Composite carbon layer for surface of cutter and preparation method therefor, and cutter

Abstract

The present application provides a composite carbon layer for a surface of a cutter and a preparation method therefor, and a cutter. The composite carbon layer comprises a low-hardness carbon layer and a high-hardness carbon layer, which are alternately deposited on a surface of a cutter from the surface outward, wherein at least two instances of alternate deposition are performed; the hardness of the low-hardness carbon layer is 15-35 GPa, and the hardness of the high-hardness carbon layer is 40-65 GPa; and the thickness ratio of the high-hardness carbon layer to the low-hardness carbon layer is 0.5-5.6. In the present application, by alternately arranging low-hardness and high-hardness coatings, the low-hardness carbon layer is periodically implanted into the high-hardness carbon layer, and therefore the accumulation of stress in the high-hardness carbon layer can be effectively buffered, the overall stress of the coatings is kept at a relatively low level, the risk of the coatings being prone to fractures due to thickening is avoided, and large-thickness deposition is achieved; moreover, the composite carbon layer is ensured to have high hardness and good wear resistance; and the composite carbon layer has a simple structure, stable performance, a low cost and a wide range of applications.

Description

Composite carbon layer for tool surface, preparation method thereof and tool Technical Field

[0001] The present application relates to the technical field of tool coatings, for example, a composite carbon layer for a tool surface, a preparation method thereof, and a tool. Background Art

[0002] As electronic products become thinner and more portable, the size of printed circuit boards (PCBs) in these products is gradually decreasing. Furthermore, as information transmission evolves toward higher frequencies, higher speeds, and lower losses, the proportion of hard fillers in PCBs is increasing. This results in a gradual decrease in the size of holes on the PCBs and an increase in the number of microvias. Consequently, the size of micro drill bits used for mechanical drilling is constantly pushing the limits of size. This leads to increased wear of the micro drill bits, difficulty in chip removal, and even, in severe cases, tool breakage, impacting the efficiency and quality of PCB processing. Therefore, there is a need to improve the wear resistance of micro tools to extend their service life.

[0003] Coating technology is one of the most effective means of improving material surface properties. The performance requirements for coatings usually include hardness, wear resistance, and friction coefficient. Existing wear-resistant coatings are usually metal coatings or ceramic coatings, such as TiAlN, CrAlN, or TiSiN. Although these coatings have high hardness, they lack wear resistance and suffer from greater wear when machining difficult-to-machine plates. Diamond coatings are also available, but the preparation of diamond coatings requires pretreatment, which will seriously reduce the strength of the tool and shorten its service life.

[0004] Diamond-like carbon (DLC) coatings, as a new type of coating, offer high hardness, excellent wear resistance, and a low coefficient of friction, making them widely used in tool coating applications. However, their high internal stresses make thickening the coating prone to breakage, making it difficult to produce thick coatings. As the size of micro-drills decreases, the size of the irregularly shaped interfaces on their surfaces also decreases, reducing the area available to support coating growth. This makes the coating susceptible to self-breakage due to excessive internal stress, making it even more difficult to achieve the designed thickness. Therefore, achieving thick coatings on the surface of micro-drills requires controlling the stress level of the overall coating.

[0005] CN 104630708A discloses a diamond-like thick film and a preparation method thereof and a workpiece. The diamond thick film comprises a bonding layer, a transition layer and a diamond-like film layer in sequence. The diamond-like film layer is composed of sp 3 The preparation method comprises the following steps: depositing a bonding layer and a transition layer on the workpiece surface, and then continuously depositing sp 3The diamond-like sub-films with different bond contents are prepared by applying different bias voltages or bombarding the surface of the deposited diamond-like sub-films with high-energy inert gas particles. Although the diamond-like film is prepared by liquid multi-layer diamond-like sub-films, only two layers are arranged alternately, and there is sp between adjacent two layers. 3 The difference in bond content is still large, which is not conducive to the control of overall stress, and the preparation process is difficult to accurately control.

[0006] CN 105152548A discloses a method for preparing diamond-like carbon film glass, which comprises: placing a glass substrate into a vacuum coating machine, evacuating the glass substrate, introducing argon gas to generate plasma, performing plasma cleaning, re-evacuating the glass substrate and introducing argon gas, turning on a carbon target emission source, turning on a pulsed DC power supply, and depositing a diamond-like carbon film on the surface of the glass substrate. The diamond-like carbon film is a high sp 2 bond content and low sp 2 The diamond-like film with the highest bond content is deposited alternately, and finally the AF film is deposited to obtain the diamond-like film glass. When depositing the diamond-like film, this method only discloses the use of a pulsed DC power supply, which makes it difficult to accurately control the sp 2 Key and sp 3 Key ratio.

[0007] In summary, for the selection of composite carbon layer on the tool surface, it is necessary to alternately deposit low sp 3 bond content and high sp 3 The carbon layer with high bond content is prepared by controlling the coating preparation process to control the overall stress level of the carbon layer, thereby achieving large thickness deposition of the coating while ensuring hardness and wear resistance.

[0008] Summary of the Invention

[0009] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0010] The purpose of the present application is to provide a composite carbon layer for the surface of a tool, a preparation method thereof and a tool. The composite carbon layer can effectively buffer the stress accumulation in the high hardness coating by alternating low hardness coatings and high hardness coatings, so that the overall stress of the coating is maintained at a low level. On the basis of ensuring the high hardness and high wear resistance of the composite carbon layer, a large thickness deposition of the composite carbon layer is achieved, the problem of coating breakage is not likely to occur, and the stability is strong.

[0011] In the first aspect, the present application provides a composite carbon layer for a tool surface, wherein the composite carbon layer includes a low hardness carbon layer and a high hardness carbon layer deposited alternately from the tool surface outward, and the number of alternating depositions is at least 2 times, for example, 2 times, 3 times, 4 times or 5 times, etc., and the hardness of the low hardness carbon layer is 15 to 35 GPa, for example, 15 GPa, 18 GPa, 20 GPa, 22 GPa, 25 GPa, 28 GPa, 30 GPa, 32 GPa or 35 GPa, etc., and the hardness of the high hardness carbon layer is 40~65GPa, for example, 40GPa, 42GPa, 45GPa, 48GPa, 50GPa, 52GPa, 55GPa, 58GPa, 60GPa or 65GPa, etc.; the thickness ratio of the high hardness carbon layer and the low hardness carbon layer in the composite carbon layer is 0.5~5.6, for example, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 or 5.6, etc., but is not limited to the listed values, and other unlisted values ​​within the respective numerical ranges are also applicable.

[0012] In this application, for the structure selection of the composite carbon layer on the tool surface, according to its performance requirements, a low hardness carbon layer and a high hardness carbon layer are periodically alternately set. 3 The bond is low and the internal stress is small. The sp 3 The bond is high and the internal stress is large. By periodically implanting a low-hardness carbon layer into the high-hardness carbon layer, the accumulation of stress in the high-hardness carbon layer can be effectively buffered, so that the overall stress of the coating is maintained at a low level, avoiding the risk of easy breakage due to thickening of the coating, and achieving large-thickness deposition, especially large-thickness deposition on the complex surface of extremely fine tools, while ensuring that the hardness of the composite carbon layer is large and the wear resistance is excellent; the composite carbon layer has a simple structure, stable performance, low cost, and a wide range of applications.

[0013] In the present application, the low hardness carbon layer and the high hardness carbon layer are alternately arranged, and their thickness is an important factor affecting the performance of the composite carbon layer. In the present application, the thickness ratio of the high hardness carbon layer and the low hardness carbon layer is controlled to be 0.5-5.6. If the thickness ratio of the two is lower than 0.5, the thickness of the high hardness carbon layer is too low, which reduces the overall hardness of the coating and the wear resistance, and cannot meet the use requirements; if the thickness ratio of the two is greater than 5.6, the thickness of the high hardness carbon layer is too large, the low hardness carbon layer cannot play the role of stress buffering, and the coating is easily broken during thickening.

[0014] In this application, X-ray photoelectron spectroscopy is used to analyze the chemical composition and bond state of the carbon layer, such as sp 3 Key and sp 2 The content of sp bonds in the carbon layer was characterized by depth profiling using a monochromatic AIX ray source. 3The change and distribution of carbon content with depth; the hardness of the carbon layer was measured using a nanoindenter in continuous stiffness mode; the curvature radius of the carbon layer / substrate was determined using a laser instrument, and the internal stress of the carbon layer was further calculated using the Stoney equation.

[0015] The following are optional technical solutions for this application, but are not intended to limit the technical solutions provided in this application. Through the following technical solutions, the technical objectives and beneficial effects of this application can be better achieved and realized.

[0016] As an optional technical solution of the present application, the total thickness of the composite carbon layer is 0.5 to 30 μm, for example, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 8 μm, 10 μm, 15 μm, 20 μm, 25 μm or 30 μm, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0017] Optionally, the thickness of a single layer of the high-hardness carbon layer is 0.03 to 2 μm, for example, 0.03 μm, 0.06 μm, 0.1 μm, 0.3 μm, 0.5 μm, 0.8 μm, 1 μm, 1.2 μm, 1.5 μm, 1.8 μm or 2 μm, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0018] Optionally, the internal stresses of the low-hardness carbon layer and the high-hardness carbon layer are both compressive stresses.

[0019] Optionally, the internal stress of the low hardness carbon layer is 0.2 to 3.8 GPa, such as 0.2 GPa, 0.5 GPa, 1.0 GPa, 1.5 GPa, 2.0 GPa, 2.5 GPa, 3.0 GPa, 3.5 GPa or 3.8 GPa, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0020] Optionally, the internal stress of the high-hardness carbon layer is 8.3 to 15.6 GPa, such as 8.3 GPa, 9.0 GPa, 10.0 GPa, 11.0 GPa, 12.0 GPa, 13.0 GPa, 14.0 GPa, 15.0 GPa or 15.6 GPa, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0021] As an optional technical solution of the present application, the low hardness carbon layer includes a first low hardness carbon layer and a second low hardness carbon layer, the first low hardness carbon layer is close to the side of the tool substrate, and the hardness of the first low hardness carbon layer is lower than that of the second low hardness carbon layer.

[0022] Optionally, the hardness of the first low hardness carbon layer is 15 to 25 GPa, for example, 15 GPa, 16 GPa, 18 GPa, 20 GPa, 22 GPa, 24 GPa or 25 GPa, and the hardness of the second low hardness carbon layer is 25 to 35 GPa, for example, 25 GPa, 26 GPa, 28 GPa, 30 GPa, 32 GPa, 34 GPa or 35 GPa, but is not limited to the listed values, and other unlisted values ​​within the respective numerical ranges are also applicable.

[0023] Optionally, the high-hardness carbon layer includes a first diamond-like coating and a second diamond-like coating, wherein the first diamond-like coating is close to a side of the tool substrate, and the hardness of the first diamond-like coating is lower than that of the second diamond-like coating.

[0024] Optionally, the hardness of the first diamond-like coating is 40 to 55 GPa, for example, 40 GPa, 42 GPa, 45 GPa, 48 GPa, 50 GPa, 52 GPa or 55 GPa, and the hardness of the second diamond-like coating is 55 to 65 GPa, for example, 55 GPa, 56 GPa, 58 GPa, 60 GPa, 62 GPa, 64 GPa or 65 GPa, but is not limited to the listed values, and other unlisted values ​​within the respective numerical ranges are also applicable.

[0025] Optionally, the high-hardness carbon layer is a hydrogen-free diamond-like carbon coating.

[0026] In the present application, the low-hardness carbon layer can be divided into an ultra-low-hardness carbon coating and a medium-low-hardness diamond-like coating, and the high-hardness coating can be divided into a medium-high-hardness diamond-like coating and an ultra-high-hardness diamond-like coating. In the high-hardness carbon layer, the stress magnitude can be consistent, or it can be composed of sub-layers with different stresses, the internal stress magnitude in the sub-layers all satisfy 8.3~15.6GPa, and the hardness is within the range of 40~65GPa; similarly, in the low-hardness carbon layer, the stress magnitude can be consistent, or it can be composed of sub-layers with different stresses, the internal stress magnitude in the sub-layers all satisfy 0.2~3.8GPa, and the hardness is within the range of 15~35GPa. Optionally, the composite carbon layer also includes a bonding layer, which is located between the low-hardness carbon layer and the tool surface.

[0027] Optionally, the material of the bonding layer includes any one or a combination of at least two of a single substance, a nitride of the corresponding single substance, a carbide of the corresponding single substance or a carbonitride of the corresponding single substance. Typical but non-limiting examples of the combination include: a combination of a single substance and a nitride of the corresponding single substance, a combination of a nitride of the corresponding single substance and a carbide of the corresponding single substance, a combination of a carbide of the corresponding single substance and a carbonitride of the corresponding single substance, a combination of a single substance, a nitride of the corresponding single substance and a carbide of the corresponding single substance, etc.

[0028] Optionally, the single substance includes any one of chromium, titanium, molybdenum, tungsten, tantalum, vanadium or silicon, or a combination of at least two of them. Typical but non-limiting examples of the combination include: a combination of chromium and titanium, a combination of tungsten and tantalum, a combination of titanium and silicon, a combination of molybdenum, tungsten and tantalum, etc.

[0029] Optionally, the number of layers of the adhesive layer is at least one, for example, one, two or three layers, and the thickness of the adhesive layer is 0.1 to 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 or 5 μm, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0030] In the present application, an adhesive layer is provided between the composite carbon layer and the tool surface to improve the bonding strength between the two, wherein the adhesive layer can be provided with one layer or multiple layers, and the multiple layers can be a combination of different materials.

[0031] In a second aspect, the present application provides a method for preparing the composite carbon layer, the method comprising the following steps:

[0032] (1) After fixing the tool drill bit, evacuate the tool bit and introduce protective gas to control the pressure. Then, start the magnetron sputtering cathode and the magnetically regulated multi-arc cathode, control the cathode current, and deposit a low-hardness carbon layer on the surface of the tool drill bit.

[0033] (2) Based on step (1), the current of the magnetron sputtering cathode is reduced, and the current of the magnetically regulated multi-arc cathode is increased to deposit a high-hardness carbon layer;

[0034] (3) Repeat the operations of step (1) and step (2), and continue to alternately deposit low-hardness carbon layers and high-hardness carbon layers to obtain a composite carbon layer.

[0035] In this application, sp in the composite carbon layer 3 Key and sp 2 The control of bond content is achieved by adjusting the ratio of carbon atoms and carbon ions reaching the tool surface. The larger the ratio of carbon atoms, the higher the sp 2 The higher the bond content, the greater the proportion of carbon ions, and the sp 3The higher the bond content; wherein, carbon atoms are obtained by a magnetron sputtering cathode through a glow discharge method, and the greater the current or power of the magnetron sputtering cathode, the more carbon atoms are produced; carbon ions are obtained by a magnetically regulated multi-arc cathode through an arc discharge method, and the greater the current or power of the magnetically regulated multi-arc cathode, the more carbon ions are produced; that is, the ratio of carbon atoms and carbon ions requires the coordinated regulation of the two types of cathodes, and a certain angle is formed between the magnetron sputtering cathode and the magnetically regulated multi-arc cathode, and the angle range can be selected from 20 to 180 degrees, such as 20 degrees, 40 degrees, 60 degrees, 90 degrees, 120 degrees, 135 degrees, 150 degrees or 180 degrees, etc., and the angle between the central axes of the two intersects near the surface of the tool to ensure that carbon atoms and carbon ions reach the surface at the same time, rather than being deposited in sequence; in addition, the magnetron sputtering cathode and the magnetically regulated multi-arc cathode are arranged in pairs, and multiple pairs can be set according to the equipment structure and coating requirements, and arranged on the periphery of the equipment.

[0036] As an optional technical solution of the present application, the tool drill bit in step (1) is formed by grinding a grinding wheel on the surface of a cylindrical blank, and the material of the cylindrical blank includes cemented carbide, high-speed steel, alloy steel, etc.

[0037] In one embodiment, the tool drill bit in step (1) is cleaned before being fixed, and the cleaning includes ultrasonic cleaning.

[0038] In one embodiment, the cleaning medium includes a liquid metal cleaning agent and water, which are used sequentially.

[0039] In one embodiment, the liquid metal cleaning agent includes any one of sodium carbonate solution, sodium hydroxide, sodium phosphate solution, anisole solution or activated carbon solution.

[0040] In this application, during cleaning, the tool drill bit is immersed in liquid metal cleaning agent and water in sequence. During the immersion process, ultrasound is introduced into the container containing the metal cleaning agent and water. The ultrasound is used to vibrate the liquid in the container to clean impurities with irregular and complex structures on the surface of the tool, and then the tool is placed in a drying oven for drying.

[0041] In the present application, the solutes of the above-mentioned liquid metal cleaning agent are divided into different types of substances, among which alkali and sodium salts are mainly used for their alkalinity, anisole is mainly used for its mutual solubility of organic matter, and activated carbon is mainly used for its adsorption, so as to play a role in cleaning tool drill bits; the above-mentioned substances can also be used in combination if they do not undergo chemical reaction after mixing.

[0042] In one embodiment, the cleaning time is independently 10 to 40 minutes, such as 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, 35 minutes or 40 minutes, etc., but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0043] In one embodiment, the tool drill bit is dried after cleaning.

[0044] In one embodiment, the tool drill bit in step (1) is placed in a vacuum chamber and fixed on a fixture.

[0045] In one embodiment, the pressure after vacuuming in step (1) is reduced to 5.0×10 -3 Pa or less, for example, 5.0×10 -3 Pa, 4.0×10 -3 Pa, 3.0×10 -3 Pa, 2.0×10 -3 Pa, 1.0×10 -3 Pa or 8.0×10 -4 Pa, etc., but are not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0046] In one embodiment, the protective gas in step (1) comprises an inert gas.

[0047] In one embodiment, the step (1) of depositing the low hardness carbon layer is preceded by ion cleaning.

[0048] In one embodiment, the ion cleaning includes: using a glow discharge method to sputter clean the tool surface using inert gas ions.

[0049] In one embodiment, during the ion cleaning, the inert gas pressure is controlled to be 0.05~10Pa, for example, 0.05Pa, 0.1Pa, 0.5Pa, 1Pa, 3Pa, 5Pa, 8Pa or 10Pa, etc., the bias voltage is 100~10000V, for example, 100V, 500V, 1000V, 2000V, 3000V, 5000V, 6000V, 8000V or 10000V, etc., and the current is 0.1~50A, for example, 0.1A, 0.5A, 1A, 5A, 10A, 15A, 20A, 25A, 30A, 40A or 50A, etc., but is not limited to the listed values, and other unlisted values ​​within the respective numerical ranges are also applicable.

[0050] In one embodiment, after the ion cleaning, the vacuum is re-evacuated and an inert gas is introduced.

[0051] In the present application, the ion cleaning mainly uses inert gas ions to clean the impurities adsorbed by the air on the surface of the tool.

[0052] In one embodiment, the current of the magnetron sputtering cathode in step (1) is 20 to 50 A, for example, 20 A, 25 A, 28 A, 30 A, 32 A, 36 A, 40 A, 45 A or 50 A, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0053] In one embodiment, the power of the magnetron sputtering cathode in step (1) is 5 to 20 kW, for example, 5 kW, 6 kW, 8 kW, 10 kW, 12 kW, 14.5 kW, 16 kW, 17 kW, 18.5 kW or 20 kW, etc., but is not limited to the listed values, and other values ​​not listed within this numerical range are also applicable.

[0054] In one embodiment, the current of the magnetically regulated multi-arc cathode in step (1) is 0.1 to 100 A, for example, 0.1 A, 0.5 A, 1 A, 5 A, 10 A, 15 A, 20 A, 30 A, 50 A, 60 A, 80 A or 100 A, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0055] In one embodiment, the power of the magnetically regulated multi-arc cathode in step (1) is 0.5 to 5 kW, for example, 0.5 kW, 1 kW, 1.5 kW, 2 kW, 2.5 kW, 3 kW, 3.5 kW, 4 kW, 4.5 kW or 5 kW, etc., but is not limited to the listed values, and other values ​​not listed within this numerical range are also applicable.

[0056] In one embodiment, when depositing the low hardness carbon layer in step (1), the pressure is controlled to be 0.1 to 5 Pa, for example, 0.1 Pa, 0.5 Pa, 1 Pa, 1.5 Pa, 2 Pa, 2.5 Pa, 3 Pa, 4 Pa ​​or 5 Pa, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0057] In one embodiment, the deposition time of the low hardness carbon layer in step (1) is 1 to 300 min, for example, 1 min, 3 min, 5 min, 10 min, 30 min, 50 min, 80 min, 120 min, 150 min, 200 min, 250 min or 300 min, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0058] As an optional technical solution of the present application, before depositing the low-hardness carbon layer in step (1), an adhesive layer is first deposited on the surface of the tool drill bit.

[0059] In one embodiment, a magnetically regulated multi-arc cathode is selected according to different materials of the adhesive layer to control different atmosphere conditions and currents.

[0060] In one embodiment, when the bonding layer is deposited, the current of the magnetically regulated multi-arc cathode is 20 to 300 A, for example, 20 A, 50 A, 70 A, 100 A, 120 A, 150 A, 180 A, 200 A, 220 A, 250 A, 270 A or 300 A, and the pressure is controlled to be 0.1 to 5 Pa, for example, 0.1 Pa, 0.5 Pa, 1 Pa, 1.5 Pa, 2 Pa, 2.5 Pa, 3 Pa, 4 Pa ​​or 5 Pa, but is not limited to the listed values, and other unlisted values ​​within the respective numerical ranges are also applicable.

[0061] In one embodiment, when the material of the adhesive layer is a single substance, a protective gas is introduced to control the pressure.

[0062] In one embodiment, when the material of the adhesive layer is a nitride of a corresponding elemental substance, nitrogen gas is introduced to control the pressure.

[0063] In one embodiment, when the material of the bonding layer is a carbide of a corresponding element, a carbon-containing gas is introduced to control the pressure.

[0064] In one embodiment, when the material of the adhesive layer is a carbonitride of a corresponding elemental substance, a mixed gas of carbon-containing gas and nitrogen is introduced to control the pressure.

[0065] In one embodiment, the carbon-containing gas comprises acetylene and / or methane.

[0066] In one embodiment, when the adhesive layer comprises two or more layers, the above-mentioned single-layer deposition processes are combined and stacked.

[0067] In the present application, according to the type of the bonding layer, in addition to the corresponding elemental target material, nitride, carbide or carbonitride also requires corresponding atmospheric conditions, such as nitrogen-containing gas or carbon-containing gas. The former can be nitrogen, and the latter can be simple organic gas, such as methane, acetylene, etc.

[0068] As an optional technical solution of the present application, the current of the magnetron sputtering cathode in step (2) is 0.1 to 20 A, for example, 0.1 A, 0.5 A, 1 A, 3 A, 5 A, 8 A, 10 A, 12 A, 15 A or 20 A, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0069] In one embodiment, the power of the magnetron sputtering cathode in step (2) is 0.5 to 5 kW, for example, 0.5 kW, 1 kW, 1.5 kW, 2 kW, 2.5 kW, 3 kW, 3.5 kW, 4 kW, 4.5 kW or 5 kW, etc., but is not limited to the listed values, and other values ​​not listed within this numerical range are also applicable.

[0070] In one embodiment, the current of the magnetically regulated multi-arc cathode in step (2) is 100 to 300 A, for example, 100 A, 120 A, 150 A, 180 A, 200 A, 230 A, 250 A, 270 A or 300 A, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0071] In one embodiment, the power of the magnetically regulated multi-arc cathode in step (2) is 5 to 20 kW, for example, 5 kW, 6 kW, 8 kW, 10 kW, 12 kW, 14 kW, 16 kW, 18 kW or 20 kW, etc., but is not limited to the listed values, and other values ​​not listed within this numerical range are also applicable.

[0072] In one embodiment, when depositing the high hardness carbon layer in step (2), the pressure is controlled to be 0.1 to 5 Pa, for example, 0.1 Pa, 0.5 Pa, 1 Pa, 1.5 Pa, 2 Pa, 2.5 Pa, 3 Pa, 4 Pa ​​or 5 Pa, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0073] In one embodiment, the deposition time of the high hardness carbon layer in step (2) is 1 to 300 min, for example, 1 min, 3 min, 5 min, 10 min, 30 min, 50 min, 80 min, 120 min, 150 min, 200 min, 250 min or 300 min, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0074] In one embodiment, step (3) continues to alternately deposit the low hardness carbon layer and the high hardness carbon layer at least once, for example, once, twice, or three times.

[0075] In a third aspect, the present application provides a tool comprising a drill bit and the above-mentioned composite carbon layer, wherein the drill bit comprises a spiral groove, a circumferential edge and a drill tip, wherein the spiral groove extends spirally from the drill tip to the end of the drill bit, and the composite carbon layer is divided into three situations: completely covering the drill bit area, partially covering the drill bit area, or partially covering the drill bit area and then adding a lubricating coating.

[0076] As an optional technical solution of the present application, the diameter of the drill bit is 0.075 to 6 mm, for example, 0.075 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm or 6 mm, etc., but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, and 0.075 to 0.5 mm can be selected.

[0077] In one embodiment, the axial length of the spiral groove accounts for more than 80% of the drill bit length, such as 80%, 85%, 90%, 95% or 100%, etc., but is not limited to the listed values. Other unlisted values ​​within this numerical range are also applicable.

[0078] In one embodiment, the number of the spiral groove is at least one, such as one, two or three.

[0079] In one embodiment, the depth of the spiral groove is 5% to 50% of the drill bit diameter, for example, 5%, 10%, 15%, 20%, 25%, 30%, 40% or 50%, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0080] As an optional technical solution of the present application, the composite carbon layer completely covers the drill bit area, that is, covers the spiral groove, the peripheral edge and the drill tip.

[0081] In this application, this method requires full coverage of the drill bit area. When the tool size is small, the full coverage coating, especially when the coating thickness is large, has a greater impact on the drill bit diameter, that is, it has a huge impact on the chip removal ability and is prone to tool breakage. Therefore, this coating coverage method is mainly suitable for printed circuit board processing with high requirements for wear resistance and slightly lower requirements for chip removal.

[0082] In one embodiment, the composite carbon layer partially covers the drill bit region by covering the peripheral edges in the drill bit region.

[0083] In one embodiment, the length of the circumferential edge covering the composite carbon layer is 5% to 100% of the length of the spiral groove, for example, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 80% or 100%, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0084] In this application, the composite carbon layer only covers the circumferential edge of the drill bit. The length of the coating on the circumferential edge extends from the drill tip to the end of the spiral groove according to the processing material and the drill bit structure, and is limited to a certain length ratio. There is no composite carbon layer on the surface of the spiral groove and the drill tip. This coating covering method is mainly aimed at the processing of difficult-to-process printed circuit boards with large coating thickness and certain requirements for chip removal. While improving the wear resistance, it does not affect the chip removal ability of the drill bit during deep hole processing.

[0085] In one embodiment, the partial covering followed by the addition of the lubricating coating is to cover the peripheral cutting edges in the drill bit area and then deposit a layer of lubricating coating on the entire area.

[0086] In one embodiment, the lubricating coating has a thickness of 0.1 to 0.5 μm, for example, 0.1 μm, 0.15 μm, 0.2 μm, 0.25 μm, 0.3 μm, 0.35 μm, 0.4 μm, 0.45 μm or 0.5 μm.

[0087] In this application, on the basis of the second coating covering method, a carbon layer with an ultra-low friction coefficient that is both wear-resistant is deposited on the entire area of ​​the drill bit. The friction coefficient is much lower than the 0.6 to 0.8 of conventional cemented carbide. This structural design is mainly aimed at applications in high-end difficult-to-process printed circuit boards where both drill wear resistance and chip removal performance are extremely high. The low-friction coating has a small thickness and has almost no effect on the core thickness, which can effectively improve the chip removal ability.

[0088] In this application, the tool is not limited to double-edged micro drills, but is also suitable for various standard and non-standard micro drills on the market. Milling cutters, reamers, broaches, molds, gears, etc. that have high requirements for wear resistance and lubricity can also be selected.

[0089] Compared with the related art, this application has the following beneficial effects:

[0090] (1) The present application alternately arranges low-hardness coatings and high-hardness coatings and periodically implants low-hardness carbon layers into high-hardness carbon layers, which can effectively buffer the accumulation of stress in the high-hardness carbon layer, so that the overall stress of the coating is maintained at a low level, avoiding the risk of easy breakage due to thickening of the coating, achieving large thickness deposition, and at the same time ensuring that the hardness of the composite carbon layer is large and the wear resistance is excellent;

[0091] (2) The composite carbon layer and tool structure described in this application are simple in structure and stable in performance, and can effectively solve the processing problems of difficult-to-process high-frequency printed circuit boards, high-speed printed circuit boards, and high-performance packaging substrates, and have a wide range of applications.

[0092] Still other aspects will become apparent upon reading and understanding the accompanying drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0093] The accompanying drawings are used to provide a further understanding of the technical solution of this article and constitute a part of the specification. Together with the embodiments of this application, they are used to explain the technical solution of this article and do not constitute a limitation on the technical solution of this article.

[0094] FIG1 is a schematic structural diagram of a composite carbon layer provided in Example 1 of the present application;

[0095] FIG2 is a schematic structural diagram of a drill bit provided in Example 3 of the present application;

[0096] FIG3 is a cross-sectional view of an area near the drill tip in the drill bit structure provided in Example 3 of the present application;

[0097] Among them, 1-low hardness carbon layer, 11-first low hardness carbon layer, 12-second low hardness carbon layer, 2-high hardness carbon layer, 21-first diamond-like coating, 22-second diamond-like coating, 3-bonding layer, 4-spiral groove, 5-circumferential edge, 6-drill tip, 7-lubricating coating. DETAILED DESCRIPTION

[0098] To better illustrate the present application and facilitate understanding of the technical solution of the present application, the present application is further described below. However, the following embodiments are merely simplified examples of the present application and do not represent or limit the scope of protection of the present application. The scope of protection of the present application shall be subject to the claims.

[0099] The following are typical but non-limiting examples of this application:

[0100] Example 1:

[0101] This embodiment provides a composite carbon layer and a tool for a tool surface. The schematic diagram of the composite carbon layer structure is shown in Figure 1. From the tool surface outward, it includes alternately deposited low-hardness carbon layers 1 and high-hardness carbon layers 2. The number of alternating depositions is 2 times. The hardness of the low-hardness carbon layer 1 is 31 GPa, and the hardness of the high-hardness carbon layer 2 is 52 GPa. The thickness ratio of the high-hardness carbon layer 2 to the low-hardness carbon layer 1 in the composite carbon layer is 1.0.

[0102] The total thickness of the composite carbon layer is 1.1 μm.

[0103] The thickness of the single-layer high-hardness carbon layer 2 is 0.25 μm.

[0104] The internal stresses of the low-hardness carbon layer 1 and the high-hardness carbon layer 2 are both compressive stresses.

[0105] The internal stress of the low-hardness carbon layer 1 is 3.6 GPa; the internal stress of the high-hardness carbon layer 2 is 12.6 GPa.

[0106] The low-hardness carbon layer 1 includes a first low-hardness carbon layer 11 and a second low-hardness carbon layer 12. The first low-hardness carbon layer 11 is close to the side of the tool substrate. The hardness of the first low-hardness carbon layer 11 is lower than the hardness of the second low-hardness carbon layer 12; the hardness of the first low-hardness carbon layer 11 is 25GPa, and the hardness of the second low-hardness carbon layer 12 is 35GPa.

[0107] The high-hardness carbon layer 2 includes a first diamond-like coating 21 and a second diamond-like coating 22. The first diamond-like coating 21 is close to the side of the tool substrate. The hardness of the first diamond-like coating 21 is lower than the hardness of the second diamond-like coating 22. The hardness of the first diamond-like coating 21 is 45 GPa, and the hardness of the second diamond-like coating 22 is 55 GPa.

[0108] The composite carbon layer further includes an adhesive layer 3 , which is located between the low-hardness carbon layer 1 and the tool surface.

[0109] The material of the adhesive layer 3 is chromium, and the thickness of the adhesive layer 3 is 0.1 μm.

[0110] The tool includes a drill bit and a composite carbon layer on the surface of the drill bit. The drill bit includes a spiral groove 4, a circumferential edge 5 and a drill tip 6. The spiral groove 4 spirally extends from the drill tip 6 to the end of the drill bit. The composite carbon layer completely covers the drill bit area, that is, the spiral groove 4, the circumferential edge 5 and the drill tip 6 are all covered.

[0111] The diameter of the drill bit is 0.2 mm.

[0112] The axial length of the spiral groove 4 accounts for 100% of the length of the drill bit. There are two spiral grooves 4 , and the depth of the spiral groove 4 accounts for 28% of the diameter of the drill bit.

[0113] Example 2:

[0114] This embodiment provides a composite carbon layer and a tool for a tool surface, wherein the composite carbon layer includes a low-hardness carbon layer 1 and a high-hardness carbon layer 2 deposited alternately from the tool surface outward, the number of alternating depositions being 3 times, the hardness of the low-hardness carbon layer 1 being 26 GPa, and the hardness of the high-hardness carbon layer 2 being 59 GPa; the thickness ratio of the high-hardness carbon layer 2 to the low-hardness carbon layer 1 in the composite carbon layer is 3.0.

[0115] The total thickness of the composite carbon layer is 1.2 μm.

[0116] The thickness of the single-layer high-hardness carbon layer 2 is 0.3 μm.

[0117] The internal stresses of the low-hardness carbon layer 1 and the high-hardness carbon layer 2 are both compressive stresses.

[0118] The internal stress of the low-hardness carbon layer 1 is 3.2 GPa; the internal stress of the high-hardness carbon layer 2 is 13.1 GPa.

[0119] The low-hardness carbon layer 1 includes a first low-hardness carbon layer 11 and a second low-hardness carbon layer 12. The first low-hardness carbon layer 11 is close to the side of the tool substrate. The hardness of the first low-hardness carbon layer 11 is lower than the hardness of the second low-hardness carbon layer 12; the hardness of the first low-hardness carbon layer 11 is 20GPa, and the hardness of the second low-hardness carbon layer 12 is 30GPa.

[0120] The high-hardness carbon layer 2 includes a first diamond-like coating 21 and a second diamond-like coating 22. The first diamond-like coating 21 is close to the side of the tool substrate. The hardness of the first diamond-like coating 21 is lower than the hardness of the second diamond-like coating 22. The hardness of the first diamond-like coating 21 is 55 GPa, and the hardness of the second diamond-like coating 22 is 64 GPa.

[0121] The tool includes a drill bit and a composite carbon layer on the surface of the drill bit. The drill bit includes a spiral groove 4, a circumferential edge 5 and a drill tip 6. The spiral groove 4 spirally extends from the drill tip 6 to the end of the drill bit. The composite carbon layer completely covers the drill bit area, that is, the spiral groove 4, the circumferential edge 5 and the drill tip 6 are all covered.

[0122] The diameter of the drill bit is 0.25 mm.

[0123] The axial length of the spiral groove 4 accounts for 95% of the length of the drill bit. There are two spiral grooves 4 . The depth of the spiral groove 4 accounts for 30% of the diameter of the drill bit.

[0124] Example 3:

[0125] This embodiment provides a composite carbon layer and a tool for a tool surface, wherein the composite carbon layer includes a low-hardness carbon layer 1 and a high-hardness carbon layer 2 deposited alternately from the tool surface outward, the number of alternating depositions being 3 times, the hardness of the low-hardness carbon layer 1 being 20 GPa, and the hardness of the high-hardness carbon layer 2 being 55 GPa; the thickness ratio of the high-hardness carbon layer 2 to the low-hardness carbon layer 1 in the composite carbon layer is 4.0.

[0126] The total thickness of the composite carbon layer is 2.1 μm.

[0127] The thickness of the single-layer high-hardness carbon layer 2 is 0.56 μm.

[0128] The internal stresses of the low-hardness carbon layer 1 and the high-hardness carbon layer 2 are both compressive stresses.

[0129] The internal stress of the low-hardness carbon layer 1 is 2.8 GPa; the internal stress of the high-hardness carbon layer 2 is 12.7 GPa.

[0130] The tool includes a drill bit and a composite carbon layer on the surface of the drill bit. The structural schematic diagram of the drill bit is shown in Figure 2, including a spiral groove 4, a circumferential blade 5 and a drill tip 6. A cross-sectional view of the drill bit structure near the drill tip is shown in Figure 3. The spiral groove 4 spirally extends from the drill tip 6 to the end of the drill bit. The composite carbon layer partially covers the drill bit area and then a lubricating coating 7 is added, that is, after covering the circumferential blade 5 in the drill bit area, a layer of lubricating coating 7 is deposited on the entire area.

[0131] The diameter of the drill bit is 0.36 mm.

[0132] The axial length of the spiral groove 4 accounts for 90% of the length of the drill bit. There are two spiral grooves 4 , and the depth of the spiral groove 4 accounts for 25% of the diameter of the drill bit.

[0133] The length of the circumferential edge 6 covered with the composite carbon layer accounts for 80% of the length of the spiral groove 5 .

[0134] The lubricating coating 7 has a thickness of 0.2 μm and covers the entire surface of the drill bit area.

[0135] Example 4:

[0136] This embodiment provides a composite carbon layer and a tool for a tool surface, wherein the composite carbon layer includes a low-hardness carbon layer 1 and a high-hardness carbon layer 2 deposited alternately from the tool surface outward, the number of alternating depositions being 4 times, the hardness of the low-hardness carbon layer 1 being 17 GPa, and the hardness of the high-hardness carbon layer 2 being 50 GPa; the thickness ratio of the high-hardness carbon layer 2 to the low-hardness carbon layer 1 in the composite carbon layer is 5.5.

[0137] The total thickness of the composite carbon layer is 3.0 μm.

[0138] The thickness of the single-layer high-hardness carbon layer 2 is 0.55 μm.

[0139] The internal stresses of the low-hardness carbon layer 1 and the high-hardness carbon layer 2 are both compressive stresses.

[0140] The internal stress of the low-hardness carbon layer 1 is 1.5 GPa; the internal stress of the high-hardness carbon layer 2 is 11.3 GPa.

[0141] The low-hardness carbon layer 1 includes a first low-hardness carbon layer 11 and a second low-hardness carbon layer 12. The first low-hardness carbon layer 11 is close to the side of the tool substrate. The hardness of the first low-hardness carbon layer 11 is lower than the hardness of the second low-hardness carbon layer 12; the hardness of the first low-hardness carbon layer 11 is 15GPa, and the hardness of the second low-hardness carbon layer 12 is 25GPa.

[0142] The high-hardness carbon layer 2 includes a first diamond-like coating 21 and a second diamond-like coating 22. The first diamond-like coating 21 is close to the side of the tool substrate. The hardness of the first diamond-like coating 21 is lower than the hardness of the second diamond-like coating 22. The hardness of the first diamond-like coating 21 is 40GPa, and the hardness of the second diamond-like coating 22 is 55GPa.

[0143] The composite carbon layer further includes an adhesive layer 3 , which is located between the low-hardness carbon layer 1 and the tool surface.

[0144] The bonding layer 3 includes a chromium bonding layer and a chromium nitride bonding layer in sequence. The thickness of the chromium bonding layer is 0.2 μm, and the thickness of the chromium nitride bonding layer is 0.2 μm.

[0145] The tool includes a drill bit and a composite carbon layer on the surface of the drill bit. The drill bit includes a spiral groove 4, a peripheral edge 5 and a drill tip 6. The spiral groove 4 spirally extends from the drill tip 6 to the end of the drill bit. The composite carbon layer partially covers the drill bit area, that is, covers the peripheral edge 5 in the drill bit area.

[0146] The diameter of the drill bit is 0.4 mm.

[0147] The axial length of the spiral groove 4 accounts for 85% of the length of the drill bit. There is one spiral groove 4 , and the depth of the spiral groove 4 accounts for 40% of the diameter of the drill bit.

[0148] The length of the circumferential edge 5 covered with the composite carbon layer accounts for 50% of the length of the spiral groove 4 .

[0149] Example 5:

[0150] This embodiment provides a composite carbon layer and a tool for a tool surface, wherein the composite carbon layer includes a low-hardness carbon layer 1 and a high-hardness carbon layer 2 deposited alternately from the tool surface outward, the number of alternating depositions being 4 times, the hardness of the low-hardness carbon layer 1 being 15 GPa, and the hardness of the high-hardness carbon layer 2 being 40 GPa; the thickness ratio of the high-hardness carbon layer 2 to the low-hardness carbon layer 1 in the composite carbon layer is 0.5.

[0151] The total thickness of the composite carbon layer is 9.6 μm.

[0152] The thickness of the single-layer high-hardness carbon layer 2 is 0.8 μm.

[0153] The internal stresses of the low-hardness carbon layer 1 and the high-hardness carbon layer 2 are both compressive stresses.

[0154] The internal stress of the low-hardness carbon layer 1 is 1.0 GPa; the internal stress of the high-hardness carbon layer 2 is 9.8 GPa.

[0155] The tool includes a drill bit and a composite carbon layer on the surface of the drill bit. The drill bit includes a spiral groove 4, a circumferential blade 5 and a drill tip 6. The spiral groove 4 spirally extends from the drill tip 5 to the end of the drill bit. The composite carbon layer partially covers the drill bit area and then a lubricating coating 7 is added, that is, after covering the circumferential blade 5 in the drill bit area, a layer of lubricating coating 7 is deposited on the entire drill bit area.

[0156] The diameter of the drill bit is 6 mm.

[0157] The axial length of the spiral groove 4 accounts for 80% of the length of the drill bit. There are two spiral grooves 4 . The depth of the spiral groove 4 accounts for 20% of the diameter of the drill bit.

[0158] The length of the circumferential edge 5 covered with the composite carbon layer accounts for 100% of the length of the spiral groove 4 .

[0159] The lubricating coating 7 has a thickness of 0.5 μm and covers the entire surface of the drill bit area.

[0160] Example 6:

[0161] This embodiment provides a method for preparing a composite carbon layer for a tool surface, wherein the composite carbon layer is the composite carbon layer in Example 1. The method comprises the following steps:

[0162] (1) The tool drill bit was first ultrasonically cleaned. The cleaning media were liquid metal cleaning agent sodium carbonate solution and water. The two media were used successively, and the cleaning time was 30 min. After cleaning, the tool drill bit was dried. Then, the tool drill bit was placed in a vacuum chamber, fixed on a fixture, and vacuumed until the pressure dropped to 5.0×10 -3 Pa, and argon gas is introduced, and the tool surface is ion cleaned with argon ions using the glow discharge method. During ion cleaning, the argon pressure is controlled to be 2.0 Pa, the bias voltage is 1000 V, and the current is 10 A;

[0163] After the ion cleaning, the evacuation was repeated and argon gas was introduced to control the pressure to 2.0 Pa. The magnetically regulated multi-arc cathode was turned on and the current of the magnetically regulated multi-arc cathode was controlled to 60 A. The chromium bonding layer was deposited on the surface of the tool drill bit for 10 minutes to obtain the chromium bonding layer.

[0164] Then, the pressure was controlled to 0.8 Pa, the magnetron sputtering cathode and the magnetically regulated multi-arc cathode were turned on, the current of the magnetron sputtering cathode was controlled to 10 A and the power was 12 kW, the current of the magnetically regulated multi-arc cathode was controlled to 50 A and the power was 1 kW, and the deposition was carried out on the surface of the tool drill bit for 4 minutes to obtain the first low-hardness carbon layer; the pressure was continued to be controlled to 0.8 Pa, the current of the magnetron sputtering cathode was controlled to 8 A and the power was 10 kW, the current of the magnetically regulated multi-arc cathode was controlled to 80 A and the power was 2 kW, and the deposition was carried out for 8 minutes to obtain the second low-hardness carbon layer;

[0165] (2) On the basis of step (1), the current of the magnetron sputtering cathode and the magnetically regulated multi-arc cathode is continued to be controlled, the current of the magnetron sputtering cathode is 1A, the power is 1kW, the current of the magnetically regulated multi-arc cathode is 250A, the power is 12kW, and the deposition is carried out for 4 minutes to obtain a first-class diamond coating; the current of the magnetron sputtering cathode and the magnetically regulated multi-arc cathode is continued to be controlled, the current of the magnetron sputtering cathode is 1A, the power is 1kW, the current of the magnetically regulated multi-arc cathode is 280A, the power is 15kW, and the deposition is carried out for 10 minutes to obtain a second-class diamond coating;

[0166] (3) Repeating the operations of step (1) and step (2), continuing to alternately deposit the low hardness carbon layer and the high hardness carbon layer once, to obtain a composite carbon layer, wherein the composite carbon layer completely covers the drill bit area of ​​the tool.

[0167] The tool covered with the composite carbon layer is used to process 30,000 holes in the HTG copper clad sheet. The tool not covered with the composite carbon layer can process 3,000 holes. In this embodiment, the tool life of the tool covered with the composite carbon layer is increased to 10 times the original.

[0168] Example 7:

[0169] This embodiment provides a method for preparing a composite carbon layer for a tool surface, wherein the composite carbon layer is the composite carbon layer in Example 2. The method comprises the following steps:

[0170] (1) The tool drill bit was first ultrasonically cleaned. The cleaning media were liquid metal cleaning agent sodium phosphate solution and water. The two media were used successively, and the cleaning time was 20 min. After cleaning, the tool drill bit was dried. Then, the tool drill bit was placed in a vacuum chamber, fixed on a fixture, and vacuumed until the pressure dropped to 4.0×10 -3 Pa, and introduce argon gas, adopt the glow discharge method, use argon ions to ion clean the tool surface. During ion cleaning, the argon pressure is controlled to 0.5Pa, the bias voltage is 200V, and the current is 50A;

[0171] After the ion cleaning, the vacuum is re-evacuated and argon gas is introduced, the pressure is controlled to 0.5 Pa, and the magnetron sputtering cathode and the magnetically regulated multi-arc cathode are turned on at the same time. The current of the magnetron sputtering cathode is controlled to 50 A and the power is 20 kW, and the current of the magnetically regulated multi-arc cathode is controlled to 100 A and the power is 0.5 kW. Deposition is carried out on the surface of the tool drill bit for 25 minutes to obtain a first low-hardness carbon layer; the pressure is continued to be controlled to 0.5 Pa, the current of the magnetron sputtering cathode is controlled to 35 A and the power is 10 kW, and the current of the magnetically regulated multi-arc cathode is controlled to 80 A and the power is 4 kW, and deposition is carried out for 35 minutes to obtain a second low-hardness carbon layer;

[0172] (2) On the basis of step (2), the current of the magnetron sputtering cathode and the magnetically regulated multi-arc cathode is continued to be controlled, the current of the magnetron sputtering cathode is 0.5A, the power is 0.5kW, the current of the magnetically regulated multi-arc cathode is 250A, the power is 10kW, and the deposition is carried out for 40 minutes to obtain a first-class diamond coating; the current of the magnetron sputtering cathode and the magnetically regulated multi-arc cathode is continued to be controlled, the current of the magnetron sputtering cathode is 0.1A, the power is 1kW, the current of the magnetically regulated multi-arc cathode is 300A, the power is 20kW, and the deposition is carried out for 60 minutes to obtain a second-class diamond coating;

[0173] (3) Repeating the operations of step (1) and step (2), continuing to alternately deposit the low hardness carbon layer and the high hardness carbon layer twice, to obtain a composite carbon layer, wherein the composite carbon layer completely covers the drill bit area of ​​the tool.

[0174] The tool covered with the composite carbon layer in this embodiment is used to process the low-CET package substrate HL832NSF. It can process 10,000 holes with almost no wear on the drill tip after processing. However, the tool without the coating suffers from severe wear on the drill tip after processing 4,000 holes, and the service life of the tool is increased to 2.5 times the original value.

[0175] Example 8:

[0176] This embodiment provides a method for preparing a composite carbon layer for a tool surface, wherein the composite carbon layer is the composite carbon layer in Example 3. The method comprises the following steps:

[0177] (1) The tool drill bit was first ultrasonically cleaned. The cleaning media were liquid metal cleaning agent anisole solution and water. The two media were used successively, and the cleaning time was 20 min. After cleaning, the tool drill bit was dried. Then, the tool drill bit was placed in a vacuum chamber, fixed on a fixture, and vacuumed until the pressure dropped to 5.0×10 -3 Pa, and introduce argon gas, adopt glow discharge method, use argon ions to ion clean the tool surface. During ion cleaning, control the argon pressure to 5.0Pa, bias voltage to 2000V, and current to 1A;

[0178] After the ion cleaning, the vacuum was re-evacuated and argon gas was introduced, the pressure was controlled to 0.2 Pa, the magnetron sputtering cathode and the magnetically regulated multi-arc cathode were turned on, the current of the magnetron sputtering cathode was controlled to 40 A and the power was 20 kW, and the current of the magnetically regulated multi-arc cathode was controlled to 50 A and the power was 2 kW, and deposition was carried out on the surface of the tool drill bit for 54 minutes to obtain a low-hardness carbon layer;

[0179] (2) Based on step (1), the current of the magnetron sputtering cathode and the magnetically regulated multi-arc cathode is continued to be controlled. The current of the magnetron sputtering cathode is 3A and the power is 1kW. The current of the magnetically regulated multi-arc cathode is 200A and the power is 10kW. The deposition time is 100 minutes to obtain a high-hardness carbon layer.

[0180] (3) Repeating the operations of step (1) and step (2), continuing to alternately deposit the low hardness carbon layer and the high hardness carbon layer twice to obtain a composite carbon layer;

[0181] The composite carbon layer covers the peripheral edge position in the drill bit area, and then the lubricating coating is deposited continuously. The lubricating coating completely covers the drill bit area. Argon gas is introduced to control the pressure to 0.1 Pa, and the current of the magnetron sputtering cathode and the magnetically regulated multi-arc cathode is controlled. The current of the magnetron sputtering cathode is 15 A and the power is 7.5 kW. The current of the magnetically regulated multi-arc cathode is 100 A and the power is 2 kW. The deposition is carried out for 10 minutes to obtain the lubricating coating.

[0182] The tool covered with the composite carbon layer in this embodiment is used to process 6063 aluminum alloy and can process 40,000 holes. However, the tool not covered with the coating breaks after processing 1,000 holes due to wire entanglement and dust clogging, and the service life of the tool is increased to 40 times the original.

[0183] Example 9:

[0184] This embodiment provides a method for preparing a composite carbon layer for a tool surface, wherein the composite carbon layer is the composite carbon layer in Example 4. The method comprises the following steps:

[0185] (1) The tool drill bit was first ultrasonically cleaned. The cleaning media were liquid metal cleaning agent activated carbon solution and water. The two media were used successively, and the cleaning time was 20 min. After cleaning, the tool drill bit was dried. Then, the tool drill bit was placed in a vacuum chamber, fixed on a fixture, and vacuumed until the pressure dropped to 5.0×10 -3 Pa, and krypton gas is introduced, and the tool surface is ion cleaned with krypton ions using the glow discharge method. During ion cleaning, the argon pressure is controlled to be 3.0 Pa, the bias voltage is 5000 V, and the current is 0.1 A;

[0186] After the ion cleaning, the vacuum was re-drawn, and krypton gas was introduced, the pressure was controlled to 3.0 Pa, the magnetically regulated multi-arc cathode was turned on, the current of the magnetically regulated multi-arc cathode was controlled to 90 A, and the chromium bonding layer was deposited on the surface of the tool drill bit for 20 minutes; the gas introduced was adjusted to nitrogen, the pressure was controlled to 3.5 Pa, the current of the magnetically regulated multi-arc cathode was controlled to 90 A, and the deposition was carried out for 15 minutes to obtain a chromium nitride bonding layer;

[0187] Then, the pressure was controlled to 0.3 Pa, and the magnetron sputtering cathode and the magnetically regulated multi-arc cathode were turned on at the same time. The current of the magnetron sputtering cathode was controlled to 30 A and the power was 8 kW, and the current of the magnetically regulated multi-arc cathode was controlled to 50 A and the power was 3 kW. The deposition was continued for 10 minutes to obtain the first low-hardness carbon layer. The pressure was continued to be controlled to 0.3 Pa, and the current of the magnetron sputtering cathode was controlled to 20 A and the power was 5 kW, and the current of the magnetically regulated multi-arc cathode was controlled to 70 A and the power was 5 kW. The deposition was continued for 40 minutes to obtain the second low-hardness carbon layer.

[0188] (2) On the basis of step (1), the current of the magnetron sputtering cathode and the magnetically regulated multi-arc cathode is continued to be controlled, the current of the magnetron sputtering cathode is 0.8A, the power is 2.5kW, the current of the magnetically regulated multi-arc cathode is 200A, the power is 8kW, and the deposition is carried out for 12 minutes to obtain a first-class diamond coating; the current of the magnetron sputtering cathode and the magnetically regulated multi-arc cathode is continued to be controlled, the current of the magnetron sputtering cathode is 0.5A, the power is 1.8kW, the current of the magnetically regulated multi-arc cathode is 250A, the power is 20kW, and the deposition is carried out for 60 minutes to obtain a second-class diamond coating;

[0189] (3) Repeating the operations of step (1) and step (2), and continuing to alternately deposit the low-hardness carbon layer and the high-hardness carbon layer three times, to obtain a composite carbon layer, wherein the composite carbon layer covers the peripheral edge in the drill bit area.

[0190] The tool covered with the composite carbon layer in this embodiment is used to process an EM390 printed circuit board and can process 2000 holes. Compared with the tool without the coating which can only process 400 holes, the processing life is increased to 5 times the original.

[0191] From the above embodiments, it can be seen that the present application can effectively buffer the accumulation of stress in the high-hardness carbon layer by alternating low-hardness coatings and high-hardness coatings and periodically implanting low-hardness carbon layers into the high-hardness carbon layer, so that the overall stress of the coating is maintained at a low level, avoiding the risk of easy breakage due to thickening of the coating, achieving large thickness deposition, and at the same time ensuring that the hardness of the composite carbon layer is large and the wear resistance is excellent; the composite carbon layer and the tool structure are simple in structure and stable in performance, and can effectively solve the processing problems of difficult-to-process high-frequency printed circuit boards, high-speed printed circuit boards, and high-performance packaging substrates, and have a wide range of applications.

[0192] The applicant declares that this application uses the above-mentioned embodiments to illustrate the detailed products and methods of this application, but this application is not limited to the above-mentioned detailed products and methods, that is, it does not mean that this application must rely on the above-mentioned detailed products and methods to be implemented. Those skilled in the art should understand that any improvements to this application, equivalent replacements for the products of this application, addition of auxiliary structures, selection of specific methods, etc., are all within the scope of protection and disclosure of this application.

Claims

1. A composite carbon layer for a tool surface, wherein: The composite carbon layer includes low hardness carbon layers and high hardness carbon layers deposited alternately from the tool surface to the outside, the number of alternating depositions is at least 2 times, the hardness of the low hardness carbon layer is 15 to 35 GPa, and the hardness of the high hardness carbon layer is 40 to 65 GPa; the thickness ratio of the high hardness carbon layer to the low hardness carbon layer in the composite carbon layer is 0.5 to 5.

6.

2. The composite carbon layer according to claim 1, wherein: The total thickness of the composite carbon layer is 0.5-30 μm.

3. The composite carbon layer according to claim 1 or 2, wherein: The thickness of the single-layer high-hardness carbon layer is 0.03-2 μm.

4. The composite carbon layer according to any one of claims 1 to 3, wherein: The internal stresses of the low-hardness carbon layer and the high-hardness carbon layer are both compressive stresses.

5. The composite carbon layer according to any one of claims 1 to 4, wherein: The internal stress of the low hardness carbon layer is 0.2 to 3.8 GPa; Optionally, the internal stress of the high-hardness carbon layer is 8.3 to 15.6 GPa.

6. The composite carbon layer according to any one of claims 1 to 5, wherein: The low-hardness carbon layer comprises a first low-hardness carbon layer and a second low-hardness carbon layer, wherein the first low-hardness carbon layer is close to a side of the tool substrate, and the hardness of the first low-hardness carbon layer is lower than the hardness of the second low-hardness carbon layer; Optionally, the hardness of the first low-hardness carbon layer is 15 to 25 GPa, and the hardness of the second low-hardness carbon layer is 25 to 35 GPa; Optionally, the high-hardness carbon layer includes a first diamond-like coating and a second diamond-like coating, the first diamond-like coating is close to a side of the tool substrate, and the hardness of the first diamond-like coating is lower than the hardness of the second diamond-like coating; Optionally, the hardness of the first diamond-like coating is 40 to 55 GPa, and the hardness of the second diamond-like coating is 55 to 65 GPa; Optionally, the high-hardness carbon layer is a hydrogen-free diamond-like coating; Optionally, the composite carbon layer further comprises a bonding layer, wherein the bonding layer is located between the low hardness carbon layer and the surface of the tool; Optionally, the material of the bonding layer includes any one of a single substance, a nitride of a corresponding single substance, a carbide of a corresponding single substance, or a carbonitride of a corresponding single substance, or a combination of at least two thereof; Optionally, the single substance includes any one of chromium, titanium, molybdenum, tungsten, tantalum, vanadium or silicon, or a combination of at least two thereof; Optionally, the adhesive layer has at least one layer, and the thickness of the adhesive layer is 0.1-5 μm.

7. The method for preparing the composite carbon layer according to any one of claims 1 to 6, comprising the following steps: (1) After fixing the tool drill bit, evacuate the tool bit, introduce protective gas to control the pressure, start the magnetron sputtering cathode and the magnetically regulated multi-arc cathode, control the cathode current, and deposit a low-hardness carbon layer on the surface of the tool drill bit; (2) Based on step (1), the current of the magnetron sputtering cathode is reduced, and the current of the magnetically regulated multi-arc cathode is increased to deposit a high-hardness carbon layer; (3) Repeat the operations of step (1) and step (2) to continue to alternately deposit low-hardness carbon layers and high-hardness carbon layers to obtain a composite carbon layer.

8. The preparation method according to claim 7, wherein: The tool drill bit in step (1) is formed by grinding a grinding wheel on the surface of a cylindrical blank.

9. The preparation method according to claim 7 or 8, wherein: The tool drill bit in step (1) is cleaned before being fixed, and the cleaning includes ultrasonic cleaning; Optionally, the cleaning medium includes a liquid metal cleaning agent and water, which are used sequentially; Optionally, the liquid metal cleaning agent includes any one of sodium carbonate solution, sodium hydroxide, sodium phosphate solution, anisole solution or activated carbon solution; Optionally, the cleaning time is independently 10 to 40 minutes; Optionally, the tool drill bit is dried after cleaning; Optionally, the tool drill bit in step (1) is placed in a vacuum chamber and fixed on a fixture; Optionally, after the vacuuming in step (1), the pressure is reduced to 5.0×10 -3 Below Pa; Optionally, the protective gas in step (1) comprises an inert gas; Optionally, the step (1) of depositing the low hardness carbon layer is firstly ion cleaned; Optionally, the ion cleaning includes: using a glow discharge method to sputter clean the tool surface using inert gas ions; Optionally, during the ion cleaning, the inert gas pressure is controlled to be 0.05-10 Pa, the bias voltage is 100-10000 V, and the current is 0.1-50 A; Optionally, after the ion cleaning, the vacuum is re-evacuated and an inert gas is introduced; Optionally, the current of the magnetron sputtering cathode in step (1) is 20 to 50 A; Optionally, the power of the magnetron sputtering cathode in step (1) is 5 to 20 kW; Optionally, the current of the magnetically regulated multi-arc cathode in step (1) is 0.1 to 100 A; Optionally, the power of the magnetically regulated multi-arc cathode in step (1) is 0.5-5 kW; Optionally, when depositing the low hardness carbon layer in step (1), the pressure is controlled to be 0.1 to 5 Pa; Optionally, the deposition time of the low hardness carbon layer in step (1) is 1 to 300 minutes.

10. The preparation method according to any one of claims 7 to 9, wherein: Before the low-hardness carbon layer is deposited in step (1), a bonding layer is first deposited on the surface of the tool drill bit; Optionally, according to the different materials of the adhesive layer, a magnetically regulated multi-arc cathode is selected to control different atmosphere conditions and currents; Optionally, during the deposition of the bonding layer, the current of the magnetically regulated multi-arc cathode is 20 to 300 A, and the pressure is controlled to be 0.1 to 5 Pa; Optionally, when the material of the adhesive layer is a single substance, a protective gas is introduced to control the pressure; Optionally, when the material of the bonding layer is a nitride of a corresponding element, nitrogen is introduced to control the pressure; Optionally, when the material of the bonding layer is a carbide of a corresponding single substance, a carbon-containing gas is introduced to control the pressure; Optionally, when the material of the bonding layer is a carbonitride of a corresponding element, a mixed gas of carbon-containing gas and nitrogen is introduced to control the pressure; Optionally, the carbon-containing gas includes acetylene and / or methane; Optionally, when the bonding layer comprises two or more layers, the above-mentioned single-layer deposition process combinations are superimposed.

11. The preparation method according to any one of claims 7 to 10, wherein: The current of the magnetron sputtering cathode in step (2) is 0.1 to 20A; Optionally, the power of the magnetron sputtering cathode in step (2) is 0.5 to 5 kW; Optionally, the current of the magnetically regulated multi-arc cathode in step (2) is 100 to 300 A; Optionally, the power of the magnetically regulated multi-arc cathode in step (2) is 5 to 20 kW; Optionally, when depositing the low hardness carbon layer in step (2), the pressure is controlled to be 0.1 to 5 Pa; Optionally, the deposition time of the low hardness carbon layer in step (2) is 1 to 300 minutes; Optionally, step (3) continues to alternately deposit low hardness carbon layers and high hardness carbon layers at least once.

12. A cutting tool, wherein: The tool comprises a drill bit and the composite carbon layer according to any one of claims 1 to 6, the drill bit comprises a spiral groove, a peripheral edge and a drill tip, the spiral groove spirally extends from the drill tip to the end of the drill bit, and the composite carbon layer is divided into three situations: completely covering the drill bit area, partially covering the drill bit area, or partially covering the drill bit area and then adding a lubricating coating.

13. The tool according to claim 12, wherein: The diameter of the drill bit is 0.075-6 mm, and can be optionally 0.075-0.5 mm.

14. The tool according to claim 12 or 13, wherein: The axial length of the spiral groove accounts for more than 80% of the length of the drill bit; Optionally, the number of the spiral groove is at least one; Optionally, the depth of the spiral groove is 5-50% of the diameter of the drill bit.

15. The tool according to any one of claims 12 to 14, wherein: The composite carbon layer completely covers the drill bit area, which means that the spiral groove, the peripheral edge and the drill tip are all covered; Optionally, the composite carbon layer partially covers the drill bit area by covering the peripheral cutting edge in the drill bit area; Optionally, the length of the circumferential edge covered with the composite carbon layer accounts for 5 to 100% of the length of the spiral groove; Optionally, the partial covering followed by adding a lubricating coating is to cover the peripheral cutting edges in the drill bit area and then deposit a layer of lubricating coating on the entire area; Optionally, the lubricating coating has a thickness of 0.1 to 0.5 μm.

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