is then placed in a tube furnace for secondary air degreasing and sintering at a temperature of 500°C for 2 hours. This allows the naturally stacked porous diamond microspheres to be bonded together by a boron aluminosilicate ceramic binder, forming a grinding wheel abrasive.

[0080] The schematic diagram of the preparation process of the grinding wheel abrasive in Embodiment 1 of the present invention is shown below. Figure 5 As shown.

[0081] Example 2 This embodiment provides a method for preparing porous diamond microspheres, the steps of which are as follows: Preparation of ceramic-bonded diamond particles: Weigh diamond (2000 mesh), aluminosilicate ceramic binder (D50 particle size of 2 μm, softening point of 550℃, refractoriness of 700℃), and pore-forming agent (PMMA microspheres as pore-forming agent, D50 particle size of 10 μm) in a mass ratio of 65:25:10. Ball mill and mix for 30 min to obtain a uniformly mixed powder. Mix 45 wt% of the mixed powder, 5 wt% of the binder dextrin, 1 wt% of the dispersant oleic acid (OA), and 49 wt% of deionized water to prepare a ceramic-bonded diamond slurry with a solid content of 35 vol%. Stir magnetically for 15 min to obtain a uniformly mixed slurry. Then, turn on the centrifugal spray granulation dryer, set the atomizer frequency to 50Hz, adjust the inlet air temperature to 200℃ and the outlet air temperature to 120℃, and turn on the blower and induced draft fan switches. Next, turn on the heating switch. When the inlet and outlet temperatures are approximately 200℃ and 100℃ respectively, simultaneously turn on the air hammer switch and the atomizer switch. Pour an appropriate amount of deionized water into the material tank, turn on the peristaltic pump, and after the deionized water has finished flowing out, pour the uniformly mixed slurry into the material tank. After the slurry in the material tank has completely flowed out, collect the obtained powder. Pour deionized water into the material tank again, and after a period of time, reverse the peristaltic pump. When bubbles emerge from the material tank, turn off the peristaltic pump. Finally, turn off the atomizer switch, air hammer switch, and heating switch. When the inlet and outlet air temperatures drop below 70℃, turn off the induced draft fan, blower, and power switch. This yields ceramic-bonded diamond particles with a particle size of 150-200μm. Preparation of porous diamond microspheres: The prepared ceramic-bonded diamond particles with a particle size of 150-200μm were placed in a tube furnace and vacuum degreased at a degreasing temperature of 550℃ for 2 hours. The degreased microspheres and crucible were then placed in a box furnace and air degreased and sintered at a sintering temperature of 650℃ for 2 hours to obtain porous diamond microspheres with a particle size of 120-180μm. Diamond porous microspheres of different sizes were graded and screened: standard metal wire mesh screens were used for grading and screening on a vibrating screener for 20 minutes and vibration frequency of 50 Hz. Microspheres with a target particle size range of 120-130 μm were collected, which are diamond porous microspheres.

[0082] This embodiment also provides a method for preparing grinding wheel abrasive, the steps of which are as follows: By mass percentage, 50wt% of the second ceramic binder, namely boroaluminosilicate ceramic binder (average particle size D50 of 2μm, softening point of 450℃, and refractoriness of 600℃), 41wt% of deionized water, 8wt% of temporary binder dextrin, and 1wt% of dispersant oleic acid were thoroughly mixed and stirred to form a low-temperature ceramic binder slurry. The slurry was magnetically stirred for 15 minutes to obtain a uniformly mixed slurry. The slurry was then coated onto porous diamond microspheres using a fluidized bed with an atomization pressure of 2MPa, an inlet air temperature of 50℃, an airflow velocity of 1m / s, and a slurry supply rate of 10mL / min. This resulted in a uniform low-temperature ceramic binder coating with a thickness of 20μm on the surface of the porous diamond microspheres, thus obtaining coated porous diamond microspheres. Coated porous diamond microspheres are added to a designed grinding wheel mold. The grinding wheel mold is then placed in a tube furnace for secondary air degreasing and sintering at a temperature of 500°C for 2 hours. This process allows the naturally stacked porous diamond microspheres to bond together with a boron aluminosilicate ceramic binder, forming a grinding wheel abrasive.

[0083] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that Comparative Example 1 uses diamond to replace the pore-forming agent in an equal amount, that is, it does not contain the pore-forming agent. Otherwise, it is the same as Example 1.

[0084] Performance testing The abrasive wheels prepared in Examples 1-2 and Comparative Example 1 were respectively bonded to a grinding wheel substrate to form ceramic-bonded diamond grinding wheels. A schematic diagram of the structure of the ceramic-bonded diamond grinding wheel is shown below. Figure 6 As shown.

[0085] Thinning grinding experiments were conducted on 4-inch single-crystal silicon carbide on a thinning machine. The single-sided removal amount was 50 μm. The rotation speed of the ceramic bonded diamond grinding wheel was 3000 rpm, the workpiece rotation speed was 151 rpm, and the feed rate was 0.5 μm / s.

[0086] Table 1 shows a comparison of the states of silicon carbide wafers processed by ceramic-bonded diamond grinding wheels in Examples 1-2 and Comparative Example 1.

[0087] Table 1: Comparison of the state of silicon carbide wafers processed by ceramic-bonded diamond grinding wheels in Examples 1-2 and Comparative Example 1

[0088] As shown in Table 1, the ceramic-bonded diamond grinding wheel prepared by the grinding wheel abrasive of the present invention has good grinding performance. That is, the present invention forms a multi-level pore structure by means of "natural pores + pre-made spherical pores + stacked pores", which can greatly improve the cooling, lubrication and chip removal effect of the grinding wheel, thereby improving the grinding performance of the grinding wheel.

[0089] After grinding a single-crystal silicon carbide wafer with the grinding wheel prepared without the pore-forming agent in Comparative Example 1, the surface quality of the single-crystal silicon carbide wafer was poor, with a surface roughness of 0.109 μm. However, after grinding with the ceramic-bonded diamond grinding wheel prepared with the abrasive from Example 1, the surface roughness of the single-crystal silicon carbide wafer was reduced to 0.005 μm. This indicates that the high-porosity structure in Example 1 can play a good role in chip containment and chip removal, thereby obtaining a better grinding surface quality.

[0090] Meanwhile, the grinding force ratio of the ceramic-bonded diamond grinding wheel in Comparative Example 1 to single-crystal silicon carbide wafers was 2.48, while the grinding force ratio of the ceramic-bonded diamond grinding wheel in Example 1 was reduced to 1.76, indicating that the ceramic-bonded diamond grinding wheel in Example 1 has better self-sharpening properties and higher grinding efficiency.

[0091] Furthermore, the wear ratio of the ceramic-bonded diamond grinding wheel in Comparative Example 1 when grinding a single-crystal silicon carbide wafer was 1.6, while the wear ratio of the ceramic-bonded diamond grinding wheel in Example 1 was increased to 2.3, indicating that the ceramic-bonded diamond grinding wheel of Example 1 with high porosity has a longer service life.

[0092] The above demonstrates that the ceramic-bonded diamond grinding wheel prepared by this invention has excellent grinding performance and service life.

[0093] In summary, this invention achieves the preparation of high-porosity diamond porous microspheres by employing a combination of "natural pores + prefabricated spherical pores," significantly improving the self-sharpening properties of diamond abrasives. Simultaneously, through secondary air degreasing and sintering between the diamond porous microspheres, while ensuring the mechanical properties of the abrasive wheel, a new three-dimensional pore structure is formed between the naturally stacked microspheres, resulting in a multi-level pore structure of "natural pores + prefabricated spherical pores + stacked pores." This structure greatly enhances the cooling, lubrication, and chip removal effects of ceramic-bonded diamond grinding wheels, thereby improving the grinding performance and service life of the grinding wheel.

[0094] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A porous diamond microsphere, characterized in that, The raw materials for preparing the diamond porous microspheres include mixed powder, binder, and water; The mixed powder includes a first ceramic binder, diamond, and a pore-forming agent.

2. The diamond porous microspheres according to claim 1, characterized in that, The particle size distribution of the diamond porous microspheres satisfies (D90-D10) / D50≤0.25; and / or, the diameter of the diamond porous microspheres is 0.01-0.5mm; and / or, the diamond porous microspheres have spherical pores and natural pores.

3. The diamond porous microspheres according to claim 2, characterized in that, In the diamond porous microspheres, the porosity of the spherical pores is 20-40%, and the porosity of the natural pores is 10-20%. And / or, by mass percentage, the raw materials for preparing the diamond porous microspheres include 40-50% mixed powder, 3-10% binder, and 45-55% water; And / or, by mass percentage, the mixed powder comprises 10-30% of a first ceramic binder, 50-70% of diamond, and 5-30% of a pore-forming agent; And / or, the softening point of the first ceramic binder is 540-560℃ and the refractoriness is 690-710℃; And / or, the pore-forming agent includes a spherical pore-forming agent.

4. The diamond porous microspheres according to claim 1, characterized in that, The first ceramic binder includes an aluminosilicate ceramic binder; And / or, the D50 particle size of the first ceramic binder is 0.1-10 μm; And / or, the D50 particle size of the pore-forming agent is 5-20 μm; And / or, the raw materials for preparing the diamond porous microspheres also include a dispersant, and by mass percentage, the raw materials for preparing the diamond porous microspheres include 40-50% mixed powder, 3-10% binder, greater than 0% and less than or equal to 2% dispersant, and 45-55% water.

5. The method for preparing diamond porous microspheres according to any one of claims 1-4, characterized in that, The preparation method includes the following steps: (1) Mix the raw materials for preparing diamond porous microspheres to obtain a slurry; then perform spray granulation to obtain powder; (2) The powder obtained in step (1) is subjected to vacuum degreasing and air degreasing sintering to obtain the diamond porous microspheres.

6. The preparation method according to claim 5, characterized in that, In step (1), the temperature of the spray granulation is 100-200℃; And / or, in step (2), the temperature of the vacuum degreasing is 400-600℃, and the time of the vacuum degreasing is 1.5-2.5h; And / or, in step (2), the temperature of the air degreasing sintering is 650-700℃, and the time of the air degreasing sintering is 1.5-2.5h.

7. A grinding wheel abrasive, characterized in that, The raw materials for preparing the abrasive wheel include the porous diamond microspheres and slurry as described in any one of claims 1-4; The slurry comprises a second ceramic binder, an adhesive, and water.

8. The abrasive wheel according to claim 7, characterized in that, The porosity of the abrasive in the grinding wheel is 45-85%; And / or, the softening point of the second ceramic binder is 440-460℃, and the refractoriness of the second ceramic binder is 590-610℃; And / or, by mass percentage, the slurry comprises 40-50% second ceramic binder, 3-10% binder, and 40-55% water.

9. The method for preparing the grinding wheel abrasive according to any one of claims 7-8, characterized in that, The preparation method includes the following steps: The slurry is sprayed onto the surface of the porous diamond microspheres to obtain microspheres with a coating. The coated microspheres are placed in a mold and subjected to air degreasing and sintering to obtain the grinding wheel abrasive.

10. A grinding wheel, characterized in that, Includes the grinding wheel abrasive as described in any one of claims 7-8.

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