Fine-grain aluminum oxide CVD (Chemical Vapor Deposition) coated cutter based on ultrasonic intervention and preparation method thereof

Abstract

The invention relates to the technical field of precision cutters, and particularly discloses a preparation method of a fine-grain aluminum oxide CVD coated cutter based on ultrasonic intervention. The preparation method comprises the following steps: S1, depositing a TiCN transition layer on a cutter substrate by adopting a CVD (Chemical Vapor Deposition) process; s2, mixed gas of AlCl3, CO2 and H2 is introduced into the CVD reaction chamber to deposit an alpha-Al2O3 layer, and ultrasonic waves are adopted to continuously intervene in the Al2O3 nucleation stage, so that the size of a primary crystal nucleus is smaller than or equal to 50 nm; and S3, ultrasonic waves are stopped, and the alpha-Al2O3 layer continues to be deposited. According to the fine-grain aluminum oxide CVD coated cutting tool based on ultrasonic intervention and the preparation method thereof, the problems that in an existing CVD technology, alpha-Al2O3 grain refinement is insufficient, and transition layer crystal nucleus distribution is uneven can be solved, and a novel coating technology for intervening crystal nucleus generation through ultrasonic waves is provided.

Description

Technical Field

[0001] The present invention relates to the technical field of precision cutting tools, and in particular to a fine-grained alumina CVD coating cutting tool based on ultrasonic intervention and a preparation method thereof. Background Art

[0002] Carbide tools are widely used in machining due to their high hardness and heat resistance. To improve tool life and performance, CVD technology is often used to deposit an aluminum oxide (Al2O3) coating on the tool surface. The α-Al2O3 crystal form is preferred due to its high hardness, oxidation resistance, and thermal stability. Traditional methods influence the transition layer structure and thus control grain size by manipulating the reaction gas flow rate, temperature distribution, or doping elements (such as Ti and Cr). However, these methods present the following challenges: 1. The grain refinement effect is limited, and the grain coarsening is easily caused by uneven temperature gradient.

[0003] 2. The distribution and density of primary crystal nuclei in the transition layer are difficult to accurately control, which affects the uniformity of the coating. Summary of the Invention

[0004] The purpose of the present invention is to propose a fine-grained alumina CVD coated tool based on ultrasonic intervention and a preparation method thereof, so as to solve the problems of insufficient α-Al2O3 grain refinement and uneven distribution of transition layer crystal nuclei in the existing CVD technology, and to provide a new coating process for crystal nucleation generation through ultrasonic intervention.

[0005] To achieve this object, the present invention adopts the following technical solutions: A method for preparing a fine-grained alumina CVD coated tool based on ultrasonic intervention comprises the following steps: S1: Using CVD process, a TiCN transition layer is deposited on the tool substrate; S2: A mixed gas of AlCl3, CO2 and H2 is introduced into the CVD reaction chamber to deposit an α-Al2O3 layer, and ultrasonic waves are used to continuously intervene in the Al2O3 nucleation stage to reduce the size of the primary crystal nucleus to ≤50 nm; S3: Stop the ultrasonic wave and continue to deposit the α-Al2O3 layer.

[0006] As a preferred embodiment of the present invention, in the S1, the thickness of the TiCN transition layer is 1 μm to 3 μm.

[0007] As a preferred embodiment of the present invention, in S2, the temperature in the CVD reaction chamber is controlled to be 900° C. to 1050° C. and the pressure is controlled to be 5 kPa to 10 kPa.

[0008] As a preferred embodiment of the present invention, in S2, the frequency of the ultrasonic wave is 20kHz to 100kHz, and the power is 50W to 300W.

[0009] As a preferred embodiment of the present invention, in S2, the ultrasonic wave is applied during the initial 5 to 15 minutes of the Al2O3 nucleation stage.

[0010] As a preferred embodiment of the present invention, in the S3, the thickness of the α-Al2O3 layer is 5 μm to 15 μm.

[0011] The present invention also provides a fine-grained alumina CVD coated tool based on ultrasonic intervention, which is prepared using the above-mentioned preparation method of the fine-grained alumina CVD coated tool based on ultrasonic intervention, and includes a tool substrate, a TiCN transition layer and an α-Al2O3 layer.

[0012] As a preference of the present invention, the grain size of the α-Al2O3 layer is ≤200 nm.

[0013] The beneficial effects of the present invention are: 1. The present invention uses ultrasound to intervene in the Al2O3 nucleation process. The cavitation effect and acoustic streaming of ultrasound can break up the clusters of gas-phase reactants, increase the density of nucleation sites, and refine the primary crystal nuclei; at the same time, it inhibits the merging growth of grains, and ultimately obtains a uniform and fine-grained α-Al2O3 layer, which significantly improves the hardness and high-temperature oxidation resistance of the tool.

[0014] 2. Suitable for turning tools and other cutting tools with demanding heat dissipation conditions, extending the service life by more than 2 times. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a flow chart of the method for preparing fine-grained alumina CVD coated cutting tools based on ultrasonic intervention provided by the present invention.

[0016] Figure 2 This is an SEM image of the grain structure of a coating in the prior art that has not been subjected to ultrasonic intervention.

[0017] Figure 3 3 is a SEM image of the grain structure of the coating after ultrasonic intervention of the present invention. DETAILED DESCRIPTION

[0018] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific implementation methods.

[0019] Example 1 like Figure 1 As shown, a method for preparing a fine-grained alumina CVD coated tool based on ultrasonic intervention includes the following steps S1 to S3.

[0020] S1: Using CVD process, a TiCN transition layer is deposited on the tool substrate.

[0021] In step S1 , the tool substrate is preferably made of WC-10% Co cemented carbide. The CVD deposition temperature is 850° C., and the thickness of the TiCN transition layer is 2 μm.

[0022] S2: A mixed gas of AlCl3, CO2 and H2 is introduced into the CVD reaction chamber, and the temperature in the CVD reaction chamber is controlled at 900℃~1050℃ and the pressure is 5kPa~10kPa; ultrasonic waves are applied in the initial 10 minutes of the Al2O3 nucleation stage, with a frequency of 40kHz and a power of 150W.

[0023] S3: Stop the ultrasonic wave and continue to deposit the α-Al2O3 layer to a thickness of 10 μm.

[0024] Example 2 The preparation method of Example 1 is used to prepare a fine-grained alumina CVD coating tool based on ultrasonic intervention, including a tool substrate, a TiCN transition layer and an α-Al2O3 layer.

[0025] In this embodiment, the material of the tool substrate is preferably WC-10%Co cemented carbide; the thickness of the TiCN transition layer is 2 μm, and the thickness of the α-Al 2 O 3 layer is 10 μm.

[0026] The fine-grained alumina CVD coated tool of the second embodiment was tested, and the test results showed that the grain size of the α-Al2O3 layer was 180 nm, the coating hardness was 28 GPa, and the turning test life was 45 minutes.

[0027] Example 3 A method for preparing a fine-grained alumina CVD coated tool based on ultrasonic intervention includes the following steps S1 to S3.

[0028] S1: Using CVD process, a TiCN transition layer is deposited on the tool substrate.

[0029] In step S1 , the tool substrate is preferably made of WC-10% Co cemented carbide, the CVD deposition temperature is 850° C., and the thickness of the TiCN transition layer is 1 μm.

[0030] S2: A mixed gas of AlCl3, CO2 and H2 is introduced into the CVD reaction chamber, and the temperature in the CVD reaction chamber is controlled at 900℃~1050℃ and the pressure is 5kPa~10kPa; ultrasonic waves are applied in the initial 5 minutes of the Al2O3 nucleation stage, with a frequency of 40kHz and a power of 150W.

[0031] S3: Stop the ultrasonic wave and continue to deposit the α-Al2O3 layer to a thickness of 5 μm.

[0032] Example 4 The preparation method of Example 3 was used to prepare a fine-grained alumina CVD-coated tool using ultrasonic interference, comprising a tool substrate, a TiCN transition layer, and an α-Al2O3 layer. The tool substrate was preferably made of WC-10% Co cemented carbide; the TiCN transition layer had a thickness of 1 μm, and the α-Al2O3 layer had a thickness of 5 μm.

[0033] The fine-grained alumina CVD coated tool of Example 4 was tested, and the test results showed that the grain size of the α-Al2O3 layer was 196 nm, the coating hardness was 22 GPa, and the turning test life was 36 minutes.

[0034] Example 5 A method for preparing a fine-grained alumina CVD coated tool based on ultrasonic intervention includes the following steps S1 to S3.

[0035] S1: Using CVD process, a TiCN transition layer is deposited on the tool substrate.

[0036] In step S1 , the tool substrate is preferably made of WC-10% Co cemented carbide. The CVD deposition temperature is 850° C., and the thickness of the TiCN transition layer is 3 μm.

[0037] S2: A mixed gas of AlCl3, CO2 and H2 is introduced into the CVD reaction chamber, and the temperature in the CVD reaction chamber is controlled at 900℃~1050℃ and the pressure is 5kPa~10kPa; ultrasonic waves are applied during the initial 15 minutes of the Al2O3 nucleation stage, with a frequency of 40kHz and a power of 150W.

[0038] S3: Stop the ultrasonic wave and continue to deposit the α-Al2O3 layer to a thickness of 15 μm.

[0039] Example 6 The preparation method of Example 5 was used to prepare a fine-grained alumina CVD-coated tool using ultrasonic interference, comprising a tool substrate, a TiCN transition layer, and an α-Al2O3 layer. The tool substrate was preferably made of WC-10% Co cemented carbide; the TiCN transition layer had a thickness of 3 μm, and the α-Al2O3 layer had a thickness of 15 μm.

[0040] The fine-grained alumina CVD coated tool of Example 6 was tested, and the test results showed that the grain size of the α-Al2O3 layer was 172 nm, the coating hardness was 33 GPa, and the turning test life was 54 minutes.

[0041] According to the test results of the above embodiment and Figure 2 and Figure 3From the comparison, it can be seen that the present invention uses ultrasound to intervene in the Al2O3 nucleation process, and uses the cavitation effect and acoustic streaming of ultrasound to break up the clusters of gas-phase reactants, increase the density of nucleation sites, and refine the primary crystal nuclei; at the same time, it inhibits the merging growth of grains, and finally obtains a uniform fine-grained α-Al2O3 layer, which significantly improves the hardness and high-temperature oxidation resistance of the tool. The coating hardness can be increased by 15%-20%, and the high-temperature oxidation resistance can be increased by 30%; the turning test life is extended by more than 2 times.

[0042] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are intended solely to illustrate the principles of the present invention and are not to be construed in any way as limiting the scope of protection of the present invention. Based on the explanations herein, those skilled in the art will readily conceive of other specific embodiments of the present invention without inventive effort, and such embodiments will fall within the scope of protection of the present invention.

Claims

1. A method for preparing a fine-grained alumina CVD coated tool based on ultrasonic intervention, characterized in that: The following steps are involved: S1: Using CVD process, a TiCN transition layer is deposited on the tool substrate; S2: A mixed gas of AlCl3, CO2 and H2 is introduced into the CVD reaction chamber to deposit an α-Al2O3 layer, and ultrasonic waves are used to continuously intervene in the Al2O3 nucleation stage to reduce the size of the primary crystal nucleus to ≤50 nm; S3: Stop the ultrasonic wave and continue to deposit the α-Al2O3 layer.

2. The method for preparing a fine-grained alumina CVD coated tool based on ultrasonic intervention according to claim 1, characterized in that: In the above-mentioned S1, the thickness of the TiCN transition layer is 1 μm to 3 μm.

3. The method for preparing a fine-grained alumina CVD coated tool based on ultrasonic intervention according to claim 1, characterized in that: In S2, the temperature in the CVD reaction chamber is controlled to be 900° C. to 1050° C. and the pressure is controlled to be 5 kPa to 10 kPa.

4. The method for preparing a fine-grained alumina CVD coated tool based on ultrasonic intervention according to claim 1, characterized in that: In the above-mentioned S2, the frequency of the ultrasonic wave is 20kHz to 100kHz, and the power is 50W to 300W.

5. The method for preparing a fine-grained alumina CVD coated tool based on ultrasonic intervention according to claim 1, characterized in that: In the above-mentioned S2, the ultrasonic wave is applied during the initial 5 to 15 minutes of the Al2O3 nucleation stage.

6. The method for preparing a fine-grained alumina CVD coated tool based on ultrasonic intervention according to claim 1, characterized in that: In the S3, the thickness of the α-Al2O3 layer is 5 μm to 15 μm.

7. A fine-grained alumina CVD coated tool based on ultrasonic intervention, characterized in that: The tool is prepared by the method for preparing a fine-grained alumina CVD coated tool based on ultrasonic intervention as described in any one of claims 1 to 6, and includes a tool substrate, a TiCN transition layer and an α-Al2O3 layer.

8. The fine-grained alumina CVD coated tool based on ultrasonic intervention according to claim 7, characterized in that: The grain size of the α-Al2O3 layer is ≤200 nm.

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