A method for in-situ reaction preparation of an aluminum-based ceramic composite bond silicon carbide thinning grinding wheel

Abstract

The application belongs to the field of grinding wheel preparation, and discloses a method for preparing a novel aluminum-based ceramic composite binder silicon carbide thinning grinding wheel through in-situ reaction, which is composed of the following components in mass percentage: Al powder, carbon nitride powder, Ti powder, Cr powder and Fe powder. The application overcomes the disadvantage of poor metal wettability of the original ceramic binder, selects low-cost carbon nitride material, prepares a novel Al-based ceramic composite binder through in-situ reaction sintering technology, and develops a novel aluminum-based ceramic composite binder silicon carbide thinning grinding wheel. The product has sharp grinding and can be applied to the silicon surface and carbon surface processing of silicon carbide wafers at the same time, has long service life, and has low production cost.

Description

Technical Field

[0001] This invention relates to the field of grinding wheel preparation, and more specifically, to a method for preparing novel aluminum-based ceramic composite bonded silicon carbide thinned grinding wheels through in-situ reaction. Background Technology

[0002] With the rapid development of modern industry, especially the booming mechanical and electronic industries, the application of grinding tools for precision and semi-precision grinding is becoming increasingly widespread. As an important substrate material in the semiconductor industry, silicon carbide single crystals possess excellent thermal and electrical properties, and have broad application prospects in high-temperature, high-frequency, and high-power integrated electronic devices. The processing precision of silicon carbide substrates directly affects device performance; therefore, epitaxial applications place extremely stringent requirements on the surface quality of silicon carbide wafers. Silicon carbide is hard, brittle, and chemically stable, making traditional processing methods not entirely applicable. Silicon carbide wafers have carbon and silicon surfaces, both of which are more difficult to grind than traditional single-crystal silicon wafers. Due to limitations in processing technology, the processing efficiency of high-surface-quality silicon carbide wafers is currently extremely low. In the thinning process of silicon carbide wafers, rough grinding is the first step, currently mainly using ceramic-bonded diamond grinding tools with good self-sharpening properties. The main problem is the low strength of ceramic-bonded diamond grinding tools and the relatively low holding force of the binder on the diamond, resulting in low grinding efficiency and short service life. Silicon carbide is a high-hardness material and is particularly wear-resistant, so diamond abrasives are required to have high strength, and the binder must have good holding power for the diamond.

[0003] Currently, ceramic binders mainly use low-melting-point ceramics directly formulated and smelted from various oxides. Although they have good self-sharpening properties, they generally suffer from poor wettability with diamond and high brittleness. To address these shortcomings, many researchers have considered adding metals to ceramic binders to construct composite metal / ceramic binders. These composite binder abrasives are expected to possess the high self-sharpening properties, high grinding efficiency, and easy dressing characteristics of ceramic abrasives, while retaining the high strength, high hardness, high toughness, and long service life of metal binders. For example, the patent "A ceramic-metal binder diamond abrasive and its preparation method (CN102152248B)" proposes a binder with a ceramic binder as the main component and a small amount of metal added. The binder formulation includes a small amount of metal (Ti 1-10%, Al 1-5%).

[0004] Research on metal / ceramic composite bonded diamond grinding wheels has a solid foundation. However, to date, the matrix of diamond tools on the market is still mainly based on simple metal or ceramic bonds, with the practical application of composite bonds being almost non-existent. The fundamental reason is that simply mixing these two bonds does not result in a beneficial and suitable chemical reaction between them, leading to poor wetting or bonding between the metal and ceramic bonds. Therefore, the inherent shortcomings of each bond have not been overcome and remain, causing the actual grinding performance of composite bonded grinding wheels to fall short of the research expectations. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a method for preparing novel aluminum-based ceramic composite binder silicon carbide thinning grinding wheels through in-situ reaction.

[0006] The principle of this technology is to select appropriate reactants (gas phase, liquid phase, or powdered solid phase) according to the material design requirements, and at an appropriate temperature, generate a very fine-sized and uniformly distributed reinforcing phase in situ through chemical reactions between the substrate metal or alloy and the reactants. The advantage of the in-situ reaction under this patent is that carbon nitride has high reactivity and readily reacts chemically with aluminum. At the temperature specified in this patent, the reaction can be completed quickly, exhibiting a significant advantage in rapid reaction. Within the short reaction time, the highly reactive carbon nitride helps to inhibit aluminum etching of diamond, effectively protecting the diamond from damage during sintering. A schematic diagram of its microstructure is shown below. Figure 1 As shown, there is a distinct reinforcing phase. From Figure 2 As can be seen, aluminum reacts in situ with carbon nitride to form Al and Al4C3 ceramics. Furthermore, trace amounts of O2 are adsorbed in carbon nitride, and aluminum reacts with O2 to form Al2O3. The reaction equations are as follows: 8Al + C3N4 = Al4C3 + 4AlN (1) 2Al + 1.5O₂ = Al₂O₃ (2) The newly generated AlN and other ceramic particles have good wettability with aluminum. Due to the clean interface, the AlN and other ceramic particles bond well with the aluminum substrate. This is significantly different from the metal-ceramic composite binders constructed by directly adding metals to ceramic binders in the background technology. The metal-ceramic composite binder prepared by this in-situ reaction overcomes the shortcomings of the above-mentioned metal and ceramic binders that cannot be well wetted or bonded, thus having good performance.

[0007] The purpose of this invention is to overcome the shortcomings of the aforementioned ceramic binders and provide a novel aluminum-based ceramic composite binder silicon carbide thinning grinding wheel with sharp grinding edge, strong holding force, long service life, and low cost, as well as its preparation method.

[0008] The present invention provides a method for in-situ reaction preparation of a novel aluminum-based ceramic composite binder silicon carbide thinning grinding wheel, which adopts the following technical solution: A method for preparing a novel aluminum-based ceramic composite binder silicon carbide thinning grinding wheel by in-situ reaction, comprising the following components by mass percentage: Al powder: 50-80%, carbon nitride powder: 20-40%, Ti powder: 0-10%, Cr powder: 0-10%, Fe powder: 0-10%.

[0009] Furthermore, as a partial replacement for Al, 0-10% (by weight) of one or a combination of two of Ti, Cr and Fe may be added to the metal binder.

[0010] Furthermore, the Al, Ti, Cr and Fe powders have a purity of 99% or higher and a particle size of 200-400 mesh.

[0011] Furthermore, the carbon nitride powder is obtained by pyrolyzing melamine powder in a muffle furnace at a heating rate of 5 degrees / minute and holding at 550 degrees for 4 hours to obtain a block product. After ball milling, it is sieved through a metal sieve to obtain different particle sizes (150 mesh-300 mesh).

[0012] Furthermore, it includes a grinding wheel matrix and an abrasive block, characterized in that: the abrasive block is composed of a binder and diamond, and the mass ratio of the binder to the diamond is 80:20.

[0013] Furthermore, the diamond has a particle size of 2000 mesh.

[0014] Furthermore, this includes the following steps: (1) Weigh the raw material powders such as aluminum powder, carbon nitride and substitute metal according to different raw material ratios, mix them with a three-dimensional mixer for 2 hours, and then obtain the mixed powder by sieving. Then mix the obtained mixed powder with diamond particles for 1 hour and sieve to obtain the final required mixed powder.

[0015] (2) The mixed powder material prepared above is loaded into a graphite mold and sintered by high temperature hot pressing. The molding pressure is 60-100KN, the sintering temperature is 600-650℃, the heat and pressure are maintained for 8-15 minutes, and the sintered abrasive block is obtained after natural cooling.

[0016] (3) The obtained abrasive blocks are bonded to the grinding wheel base, and the finished product specifications are achieved by machining according to the shape and size of the grinding wheel, thus obtaining an aluminum-based bonded diamond grinding wheel.

[0017] In summary, the present invention has at least one of the following beneficial technical effects: The present invention overcomes the disadvantage of poor wettability between the original ceramic binder and the metal, selects low-cost carbon nitride material, and prepares a new type of Al-based ceramic composite binder through in-situ reaction sintering technology, and develops a new type of aluminum-based ceramic composite binder silicon carbide thinning grinding wheel. This product has sharp grinding edge, can be applied to the processing of both silicon and carbon surfaces of silicon carbide wafers, has a long service life, and low production cost. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the microstructure of a grinding wheel.

[0019] Figure 2 XRD patterns of grinding wheels were prepared for this example.

[0020] Figure 3 This is a schematic diagram of the finished grinding wheel structure.

[0021] Detailed implementation method.

[0022] The following is in conjunction with the appendix Figure 1-3 The present invention will be described in further detail below.

[0023] This invention discloses a method for in-situ reaction preparation of novel aluminum-based ceramic composite binder silicon carbide thinning grinding wheels: Example 1: This example describes a novel aluminum-based ceramic composite bonded silicon carbide thinning grinding wheel, comprising a grinding wheel matrix and an abrasive block. The abrasive block is composed of a binder and diamond, with a binder-to-diamond mass ratio of 80:20. The binder is made from the following raw materials by mass percentage: Al powder: 70%, carbon nitride powder: 30%. The particle sizes of the Al powder, carbon nitride powder, and diamond are 200 mesh, 200 mesh, and 2000#, respectively.

[0024] The above carbon nitride is produced by using industrial-grade (purity ≥ 99.8%) melamine powder as raw material. The powder is pyrolyzed in a muffle furnace at a heating rate of 5 degrees / minute and held at 550 degrees for 4 hours to obtain a blocky product. After being ball-milled and finely ground, the powder is sieved through a metal sieve to obtain a 200-mesh powder.

[0025] The method for preparing the aluminum-based bonded diamond grinding wheel in this embodiment includes the following steps: a) According to the above raw material ratio, weigh the aluminum powder and carbon nitride powder, mix them in a three-dimensional mixer for 2 hours, and then sieve them to obtain the mixed powder. Then mix the obtained mixed powder with diamond particles for 1 hour, and sieve them to obtain the final required mixed powder. b) The mixture obtained in step a) is loaded into a graphite mold and placed in a hot press sintering machine under an air atmosphere for pressing and sintering. Specifically, the temperature is raised to 630°C at a rate of 50°C / min, the forming pressure is 60KN, the temperature and pressure are held for 8 minutes, and the abrasive block is demolded after natural cooling. c) The abrasive block obtained in step b is bonded to the grinding wheel substrate and processed to achieve the finished product specifications and dimensions, thus obtaining the aluminum-based bonded diamond grinding wheel.

[0026] Example 2: This example describes a novel aluminum-based ceramic composite bonded silicon carbide thinning grinding wheel, comprising a grinding wheel matrix and an abrasive block. The abrasive block is composed of a binder and diamond, with a binder-to-diamond mass ratio of 80:20. The binder is made from the following raw materials by mass percentage: Al powder: 60%, Ti powder: 5%, and carbon nitride powder: 35%. The particle sizes of the Al powder, Ti powder, carbon nitride powder, and diamond are 200 mesh, 300 mesh, 150 mesh, and 2000#, respectively.

[0027] The carbon nitride described above was produced by pyrolyzing industrial-grade (purity ≥ 99.8%) melamine powder in a muffle furnace at a heating rate of 5 degrees Celsius / minute for 4 hours to obtain a blocky product. After ball milling, the powder was sieved through a metal sieve to obtain a 150-mesh powder.

[0028] The method for preparing the aluminum-based bonded diamond grinding wheel in this embodiment includes the following steps: a) According to the above raw material ratio, weigh the aluminum powder, titanium powder and carbon nitride powder, mix them in a three-dimensional mixer for 2 hours, and then sieve them to obtain the mixed powder. Then mix the obtained mixed powder with diamond particles for 1 hour, and sieve them to obtain the final required mixed powder. b) The mixture obtained in step a) is loaded into a graphite mold and placed in a hot press sintering machine under an air atmosphere for pressing and sintering. Specifically, the temperature is raised to 650°C at a rate of 50°C / min, the forming pressure is 80KN, the temperature and pressure are held for 10 minutes, and the abrasive block is demolded after natural cooling. c) The abrasive block obtained in step b is bonded to the grinding wheel substrate and processed to achieve the finished product specifications and dimensions, thus obtaining the aluminum-based bonded diamond grinding wheel.

[0029] Example 3: This example describes a novel aluminum-based ceramic composite bonded silicon carbide thinning grinding wheel, comprising a grinding wheel matrix and an abrasive block. The abrasive block is composed of a binder and diamond, with a binder-to-diamond mass ratio of 80:20. The binder is made from the following raw materials by mass percentage: Al powder: 50%, Ti powder: 10%, and carbon nitride powder: 40%. The particle sizes of the Al powder, Ti powder, carbon nitride powder, and diamond are 300 mesh, 200 mesh, 300 mesh, and 2000#, respectively.

[0030] The above carbon nitride is produced by using industrial-grade (purity ≥ 99.8%) melamine powder as raw material. The powder is pyrolyzed in a muffle furnace at a heating rate of 5 degrees / minute and held at 550 degrees for 4 hours to obtain a blocky product. After being ball-milled and finely ground, the powder is sieved through a metal sieve to obtain a 300-mesh powder.

[0031] The method for preparing the aluminum-based bonded diamond grinding wheel in this embodiment includes the following steps: a) According to the above raw material ratio, weigh the aluminum powder, titanium powder and carbon nitride powder, mix them in a three-dimensional mixer for 2 hours, and then sieve them to obtain the mixed powder. Then mix the obtained mixed powder with diamond particles for 1 hour, and sieve them to obtain the final required mixed powder. b) The mixture obtained in step a) is loaded into a graphite mold and placed in a hot press sintering machine under an air atmosphere for pressing and sintering. Specifically, the temperature is raised to 630°C at a rate of 50°C / min, the forming pressure is 80KN, the temperature and pressure are held for 12 minutes, and the abrasive block is obtained after natural cooling. c) The abrasive block obtained in step b is bonded to the grinding wheel substrate and processed to achieve the finished product specifications and dimensions, thus obtaining the aluminum-based bonded diamond grinding wheel.

[0032] Example 4: This example describes a novel aluminum-based ceramic composite bonded silicon carbide thinning grinding wheel, comprising a grinding wheel matrix and an abrasive block. The abrasive block is composed of a binder and diamond, with a binder-to-diamond mass ratio of 80:20. The binder is made from the following raw materials by mass percentage: Al powder: 75%, Cr powder: 5%, and carbon nitride powder: 20%. The particle sizes of the Al powder, Cr powder, carbon nitride powder, and diamond are 300 mesh, 400 mesh, 200 mesh, and 2000#, respectively.

[0033] The carbon nitride described above was produced by pyrolyzing industrial-grade (purity ≥ 99.8%) melamine powder in a muffle furnace at a heating rate of 5 degrees Celsius / minute for 4 hours to obtain a blocky product. After ball milling, the powder was sieved through a metal sieve to obtain a 200-mesh powder.

[0034] The method for preparing the aluminum-based bonded diamond grinding wheel in this embodiment includes the following steps: a) According to the above raw material ratio, weigh the aluminum powder, chromium powder and carbon nitride powder, mix them in a three-dimensional mixer for 2 hours, and then sieve them to obtain the mixed powder. Then mix the obtained mixed powder with diamond particles for 1 hour, and sieve them to obtain the final required mixed powder. b) The mixture obtained in step a) is loaded into a graphite mold and placed in a hot press sintering machine under an air atmosphere for pressing and sintering. Specifically, the temperature is raised to 630°C at a rate of 30°C / min, the forming pressure is 100KN, the temperature and pressure are held for 15 minutes, and the abrasive block is obtained after natural cooling. c) The abrasive block obtained in step b is bonded to the grinding wheel substrate and processed to achieve the finished product specifications and dimensions, thus obtaining the aluminum-based bonded diamond grinding wheel.

[0035] Example 5: This example describes a novel aluminum-based ceramic composite bonded silicon carbide thinning grinding wheel, comprising a grinding wheel matrix and an abrasive block. The abrasive block is composed of a binder and diamond, with a binder-to-diamond mass ratio of 80:20. The binder is made from the following raw materials by mass percentage: Al powder: 55%, Fe powder: 5%, and carbon nitride powder: 40%. The particle sizes of the Al powder, Fe powder, carbon nitride powder, and diamond are 300 mesh, 300 mesh, 200 mesh, and 2000#, respectively.

[0036] The above carbon nitride is produced by using industrial-grade (purity ≥ 99.8%) melamine powder as raw material. The powder is pyrolyzed in a muffle furnace at a heating rate of 5 degrees / minute and held at 550 degrees for 4 hours to obtain a blocky product. After being ball-milled and finely ground, the powder is sieved through a metal sieve to obtain a 200-mesh powder.

[0037] The method for preparing the aluminum-based bonded diamond grinding wheel in this embodiment includes the following steps: a) According to the above raw material ratio, weigh the aluminum powder, iron powder and carbon nitride powder, mix them in a three-dimensional mixer for 2 hours, and then sieve them to obtain the mixed powder. Then mix the obtained mixed powder with diamond particles for 1 hour, and sieve them to obtain the final required mixed powder. b) The mixture obtained in step a) is loaded into a graphite mold and placed in a hot press sintering machine under an air atmosphere for pressing and sintering. Specifically, the temperature is raised to 650°C at a rate of 30°C / min, the forming pressure is 100KN, the temperature and pressure are held for 15 minutes, and the abrasive block is obtained after natural cooling. c) The abrasive block obtained in step b is bonded to the grinding wheel substrate and processed to the finished product size to obtain the aluminum-based bonded diamond grinding wheel.

[0038] Example 6: This example describes a novel aluminum-based ceramic composite bonded silicon carbide thinning grinding wheel, comprising a grinding wheel matrix and an abrasive block. The abrasive block is composed of a binder and diamond, with a binder-to-diamond mass ratio of 80:20. The binder is made from the following raw materials by mass percentage: Al powder: 80%, carbon nitride powder: 20%. The particle sizes of the Al powder, carbon nitride powder, and diamond are 300 mesh, 200 mesh, and 2000#, respectively.

[0039] The above carbon nitride is produced by using industrial-grade (purity ≥ 99.8%) melamine powder as raw material. The powder is pyrolyzed in a muffle furnace at a heating rate of 5 degrees / minute and held at 550 degrees for 4 hours to obtain a blocky product. After being ball-milled and finely ground, the powder is sieved through a metal sieve to obtain a 200-mesh powder.

[0040] The method for preparing the aluminum-based bonded diamond grinding wheel in this embodiment includes the following steps: a) According to the above raw material ratio, weigh the aluminum powder and carbon nitride powder, mix them in a three-dimensional mixer for 2 hours, and then sieve them to obtain the mixed powder. Then mix the obtained mixed powder with diamond particles for 1 hour, and sieve them to obtain the final required mixed powder. b) The mixture obtained in step a) is loaded into a graphite mold and placed in a hot press sintering machine under an air atmosphere for pressing and sintering. Specifically, the temperature is raised to 600°C at a rate of 30°C / min, the forming pressure is 100KN, the temperature and pressure are held for 15 minutes, and the abrasive block is obtained after natural cooling. c) The abrasive block obtained in step b is bonded to the grinding wheel substrate and processed to the finished product size to obtain the aluminum-based bonded diamond grinding wheel.

[0041] Table 2 shows the application of the novel aluminum-based ceramic composite binder silicon carbide thinning grinding wheel of the present invention in the thinning process of silicon carbide wafers.

[0042] Table 1 shows the mass content and particle size of the binder raw materials.

[0043] Table 2 shows the grinding performance of the implementation case and the control case.

[0044]

[0045] Table 1

[0046] Table 2 Compared to the commonly used ceramic-bonded grinding wheels for silicon carbide thinning, the novel aluminum-based ceramic composite-bonded grinding wheels prepared using the method of this invention exhibit significantly improved abrasive holding power due to the in-situ reaction of carbon nitride with the metal to form a reinforcing phase. The service life (grinding ratio), sharpness (grinding current), and machining quality of the examples are all superior to the control examples. In the six examples, Examples 2-5, due to the addition of Ti, Cr, Fe, and other substitute metal components, allow for a more complete reaction between the added carbon nitride and the metal. The resulting fine nitrides or carbides provide reinforcement and toughening, further improving the bond performance. Their various application indicators are significantly better than those of Examples 1 and 6, which did not contain substitute metal components.

[0047] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for in-situ reaction preparation of aluminum-based ceramic composite binder silicon carbide thinning grinding wheels, characterized in that: The aluminum-based ceramic composite binder consists of the following components by mass percentage. Composition: Al powder: 50-80%, carbon nitride powder: 20-40%, Ti powder: 0-10%, Cr powder: 0-10%, Fe powder: 0-10%; The carbon nitride powder is obtained by pyrolyzing melamine powder in a muffle furnace at a heating rate of 5 degrees / minute and holding at 550 degrees for 4 hours to obtain a block product. After being ball-milled and finely ground, it is sieved through a metal sieve to obtain different particle sizes (150 mesh-300 mesh). Includes the following steps: Step 1: Weigh Al powder, carbon nitride and substitute metal raw material powder according to different raw material ratios, mix them in a three-dimensional mixer for 2 hours, and then obtain the mixed powder by sieving; then mix the obtained mixed powder with diamond particles for 1 hour, and then obtain the final required mixed powder by sieving. Step 2: The mixed powder material obtained above is loaded into a graphite mold and sintered by high temperature hot pressing. The molding pressure is 60-100KN, the sintering temperature is 600-650℃, and the temperature and pressure are maintained for 8-15 minutes. After natural cooling, the sintered abrasive block is demolded. Step 3: Bond the obtained abrasive block to the grinding wheel base, and machine it to the finished product size according to the shape and size of the grinding wheel to obtain the aluminum-based bonded diamond grinding wheel.

2. The method for preparing aluminum-based ceramic composite binder silicon carbide thinning grinding wheels by in-situ reaction according to claim 1, characterized in that: As a partial replacement for Al, 0-10% (by weight) of one or two combinations of Ti, Cr and Fe may also be added to the metal binder.

3. The method for preparing aluminum-based ceramic composite binder silicon carbide thinning grinding wheels by in-situ reaction according to claim 1, characterized in that: The Al, Ti, Cr and Fe powders have a purity of 99% or higher and a particle size of 200-400 mesh.

4. The method for preparing an aluminum-based ceramic composite bonded silicon carbide thinned grinding wheel according to claim 1, comprising a grinding wheel matrix and an abrasive block, characterized in that: The abrasive block is composed of a binder and diamond, with a binder to diamond mass ratio of 80:

20.

5. The method for preparing aluminum-based ceramic composite binder silicon carbide thinning grinding wheels by in-situ reaction according to claim 4, characterized in that: The diamond has a particle size of 2000 mesh.

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