Titanium diboride hard coating, coated tool and preparation method

Abstract

The present invention provides a titanium diboride hard coating, a coated tool and a preparation method, wherein the titanium diboride hard coating comprises a TiB2-C coating and a TiB2 coating that are alternately superimposed; the modulation ratio of the TiB2 coating to the TiB2-C coating is (1-3):1. The titanium diboride hard coating provided by the present invention has the characteristics of good bonding force, high toughness, high wear resistance and high self-lubricity, and when applied to a coated tool, the processing performance of the coated tool can be greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of ceramic coatings and relates to a hard coating, in particular to a titanium diboride hard coating, a coating tool and a preparation method. Background Art

[0002] Tool surface coating technology is a high-quality surface modification technology that effectively improves the service life and processing efficiency of tools. TiB2 is a superhard tool coating material developed in recent years, with properties such as high hardness, high melting point and good oxidation resistance. It also has a relatively low chemical affinity with non-ferrous metals and has broad application prospects in the processing of non-ferrous metals such as aluminum alloys and titanium alloys. However, during the use of TiB2 coating, due to its poor toughness, high hardness, and poor bonding to the substrate, it shows the characteristic of easy fragmentation, which limits its application in cutting tools.

[0003] Doping TiB2 with carbon can improve the adhesion, toughness and anti-friction performance of the coating while ensuring high hardness of the coating, so as to obtain an excellent cutting tool coating. Existing coatings are generally doped with carbon by using carbon source gas.

[0004] However, it is difficult to control the uniformity of the coating of the whole furnace in the preparation method of carbon doping by gas in production, and it is also difficult to achieve the composite preparation of carbon doped coating and non-carbon doped coating. Therefore, it is necessary to provide a titanium diboride hard coating, a coated tool and a preparation method, so that a uniform coating can be obtained in industrial production, and the composite preparation of carbon doped coating and non-carbon doped coating can be achieved. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a titanium diboride hard coating, a coated tool and a preparation method. The titanium diboride hard coating has the characteristics of good bonding strength, high toughness, high wear resistance and high self-lubricity. When applied to coated tools, it can greatly improve the processing performance of the coated tools.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a titanium diboride hard coating, wherein the titanium diboride hard coating comprises a TiB2-C coating and a TiB2 coating that are alternately stacked;

[0008] The modulation ratio of the TiB2 coating to the TiB2-C coating is (1-3):1, for example, it can be 1:1, 1.5:1, 2:1, 2.5:1 or 3:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0009] The "modulation ratio" mentioned in the present invention refers to the thickness ratio of the TiB2 coating to the TiB2-C coating in a single cycle.

[0010] In the titanium diboride hard coating of the present invention, the addition of carbon in the TiB2-C coating changes the original TiB2 structure and also plays a role in refining the TiB2 grains. Specifically, part of the carbon will be dissolved into the TiB2 lattice, thereby changing the TiB2 structure and improving the toughness of the TiB2-C coating; part of the carbon forms TiC with Ti, which plays a self-lubricating role and reduces the friction coefficient; at the same time, the refinement of the grains can also ensure the hardness of the obtained TiB2-C coating.

[0011] In the titanium diboride hard coating of the present invention, the TiB2 coating has properties such as high hardness and high oxidation resistance, and the TiB2 coating deposited on the TiB2-C coating will also obtain finer grains due to epitaxial growth. The present invention reduces the stress of the obtained titanium diboride hard coating by alternately stacking the TiB2-C coating and the TiB2 coating, so that the titanium diboride hard coating has good bonding force, and has the characteristics of high hardness, high wear resistance and low friction coefficient.

[0012] The carbon content in the TiB2-C coating of the present invention can be adjusted according to the carbon content in the target material used for depositing the TiB2-C coating. For example, conventional targets in the art are prepared by powder metallurgy, and by controlling the ratio of TiB2 to carbon powder, a target material that meets the process requirements of the present invention can be obtained.

[0013] Preferably, the C content in the TiB2-C coating is 0.01-10at%, for example, it can be 0.01at%, 0.05at%, 0.08at%, 0.1at%, 0.5at%, 0.8at%, 1at%, 2at%, 3at%, 5at%, 6at%, 8at% or 10at%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 0.1-6at%.

[0014] Preferably, in the titanium diboride hard coating, the thickness of a single-layer TiB2-C coating is 3-100 nm, for example, it can be 3 nm, 5 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm or 100 nm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0015] Preferably, in the titanium diboride hard coating, the thickness of a single-layer TiB2 coating is 5-300nm, for example, it can be 5nm, 10nm, 30nm, 50nm, 80nm, 100nm, 150nm, 200nm, 250nm or 300nm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0016] Preferably, the thickness of the titanium diboride hard coating is 0.1-5 μm, for example, it can be 0.1 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm or 5 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] In a second aspect, the present invention provides a method for preparing the titanium diboride hard coating as described in the first aspect, the preparation method comprising the following steps:

[0018] The TiB2-C target and the TiB2 target are periodically magnetron sputtered under vacuum conditions to alternately deposit the TiB2-C coating and the TiB2 coating to obtain the titanium diboride hard coating.

[0019] Illustratively, the preparation method described in the second aspect of the present invention is carried out in a vacuum chamber.

[0020] When carrying out the preparation method described in the second aspect of the present invention, argon gas is introduced into the vacuum chamber and the vacuum chamber is evacuated to make the vacuum chamber a vacuum condition.

[0021] Preferably, the absolute pressure of the vacuum condition is ≤1Pa, for example, it may be 0.2Pa, 0.3Pa, 0.5Pa, 0.6Pa, 0.8Pa or 1Pa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0022] When carrying out the preparation method described in the second aspect of the present invention, the target material parameters during magnetron sputtering are set according to the modulation ratio of the TiB2 coating and the TiB2-C coating.

[0023] Preferably, the power of the magnetron sputtering is 1-8 kW, the frequency is 300-1000 Hz, and the pulse ratio is 1-10%.

[0024] The power of magnetron sputtering in the second aspect of the present invention is 1-8kW, for example, 1kW, 2kW, 3kW, 5kW, 6kW or 8kW, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] In the second aspect of the present invention, the frequency of magnetron sputtering is 300-1000 Hz, for example, 300 Hz, 400 Hz, 500 Hz, 600 Hz, 800 Hz or 1000 Hz, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0026] In the second aspect of the present invention, the pulse proportion of magnetron sputtering is 1-10%, for example, it can be 1%, 2%, 3%, 5%, 6%, 8% or 10%, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] Preferably, during the magnetron sputtering, the bias voltage is -40V to -100V, for example, -40V, -50V, -60V, -70V, -80V or -100V, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0028] When the magnetron sputtering according to the second aspect of the present invention is performed, the TiB2-C coating and the TiB2 coating are deposited on the substrate, and the bias voltage is the bias voltage of the substrate.

[0029] In a third aspect, the present invention provides a coated tool, the coated tool comprising a substrate and a composite coating disposed on a surface of the substrate;

[0030] The composite coating comprises a TiBCN coating disposed on the surface of the substrate and a titanium diboride hard coating as described in the first aspect disposed on the surface of the TiBCN.

[0031] The outermost layer of the titanium diboride hard coating of the coated tool described in the third aspect of the present invention may be a TiB2-C coating or a TiB2 coating, which does not affect the performance of the finally obtained coated tool.

[0032] The titanium diboride hard coating provided in the first aspect of the present invention has good bonding strength, and has the characteristics of high hardness, high wear resistance and low friction coefficient. The TiBCN coating has structures such as Ti(B, C) and Ti(N, C), so that the TiBCN coating has high toughness and high bonding strength; and then with the setting of the titanium diboride hard coating, the coated tool has good cutting performance.

[0033] The substrate of the present invention includes conventional cemented carbide substrates or metal ceramic substrates in the art, and the present invention does not make any specific limitation thereto.

[0034] Preferably, in the TiBCN coating, the atomic ratio of B to Ti is (1.5-2.5):1, for example, it can be 1.5:1, 1.6:1, 1.8:1, 2:1, 2.1:1, 2.4:1 or 2.5:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] Preferably, in the TiBCN coating, the proportion of C element is 0.01-10at%, for example, it can be 0.01at%, 0.05at%, 0.1at%, 0.5at%, 1at%, 3at%, 5at%, 6at%, 8at% or 10at%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] Preferably, in the TiBCN coating, the proportion of N element is 5-35at%, for example, it can be 5at%, 10at%, 15at%, 20at%, 25at%, 30at% or 35at%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] Preferably, the thickness of the TiBCN coating is 0.1-5 μm, for example, 0.1 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm or 5 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] The composite coating of the invention has a total thickness of 0.2-10 μm, a coating hardness of 38-45 GPa, a plastic deformation rate of 25-45%, a residual compressive stress of 1-4 GPa, a friction coefficient of ≤0.3, and a coating grain size of 3-50 nm.

[0039] In a fourth aspect, the present invention provides a method for preparing the coated tool as described in the third aspect, the preparation method comprising the following steps:

[0040] The substrate is subjected to surface treatment, and then a TiBCN coating and a titanium diboride hard coating are deposited in sequence to obtain the coated tool.

[0041] Preferably, the surface treatment comprises pretreatment, gas ion etching and metal ion bombardment performed in sequence.

[0042] Preferably, the pretreatment method includes any one of grinding, sandblasting, polishing or cleaning, or a combination of at least two of them.

[0043] The gas ion etching, metal ion bombardment and deposition of the TiBCN coating and the titanium diboride hard coating of the present invention are carried out in a vacuum chamber.

[0044] The gas ion etching of the present invention can effectively remove oxides and dirt on the surface of the substrate, thereby ensuring the bonding strength between the subsequent TiBCN coating and the substrate surface.

[0045] Preferably, the temperature of the gas ion etching is 300-650° C., and the absolute pressure is 0.2-1.5 Pa.

[0046] The temperature of the gas ion etching in the present invention is 300-650°C, for example, it can be 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C or 650°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0047] The absolute pressure of the gas ion etching described in the present invention is the pressure in the vacuum chamber, which is 0.2-1.5Pa, for example, it can be 0.2Pa, 0.3Pa, 0.5Pa, 0.8Pa, 1Pa, 1.2Pa or 1.5Pa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0048] Preferably, the gas used for gas ion etching is argon gas with a flow rate of 50-500sccm, for example, 50sccm, 100sccm, 200sccm, 300sccm, 400sccm or 500sccm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0049] Preferably, the substrate bias voltage of the gas ion etching is -200V to -800V, for example, -200V, -300V, -400V, -500V, -600V or -800V, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0050] Preferably, the gas ion etching time is 10-60 min, for example, 10 min, 20 min, 30 min, 40 min, 50 min or 60 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0051] The present invention injects metal ions into the substrate through metal ion bombardment, forms a certain chaotic area on the surface of the substrate, and further ensures the bonding force between the substrate and the TiBCN coating.

[0052] Preferably, the atmosphere for metal ion bombardment is an argon atmosphere, and the argon flow rate is 100-500sccm, for example, it can be 100sccm, 150sccm, 200sccm, 250sccm, 300sccm, 400sccm or 500sccm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0053] Preferably, the absolute pressure of the metal ion bombardment is 0.2-1 Pa, for example, 0.2 Pa, 0.4 Pa, 0.5 Pa, 0.6 Pa, 0.8 Pa or 1 Pa, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0054] The absolute pressure of the metal particle bombardment described in the present invention is the absolute pressure in the vacuum chamber.

[0055] Preferably, the metal source for metal ion bombardment includes but is not limited to a Cr target.

[0056] Preferably, the power of the metal ion bombardment is 1-5 kW and the frequency is 100-1000 Hz.

[0057] The power of the metal ion bombardment in the present invention is 1-5 kW, for example, 1 kW, 2 kW, 3 kW, 4 kW or 5 kW, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0058] The frequency of the metal ion bombardment in the present invention is 100-1000 Hz, for example, 100 Hz, 300 Hz, 500 Hz, 600 Hz, 800 Hz or 1000 Hz, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0059] Preferably, the substrate bias voltage for metal ion bombardment is -800V to -1200V, for example, -800V, -900V, -1000V, -1100V or -1200V, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0060] Preferably, the metal ion bombardment time is 2-10 min, for example, 2 min, 3 min, 5 min, 6 min, 8 min or 10 min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0061] When the TiBCN coating is deposited in the present invention, nitrogen and argon are introduced into the vacuum chamber at the same time.

[0062] Preferably, the nitrogen flow rate during the deposition of the TiBCN coating is 50-300 sccm, for example, 50 sccm, 100 sccm, 150 sccm, 200 sccm, 250 sccm or 300 sccm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0063] Preferably, the absolute pressure during the deposition of the TiBCN coating is 0.2-1 Pa, for example, 0.2 Pa, 0.4 Pa, 0.5 Pa, 0.8 Pa or 1 Pa, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0064] The absolute pressure during the deposition of the TiBCN coating in the present invention is the absolute pressure in the vacuum chamber.

[0065] Preferably, the deposition of the TiBCN coating is carried out using a TiB2-C target with a power of 1-8 kW, a frequency of 300-1000 Hz, and a pulse ratio of 1-10%.

[0066] The ratio of B, Ti, C and N elements in the TiBCN coating of the present invention can be adjusted by adjusting the content of each element in TiB2-C.

[0067] The power for depositing the TiBCN coating in the present invention is 1-8 kW, for example, 1 kW, 3 kW, 5 kW, 6 kW or 8 kW, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0068] The frequency of depositing the TiBCN coating in the present invention is 300-1000 Hz, for example, 300 Hz, 400 Hz, 500 Hz, 600 Hz, 800 Hz or 1000 Hz, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0069] The pulse ratio when depositing the TiBCN coating in the present invention is 1-10%, for example, it can be 1%, 2%, 3%, 5%, 6%, 8% or 10%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0070] Preferably, the substrate bias voltage during the deposition of the TiBCN coating is -40 V to -100 V, for example, -40 V, -50 V, -60 V, -80 V or -100 V, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0071] After the deposition of the TiBCN coating is completed, the nitrogen gas is stopped from entering the vacuum chamber, and only argon gas is introduced into the vacuum chamber to deposit the titanium diboride hard coating.

[0072] Preferably, when the titanium diboride hard coating is deposited in the present invention, the absolute pressure in the vacuum chamber is ≤1Pa, for example, it can be 0.2Pa, 0.3Pa, 0.5Pa, 0.6Pa, 0.8Pa or 1Pa, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0073] Preferably, when the titanium diboride hard coating is deposited in the present invention, the power of magnetron sputtering is 1-8kW, for example, 1kW, 2kW, 3kW, 5kW, 6kW or 8kW, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0074] Preferably, when the titanium diboride hard coating is deposited in the present invention, the frequency of magnetron sputtering is 300-1000 Hz, for example, 300 Hz, 400 Hz, 500 Hz, 600 Hz, 800 Hz or 1000 Hz, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0075] Preferably, when the titanium diboride hard coating is deposited in the present invention, the pulse ratio is 1-10%, for example, it can be 1%, 2%, 3%, 5%, 6%, 8% or 10%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0076] Preferably, when the titanium diboride hard coating is deposited in the present invention, the bias voltage of the substrate is -40V to -100V, for example, it can be -40V, -50V, -60V, -70V, -80V or -100V, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0077] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0078] Compared with the prior art, the present invention has the following beneficial effects:

[0079] (1) The titanium diboride hard coating provided by the present invention includes an alternately stacked TiB2-C coating and a TiB2 coating. The addition of carbon to the TiB2-C coating changes the original TiB2 organizational structure and can also refine the TiB2 grains. The TiB2 coating has properties such as high hardness and high oxidation resistance. The TiB2 coating deposited on the TiB2-C coating will also obtain finer grains due to epitaxial growth. The stacked TiB2-C coating and the TiB2 coating reduce the stress of the obtained titanium diboride hard coating, so that the titanium diboride hard coating has good bonding strength and has the characteristics of high hardness, high wear resistance and low friction coefficient.

[0080] (2) In the coated tool provided by the present invention, the TiBCN coating has structures such as Ti(B, C) and Ti(N, C), so that the TiBCN coating has high toughness and high bonding strength; and then combined with the setting of the titanium diboride hard coating, the coated tool has good cutting performance. DETAILED DESCRIPTION

[0081] The technical solution of the present invention is further illustrated below through specific implementation methods.

[0082] In a specific embodiment of the present invention, the C content, B content, Ti content and N content in the coating are measured by X-ray photoelectron spectroscopy (XPS);

[0083] In a specific embodiment of the present invention, the thickness of the single-layer coating is measured using a transmission electron microscope (TEM).

[0084] Example 1

[0085] This embodiment provides a coated tool, which includes a substrate and a composite coating disposed on the surface of the substrate;

[0086] The composite coating comprises a TiBCN coating disposed on the surface of the substrate and a titanium diboride hard coating disposed on the surface of the TiBCN;

[0087] In the TiBCN coating, the atomic ratio of B to Ti is 2:1; in the TiBCN coating, the proportion of C element is 1at%, and the proportion of N element is 30at%; the thickness of the TiBCN coating is 0.5 μm;

[0088] The titanium diboride hard coating comprises alternately stacked TiB2-C coatings and TiB2 coatings, the modulation ratio of the TiB2 coating to the TiB2-C coating is 1:1; the C content in the TiB2-C coating is 1at%; the thickness of a single-layer TiB2-C coating is 10nm, and the thickness of a single-layer TiB2 coating is 10nm; the total thickness of the titanium diboride hard coating is 3μm;

[0089] The coated tool in this embodiment is obtained by the following preparation method, which comprises the following steps:

[0090] (1) The pretreated substrate is placed in a vacuum chamber, heated to 450°C, argon gas is introduced at a flow rate of 300 sccm, and the absolute pressure in the vacuum chamber is controlled to be 0.3 Pa, and the substrate bias voltage is set to -300 V; the ion source is turned on, and the substrate is subjected to gas ion etching for 30 minutes;

[0091] (2) Argon gas was continuously introduced into the vacuum chamber at a flow rate of 300 sccm, and the absolute pressure in the vacuum chamber was controlled to be 0.3 Pa; the metal Cr target was turned on, and its power supply parameters were: power of 4 kW, frequency of 600 Hz; substrate bias voltage was set to -1000 V; and the metal ion bombardment time was 5 min;

[0092] (3) Then, argon and nitrogen are introduced into the vacuum chamber at the same time, with a nitrogen flow rate of 100 sccm, and the absolute pressure in the vacuum chamber is maintained at 0.5 Pa; the TiB2-C target is turned on, and its power supply parameters are: power 3kW, frequency 700Hz, pulse ratio 7%; substrate bias voltage is -50V; and the TiBCN coating is deposited until the thickness reaches 0.5μm;

[0093] (4) Stop introducing nitrogen and introduce only argon to maintain the absolute pressure in the vacuum chamber at 0.5 Pa; start the TiB2-C target and the TiB2 target at the same time, and deposit the TiB2-C coating and the TiB2 coating alternately; the power supply parameters are set to the same: power 3 kW, frequency 700 Hz, pulse ratio 7%; the substrate bias is set to -50 V; and the titanium diboride hard coating is deposited until the thickness reaches 3 μm.

[0094] Example 2

[0095] This embodiment provides a coated tool, which includes a substrate and a composite coating disposed on the surface of the substrate;

[0096] The composite coating comprises a TiBCN coating disposed on the surface of the substrate and a titanium diboride hard coating disposed on the surface of the TiBCN;

[0097] In the TiBCN coating, the atomic ratio of B to Ti is 2.5:1; in the TiBCN coating, the proportion of C element is 10at%, and the proportion of N element is 5at%; the thickness of the TiBCN coating is 4.5μm;

[0098] The titanium diboride hard coating comprises alternately stacked TiB2-C coatings and TiB2 coatings, the modulation ratio of the TiB2 coating to the TiB2-C coating is 2:1; the C content in the TiB2-C coating is 10at%; the thickness of the single-layer TiB2-C coating is 3nm, and the thickness of the single-layer TiB2 coating is 6nm; the total thickness of the titanium diboride hard coating is 0.495μm;

[0099] The coated tool in this embodiment is obtained by the following preparation method, which comprises the following steps:

[0100] (1) The pretreated substrate was placed in a vacuum chamber, heated to 300°C, argon gas was introduced at a flow rate of 50 sccm, and the absolute pressure in the vacuum chamber was controlled to be 0.2 Pa, and the substrate bias voltage was set to -200 V; the ion source was turned on, and the substrate was subjected to gas ion etching for 60 min;

[0101] (2) Argon gas was continuously introduced into the vacuum chamber at a flow rate of 100 sccm, and the absolute pressure in the vacuum chamber was controlled to be 0.2 Pa; the metal Cr target was turned on, and its power supply parameters were: power of 1 kW, frequency of 100 Hz; the substrate bias voltage was set to -800 V; and the metal ion bombardment time was 10 min;

[0102] (3) Then, argon and nitrogen are introduced into the vacuum chamber at the same time, with a nitrogen flow rate of 50 sccm, and the absolute pressure in the vacuum chamber is maintained at 0.2 Pa; the TiB2-C target is turned on, and its power supply parameters are: power 5 kW, frequency 300 Hz, pulse ratio 10%; substrate bias voltage is -40 V; and the TiBCN coating is deposited until the thickness reaches 4.5 μm;

[0103] (4) Stop the nitrogen gas flow and only flow argon gas, maintaining the absolute pressure in the vacuum chamber at 0.2Pa; turn on the TiB2-C target and the TiB2 target at the same time, and alternately deposit the TiB2-C coating and the TiB2 coating; the power supply parameters of the TiB2 target are: power 2kW, frequency 1000Hz, pulse ratio 10%; the power supply parameters of the TiB2-C target are: power 1kW, frequency 1000Hz, pulse ratio 10%; the substrate bias is set to -40V; the titanium diboride hard coating is deposited until the thickness reaches 0.495μm.

[0104] Example 3

[0105] This embodiment provides a coated tool, which includes a substrate and a composite coating disposed on the surface of the substrate;

[0106] The composite coating comprises a TiBCN coating disposed on the surface of the substrate and a titanium diboride hard coating disposed on the surface of the TiBCN;

[0107] In the TiBCN coating, the atomic ratio of B to Ti is 1.5:1; in the TiBCN coating, the proportion of C element is 0.1at%, and the proportion of N element is 35at%; the thickness of the TiBCN coating is 0.2μm;

[0108] The titanium diboride hard coating comprises alternately stacked TiB2-C coatings and TiB2 coatings, the modulation ratio of the TiB2 coating to the TiB2-C coating is 3:1; the C content in the TiB2-C coating is 0.01at%; the thickness of a single-layer TiB2-C coating is 100nm, and the thickness of a single-layer TiB2 coating is 300nm; the total thickness of the titanium diboride hard coating is 4.8μm;

[0109] The coated tool in this embodiment is obtained by the following preparation method, which comprises the following steps:

[0110] (1) The pretreated substrate was placed in a vacuum chamber, heated to 650°C, argon gas was introduced at a flow rate of 500 sccm, and the absolute pressure in the vacuum chamber was controlled to be 1.5 Pa, and the substrate bias voltage was set to -800 V; the ion source was turned on, and the substrate was subjected to gas ion etching for 10 min;

[0111] (2) Argon gas was continuously introduced into the vacuum chamber at a flow rate of 500 sccm, and the absolute pressure in the vacuum chamber was controlled to be 1 Pa; the metal Cr target was turned on, and its power supply parameters were: power of 5 kW, frequency of 1000 Hz; the substrate bias voltage was set to -1200 V; and the metal ion bombardment time was 2 min;

[0112] (3) Then, argon and nitrogen are introduced into the vacuum chamber at the same time, and the flow rate of nitrogen is 300 sccm, and the absolute pressure in the vacuum chamber is maintained at 1 Pa; the TiB2-C target is turned on, and its power supply parameters are: power 6 kW, frequency 1000 Hz, pulse ratio 1%; substrate bias voltage is -100 V; and the TiBCN coating is deposited until the thickness reaches 0.2 μm;

[0113] (4) Stop the nitrogen gas flow and only flow argon gas, maintaining the absolute pressure in the vacuum chamber at 1Pa; turn on the TiB2-C target and the TiB2 target alternately, and deposit the TiB2-C coating and the TiB2 coating alternately; the power supply parameters are set to the same: power 4kW, frequency 500Hz, pulse ratio 2%; the substrate bias is set to -100V; and the thickness of the titanium diboride hard coating is deposited to reach 4.8μm.

[0114] Example 4

[0115] This embodiment provides a coated tool, which includes a substrate and a composite coating disposed on the surface of the substrate;

[0116] The composition of the composite coating is the same as that of Example 1;

[0117] The coated tool in this embodiment is obtained by the following preparation method, which comprises the following steps:

[0118] (1) The pretreated substrate is placed in a vacuum chamber, heated to 450°C, argon gas is introduced at a flow rate of 300 sccm, and the absolute pressure in the vacuum chamber is controlled to be 0.3 Pa, and the substrate bias voltage is set to -300 V; the ion source is turned on, and the substrate is subjected to gas ion etching for 30 minutes;

[0119] (2) Argon and nitrogen are introduced into the vacuum chamber at the same time, with a nitrogen flow rate of 100 sccm, and the absolute pressure in the vacuum chamber is maintained at 0.5 Pa; the TiB2-C target is turned on, and its power supply parameters are: power 3 kW, frequency 700 Hz, pulse ratio 7%; substrate bias voltage is -50 V; and the TiBCN coating is deposited until the thickness reaches 0.5 μm;

[0120] (3) Stop introducing nitrogen and introduce only argon to maintain the absolute pressure in the vacuum chamber at 0.5 Pa; start the TiB2-C target and the TiB2 target at the same time, and deposit the TiB2-C coating and the TiB2 coating alternately; the power supply parameters are set to the same: power 3 kW, frequency 700 Hz, pulse ratio 7%; the substrate bias is set to -50 V; and the titanium diboride hard coating is deposited until the thickness reaches 3 μm.

[0121] Comparative Example 1

[0122] This comparative example provides a coated tool, which is different from Example 1 in that: the modulation ratio of the TiB2 coating to the TiB2-C coating in this comparative example is 0.5:1; the C content in the TiB2-C coating is 1at%; the thickness of the single-layer TiB2-C coating is 10nm, and the thickness of the single-layer TiB2 coating is 5nm; the total thickness of the titanium diboride hard coating is 3μm;

[0123] In the preparation method of the coated tool described in this comparative example, when depositing the titanium diboride hard coating, the power supply parameters of the TiB2-C target and the TiB2 target were appropriately adjusted; among them, the power supply parameters of the TiB2 target were: power 1.5kW, frequency 700Hz, and pulse proportion 7%; the power supply parameters of the TiB2-C target were: power 3kW, frequency 700Hz, and pulse proportion 7%; the substrate bias was set to -50V; and the thickness of the titanium diboride hard coating was deposited to reach 3μm.

[0124] Comparative Example 2

[0125] This comparative example provides a coated tool, which is different from Example 1 in that: the modulation ratio of the TiB2 coating to the TiB2-C coating in this comparative example is 4:1; the C content in the TiB2-C coating is 1at%; the thickness of the single-layer TiB2-C coating is 6nm, and the thickness of the single-layer TiB2 coating is 24nm; the total thickness of the titanium diboride hard coating is 3μm;

[0126] In the preparation method of the coated tool described in this comparative example, when depositing the titanium diboride hard coating, the power supply parameters of the TiB2-C target and the TiB2 target are appropriately adjusted; among them, the power supply parameters of the TiB2 target are: 8kW, frequency 700Hz, and pulse proportion 7%; the power supply parameters of the TiB2-C target are: power 2kW, frequency 700Hz, and pulse proportion 7%; the substrate bias voltage is set to -50V; and the thickness of the titanium diboride hard coating deposited reaches 3μm.

[0127] Comparative Example 3

[0128] This comparative example provides a coated tool, which comprises a substrate and a composite coating disposed on the surface of the substrate;

[0129] The difference from Example 1 is that, in this comparative example, when depositing the TiBCN coating in Example 1, the flow rate of nitrogen is 0 sccm, and the flow rate of argon is increased accordingly to maintain the absolute pressure in the vacuum chamber at 0.5 Pa.

[0130] Comparative Example 4

[0131] This comparative example provides a coated tool, which comprises a substrate and a composite coating disposed on the surface of the substrate;

[0132] The composite coating comprises a TiBCN coating disposed on the surface of the substrate and a titanium diboride hard coating disposed on the surface of the TiBCN;

[0133] The composition of the TiBCN coating is the same as that of Example 1;

[0134] The titanium diboride hard coating is a TiB2-C coating with a thickness of 3 μm;

[0135] The coated tool in this comparative example is obtained by the following preparation method, which comprises the following steps:

[0136] (1) The pretreated substrate is placed in a vacuum chamber, heated to 450°C, argon gas is introduced at a flow rate of 300 sccm, and the absolute pressure in the vacuum chamber is controlled to be 0.3 Pa, and the substrate bias voltage is set to -300 V; the ion source is turned on, and the substrate is subjected to gas ion etching for 30 minutes;

[0137] (2) Argon gas was continuously introduced into the vacuum chamber at a flow rate of 300 sccm, and the absolute pressure in the vacuum chamber was controlled to be 0.3 Pa; the metal Cr target was turned on, and its power supply parameters were: power of 4 kW, frequency of 600 Hz; substrate bias voltage was set to -1000 V; and the metal ion bombardment time was 5 min;

[0138] (3) Then, argon and nitrogen are introduced into the vacuum chamber at the same time, with a nitrogen flow rate of 100 sccm, and the absolute pressure in the vacuum chamber is maintained at 0.5 Pa; the TiB2-C target is turned on, and its power supply parameters are: power 3kW, frequency 700Hz, pulse ratio 7%; substrate bias voltage is -50V; and the TiBCN coating is deposited until the thickness reaches 0.5μm;

[0139] (4) Stop the nitrogen gas flow and only flow argon gas to maintain the absolute pressure in the vacuum chamber at 0.5 Pa; turn on the TiB2-C target to deposit the TiB2-C coating; the power supply parameters are: power 3 kW, frequency 700 Hz, pulse ratio 7%; the substrate bias voltage is set to -50 V; the TiB2-C coating is deposited until the thickness reaches 3 μm.

[0140] Comparative Example 5

[0141] This comparative example provides a coated tool, which comprises a substrate and a composite coating disposed on the surface of the substrate;

[0142] The composite coating comprises a TiBCN coating disposed on the surface of the substrate and a titanium diboride hard coating disposed on the surface of the TiBCN;

[0143] The composition of the TiBCN coating is the same as that of Example 1;

[0144] The titanium diboride hard coating is a TiB2 coating with a thickness of 3 μm;

[0145] The coated tool in this comparative example is obtained by the following preparation method, which comprises the following steps:

[0146] (1) The pretreated substrate is placed in a vacuum chamber, heated to 450°C, argon gas is introduced at a flow rate of 300 sccm, and the absolute pressure in the vacuum chamber is controlled to be 0.3 Pa, and the substrate bias voltage is set to -300 V; the ion source is turned on, and the substrate is subjected to gas ion etching for 30 minutes;

[0147] (2) Argon gas was continuously introduced into the vacuum chamber at a flow rate of 300 sccm, and the absolute pressure in the vacuum chamber was controlled to be 0.3 Pa; the metal Cr target was turned on, and its power supply parameters were: power of 4 kW, frequency of 600 Hz; substrate bias voltage was set to -1000 V; and the metal ion bombardment time was 5 min;

[0148] (3) Then, argon and nitrogen are introduced into the vacuum chamber at the same time, with a nitrogen flow rate of 100 sccm, and the absolute pressure in the vacuum chamber is maintained at 0.5 Pa; the TiB2-C target is turned on, and its power supply parameters are: power 3kW, frequency 700Hz, pulse ratio 7%; substrate bias voltage is -50V; and the TiBCN coating is deposited until the thickness reaches 0.5μm;

[0149] (4) Stop the nitrogen gas flow and only flow argon gas, maintain the absolute pressure in the vacuum chamber at 0.5 Pa; turn on the TiB2 target and deposit the TiB2 coating; the power supply parameters are: power 3 kW, frequency 700 Hz, pulse ratio 7%; the substrate bias voltage is set to -50 V; deposit until the thickness of the TiB2 coating reaches 3 μm.

[0150] Performance Characterization

[0151] The coating hardness, plastic deformation rate, friction coefficient, coating stress, coating bonding force and cutting performance of the composite coating of the coated cutting tools obtained in the above examples and comparative examples were measured.

[0152] The hardness and plastic deformation rate of the coating are measured by a FISCHERSCOPE HM2000 nanohardness tester; wherein, plastic deformation rate = (plastic deformation work / total mechanical work generated by indentation) × 100%. The plastic deformation rate characterizes the relative toughness of the composite coating. The larger the value, the more energy is consumed by plastic deformation, which can effectively prevent the brittle fracture of the coated tool caused by excessive residual stress during the cutting process.

[0153] The friction coefficient was measured using a ball-on-disc friction and wear machine (HT-THT1000) produced by Anton Paar TriTec;

[0154] The coating stress was measured by a Bruker D8 Discovers X-ray diffraction device, and the internal stress of the coating was evaluated by the sin2ψ method;

[0155] The coating bonding strength is tested using the Rockwell indentation method with a load of 60 kg to examine whether the coating falls off;

[0156] The cutting performance is measured using a tool with the same geometry and base material. The tool name is ADGT180630R-SM, the processing material is TC4 with a hardness of 35HRC, the cutting method is cavity milling, the cutting speed Vc is 40m / min, the feed rate is 0.15mm / r, the cutting depth is ap=2mm, the cutting width is ae=18mm, the cooling method is wet cutting, and the coating life is recorded.

[0157] The performance characterization results of coating hardness, plastic deformation rate, friction coefficient, coating stress, coating adhesion and coating life are shown in Table 1.

[0158] Table 1

[0159]

[0160]

[0161] From the comparison between Example 4 and Example 1 in Table 1, it can be seen that if metal ion bombardment is not performed when preparing the composite tool, the performance of the composite coating on the surface of the coated tool is reduced.

[0162] From the comparison of comparative example 1 and example 1 in Table 1, it can be seen that when the modulation ratio of the TiB2 coating to the TiB2-C coating is too low, the coating life of the coated tool obtained in the end is reduced; from the comparison of comparative example 2 and example 1, it can be seen that when the modulation ratio of the TiB2 coating to the TiB2-C coating is too high, the coating life of the coated tool obtained in the end is reduced, and the coating stress is high. Therefore, the modulation ratio of the TiB2 coating to the TiB2-C coating is (1-3):1.

[0163] From the comparison between comparative example 3 and example 1 in Table 1, it can be seen that if the flow rate of nitrogen is controlled to 0 sccm when depositing the TiBCN coating, it is not conducive to improving the performance of the coated tool, and the coating bonding strength is significantly reduced.

[0164] From the comparison between Comparative Examples 4 and 5 in Table 1 and Example 1, it can be seen that when the TiB2 coating or the TiB2-C coating is not provided in the composite coating, the performance of the obtained coated tool is poor and the surface improvement of the tool cannot be achieved.

[0165] In summary, the titanium diboride hard coating provided by the present invention includes alternately superimposed TiB2-C coatings and TiB2 coatings. The addition of carbon in the TiB2-C coating changes the original TiB2 organizational structure and can also refine the TiB2 grains. The TiB2 coating has properties such as high hardness and high oxidation resistance. The TiB2 coating deposited on the TiB2-C coating will also obtain finer grains due to epitaxial growth. The superimposed TiB2-C coating and the TiB2 coating reduce the stress of the obtained titanium diboride hard coating, so that the titanium diboride hard coating has good bonding strength, and has the characteristics of high hardness, high wear resistance and low friction coefficient. In the coated tool provided by the present invention, the TiBCN coating has structures such as Ti(B, C) and Ti(N, C), so that the TiBCN coating has high toughness and high bonding strength; and then combined with the setting of the titanium diboride hard coating, the coated tool has good cutting performance.

[0166] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A coated tool, characterized in that: The coated tool comprises a substrate and a composite coating arranged on the surface of the substrate; The composite coating comprises a TiBCN coating disposed on the surface of the substrate and a titanium diboride hard coating disposed on the surface of the TiBCN; The titanium diboride hard coating comprises a TiB2-C coating and a TiB2 coating that are alternately stacked; The modulation ratio of the TiB2 coating to the TiB2-C coating is (1-3):

1.

2. The coated tool according to claim 1, characterized in that: The C content in the TiB2-C coating is 0.01-10at%.

3. The coated tool according to claim 1, characterized in that: In the titanium diboride hard coating, the thickness of a single-layer TiB2-C coating is 3-100 nm.

4. The coated tool according to claim 1, characterized in that: In the titanium diboride hard coating, the thickness of a single-layer TiB2 coating is 5-300 nm.

5. The coated tool according to claim 1, characterized in that: The thickness of the titanium diboride hard coating is 0.1-5 μm.

6. The coated tool according to claim 1, characterized in that: The titanium diboride hard coating is prepared by the following method, which comprises the following steps: The TiB2-C target and the TiB2 target are periodically magnetron sputtered under vacuum conditions to alternately deposit the TiB2-C coating and the TiB2 coating to obtain the titanium diboride hard coating.

7. The coated tool according to claim 6, characterized in that: The absolute pressure of the vacuum condition is ≤1Pa.

8. The coated tool according to claim 6, characterized in that: The power of the magnetron sputtering is 1-8 kW, the frequency is 300-1000 Hz, and the pulse ratio is 1-10%.

9. The coated tool according to claim 6, characterized in that: During the magnetron sputtering, the bias voltage is -40V to -100V.

10. The coated tool according to claim 1, characterized in that: In the TiBCN coating, the atomic ratio of B to Ti is (1.5-2.5):

1.

11. The coated tool according to claim 1, characterized in that: In the TiBCN coating, the proportion of C element is 0.01-10 at %.

12. The coated tool according to claim 1, characterized in that: In the TiBCN coating, the proportion of N element is 5-35at%.

13. The coated tool according to claim 1, characterized in that: The thickness of the TiBCN coating is 0.1-5 μm.

14. A method for preparing a coated tool as claimed in any one of claims 1 to 13, characterized in that: The preparation method comprises the following steps: The substrate is subjected to surface treatment, and then a TiBCN coating and a titanium diboride hard coating are deposited in sequence to obtain the coated tool.

15. The preparation method according to claim 14, characterized in that: The surface treatment includes pretreatment, gas ion etching and metal ion bombardment performed in sequence.

16. The preparation method according to claim 15, characterized in that: The pretreatment method includes any one of grinding, sandblasting, polishing or cleaning, or a combination of at least two of them.

17. The preparation method according to claim 15, characterized in that: The temperature of the gas ion etching is 300-650° C., and the absolute pressure is 0.2-1.5 Pa.

18. The preparation method according to claim 15, characterized in that: The gas used for the gas ion etching is argon gas with a flow rate of 50-500 sccm.

19. The preparation method according to claim 15, characterized in that: The substrate bias voltage of the gas ion etching is -200V to -800V.

20. The preparation method according to claim 15, characterized in that: The gas ion etching time is 10-60 minutes.

21. The preparation method according to claim 15, characterized in that: The atmosphere for the metal ion bombardment is an argon atmosphere, and the argon flow rate is 100-500 sccm.

22. The preparation method according to claim 15, characterized in that: The absolute pressure of the metal ion bombardment is 0.2-1Pa.

23. The preparation method according to claim 15, characterized in that: The metal source for metal ion bombardment includes a Cr target.

24. The preparation method according to claim 15, characterized in that: The power of the metal ion bombardment is 1-5 kW and the frequency is 100-1000 Hz.

25. The preparation method according to claim 15, characterized in that: The substrate bias voltage for the metal ion bombardment is -800V to -1200V.

26. The preparation method according to claim 15, characterized in that: The metal ion bombardment time is 2-10 minutes.

27. The preparation method according to claim 14, characterized in that: The nitrogen flow rate during the deposition of the TiBCN coating is 50-300 sccm.

28. The preparation method according to claim 14, characterized in that: The absolute pressure during the deposition of the TiBCN coating is 0.2-1Pa.

29. The preparation method according to claim 14, characterized in that: The TiBCN coating is deposited using a TiB2-C target, with a power of 1-8 kW, a frequency of 300-1000 Hz, and a pulse ratio of 1-10%.

30. The preparation method according to claim 14, characterized in that: The substrate bias voltage during the deposition of the TiBCN coating is -40V to -100V.

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