A cvd modified coating and method of making and use thereof

Abstract

This invention relates to a CVD-modified coating, its preparation method, and its application, belonging to the field of coating technology. The preparation method includes the following steps: obtaining a CVD coating using chemical vapor deposition; subjecting the CVD coating to freeze-drying to obtain a first CVD coating; subjecting the first CVD coating to magnetic field heat treatment to obtain a second CVD coating; and sequentially alternatingly processing the second CVD coating with the freeze-drying and magnetic field heat treatments to obtain the CVD-modified coating. Based on existing CVD coating preparation methods, this invention utilizes a combined magnetic field heat treatment and freeze-drying process for synergistic modification, optimizing the microstructure of the CVD coating. When applied to a substrate surface, it can improve its hardness and wear resistance, thereby extending the service life of devices such as cutting tools, molds, and machine parts, and has a wide range of applications.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and in particular to a CVD modified coating, its preparation method, and its application. Background Technology

[0002] In the field of coating technology, chemical vapor deposition (CVD) is an important surface treatment technology that has been widely used in various industrial sectors. CVD coating preparation technology involves the chemical reaction of gaseous precursors at high temperatures to deposit a coating with specific composition, structure, and properties on the substrate surface. This coating can impart the desired hardness, wear resistance, corrosion resistance, and other properties to the substrate surface, thereby improving the lifespan and performance of devices.

[0003] With the continuous development of industrial technology, the requirements for coating performance are becoming increasingly stringent. While traditional CVD coatings can meet the needs of certain applications to some extent, their performance often falls short of ideal in high-end applications. To improve the performance of CVD coatings, researchers have explored various modification methods. However, current research largely focuses on controlling and adjusting the conditions and parameters during chemical vapor deposition (CVD), and there are no reports on combining magnetic field heat treatment and cryogenic processes to enhance the performance of CVD coatings. Summary of the Invention

[0004] To address the above problems, this invention provides a CVD modified coating, its preparation method, and its application.

[0005] In a first aspect, the present invention provides a method for preparing a CVD modified coating, the method comprising the following steps:

[0006] A CVD coating was prepared using chemical vapor deposition.

[0007] The CVD coating is subjected to freeze treatment to obtain a first CVD coating;

[0008] The first CVD coating is subjected to magnetic field heat treatment to obtain the second CVD coating;

[0009] The second CVD coating is subjected to alternating cycles of freezing treatment and magnetic field heat treatment to obtain the CVD modified coating.

[0010] Furthermore, the steps for preparing the CVD coating using chemical vapor deposition include the following processes:

[0011] A TiN coating was formed by first chemical vapor deposition on the substrate surface using a first gas mixture consisting of N2 as a nitrogen source, TiCl4 as a titanium source, and H2 as a carrier gas under conditions of 840–860 °C and 110–130 mbar.

[0012] A transition layer is formed by second chemical vapor deposition on the surface of the TiN coating under conditions of 840–860 °C and 90–110 mbar, using a second gas mixture of N2 as nitrogen source, BCl3 as boron source, TiCl4 as titanium source and H2 as carrier gas.

[0013] A Ti-B coating is formed by third chemical vapor deposition on the surface of the TiN coating under conditions of 890–910 °C and 140–160 mbar using a third gas mixture consisting of BCl3 as a boron source, TiCl4 as a titanium source, and H2 as a carrier gas, to obtain the CVD coating.

[0014] Further, by volume percentage, the first gas mixture comprises the following components:

[0015] N2 35-45%, TiCl4 1-2%, balance H2;

[0016] The second gas mixture comprises the following components by volume percentage:

[0017] N2 0-40%, TiCl4 1-2%, BCl3 0.1-0.71%, balance H2;

[0018] The third gas mixture comprises the following components by volume percentage:

[0019] TiCl4 0.40-0.55%, BCl3 0.40-0.55%, balance H2.

[0020] Furthermore, the operating conditions for the freezing process include: a temperature of -30 to -20°C and a time of 30 to 60 minutes.

[0021] Furthermore, the freezing temperature is -25°C, and the freezing time is 45 minutes.

[0022] Furthermore, the operating conditions for the magnetic field heat treatment include: a magnetic flux coil current of 5–10 A, a temperature of 80–90 °C, and a time of 20–30 minutes.

[0023] Furthermore, the magnetic flux coil current for the magnetic field heat treatment is 7A, the temperature for the magnetic field heat treatment is 85℃, and the duration of the magnetic field heat treatment is 25 minutes.

[0024] Furthermore, the alternating cyclic processing is performed 5 to 8 times.

[0025] In a second aspect, the present invention provides a CVD modified coating, wherein the CVD modified coating is prepared by the preparation method of the CVD modified coating described in any one of the first aspects.

[0026] Thirdly, the present invention provides a method for preparing a CVD modified coating according to any one of the first aspects to obtain a CVD modified coating or an application of a CVD modified coating according to any one of the second aspects in improving the service life of a device, wherein the device includes at least one of a cutting tool, a mold, and a machine component.

[0027] The technical solutions provided in the embodiments of the present invention have at least the following advantages compared with the prior art:

[0028] This invention provides a CVD-modified coating, its preparation method, and its application. Based on existing CVD coating preparation methods, this invention utilizes a combined magnetic field heat treatment and cryogenic process for synergistic modification, optimizing the microstructure of the CVD coating. When applied to a substrate surface, it can improve its hardness and wear resistance, thereby extending the service life of devices such as cutting tools, molds, and machine parts, and has a wide range of applications. Specifically:

[0029] 1. Freezing treatment

[0030] The initial CVD coating has a certain internal stress. This invention, through freeze treatment, not only helps to reduce the internal stress in the CVD coating and improve the density of the coating, but also facilitates the subsequent magnetic field heat treatment to induce and optimize the microstructure of the CVD coating.

[0031] 2. Magnetic field heat treatment

[0032] After cryogenic treatment, the CVD coating is further enhanced by magnetic field heat treatment, which promotes the crystallization process, optimizes grain orientation and microstructure, and thus improves the overall performance of the CVD coating.

[0033] Therefore, this invention, through multiple alternating freezing and magnetic field heat treatments, allows the CVD coating to undergo multiple microstructure adjustments and optimizations, thereby significantly improving the hardness and wear resistance of the CVD coating. When applied to substrate surfaces, such as cutting tools, molds, and machine parts, this CVD-modified coating can effectively resist wear, extend the service life of the devices, and improve their working efficiency and reliability. This invention provides a new approach and method for modifying CVD coatings, and is expected to further promote the development of coating technology and provide more high-performance, high-reliability coating solutions for the industrial sector. Attached Figure Description

[0034] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic flowchart of a method for preparing a CVD modified coating according to an embodiment of the present invention. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0039] In a first aspect, the present invention provides a method for preparing a CVD modified coating, such as... Figure 1 As shown, the preparation method includes the following steps:

[0040] A CVD coating was prepared using chemical vapor deposition.

[0041] The CVD coating is subjected to freeze treatment to obtain a first CVD coating;

[0042] The first CVD coating is subjected to magnetic field heat treatment to obtain the second CVD coating;

[0043] The second CVD coating is subjected to alternating cycles of freezing treatment and magnetic field heat treatment to obtain the CVD modified coating.

[0044] This invention provides a method for preparing a CVD-modified coating. Based on existing CVD coating preparation methods, this invention utilizes a combined magnetic field heat treatment process and a cryogenic process for synergistic modification, optimizing the microstructure of the CVD coating. When applied to a substrate surface, it can improve its hardness and wear resistance, thereby extending the service life of devices such as cutting tools, molds, and machine parts, and has a wide range of applications.

[0045] In this invention, a chemical vapor deposition method is used to prepare the CVD coating, which can be done using existing CVD coating preparation methods.

[0046] In some specific embodiments, the steps for preparing a CVD coating using chemical vapor deposition include the following processes:

[0047] A TiN coating was formed by first chemical vapor deposition on the substrate surface using a first gas mixture consisting of N2 as a nitrogen source, TiCl4 as a titanium source, and H2 as a carrier gas under conditions of 840–860 °C and 110–130 mbar.

[0048] A transition layer is formed by second chemical vapor deposition on the surface of the TiN coating under conditions of 840–860 °C and 90–110 mbar, using a second gas mixture of N2 as nitrogen source, BCl3 as boron source, TiCl4 as titanium source and H2 as carrier gas.

[0049] A Ti-B coating is formed by third chemical vapor deposition on the surface of the TiN coating under conditions of 890–910 °C and 140–160 mbar using a third gas mixture consisting of BCl3 as a boron source, TiCl4 as a titanium source, and H2 as a carrier gas, to obtain the CVD coating.

[0050] In some specific embodiments, the steps for preparing a CVD coating using chemical vapor deposition include the following processes:

[0051] A TiN coating was formed by first chemical vapor deposition on the substrate surface using a first gas mixture consisting of N2 as nitrogen source, TiCl4 as titanium source and H2 as carrier gas at 850℃ and 120mbar.

[0052] A second chemical vapor deposition was performed on the TiN coating surface at 850℃ and 100mbar to form a transition layer, using a second gas mixture consisting of N2 as a nitrogen source, BCl3 as a boron source, TiCl4 as a titanium source, and H2 as a carrier gas.

[0053] A Ti-B coating was formed by third chemical vapor deposition on the surface of the TiN coating under conditions of 900℃ and 150mbar using a third gas mixture consisting of BCl3 as a boron source, TiCl4 as a titanium source, and H2 as a carrier gas, to obtain the CVD coating.

[0054] In some specific embodiments, the first gas mixture comprises the following components, by volume percentage:

[0055] N2 35-45%, TiCl4 1-2%, balance H2;

[0056] The second gas mixture comprises the following components by volume percentage:

[0057] N2 0-40%, TiCl4 1-2%, BCl3 0.1-0.71%, balance H2;

[0058] The third gas mixture comprises the following components by volume percentage:

[0059] TiCl4 0.40-0.55%, BCl3 0.40-0.55%, balance H2.

[0060] In some specific embodiments, the first gas mixture comprises the following components, by volume percentage:

[0061] N2 40%, TiCl4 1.5%, balance H2;

[0062] The second gas mixture comprises the following components by volume percentage:

[0063] N2 0-40%, TiCl4 1.5%, BCl3 0.1-0.71%, balance H2;

[0064] The third gas mixture comprises the following components by volume percentage:

[0065] TiCl4 0.49%, BCl3 0.45%, balance H2.

[0066] In some specific embodiments, the operating conditions for the freezing process include: a temperature of -30 to -20°C and a time of 30 to 60 minutes.

[0067] In some specific embodiments, the freezing temperature is -25°C and the freezing time is 45 minutes.

[0068] In some specific embodiments, the operating conditions for the magnetic field heat treatment include: a magnetic flux coil current of 5–10 A, a temperature of 80–90 °C, and a time of 20–30 minutes.

[0069] In some specific embodiments, the magnetic flux coil current of the magnetic field heat treatment is 7A, the temperature of the magnetic field heat treatment is 85°C, and the time of the magnetic field heat treatment is 25 minutes.

[0070] In some specific embodiments, the alternating cyclic processing is performed 5 to 8 times.

[0071] In a second aspect, the present invention provides a CVD modified coating, wherein the CVD modified coating is prepared by the preparation method of the CVD modified coating described in any one of the first aspects.

[0072] Thirdly, the present invention provides a method for preparing a CVD modified coating according to any one of the first aspects to obtain a CVD modified coating or an application of a CVD modified coating according to any one of the second aspects in improving the service life of a device, wherein the device includes at least one of a cutting tool, a mold, and a machine component.

[0073] It should be noted that, unless otherwise specified or specifically stated, the raw materials involved in the CVD modified coatings, their preparation methods, and applications provided in the embodiments of the present invention can be directly made from commercially available products or from existing publicly disclosed preparation methods.

[0074] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed according to national standards. If no corresponding national standard exists, then generally accepted international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0075] Example 1

[0076] This example provides a CVD-modified coating, the preparation method of which includes the following steps:

[0077] Step (1): Select a substrate and place the substrate in a chemical vapor deposition apparatus for coating deposition using a chemical vapor deposition method;

[0078] Step (2): At 850°C and 120 mbar, a first gas mixture consisting of N2 as nitrogen source, TiCl4 as titanium source and H2 as carrier gas is deposited on the substrate surface to form a TiN coating through first chemical vapor deposition; the first gas mixture comprises the following components by volume percentage: N2 40%, TiCl4 1.5%, and the balance being H2;

[0079] Step (3): At 850℃ and 100mbar, a second gas mixture consisting of N2 as nitrogen source, BCl3 as boron source, TiCl4 as titanium source and H2 as carrier gas is deposited on the surface of the TiN coating to form a transition layer. By volume percentage, N2 in the second gas mixture gradually decreases from 40% to 0%, TiCl4 is 1.5%, BCl3 gradually increases from 0.1% to 0.71%, and the balance is H2.

[0080] Step (4): At 900℃ and 150mbar, a third gas mixture formed by BCl3 as boron source, TiCl4 as titanium source and H2 as carrier gas is subjected to third chemical vapor deposition on the surface of the TiN coating to form a Ti-B coating, thereby obtaining the CVD coating; the third gas mixture comprises the following components by volume percentage: TiCl4 0.49%, BCl3 0.45%, and the balance being H2;

[0081] Step (5): The CVD coating is subjected to freezing treatment at a temperature of -25°C for 45 minutes to obtain the first CVD coating;

[0082] Step (6): The first CVD coating is subjected to magnetic field heat treatment. The magnetic flux coil current of the magnetic field heat treatment is 7A, the temperature of the magnetic field heat treatment is 85℃, and the time of the magnetic field heat treatment is 25 minutes to obtain the second CVD coating.

[0083] Step (7): The second CVD coating is subjected to alternating cycles of freezing treatment and magnetic field heat treatment, and the alternating cycles are repeated 6 times. Finally, the coating is restored to room temperature to obtain the CVD modified coating.

[0084] Example 2

[0085] This example provides a CVD-modified coating, the preparation method of which includes the following steps:

[0086] Step (1): Select a substrate and place the substrate in a chemical vapor deposition apparatus for coating deposition using a chemical vapor deposition method;

[0087] Step (2): At 850°C and 120 mbar, a first gas mixture consisting of N2 as nitrogen source, TiCl4 as titanium source and H2 as carrier gas is deposited on the substrate surface to form a TiN coating through first chemical vapor deposition; the first gas mixture comprises the following components by volume percentage: N2 40%, TiCl4 1.5%, and the balance being H2;

[0088] Step (3): At 850℃ and 100mbar, a second gas mixture consisting of N2 as nitrogen source, BCl3 as boron source, TiCl4 as titanium source and H2 as carrier gas is deposited on the surface of the TiN coating to form a transition layer. By volume percentage, N2 in the second gas mixture gradually decreases from 40% to 0%, TiCl4 is 1.5%, BCl3 gradually increases from 0.1% to 0.71%, and the balance is H2.

[0089] Step (4): At 900℃ and 150mbar, a third gas mixture formed by BCl3 as boron source, TiCl4 as titanium source and H2 as carrier gas is subjected to third chemical vapor deposition on the surface of the TiN coating to form a Ti-B coating, thereby obtaining the CVD coating; the third gas mixture comprises the following components by volume percentage: TiCl4 0.49%, BCl3 0.45%, and the balance being H2;

[0090] Step (5): The CVD coating is subjected to freezing treatment at a temperature of -20°C for 60 minutes to obtain the first CVD coating;

[0091] Step (6): The first CVD coating is subjected to magnetic field heat treatment. The magnetic flux coil current of the magnetic field heat treatment is 10A, the temperature of the magnetic field heat treatment is 80℃, and the time of the magnetic field heat treatment is 30 minutes to obtain the second CVD coating.

[0092] Step (7): The second CVD coating is subjected to alternating cycles of freezing treatment and magnetic field heat treatment, and the alternating cycles are performed 5 times. Finally, the coating is restored to room temperature to obtain the CVD modified coating.

[0093] Example 3

[0094] This example provides a CVD-modified coating, the preparation method of which includes the following steps:

[0095] Step (1): Select a substrate and place the substrate in a chemical vapor deposition apparatus for coating deposition using a chemical vapor deposition method;

[0096] Step (2): At 850°C and 120 mbar, a first gas mixture consisting of N2 as nitrogen source, TiCl4 as titanium source and H2 as carrier gas is deposited on the substrate surface to form a TiN coating through first chemical vapor deposition; the first gas mixture comprises the following components by volume percentage: N2 40%, TiCl4 1.5%, and the balance being H2;

[0097] Step (3): At 850℃ and 100mbar, a second gas mixture consisting of N2 as nitrogen source, BCl3 as boron source, TiCl4 as titanium source and H2 as carrier gas is deposited on the surface of the TiN coating to form a transition layer. By volume percentage, N2 in the second gas mixture gradually decreases from 40% to 0%, TiCl4 is 1.5%, BCl3 gradually increases from 0.1% to 0.71%, and the balance is H2.

[0098] Step (4): At 900℃ and 150mbar, a third gas mixture formed by BCl3 as boron source, TiCl4 as titanium source and H2 as carrier gas is subjected to third chemical vapor deposition on the surface of the TiN coating to form a Ti-B coating, thereby obtaining the CVD coating; the third gas mixture comprises the following components by volume percentage: TiCl4 0.49%, BCl3 0.45%, and the balance being H2;

[0099] Step (5): The CVD coating is subjected to freezing treatment at a temperature of -30°C for 30 minutes to obtain the first CVD coating;

[0100] Step (6): The first CVD coating is subjected to magnetic field heat treatment. The magnetic flux coil current of the magnetic field heat treatment is 5A, the temperature of the magnetic field heat treatment is 90℃, and the time of the magnetic field heat treatment is 20 minutes to obtain the second CVD coating.

[0101] Step (7): The second CVD coating is subjected to alternating cycles of freezing treatment and magnetic field heat treatment, and the alternating cycles are repeated 8 times. Finally, the coating is restored to room temperature to obtain the CVD modified coating.

[0102] Comparative Example 1

[0103] This example provides a CVD coating, the preparation method of which includes the following steps:

[0104] Step (1): Select a substrate and place the substrate in a chemical vapor deposition apparatus for coating deposition using a chemical vapor deposition method;

[0105] Step (2): At 850°C and 120 mbar, a first gas mixture consisting of N2 as nitrogen source, TiCl4 as titanium source and H2 as carrier gas is deposited on the substrate surface to form a TiN coating through first chemical vapor deposition; the first gas mixture comprises the following components by volume percentage: N2 40%, TiCl4 1.5%, and the balance being H2;

[0106] Step (3): At 850℃ and 100mbar, a second gas mixture consisting of N2 as nitrogen source, BCl3 as boron source, TiCl4 as titanium source and H2 as carrier gas is deposited on the surface of the TiN coating to form a transition layer. By volume percentage, N2 in the second gas mixture gradually decreases from 40% to 0%, TiCl4 is 1.5%, BCl3 gradually increases from 0.1% to 0.71%, and the balance is H2.

[0107] Step (4): At 900℃ and 150mbar, a third gas mixture formed by BCl3 as boron source, TiCl4 as titanium source and H2 as carrier gas is subjected to third chemical vapor deposition on the surface of the TiN coating to form a Ti-B coating, thereby obtaining the CVD coating; the third gas mixture comprises the following components by volume percentage: TiCl4 0.49%, BCl3 0.45%, and the balance being H2.

[0108] Comparative Example 2

[0109] This example provides a CVD modified coating and its preparation method, which differs from Example 1 in that only magnetic field heat treatment is used; the remaining steps and parameters are the same.

[0110] The preparation method of the above-mentioned CVD modified coating includes the following steps:

[0111] Step (1): Select a substrate and place the substrate in a chemical vapor deposition apparatus for coating deposition using a chemical vapor deposition method;

[0112] Step (2): At 850°C and 120 mbar, a first gas mixture consisting of N2 as nitrogen source, TiCl4 as titanium source and H2 as carrier gas is deposited on the substrate surface to form a TiN coating through first chemical vapor deposition; the first gas mixture comprises the following components by volume percentage: N2 40%, TiCl4 1.5%, and the balance being H2;

[0113] Step (3): At 850℃ and 100mbar, a second gas mixture consisting of N2 as nitrogen source, BCl3 as boron source, TiCl4 as titanium source and H2 as carrier gas is deposited on the surface of the TiN coating to form a transition layer. By volume percentage, N2 in the second gas mixture gradually decreases from 40% to 0%, TiCl4 is 1.5%, BCl3 gradually increases from 0.1% to 0.71%, and the balance is H2.

[0114] Step (4): At 900℃ and 150mbar, a third gas mixture formed by BCl3 as boron source, TiCl4 as titanium source and H2 as carrier gas is subjected to third chemical vapor deposition on the surface of the TiN coating to form a Ti-B coating, thereby obtaining the CVD coating; the third gas mixture comprises the following components by volume percentage: TiCl4 0.49%, BCl3 0.45%, and the balance being H2;

[0115] Step (5): The CVD coating is subjected to magnetic field heat treatment. The magnetic flux coil current of the magnetic field heat treatment is 7A, the temperature of the magnetic field heat treatment is 85℃, and the time of the magnetic field heat treatment is 25 minutes to obtain the first CVD coating.

[0116] Step (6): The first CVD coating is subjected to repeated magnetic field heat treatment for a total of 6 times, and finally restored to room temperature to obtain the CVD modified coating.

[0117] Comparative Example 3

[0118] This example provides a CVD modified coating and its preparation method, which differs from Example 1 in that only freezing treatment is used; the remaining steps and parameters are the same.

[0119] The preparation method of the above-mentioned CVD modified coating includes the following steps:

[0120] Step (1): Select a substrate and place the substrate in a chemical vapor deposition apparatus for coating deposition using a chemical vapor deposition method;

[0121] Step (2): At 850°C and 120 mbar, a first gas mixture consisting of N2 as nitrogen source, TiCl4 as titanium source and H2 as carrier gas is deposited on the substrate surface to form a TiN coating through first chemical vapor deposition; the first gas mixture comprises the following components by volume percentage: N2 40%, TiCl4 1.5%, and the balance being H2;

[0122] Step (3): At 850℃ and 100mbar, a second gas mixture consisting of N2 as nitrogen source, BCl3 as boron source, TiCl4 as titanium source and H2 as carrier gas is deposited on the surface of the TiN coating to form a transition layer. By volume percentage, N2 in the second gas mixture gradually decreases from 40% to 0%, TiCl4 is 1.5%, BCl3 gradually increases from 0.1% to 0.71%, and the balance is H2.

[0123] Step (4): At 900℃ and 150mbar, a third gas mixture formed by BCl3 as boron source, TiCl4 as titanium source and H2 as carrier gas is subjected to third chemical vapor deposition on the surface of the TiN coating to form a Ti-B coating, thereby obtaining the CVD coating; the third gas mixture comprises the following components by volume percentage: TiCl4 0.49%, BCl3 0.45%, and the balance being H2;

[0124] Step (5): The CVD coating is subjected to freezing treatment at a temperature of -25°C for 45 minutes to obtain the first CVD coating;

[0125] Step (6): Repeat the freezing treatment of the first CVD coating six times, and finally restore it to room temperature to obtain the CVD modified coating.

[0126] Test case

[0127] In this example, the cutting tool is used as the substrate. The coating is applied to the surface of the cutting tool using the coating preparation methods of Examples 1-3 and Comparative Examples 1-3 described above, and then the cutting life of the cutting tool is examined.

[0128] Test method: The cutting life of the tools containing the coatings prepared in Examples 1-3 and Comparative Examples 1-3 were tested and compared by milling with nickel-based superalloys. The operation mode was face milling, the workpiece was a block part, the material was GH4169, the cutting speed was 45m / min, the feed was 0.2mm / tooth, the depth of cut was 1mm, the cutting width was 35mm, and wet cutting was used.

[0129] The test results are shown in Table 1.

[0130] Table 1

[0131] Test sample coating Cutting life (min) Example 1 28 Example 2 21 Example 3 24 Comparative Example 1 7 Comparative Example 2 12 Comparative Example 3 10

[0132] As shown in Table 1, compared with Comparative Examples 1-3, the service life of the cutting tools containing the coating prepared in the embodiments of the present invention is significantly improved. This indicates that the present invention uses a combination of magnetic field heat treatment and freezing process for modification, which synergistically enhances the effect of both processes and optimizes the microstructure of the CVD coating, thereby extending the service life of devices such as cutting tools, molds, and machine parts.

[0133] Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible subranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the range referred to.

[0134] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing a CVD-modified coating, characterized in that, The preparation method includes the following steps: A TiN coating is formed by first chemical vapor deposition on the substrate surface using a first gas mixture (N2 as nitrogen source, TiCl4 as titanium source, and H2 as carrier gas) at 840–860 °C and 110–130 mbar. A transition layer is formed by second chemical vapor deposition on the TiN coating surface using a second gas mixture (N2 as nitrogen source, BCl3 as boron source, TiCl4 as titanium source, and H2 as carrier gas) at 840–860 °C and 90–110 mbar. A Ti-B coating is formed by third chemical vapor deposition on the TiN coating surface using a third gas mixture (BCl3 as boron source, TiCl4 as titanium source, and H2 as carrier gas) at 890–910 °C and 140–160 mbar, thus obtaining a CVD coating. The CVD coating is subjected to freeze treatment to obtain a first CVD coating; The first CVD coating is subjected to magnetic field heat treatment to obtain the second CVD coating; The second CVD coating is subjected to alternating cycles of freezing treatment and magnetic field heat treatment to obtain the CVD modified coating; The working conditions parameters for the freezing process include: temperature of -30 to -20°C and time of 30 to 60 minutes. The working conditions for the magnetic field heat treatment include: magnetic flux coil current of 5~10A, temperature of 80~90℃, and time of 20~30 minutes. The third gas mixture comprises the following components by volume percentage: TiCl4 0.40~0.55%, BCl3 0.40~0.55%, balance H2; The first gas mixture comprises the following components by volume percentage: N2 35~45%, TiCl4 1~2%, balance H2; The second gas mixture comprises the following components by volume percentage: N20~40%, TiCl41~2%, BCl30.1~0.71%, balance H2.

2. The method for preparing the CVD modified coating according to claim 1, characterized in that, The freezing temperature is -25°C, and the freezing time is 45 minutes.

3. The method for preparing the CVD modified coating according to claim 1, characterized in that, The magnetic flux coil current for the magnetic field heat treatment is 7A, the temperature for the magnetic field heat treatment is 85℃, and the time for the magnetic field heat treatment is 25 minutes.

4. The method for preparing the CVD modified coating according to claim 1, characterized in that, The alternating cycle is performed 5 to 8 times.

5. A CVD-modified coating, characterized in that, The CVD modified coating is prepared by the method described in any one of claims 1 to 4.

6. An application of a CVD-modified coating prepared using the method described in any one of claims 1 to 4, or the CVD-modified coating described in claim 5, in improving device lifespan, characterized in that... The device includes at least one of cutting tools, molds, and machine parts.

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