Carbon-based coating for tool surface, preparation method therefor, and tool

Abstract

A carbon-based coating for a tool surface. The carbon-based coating sequentially comprises, from a tool surface to the outside, a high-content sp3 bond carbon layer, a gradient layer, and a high-content sp2 bond carbon layer, wherein the high-content sp3 bond carbon layer has an sp3 bond content of 50-80%, the high-content sp2 bond carbon layer has an sp2 bond content of 50-80%, and the sp3 bond content in the gradient layer decreases from high to low from the inside to the outside. In the carbon-based coating, a carbon layer mainly comprising an sp3 bond and a carbon layer mainly comprising an sp2 bond are separately provided, the former provides high hardness and wear resistance, and the latter has a low friction coefficient and good lubricity; the carbon-based coating has a gradient layer between the two carbon layers, so that a gradual transition is achieved between the properties of the two layers, avoiding the problem of poor bonding, improving stability, reducing the internal stress in the coating, avoiding the risk of easy breakage, achieving high thickness deposition.

Description

A carbon-based coating 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 carbon-based coating for a tool surface, a preparation method thereof, and a tool. Background Art

[0002] Printed circuit boards (PCBs) are the backbone of the modern information industry. As information transmission evolves toward higher frequencies, higher speeds, and lower losses, the thickness and proportion of hard fillers in PCBs are gradually increasing, along with the number of micropores and the viscosity of modified resins. This leads to increased wear of the micro drill bits used in mechanical drilling, making chip removal difficult and, in severe cases, even tool breakage, impacting PCB processing efficiency and quality. Therefore, micro tool wear resistance must be enhanced to extend their service life. Furthermore, the drill bit surface must possess high lubricity to improve chip removal and prevent tool breakage caused by dust buildup.

[0003] Coating technology is one of the most effective means of improving material surface properties. Coating performance requirements typically include hardness, wear resistance, and coefficient of friction. Existing wear-resistant coatings are typically metal or ceramic coatings, such as TiAlN, CrAlN, or TiSiN. While these coatings offer high hardness and excellent wear resistance, they also have high coefficients of friction, making them inadequate for effective chip removal. Diamond-like carbon (DLC) coatings, as self-lubricating coatings, exhibit high hardness and low coefficients of friction and are widely used in tool coating processes. However, they have high internal stresses, and thickening the coating can easily lead to cracking and breakage risks. Thick coatings cannot be produced, and relatively low coating thicknesses offer limited improvement in tool wear resistance, impacting tool life.

[0004] CN 101432462A discloses a substrate coated with a multilayer structure comprising a tetrahedral carbon layer and a softer outer layer, the multilayer structure comprising an adhesion promoting layer, an intermediate layer and an amorphous carbon layer, the intermediate layer comprising a tetrahedral carbon layer having a Young's modulus higher than 200 GPa, having a sp higher than 50% 3 The bond carbon content, including non-hydrogenated tetrahedral carbon or hydrogenated tetrahedral carbon, the Young's modulus of the amorphous carbon layer is less than 200 GPa, with less than 40% sp 3 Bond carbon content, including amorphous hydrogenated carbon or diamond-like nanocomposite layer; in this multilayer structure, the tetrahedral carbon layer and the amorphous carbon layer are in direct contact, and the performance changes between the two are relatively abrupt, which can easily lead to weakening of the bonding strength. During application, the structural layer is prone to breakage or separation, affecting the service life.

[0005] CN 103317793A discloses a diamond-like carbon-based nanocomposite coating tool and its preparation method. The tool substrate is sequentially attached with a connecting layer, a gradient layer, and a main wear-resistant layer from the inside to the outside. The connecting layer is molybdenum, and the gradient layer is attached to the connecting layer. The gradient layer is a Mo-C layer, and the carbon content in the gradient layer gradually increases from the inside to the outside. The main wear-resistant layer is attached to the gradient layer. The main wear-resistant layer is a diamond-like coating doped with molybdenum carbide, that is, a MoC-DLC layer. The diamond-like coating in the composite coating is located on the outermost side. This structural layer mainly plays a wear-resistant role, but it still belongs to sp 3 The structural layer with a high bond content has a large internal stress, and the thickening of the coating is prone to breakage, which makes it impossible to achieve long-term wear resistance and has a short service life.

[0006] In summary, the selection of carbon-based coatings on tool surfaces requires consideration of sp 3 Key and sp 2 According to the characteristics of the key, different carbon-based structural layers are set to reduce the friction coefficient, improve lubricity and achieve large thickness deposition of the coating while ensuring hardness and wear resistance.

[0007] Summary of the Invention

[0008] 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.

[0009] The present application provides a carbon-based coating for a tool surface, a preparation method thereof, and a tool, wherein the carbon-based coating is applied to a tool surface according to sp 3 Key and sp 2 Different key contents are set to sp 3 key or sp 2 The carbon layer is mainly composed of bonds, the former provides higher hardness and wear resistance, and the latter has a low friction coefficient and better lubricity; and a gradient layer is set between the two, so that the properties of the two can be gradually transitioned, avoiding the problem of poor bonding due to large differences in properties, easy delamination or breakage, and improving the stability of the carbon-based coating.

[0010] In a first aspect, the present application provides a carbon-based coating for a tool surface, wherein the carbon-based coating comprises a high content of sp 3 Bonded carbon layer, graded layer and high content sp 2 bond carbon layer, the high content sp 3 sp in bonded carbon layer 3 The bond content is 50-80%, such as 50%, 55%, 60%, 65%, 70%, 75% or 80%, etc., and the high content sp 2 sp in bonded carbon layer 2The bond content is 50-80%, such as 50%, 55%, 60%, 65%, 70%, 75% or 80%, etc., but is not limited to the listed values. Other values ​​not listed within the respective numerical ranges are also applicable; the gradient layer from the inside to the outside sp 3 The bond content is from high to low, sp 2 Key content from low to high.

[0011] In this application, for the structure selection of carbon-based coating on the tool surface, high content sp 3 bonds and high sp 2 bonded carbon layer, sp 3 The bond is a diamond structure, and the sp 2 The bond is a graphite structure. The difference in the ratio of the two will affect the performance of the coating. The former is located on the side of the tool substrate, sp 3 The bond content is high, the hardness is large, and the wear resistance is excellent. The latter is located on the air side, sp 2 The key content is high, the friction coefficient is low, and the lubrication performance is better; in this application, a gradient layer is set between the two, that is, sp 3 Key and sp 2 The bond content changes gradually to achieve a transition in performance between the two carbon layers, avoiding the problem of poor bonding due to a large difference in performance, improving the stability of the carbon-based coating, and at the same time reducing the internal stress in the coating, avoiding the risk of easy breakage due to thickening of the coating, and achieving large thickness deposition; the carbon-based coating has a simple structure, stable performance, low cost, and a wide range of applications.

[0012] In this application, sp in the carbon layer 3 The bond content test includes: sp of carbon layer at different depths from coating surface to tool direction 3 The bond content is obtained by etching the carbon-based coating to a certain thickness using argon ions to obtain the carbon-based coating surface of the corresponding depth, and then using X-ray photoelectron spectroscopy to measure the sp 3 The carbon bond accounts for sp 3 Key and sp 2 The ratio of the total number of keys.

[0013] 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.

[0014] As an optional technical solution of this application, the high content sp 3The thickness of the bonded carbon 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, 4.5 μm or 5 μm, but is not limited to the listed values. Other unlisted values ​​within this numerical range are also applicable.

[0015] In one embodiment, the high content sp 3 The hardness of the bonded carbon layer is 45 to 65 GPa, such as 45 GPa, 50 GPa, 55 GPa, 60 GPa or 65 GPa, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0016] In one embodiment, the high content sp 2 The thickness of the bonded carbon 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, 4.5 μm or 5 μm, but is not limited to the listed values. Other unlisted values ​​within this numerical range are also applicable.

[0017] In one embodiment, the high content sp 2 The hardness of the bonded carbon layer is 20 to 45 GPa, such as 20 GPa, 25 GPa, 30 GPa, 35 GPa, 40 GPa or 45 GPa, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0018] In the present application, the hardness of the carbon layer is obtained by nanoindentation testing.

[0019] In one embodiment, the thickness of the gradient layer is 0.1 to 3 μm, for example, 0.1 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm or 3 μm, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0020] In one embodiment, the sp in the gradient layer 3 The bond content is composed of high content sp 3 sp in bonded carbon layer 3 The bond content is reduced to high content sp 2 sp in bonded carbon layer 3 Key content.

[0021] In one embodiment, the sp in the gradient layer 3 Bond content or sp 2 The key content changes continuously or gradually.

[0022] In one embodiment, when the continuous gradient is applied, sp3 Bond content or sp 2 The bond content changes linearly or nonlinearly.

[0023] In one embodiment, when the gradient changes gradually, the gradient layer is composed of at least two layers of sp 3 It is composed of gradient layers with different bond contents.

[0024] In one embodiment, the thickness of a single gradient layer is 0.02 to 1 μm, for example, 0.02 μm, 0.05 μm, 0.1 μm, 0.3 μm, 0.5 μm, 0.6 μm, 0.8 μm or 1 μm, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] In this application, as the sp 3 Bond content or sp 2 The change of bond content will cause the corresponding hardness to change, and the trend is: sp 3 The bond content decreases continuously or gradually, while sp 2 The bond content increases continuously or gradually, and the hardness of the coating decreases gradually, that is, by controlling the sp 3 Key and sp 2 The ratio of bonds in the coating realizes a gradual transition, which is divided into continuous gradual transition and gradient gradual transition; in the case of continuous gradual transition, sp 3 The bond content decreases along the thickness direction, and the rate curve can be linear and uniform, or it can be nonlinear. As shown in Figure 1, when the gradient changes gradually, the gradient layer consists of multiple sp 3 The structure is composed of layers with different bond contents, and the sp 3 The difference in bond content and the thickness of the single layer can be equal or different, as shown in Figure 2.

[0026] In the present application, the hardness of the carbon-based coating is 20 to 65 GPa, for example, 20 GPa, 25 GPa, 30 GPa, 35 GPa, 40 GPa, 45 GPa, 50 GPa, 55 GPa, 60 GPa or 65 GPa, and the overall thickness is 0.5 to 8 μm, for example, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm or 8 μm, etc.

[0027] As an optional technical solution of this application, the high content sp 2 The bonded carbon layer includes a pure carbon coating or an element-doped carbon coating.

[0028] In one embodiment, the doped element includes any one of silicon, nitrogen, hydrogen, chromium, titanium, tantalum, molybdenum, niobium or aluminum, or a combination of at least two thereof. Typical but non-limiting examples of the combination include: a combination of silicon and nitrogen, a combination of chromium and titanium, a combination of nitrogen and aluminum, a combination of silicon, titanium and tantalum, a combination of tantalum, molybdenum and niobium, etc.

[0029] In one embodiment, the carbon-based coating further comprises an adhesive layer, wherein the adhesive layer is located between the carbon-based coating and the surface of the tool.

[0030] In one embodiment, 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.

[0031] In one embodiment, the element 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.

[0032] In one embodiment, the number of layers of the adhesive layer is at least one, for example, one, two or three layers, and the thickness of each adhesive layer is 0.1 to 1 μm, for example, 0.1 μm, 0.3 μm, 0.5 μm, 0.6 μm, 0.8 μm or 1 μm, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0033] In the present application, an adhesive layer is provided to improve the bonding strength between the carbon-based coating and the tool surface, wherein the adhesive layer can be provided as one layer or multiple layers, and the multiple layers can be a combination of different materials.

[0034] In a second aspect, the present application provides a method for preparing the above-mentioned carbon-based coating, the preparation method comprising the following steps:

[0035] (1) Fix the tool drill bit and evacuate the vacuum, introduce protective gas to control the pressure, turn on the magnetron sputtering cathode and magnetically regulated multi-arc cathode, control the cathode current, and deposit high-content sp on the surface of the tool drill bit. 3 bond carbon layer;

[0036] (2) Based on step (1), the current of the magnetron sputtering cathode is adjusted to continuously increase, and the current of the magnetically regulated multi-arc cathode is adjusted to continuously decrease, thereby depositing a gradient layer;

[0037] (3) Based on step (2), continue to control the current of the magnetron sputtering cathode and the magnetically regulated multi-arc cathode to deposit high-content sp 2 bonded carbon layer, thereby obtaining a carbon-based coating.

[0038] In this application, sp 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 3 The 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.

[0039] As an optional technical solution of the present application, the tool drill bit in step (1) is cleaned before being fixed, and the cleaning includes ultrasonic cleaning.

[0040] In one embodiment, the cleaning medium includes any one of acetone, alcohol or water, or a combination of at least two of them. Typical but non-limiting examples of the combination include: a combination of acetone and alcohol, a combination of alcohol and water, and a combination of acetone, alcohol and water. The three can be used in sequence, and the medium is used alone.

[0041] In one embodiment, the cleaning time is independently 10 to 60 minutes, such as 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes or 60 minutes, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0042] In one embodiment, the tool drill bit is dried after cleaning.

[0043] In one embodiment, the tool drill bit in step (1) is placed in a vacuum chamber and fixed on a fixture.

[0044] In one embodiment, the pressure after vacuuming in step (1) is reduced to 1.0×10 -2 Pa or less, for example, 1.0×10 -2 Pa, 8.0×10 -3 Pa, 6.0×10 -3 Pa, 5.0×10 -3 Pa, 4.0×10 -3 Pa, 2.0×10 -3 Pa or 1.0×10 -3 Pa, etc., but are not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0045] In one embodiment, the protective gas in step (1) comprises an inert gas.

[0046] In one embodiment, the pressure after the protective gas is introduced in step (1) is 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 values ​​not listed within the numerical range are also applicable.

[0047] In one embodiment, the current of the magnetron sputtering cathode in step (1) is 0.1 to 2 A, for example, 0.1 A, 0.3 A, 0.5 A, 0.8 A, 1 A, 1.2 A, 1.5 A, 1.8 A or 2 A, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0048] In one embodiment, the power of the magnetron sputtering cathode in step (1) is 0.05 to 3 kW, for example, 0.05 kW, 0.1 kW, 0.5 kW, 1 kW, 1.5 kW, 2 kW, 2.5 kW or 3 kW, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0049] In one embodiment, the current of the magnetically regulated multi-arc cathode in step (1) is 70 to 300 A, for example, 70 A, 100 A, 120 A, 150 A, 180 A, 200 A, 220 A, 250 A, 270 A or 300 A, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0050] In one embodiment, the power of the magnetically regulated multi-arc cathode in step (1) is 0.5 to 20 kW, for example, 0.5 kW, 1 kW, 3 kW, 5 kW, 8 kW, 10 kW, 12 kW, 15 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.

[0051] In one embodiment, the high content sp 3 The deposition time of the bonded carbon layer is 5 to 60 minutes, for example, 5 minutes, 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes or 60 minutes, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0052] As an optional technical solution of this application, the high content sp 3 Before the bonding carbon layer is deposited, a bonding layer is first deposited on the surface of the tool drill bit.

[0053] 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.

[0054] In one embodiment, when the material of the bonding layer is a single substance, the protective gas is introduced to control the pressure 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., and 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, etc., but is not limited to the listed values, and other unlisted values ​​within the respective numerical ranges are also applicable.

[0055] In one embodiment, when the material of the bonding layer is a nitride of a corresponding element, the nitrogen gas is introduced to control the pressure to be 0.5 to 5 Pa, for example, 0.5 Pa, 1 Pa, 1.5 Pa, 2 Pa, 2.5 Pa, 3 Pa, 4 Pa ​​or 5 Pa, and 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, but is not limited to the listed values, and other values ​​not listed within the respective numerical ranges are also applicable.

[0056] In one embodiment, when the material of the bonding layer is a carbide of a corresponding element, the carbon-containing gas is introduced to control the pressure to be 0.2 to 5 Pa, for example, 0.2 Pa, 0.5 Pa, 1 Pa, 1.5 Pa, 2 Pa, 2.5 Pa, 3 Pa, 4 Pa ​​or 5 Pa, etc., and 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, etc., but is not limited to the listed values, and other unlisted values ​​within the respective numerical ranges are also applicable.

[0057] In one embodiment, when the material of the bonding layer is a carbonitride of a corresponding element, the pressure of a mixed gas of carbon-containing gas and nitrogen is controlled to be 0.5 to 5 Pa, for example, 0.5 Pa, 1 Pa, 1.5 Pa, 2 Pa, 2.5 Pa, 3 Pa, 4 Pa ​​or 5 Pa, etc., and 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, etc., but is not limited to the listed values, and other unlisted values ​​within the respective numerical ranges are also applicable.

[0058] In one embodiment, the carbon-containing gas comprises acetylene and / or methane.

[0059] In one embodiment, when the adhesive layer comprises two or more layers, the above-mentioned single-layer deposition processes are combined and stacked.

[0060] 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.

[0061] As an optional technical solution of the present application, the current of the magnetron sputtering cathode in step (2) is continuously increased from 0.1 to 2 A, for example, 0.1A, 0.3A, 0.5A, 0.8A, 1.0A, 1.2A, 1.5A, 1.8A or 2.0A, to 20 to 30 A, for example, 20A, 22A, 24A, 25A, 27A, 28A or 30A, but is not limited to the listed values, and other unlisted values ​​within the respective numerical ranges are also applicable.

[0062] In one embodiment, the current of the magnetically regulated multi-arc cathode in step (2) is continuously reduced from 70 to 300 A, for example, 70A, 90A, 100A, 120A, 150A, 180A, 200A, 250A or 300A, to 20 to 80 A, for example, 20A, 30A, 40A, 50A, 60A, 70A, 80A, etc., but is not limited to the listed values, and other unlisted values ​​within the respective numerical ranges are also applicable.

[0063] In one embodiment, the current of the magnetron sputtering cathode and the magnetically regulated multi-arc cathode in step (2) varies continuously or gradiently.

[0064] In one embodiment, the deposition time of the gradient layer in step (2) is 2 to 120 min, for example, 2 min, 5 min, 10 min, 20 min, 30 min, 45 min, 60 min, 80 min, 100 min or 120 min, etc., but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0065] In this application, the deposition of the graded layer is due to sp 3 Key and sp 2 The change of bond content requires the corresponding cathode current, power and other conditions to change in real time. The two also have a corresponding relationship, but according to sp 3 Key and sp 2 The gradual change of bond content determines whether the cathode current and power change continuously or in a gradient manner.

[0066] In one embodiment, the current of the magnetron sputtering cathode in step (3) is 20 to 30 A, for example, 20 A, 22 A, 24 A, 25 A, 26 A, 28 A or 30 A, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0067] In one embodiment, the power of the magnetron sputtering cathode in step (3) is 10 to 30 kW, for example, 10 kW, 12 kW, 15 kW, 18 kW, 20 kW, 22 kW, 25 kW, 27 kW or 30 kW, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0068] In one embodiment, the current of the magnetically regulated multi-arc cathode in step (3) is 20 to 30 A, for example, 20 A, 22 A, 24 A, 25 A, 26 A, 28 A or 30 A, etc., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0069] In one embodiment, the power of the magnetically regulated multi-arc cathode in step (3) is 0.05 to 1 kW, for example, 0.05 kW, 0.1 kW, 0.2 kW, 0.3 kW, 0.4 kW, 0.5 kW, 0.6 kW, 0.8 kW or 1.0 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 deposition time of the high-content sp2 bond carbon layer in step (3) is 2 to 600 min, for example, 2 min, 10 min, 30 min, 50 min, 75 min, 100 min, 150 min, 200 min, 300 min, 400 min, 500 min or 600 min, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0071] In a third aspect, the present application provides a tool comprising a drill bit and the above-mentioned carbon-based coating, 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 carbon-based coating 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 an overall protective layer.

[0072] As an optional technical solution of the present application, the body diameter of the drill bit is 0.075 to 6 mm, for example, 0.075 mm, 0.1 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, and other unlisted values ​​within this numerical range are also applicable.

[0073] 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.

[0074] In one embodiment, the number of the spiral groove is at least one, such as one, two or three.

[0075] In one embodiment, the depth of the spiral groove is 5% to 52% of the drill bit diameter, for example, 5%, 10%, 15%, 20%, 25%, 30%, 40%, 50% or 52%, etc., but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0076] As an optional technical solution of the present application, the carbon-based coating completely covers the drill bit area, that is, covers the spiral groove, the peripheral edge and the drill tip.

[0077] 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.

[0078] In one embodiment, the carbon-based coating partially covers the drill bit region by covering the peripheral edges in the drill bit region.

[0079] In one embodiment, the length of the circumferential edge covered with the carbon-based coating 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.

[0080] In this application, the carbon-based coating 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 carbon-based coating 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.

[0081] In one embodiment, the partial covering followed by the overall protective layer is to cover the peripheral edges in the drill bit area and then deposit a layer of low-friction coating on the entire area.

[0082] In one embodiment, the thickness of the low-friction coating is 0.05 to 0.51 μm, for example, 0.05 μm, 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, and the friction coefficient is less than 0.1, for example, 0.1, 0.08, 0.06, 0.05, 0.04, 0.02 or 0.01, but is not limited to the listed values, and other unlisted values ​​within the respective numerical ranges are also applicable.

[0083] In this application, on the basis of the second coating coverage, a layer of carbon-based coating with ultra-low friction coefficient and wear resistance is deposited on the entire area of ​​the drill bit. The friction coefficient is much lower than the 0.6-0.8 of conventional cemented carbide. This structural design is mainly aimed at the application of high-end difficult-to-process printed circuit boards where the drill bit requires extremely high wear resistance and chip removal performance. 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.

[0084] 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.

[0085] Compared with the related art, this application has the following beneficial effects:

[0086] (1) This application is based on sp 3 Key and sp2 Different key contents are set to sp 3 Key and sp 2 The carbon layer mainly consists of a carbon bond, the former provides higher hardness and wear resistance, and the latter has a low friction coefficient and good lubricity;

[0087] (2) This application is filed under sp 3 Key and sp 2 A gradient layer is set between the bond-based carbon layers to achieve a gradual transition in the properties of the two, avoiding poor bonding due to large differences in properties, improving the stability of the carbon-based coating, and at the same time reducing the internal stress in the coating, avoiding the risk of easy breakage due to thickening of the coating, and achieving large thickness deposition;

[0088] (3) The carbon-based coating and tool structure described in this application 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 contribute to the development of the next generation of communication technology, chip industry, and high-performance computing industry, and has a wide range of applications.

[0089] Still other aspects will become apparent upon reading and understanding the accompanying drawings and detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0090] 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.

[0091] FIG1 is a diagram of a continuous gradient layer provided in this application specification. 3 Curve of bond content variation along the thickness direction;

[0092] FIG2 is a diagram of the gradient layer gradient provided in this application specification. 3 Curve of bond content variation along the thickness direction;

[0093] FIG3 is a schematic structural diagram of a drill bit provided in Example 1 of the present application;

[0094] FIG4 is a partial enlarged view of the drill bit provided in Example 1 of the present application;

[0095] FIG5 is a schematic structural diagram of a drill tip in a drill bit provided in Example 1 of the present application;

[0096] FIG6 is a schematic structural diagram of a carbon-based coating provided in Example 2 of the present application;

[0097] FIG7 is a schematic structural diagram of a drill bit provided in Example 2 of the present application;

[0098] FIG8 is a partial enlarged view of the drill bit provided in Example 2 of the present application;

[0099] FIG9 is a schematic structural diagram of a drill tip in a drill bit provided in Example 2 of the present application;

[0100] FIG10 is a schematic structural diagram of a drill bit provided in Example 3 of the present application;

[0101] FIG11 is a partial enlarged view of the drill bit provided in Example 3 of the present application;

[0102] FIG12 is a schematic structural diagram of a drill tip in a drill bit provided in Example 3 of the present application;

[0103] FIG. 13 is a graph showing a high content of sp in a carbon-based coating provided in Example 6 of the present application. 3 XPS test results of the bond carbon layer;

[0104] Figure 14 is a graph showing a high content of sp in the carbon-based coating provided in Example 6 of the present application. 2 XPS test results of the bond carbon layer;

[0105] FIG15 is a graph showing the tool breakage rate when processing an E705G package substrate using different tools provided in Example 6 of the present application;

[0106] FIG16 is a diagram showing the wear results of different cutting tools after machining an E705G package substrate according to Example 6 of the present application;

[0107] Among them, 1-high content sp 3 bonded carbon layer, 2-graded layer, 3-high content sp 2 1-carbon layer, 4-bonding layer, 5-spiral groove, 6-circumferential edge, 7-drill tip. DETAILED DESCRIPTION

[0108] 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.

[0109] The following are typical but non-limiting examples of this application:

[0110] Example 1:

[0111] This embodiment provides a carbon-based coating for a tool surface and a tool, wherein the carbon-based coating includes a high content of sp 3 Bonded carbon layer 1, graded layer 2 and high content sp 2 bond carbon layer 3, the high content sp 3 sp in bonded carbon layer 1 3 The bond content is 52.9%, the high content sp 2 sp in bonded carbon layer 3 2The bond content is 62.6%, and the gradient layer 2 has sp 3 The bond content is from high to low, sp 2 Key content from low to high.

[0112] The high content of sp 3 The bonded carbon layer 1 has a thickness of 0.15 μm and a hardness of 52.1 GPa.

[0113] The high content of sp 2 The bonded carbon layer 3 has a thickness of 0.2 μm and a hardness of 35.6 GPa.

[0114] The thickness of the gradient layer 2 is 0.2 μm, and the sp 3 The bond content changes linearly and continuously at a uniform speed, from 52.9% to 37.4%.

[0115] The tool includes a drill bit and a carbon-based coating on the surface of the drill bit. The structural schematic diagram of the drill bit is shown in Figure 3, and its partial enlarged view is shown in Figure 4. It includes a spiral groove 5, a peripheral edge 6 and a drill tip 7. The structural schematic diagram of the drill tip is shown in Figure 5. The spiral groove 5 spirally extends from the drill tip 7 to the end of the drill bit. The carbon-based coating partially covers the drill bit area, that is, covers the peripheral edge 6 in the drill bit area.

[0116] The body diameter of the drill bit is 0.15 mm.

[0117] The axial length of the spiral groove 5 accounts for 100% of the length of the drill bit. There are two spiral grooves 5 , and the depth of the spiral groove 5 accounts for 28% of the diameter of the drill bit.

[0118] The length of the circumferential edge 6 covered with the carbon-based coating accounts for 50% of the length of the spiral groove 5 .

[0119] Example 2:

[0120] This embodiment provides a carbon-based coating for the surface of a tool and a tool. The structural diagram of the carbon-based coating is shown in FIG6 , which includes a high content of sp 3 Bonded carbon layer 1, graded layer 2 and high content sp 2 bond carbon layer 3, the high content sp 3 sp in bonded carbon layer 1 3 The bond content is 60.3%, the high content sp 2 sp in bonded carbon layer 3 2 The bond content is 75.4%, and the gradient layer 2 has sp 3 The bond content is from high to low, sp 2 Key content from low to high.

[0121] The high content of sp 3The bond carbon layer 1 has a thickness of 0.2 μm and a hardness of 56.5 GPa.

[0122] The high content of sp 2 The bonded carbon layer 3 has a thickness of 0.3 μm and a hardness of 22.5 GPa.

[0123] The thickness of the gradient layer 2 is 0.5 μm, and the sp 3 The bond content changes nonlinearly and continuously from 60.3% to 24.6%.

[0124] The carbon-based coating further comprises an adhesive layer 4 , which is located between the carbon-based coating and the surface of the tool.

[0125] The adhesive layer 4 is made of chromium, and has a thickness of 0.2 μm.

[0126] The tool includes a drill bit and a carbon-based coating on the surface of the drill bit. The structural schematic diagram of the drill bit is shown in Figure 7, and its partial enlarged view is shown in Figure 8. It includes a spiral groove 5, a circumferential blade 6 and a drill tip 7. The structural schematic diagram of the drill tip is shown in Figure 9. The spiral groove 5 spirally extends from the drill tip 7 to the end of the drill bit. The carbon-based coating completely covers the drill bit area, that is, the spiral groove 5, the circumferential blade 6 and the drill tip 7 are all covered.

[0127] The body diameter of the drill bit is 0.25 mm.

[0128] The axial length of the spiral groove 5 accounts for 95% of the length of the drill bit. There are two spiral grooves 5 , and the depth of the spiral groove 5 accounts for 30% of the diameter of the drill bit.

[0129] Example 3:

[0130] This embodiment provides a carbon-based coating for a tool surface and a tool, wherein the carbon-based coating includes a high content of sp 3 Bonded carbon layer 1, graded layer 2 and high content sp 2 bond carbon layer 3, the high content sp 3 sp in bonded carbon layer 1 3 The bond content is 71.7%, the high content sp 2 sp in bonded carbon layer 3 2 The bond content is 60.6%, and the gradient layer 2 has sp 3 The bond content is from high to low, sp 2 Key content from low to high.

[0131] The high content of sp 3 The bond carbon layer 1 has a thickness of 0.5 μm and a hardness of 60.8 GPa.

[0132] The high content of sp 2The bonded carbon layer 3 has a thickness of 1.5 μm and a hardness of 33.9 GPa.

[0133] The thickness of the gradient layer 2 is 1.0 μm, and the sp 3 The bond content changes gradually from 71.7% to 30.4%.

[0134] The gradient layer 2 is composed of two layers of sp 3 The thickness of a single gradient layer is 0.5 μm.

[0135] The tool includes a drill bit and a carbon-based coating on the surface of the drill bit. The structural schematic diagram of the drill bit is shown in Figure 10, and its partial enlarged view is shown in Figure 11. It includes a spiral groove 5, a circumferential blade 6 and a drill tip 7. The structural schematic diagram of the drill tip is shown in Figure 12. The spiral groove 5 spirally extends from the drill tip 7 to the end of the drill bit. The carbon-based coating partially covers the drill bit area and then adds an overall protective layer, that is, after covering the circumferential blade 6 in the drill bit area, a layer of low-friction coating is deposited on the entire drill bit.

[0136] The body diameter of the drill bit is 0.9 mm.

[0137] The axial length of the spiral groove 5 accounts for 90% of the length of the drill bit. There are two spiral grooves 5 , and the depth of the spiral groove 5 accounts for 25% of the diameter of the drill bit.

[0138] The length of the peripheral edge 6 covered with the carbon-based coating accounts for 80% of the length of the spiral groove 5 .

[0139] The low-friction coating has a thickness of 0.1 μm, covers the entire surface of the drill bit area, and has a friction coefficient of 0.08.

[0140] Example 4:

[0141] This embodiment provides a carbon-based coating for a tool surface and a tool, wherein the carbon-based coating includes a high content of sp 3 Bonded carbon layer 1, graded layer 2 and high content sp 2 bond carbon layer 3, the high content sp 3 sp in bonded carbon layer 1 3 The bond content is 76%, the high content sp 2 sp in bonded carbon layer 3 2 The bond content is 77%, and the gradient layer 2 has sp 3 The bond content is from high to low, sp 2 Key content from low to high.

[0142] The high content of sp 3 The bonded carbon layer 1 has a thickness of 0.8 μm and a hardness of 62.2 GPa.

[0143] The high content of sp 2 The bonded carbon layer 3 has a thickness of 0.9 μm and a hardness of 20.6 GPa.

[0144] The thickness of the gradient layer 2 is 0.8 μm, and the sp 3 The bond content changes continuously and nonlinearly from 76% to 23%.

[0145] The carbon-based coating further comprises an adhesive layer 4 , which is located between the carbon-based coating and the surface of the tool.

[0146] The bonding layer 4 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 0.3 μm.

[0147] The tool includes a drill bit and a carbon-based coating on the surface of the drill bit. The drill bit includes a spiral groove 5, a circumferential edge 6 and a drill tip 7. The spiral groove 5 spirally extends from the drill tip 7 to the end of the drill bit. The carbon-based coating completely covers the drill bit area, that is, the spiral groove 5, the circumferential edge 6 and the drill tip 7 are all covered.

[0148] The body diameter of the drill bit is 2.0 mm.

[0149] The axial length of the spiral groove 5 accounts for 85% of the length of the drill bit. There is one spiral groove 5 , and the depth of the spiral groove 5 accounts for 40% of the diameter of the drill bit.

[0150] Example 5:

[0151] This embodiment provides a carbon-based coating for a tool surface and a tool, wherein the carbon-based coating includes a high content of sp 3 Bonded carbon layer 1, graded layer 2 and high content sp 2 bond carbon layer 3, the high content sp 3 sp in bonded carbon layer 1 3 The bond content is 65%, the high content sp 2 sp in bonded carbon layer 3 2 The bond content is 55%, and the gradient layer 2 has sp 3 The bond content is from high to low, sp 2 Key content from low to high.

[0152] The high content of sp 3 The bonded carbon layer 1 has a thickness of 5 μm and a hardness of 58.5 GPa.

[0153] The high content of sp 2 The bonded carbon layer 3 has a thickness of 4.5 μm and a hardness of 40.5 GPa.

[0154] The high content of sp 2The bonded carbon layer 3 is an element-doped carbon coating, and the doping element is silicon.

[0155] The thickness of the gradient layer 2 is 2.5 μm, and the sp 3 The bond content is gradually reduced from 65% to 45%.

[0156] The gradient layer 2 is composed of three layers of sp 3 The gradient layers have different bond contents of 60%, 55% and 50%, respectively, and their corresponding thicknesses are 0.8 μm, 0.9 μm and 0.8 μm, respectively.

[0157] The carbon-based coating further comprises an adhesive layer 4 , which is located between the carbon-based coating and the surface of the tool.

[0158] The bonding layer 4 includes a silicon nitride bonding layer, and the thickness of the bonding layer 4 is 1 μm.

[0159] The tool includes a drill bit and a carbon-based coating on the surface of the drill bit. The drill bit includes a spiral groove 5, a peripheral edge 6 and a drill tip 7. The spiral groove 5 spirally extends from the drill tip 7 to the end of the drill bit. The carbon-based coating partially covers the drill bit area and then adds an overall protective layer, that is, after covering the peripheral edge 6 in the drill bit area, a low-friction coating is deposited on the entire drill bit.

[0160] The body diameter of the drill bit is 6 mm.

[0161] The axial length of the spiral groove 5 accounts for 80% of the length of the drill bit. There are two spiral grooves 5 , and the depth of the spiral groove 5 accounts for 20% of the diameter of the drill bit.

[0162] The length of the circumferential edge 6 covered with the carbon-based coating occupies 100% of the length of the spiral groove 5 .

[0163] The low-friction coating has a thickness of 0.5 μm, covers the entire surface of the drill bit area, and has a friction coefficient of 0.1.

[0164] Example 6:

[0165] This embodiment provides a method for preparing a carbon-based coating for a tool surface, wherein the carbon-based coating is the carbon-based coating in Example 1. The method comprises the following steps:

[0166] (1) The tool drill bit was first ultrasonically cleaned with acetone, alcohol, and water. Each medium was used separately and the cleaning time was 20 min. After cleaning, the tool drill bit was dried. The tool drill bit was then placed in a vacuum chamber and fixed on a fixture. The vacuum was evacuated until the pressure dropped to 1.0×10 -2Pa, and introduced argon to control the pressure to 0.3Pa, turned on the magnetron sputtering cathode and the magnetically regulated multi-arc cathode, controlled the current of the magnetron sputtering cathode to 0.4A, the power to 0.2kW, the current of the magnetically regulated multi-arc cathode to 200A, the power to 5kW, and deposited it on the surface of the tool drill bit for 20 minutes to obtain a high content of sp 3 bond carbon layer;

[0167] (2) Based on step (1), the current of the magnetron sputtering cathode was adjusted to increase continuously from 0.4 A to 20 A, and the current of the magnetically regulated multi-arc cathode was adjusted to decrease continuously from 200 A to 30 A. The deposition was continued for 20 min to obtain a gradient layer.

[0168] (3) Based on step (2), argon gas was introduced to control the pressure to 0.85 Pa, and the current of the magnetron sputtering cathode and the magnetically regulated multi-arc cathode was continued to be controlled. The current of the magnetron sputtering cathode was 20 A and the power was 12 kW, and the current of the magnetically regulated multi-arc cathode was 30 A and the power was 0.8 kW. The deposition was carried out for 80 min to obtain a high content sp 2 A carbon layer is bonded to the drill head, thereby obtaining a carbon-based coating which covers the peripheral edge locations in the drill head area.

[0169] The high content of sp in the carbon-based coating obtained in this embodiment 3 bonded carbon layer and high content of sp 2 The bond carbon layer was subjected to XPS testing, and the test results are shown in Figures 13 and 14 respectively. The tool covered with the carbon-based coating was used to process the E705G package substrate, and the number of holes processed was 10,000. The tool was compared with the usage of the tool without coating and the tool covered with TiAlN coating. The tool breakage rate results are shown in Figure 15. The outer diameter of the tool changed after processing, and its wear condition is shown in Figure 16.

[0170] In this embodiment, according to the curve in FIG13 , it can be calculated that the high content sp 3 sp in the bonded carbon layer 3 The bond content is 52.9%. According to the curve in Figure 14, it can be calculated that the high content sp 2 sp in the bonded carbon layer 2 The bond content is 62.6%. As shown in FIG15 , the coated tool in this embodiment did not break after use, while the tool breakage rates of the uncoated tool and the tool covered with the TiAlN coating were 3‰ and 2‰, respectively. As shown in FIG16 , after processing 10,000 holes of the E705G package substrate, the outer diameter of the coated tool in this embodiment was reduced by only 2.1 μm, the outer diameter of the uncoated tool was reduced by 14.2 μm, and the outer diameter of the tool covered with the TiAlN coating was reduced by 7.7 μm. This shows that the pure carbon coating in this embodiment has obvious wear resistance advantages.

[0171] In summary, the carbon-based coating reduces the tool breakage rate and improves the tool wear resistance by increasing the lubricity and wear resistance of the tool surface, thereby effectively extending the tool's service life.

[0172] Example 7:

[0173] This embodiment provides a method for preparing a carbon-based coating for a tool surface, wherein the carbon-based coating is the carbon-based coating in Example 2. The method comprises the following steps:

[0174] (1) The tool drill bit was first ultrasonically cleaned with acetone, alcohol, and water. Each medium was used separately and the cleaning time was 30 min. After cleaning, the tool drill bit was dried. The tool drill bit was then placed in a vacuum chamber and fixed on a fixture. The vacuum was evacuated until the pressure dropped to 9.0×10 -3 Pa, and introduce argon gas to control the pressure to 2.0 Pa, turn on the magnetically regulated multi-arc cathode, control the current of the magnetically regulated multi-arc cathode to 60 A, and deposit on the surface of the tool drill bit for 10 minutes to obtain a chromium bonding layer;

[0175] The pressure was adjusted to 0.6 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 be 0.1 A and the power was 0.1 kW, and the current of the magnetically regulated multi-arc cathode was controlled to be 150 A and the power was 10 kW. The deposited material was deposited on the surface of the tool drill bit for 30 minutes to obtain a high content of sp. 3 bond carbon layer;

[0176] (2) Based on step (1), the current of the magnetron sputtering cathode was adjusted to increase continuously from 0.1A to 25A, and the current of the magnetically regulated multi-arc cathode was adjusted to decrease continuously from 150A to 26A. The deposition was continued for 50 minutes to obtain a gradient layer.

[0177] (3) Based on step (2), argon gas was introduced to control the pressure to 1.5 Pa, and the current of the magnetron sputtering cathode and the magnetically regulated multi-arc cathode was continued to be controlled. The current of the magnetron sputtering cathode was 30 A and the power was 28 kW, and the current of the magnetically regulated multi-arc cathode was 20 A and the power was 0.2 kW. The deposition was carried out for 120 min to obtain a high content sp 2 A carbon layer is bonded to the drill head, thereby obtaining a carbon-based coating that completely covers the drill head area.

[0178] The tool covered with the carbon-based coating in this embodiment is used to process the EM390 difficult-to-process printed circuit board, and can process 800 holes with satisfactory processing quality. Compared with the tool without the coating that can only process 200 holes, the processing life is increased to 4 times the original.

[0179] Example 8:

[0180] This embodiment provides a method for preparing a carbon-based coating for a tool surface, wherein the carbon-based coating is the carbon-based coating in Example 3. The method comprises the following steps:

[0181] (1) The tool drill bit was first ultrasonically cleaned with acetone, alcohol, and water. Each medium was used separately and the cleaning time was 40 min. After cleaning, the tool drill bit was dried. The tool drill bit was then placed in a vacuum chamber and fixed on a fixture. The vacuum was evacuated until the pressure dropped to 1.0×10 -2 Pa, and introduced argon to control the pressure to 0.1Pa, turned on the magnetron sputtering cathode and the magnetically regulated multi-arc cathode, controlled the current of the magnetron sputtering cathode to 0.1A, the power to 0.15kW, the current of the magnetically regulated multi-arc cathode to 300A, the power to 18kW, and deposited it on the surface of the tool drill bit for 30 minutes to obtain a high content of sp 3 bond carbon layer;

[0182] (2) Based on step (1), argon gas was introduced to control the pressure to 0.3 Pa, and the current gradient of the magnetron sputtering cathode was adjusted to increase from 0.4 A to 18 A, and the current gradient of the magnetically regulated multi-arc cathode was reduced from 300 A to 70 A. After deposition for 4 minutes, the current of the magnetron sputtering cathode was adjusted to increase from 18 A to 27 A, and the current of the magnetically regulated multi-arc cathode was reduced from 70 A to 20 A. Deposition was continued for 16 minutes to obtain a gradient layer consisting of two gradient layers.

[0183] (3) Based on step (2), argon gas was introduced to control the pressure to 1.2 Pa, and the current of the magnetron sputtering cathode and the magnetically regulated multi-arc cathode was continued to be controlled. The current of the magnetron sputtering cathode was 27 A and the power was 22 kW, and the current of the magnetically regulated multi-arc cathode was 20 A and the power was 0.5 kW. The deposition was carried out for 60 min to obtain a high content sp 2 bond carbon layer, thereby obtaining a carbon-based coating,

[0184] The carbon-based coating covers the peripheral edge position in the drill bit area, and then the low-friction coating is deposited. The low-friction 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 20 minutes to obtain the low-friction coating.

[0185] The tool covered with the carbon-based coating in this embodiment is used to process the EM526 difficult-to-process printed circuit board, and can process 700 holes with satisfactory processing quality. Compared with the tool without the coating that can only process 150 holes, the processing life is increased to 4.67 times the original.

[0186] Example 9:

[0187] This embodiment provides a method for preparing a carbon-based coating for a tool surface, wherein the carbon-based coating is the carbon-based coating in Example 4. The method comprises the following steps:

[0188] (1) The tool drill bit was first ultrasonically cleaned with acetone, alcohol, and water. Each medium was used separately and the cleaning time was 50 min. After cleaning, the tool drill bit was dried. The tool drill bit was then placed in a vacuum chamber and fixed on a fixture. The vacuum was evacuated until the pressure dropped to 5.0×10 -3 Pa, and neon gas is introduced to control the pressure to 3.0 Pa, the magnetically regulated multi-arc cathode is turned on, the current of the magnetically regulated multi-arc cathode is controlled to 90 A, and deposition is carried out on the surface of the tool drill bit for 20 minutes to obtain a chromium bonding layer; the gas introduced is adjusted to nitrogen, the pressure is controlled to 3.5 Pa, the current of the magnetically regulated multi-arc cathode is controlled to 90 A, and deposition is carried out for 15 minutes to obtain a chromium nitride bonding layer;

[0189] The krypton gas pressure was adjusted 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 be 0.2 A and the power to be 0.05 kW, and the current of the magnetically regulated multi-arc cathode was controlled to be 290 A and the power to be 17 kW. The deposition was continued for 30 min to obtain a high content sp 3 bond carbon layer;

[0190] (2) Based on step (1), the current of the magnetron sputtering cathode was adjusted to increase continuously from 0.1A to 25A, and the current of the magnetically regulated multi-arc cathode was adjusted to decrease continuously from 290A to 30A. The deposition was performed for 50 minutes to obtain a gradient layer.

[0191] (3) Based on step (2), krypton gas was introduced to control the pressure to 1.6 Pa, and the current of the magnetron sputtering cathode and the magnetically regulated multi-arc cathode was continued to be controlled. The current of the magnetron sputtering cathode was 28.6 A and the power was 27.8 kW, and the current of the magnetically regulated multi-arc cathode was 20 A and the power was 0.9 kW. The deposition time was 350 min to obtain a high content sp 2 A carbon layer is bonded to the drill head, thereby obtaining a carbon-based coating that completely covers the drill head area.

[0192] The tool covered with the carbon-based coating in this embodiment is used to process aluminum-based printed circuit boards, and can process 15,000 holes with satisfactory processing quality. Compared with the tool without the coating that can only process 3,000 holes, the processing life is increased to 5 times the original.

[0193] From the above embodiments, it can be seen that the present application is based on sp 3 Key and sp 2 Different key contents are set to sp 3 Key and sp 2The carbon layer mainly composed of sp 3 Key and sp 2 A gradient layer is set between the carbon layers mainly composed of bonds, so that the properties of the two are gradually transitioned, avoiding poor bonding due to large differences in properties, improving the stability of the carbon-based coating, and at the same time reducing the internal stress in the coating, avoiding the risk of easy breakage due to thickening of the coating, and achieving large thickness deposition; the carbon-based coating and tool structure 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 has a wide range of applications.

[0194] 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 carbon-based coating for a tool surface, wherein: The carbon-based coating includes a high content of sp 3 Bonded carbon layer, graded layer and high content sp 2 bond carbon layer, the high content of sp 3 sp in bonded carbon layer 3 The bond content is 50-80%, and the high content sp 2 sp in bonded carbon layer 2 The bond content is 50-80%, and the gradient layer has sp 3 The bond content is from high to low, sp 2 Key content from low to high.

2. The carbon-based coating according to claim 1, wherein The high content of sp 3 The thickness of the bond carbon layer is 0.1 to 5 μm.

3. The carbon-based coating according to claim 1 or 2, wherein: The high content of sp 3 The hardness of the bond carbon layer is 45 to 65 GPa.

4. The carbon-based coating according to any one of claims 1 to 3, wherein: The high content of sp 2 The thickness of the bond carbon layer is 0.1 to 5 μm.

5. The carbon-based coating according to any one of claims 1 to 4, wherein: The high content of sp 2 The hardness of the bonded carbon layer is 20 to 45 GPa.

6. The carbon-based coating according to any one of claims 1 to 5, wherein: The thickness of the gradient layer is 0.1 to 3 μm; Optionally, the sp in the gradient layer 3 The bond content is composed of high content sp 3 sp in bonded carbon layer 3 The bond content is reduced to high content sp 2 sp in bonded carbon layer 3 Key content; Optionally, the sp in the gradient layer 3 Bond content or sp 2 The bond content changes continuously or gradually; Optionally, when the continuous gradient is applied, sp 3 Bond content or sp 2 The bond content changes linearly and uniformly or nonlinearly; Optionally, when the gradient changes gradually, the gradient layer consists of at least two layers of sp 3 It is composed of gradient layers with different bond contents; Optionally, the thickness of a single gradient layer is 0.02-1 μm.

7. The carbon-based coating according to any one of claims 1 to 6, wherein: The high content of sp 2 The bonded carbon layer includes a pure carbon coating or an element-doped carbon coating; Optionally, the doped element includes any one or a combination of at least two of silicon, nitrogen, hydrogen, chromium, titanium, tantalum, molybdenum, niobium or aluminum; Optionally, the carbon-based coating further comprises an adhesive layer, wherein the adhesive layer is located between the carbon-based coating 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 number of the adhesive layer is at least one, and the thickness of each adhesive layer is 0.1-1 μm.

8. The method for preparing a carbon-based coating according to any one of claims 1 to 7, comprising the following steps: (1) After fixing the tool drill bit, evacuate the vacuum, introduce protective gas to control the pressure, turn on the magnetron sputtering cathode and magnetically regulated multi-arc cathode, control the cathode current, and deposit high-content sp on the surface of the tool drill bit. 3 Bond carbon layer; (2) Based on step (1), the current of the magnetron sputtering cathode is adjusted to continuously increase, and the current of the magnetically regulated multi-arc cathode is adjusted to continuously decrease, so as to deposit a gradient layer; (3) Based on step (2), continue to control the current of the magnetron sputtering cathode and the magnetically regulated multi-arc cathode to deposit a high content sp 2 bond carbon layer to obtain a carbon-based coating.

9. The preparation method according to claim 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 any one of acetone, alcohol or water or a combination of at least two of them, and the medium is used alone; Optionally, the cleaning time is independently 10 to 60 minutes; Optionally, the tool drill bit is dried after cleaning.

10. The preparation method according to claim 8 or 9, wherein: 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 1.0×10 -2 Below Pa; Optionally, the protective gas in step (1) comprises an inert gas; Optionally, the pressure after the protective gas is introduced in step (1) is 0.1 to 5 Pa; Optionally, the current of the magnetron sputtering cathode in step (1) is 0.1 to 2A; Optionally, the power of the magnetron sputtering cathode in step (1) is 0.05 to 3 kW; Optionally, the current of the magnetically regulated multi-arc cathode in step (1) is 70 to 300 A; Optionally, the power of the magnetically regulated multi-arc cathode in step (1) is 0.5-20 kW; Optionally, the high content sp in step (1) 3 The deposition time of the bonded carbon layer is 5 to 60 minutes.

11. The preparation method according to any one of claims 8 to 10, wherein: Step (1) The high content of sp 3 Before the bonding carbon layer is deposited, a bonding layer is deposited on the surface of the tool drill bit; Optionally, depending on the material of the adhesive layer, select a magnetically regulated multi-arc cathode to control different atmospheres conditions and currents; Optionally, when the material of the bonding layer is a single substance, the protective gas is introduced to control the pressure to be 0.1-5 Pa, and the current of the magnetically regulated multi-arc cathode is 20-300 A; Optionally, when the material of the bonding layer is a nitride of a corresponding single substance, the nitrogen gas is introduced to control the pressure to be 0.5-5 Pa, and the current of the magnetically regulated multi-arc cathode is 20-300 A; Optionally, when the material of the bonding layer is a carbide of a corresponding single substance, the carbon-containing gas is introduced to control the pressure to be 0.2 to 5 Pa, and the current of the magnetically regulated multi-arc cathode is 20 to 300 A; Optionally, when the material of the bonding layer is a carbonitride of a corresponding single substance, the pressure of the mixed gas of carbon-containing gas and nitrogen is controlled to be 0.5-5 Pa, and the current of the magnetically regulated multi-arc cathode is 20-300 A; 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.

12. The preparation method according to any one of claims 8 to 11, wherein: The current of the magnetron sputtering cathode in step (2) is continuously increased from 0.1-2A to 20-30A; Optionally, in step (2), the current of the magnetically regulated multi-arc cathode is continuously reduced from 70 to 300 A to 20 to 80 A; Optionally, in step (2), the current of the magnetron sputtering cathode and the magnetically regulated multi-arc cathode varies continuously or gradiently; Optionally, the deposition time of the gradient layer in step (2) is 2 to 120 minutes; Optionally, the current of the magnetron sputtering cathode in step (3) is 20 to 30 A; Optionally, the power of the magnetron sputtering cathode in step (3) is 10 to 30 kW; Optionally, the current of the magnetically regulated multi-arc cathode in step (3) is 20 to 30 A; Optionally, the power of the magnetically regulated multi-arc cathode in step (3) is 0.05-1 kW; Optionally, the high content sp in step (3) 2 The deposition time of the bonded carbon layer is 2 to 600 minutes.

13. A cutting tool, wherein: The tool comprises a drill bit and the carbon-based coating according to any one of claims 1 to 7, wherein the drill bit comprises a spiral groove, a peripheral edge and a drill tip, wherein the spiral groove spirally extends from the drill tip to the end of the drill bit, and the carbon-based coating is divided into three situations: completely covering the drill bit area, partially covering the drill bit area, or partially covering the drill bit area followed by an overall protective layer.

14. The tool according to claim 13, wherein: The body diameter of the drill bit is 0.075-6 mm; Optionally, 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 accounts for 5-52% of the diameter of the drill bit.

15. The tool according to claim 13 or 14, wherein: The carbon-based coating completely covers the drill bit area, that is, the spiral groove, the peripheral edge and the drill tip are all covered; Optionally, the carbon-based coating partially covers the drill bit area by covering the peripheral cutting edge in the drill bit area; Optionally, the length of the peripheral edge covered with the carbon-based coating accounts for 5 to 100% of the length of the spiral groove; Optionally, the partial covering followed by the overall protective layer is to cover the peripheral cutting edges in the drill bit area and then deposit a layer of low-friction coating on the entire area; Optionally, the low-friction coating has a thickness of 0.05-0.5 μm and a friction coefficient of less than 0.1.

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