Diamond cutting tool and cutting method
By introducing a gradient transition layer and a wear-resistant conductive layer into diamond cutting tools, a three-dimensional conductive network is formed, which solves the problems of conductivity, wear resistance and bonding strength, and realizes the ability to prepare cutting tools and process non-conductive materials with high efficiency and low cost.
Patent Information
- Application Number
- CN202610151086.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-03
- Publication Date
- 2026-05-15
AI Technical Summary
Existing diamond-coated cutting tools are difficult to optimize in a synergistic way in terms of conductivity, wear resistance, bonding strength and manufacturing cost, and are not suitable for processing non-conductive materials.
The structure employs a gradient transition layer and a wear-resistant conductive layer, including a first sublayer of carbide or nitride compatible with the tool substrate and a second sublayer of gradually doped diamond. This is combined with a continuous diamond phase and conductive nanoparticles to form a three-dimensional conductive network, which is prepared by a single chemical vapor deposition process.
It improves the bonding strength between the coating and the substrate, maintains the stability and wear resistance of the conductive function, reduces the preparation cost, and enables the processing of non-conductive materials.
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Figure CN122033308A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of drill bit processing technology, and in particular to a diamond cutting tool and cutting method. Background Technology
[0002] Diamond-coated cutting tools are widely used in precision machining such as printed circuit boards (PCBs), but their non-conductive properties cannot meet the electrical conductivity detection functions required in CNC machining, such as drilling depth control and tool breakage detection.
[0003] Some technologies employ a double-layer stacked structure of a diamond wear-resistant layer and an outer metal conductive film to address the conductivity issue of cutting tools. However, the outermost metal conductive film is prone to wear and peeling during processing, leading to unstable electrical signals and detection failure. Furthermore, the significant differences in physical properties between the diamond and metal layers result in weak interfacial adhesion, making the coating susceptible to premature peeling. The fabrication process requires two sequential steps, CVD and PVD, which is complex and costly. The electrical conductivity relies entirely on the workpiece's conductivity, making it unsuitable for processing non-conductive materials such as ceramics. Therefore, current cutting tools face a challenge in achieving a harmonious balance between conductivity, wear resistance, bonding strength, and manufacturing cost. Summary of the Invention
[0004] This application provides a diamond cutting tool and a cutting method to solve the technical problem that current cutting tools are difficult to optimize in a synergistic way in terms of conductivity, wear resistance, bonding strength and manufacturing cost.
[0005] In a first aspect, this application provides a diamond cutting tool, comprising a tool substrate, a gradient transition layer, and a wear-resistant conductive layer deposited on the gradient transition layer; the gradient transition layer comprises a first sub-layer and a second sub-layer sequentially from the surface of the tool substrate outward, wherein the first sub-layer is a carbide or nitride compatible with the tool substrate, and the second sub-layer is a gradually doped diamond. The wear-resistant conductive layer comprises a continuous diamond phase and conductive nanoparticles, wherein the conductive nanoparticles are interconnected in the diamond phase to form a three-dimensional conductive network extending from the gradient transition layer interface to the tool surface.
[0006] In some embodiments, the conductive nanoparticles form conductive paths in at least two directions in the wear-resistant conductive layer, including a normal direction from the gradient transition layer interface toward the tool surface and at least one transverse direction perpendicular to the normal direction.
[0007] In some embodiments, the conductive nanoparticles are selected from nitride nanocrystals, carbide nanocrystals, or carbonitride nanocrystals of metals in Groups IVB, VB, and VIB of the periodic table. The average grain size of the conductive nanoparticles is smaller than the average grain size of the diamond phase, and the conductive nanoparticles are non-uniformly distributed in the thickness direction of the wear-resistant conductive layer, with a higher concentration in the region closer to the gradient transition layer than in the region farther from the gradient transition layer.
[0008] In some of these embodiments, the average grain size of the diamond phase is 0.5 μm to 3 μm, and the average grain size of the conductive nanoparticles is 20 nm to 100 nm.
[0009] In some embodiments, the first sublayer is made of TiC, TiN, CrN or WC, and the second sublayer is doped with one or more of Si, B, Ti and Cr.
[0010] Secondly, this application provides a method for manufacturing a diamond cutting tool, comprising the following steps: In the reaction chamber of a single chemical vapor deposition apparatus, a gradient transition layer and a wear-resistant conductive layer are sequentially deposited on the surface of a tool substrate, wherein the deposition step of the wear-resistant conductive layer includes: A diamond growth source, a conductive nanoparticle formation source, and a reactive gas are simultaneously introduced into the reaction chamber. A pulsed bias field is applied to the tool substrate, and the energy parameters of the pulsed bias field are adjusted to control the activity of conductive nanoparticles generated by the in-situ reaction between the conductive nanoparticle formation source and the reactive gas within the diamond growth source. This allows the conductive nanoparticles to self-assemble in situ from the gradient transition layer interface to the tool surface to form a three-dimensional conductive network.
[0011] In some embodiments, the pulsed bias field is controlled as follows: a first pulsed bias condition is applied during a first time period of the deposition stage, the first pulsed bias condition including a first negative bias amplitude of -150V to -300V and a first duty cycle of 40% to 70%; a second pulsed bias condition is applied during a second time period of the deposition stage, the second pulsed bias condition including a second negative bias amplitude of -50V to -140V and a second duty cycle of 20% to 50%, wherein the second negative bias amplitude is less than the first negative bias amplitude, and the second duty cycle is not greater than the first duty cycle; the first pulsed bias condition and the second pulsed bias condition decay over time.
[0012] In some embodiments, the diamond growth source gas is a mixture of hydrogen and methane, wherein methane accounts for 1% to 5% of the total volume of the mixture; the conductive nanoparticle formation source is the vapor of at least one metal compound selected from titanium tetrachloride, chromium hexacarbonyl, molybdenum hexacarbonyl, and trimethylaluminum; and the reaction gas is nitrogen or acetylene.
[0013] In some embodiments, the deposition step of the gradient transition layer includes: In a halide or organometallic precursor atmosphere containing titanium, chromium or tungsten, a first sublayer composed of carbides, nitrides or carbonitrides is deposited on the surface of the tool substrate; While maintaining the diamond growth atmosphere, silane, borane, or phosphine are simultaneously introduced as dopants, and the flow rate of the dopants is reduced in a stepwise manner until a preset value is reached, forming a second sublayer in which the concentration of doped elements continuously decreases from the inside to the outside.
[0014] Thirdly, this application provides a cutting method using a diamond cutting tool, comprising the following steps: The tool body of the diamond cutting tool is electrically connected to the signal output terminal of the monitoring circuit, and the conductive area on the workpiece is electrically connected to the signal return terminal of the monitoring circuit. The diamond cutting tool is driven to cut the workpiece, and during the cutting process, the monitoring circuit continuously acquires real-time loop electrical signals. Based on the real-time loop electrical signal, the working state or machining position of the diamond cutting tool is determined, and control operations are executed.
[0015] Compared with the prior art, this application has the following beneficial effects: By constructing an intermediate layer between the tool substrate and the functional coating, consisting of a compatible carbide / nitride sublayer and a graded-doped diamond sublayer, the interfacial stress caused by the mismatch between the coefficient of thermal expansion and the modulus is effectively alleviated, thereby greatly enhancing the adhesion and bonding strength of the coating and fundamentally solving the problem of easy coating peeling. The conductive function is transferred from the traditional surface metal film to the interior of the coating through a wear-resistant conductive layer. High-hardness conductive nanoparticles are embedded in situ into a continuous diamond phase and interconnected to form a three-dimensional network extending from the interface to the surface. This eliminates the dependence on the easily worn surface layer, providing the conductive pathways from the entire coating bulk phase. During cutting, the conductive network ensures stable current flow. Even if the surface layer is worn away, the internal network maintains effective conductivity, thus achieving durable conductivity. Furthermore, this tool can be sequentially or simultaneously deposited in a single reaction chamber using chemical vapor deposition (CVD), eliminating the need for additional physical vapor deposition steps, thereby simplifying the process and reducing equipment investment and production costs. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the stacked structure of a diamond cutting tool as shown in an embodiment of this application; Figure 2 This is a schematic flowchart illustrating a method for manufacturing a diamond cutting tool according to an embodiment of this application. Figure 3 This is a schematic flowchart illustrating the cutting method of a diamond cutting tool according to an embodiment of this application. Detailed Implementation
[0017] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.
[0018] See Figure 1 The embodiments of this application illustrate a diamond cutting tool, which includes a tool substrate, a gradient transition layer, and a wear-resistant conductive layer deposited on the gradient transition layer; the gradient transition layer includes a first sub-layer and a second sub-layer from the surface of the tool substrate outward, wherein the first sub-layer is a carbide or nitride compatible with the tool substrate, and the second sub-layer is a graded-doped diamond; The wear-resistant conductive layer comprises a continuous diamond phase and conductive nanoparticles, wherein the conductive nanoparticles are interconnected in the diamond phase to form a three-dimensional conductive network extending from the gradient transition layer interface to the tool surface.
[0019] In this embodiment, the gradient transition layer is an intermediate layer located between the tool substrate and the functional layer, with a continuous or gradual change in composition and structure, serving as a buffer and adhesive. Strong adhesion is achieved by using carbides / nitrides, chemically compatible with the substrate material, as the first sublayer; and by using diamond, with doped element concentrations gradually decreasing from the inside out, as the second sublayer, a smooth transition in the lattice and properties of diamond is achieved from the bottom to the top layer, thereby greatly alleviating internal stress caused by abrupt changes in the coefficient of thermal expansion and elastic modulus, and preventing coating peeling.
[0020] The wear-resistant conductive layer is a functional layer that combines mechanical wear resistance and electrical conductivity. The continuous diamond phase provides the coating with ultra-high hardness and overall wear resistance. Conductive nanoparticles, acting as the conductive medium, are interconnected within the continuous diamond phase, forming a three-dimensional conductive network extending from the interface to the surface. This transforms the conductive pathway from a traditional easily worn surface film into a three-dimensional structure supported by the entire coating bulk phase. Thus, even if the surface layer wears during processing, the internal conductive network can still provide a stable conductive path, thereby achieving durable conductivity.
[0021] This embodiment significantly enhances the bonding strength between the coating and the substrate through a gradient transition layer, making the coating less prone to peeling. A wear-resistant conductive layer maintains the wear resistance of the diamond-holding tool and imparts stable and durable conductivity to the coating, enabling reliable low-contact depth control or tool breakage detection even after long-term cutting wear. Furthermore, the tool structure can be completed in a single chemical vapor deposition process, reducing manufacturing costs compared to the two processes of traditional CVD diamond and PVD metal conductive layers.
[0022] In some embodiments, the conductive nanoparticles form conductive paths in at least two directions in the wear-resistant conductive layer, the directions including a normal direction from the gradient transition layer interface toward the tool surface, and at least one transverse direction perpendicular to the normal direction.
[0023] In this embodiment, the normal conductive path is a conductive path established along the coating growth direction (i.e., the thickness direction) to ensure that current can vertically penetrate from the inner gradient transition layer interface to the outermost tool working surface. The transverse conductive path is a conductive path established in a plane parallel to the coating surface to ensure the extension and interconnection of the conductive network in a two-dimensional plane.
[0024] The interlacing of normal and lateral conductive paths forms a three-dimensional conductive circuit. Even if some material is lost due to wear on the surface, the internal network can still conduct electricity through the remaining normal and lateral paths, greatly buffering the impact of local damage on overall conductivity and achieving long lifespan and high stability of the conductive function. Simultaneously, the lateral path ensures that the current is evenly distributed across the entire tool working surface, allowing for a consistent low-resistance connection regardless of the contact point's location on the surface. This provides electrical signals for high-precision depth control or condition detection, preventing signal fluctuations due to changes in contact position.
[0025] In some embodiments, the conductive nanoparticles are selected from nitride nanocrystals, carbide nanocrystals, or carbonitride nanocrystals of metals in Groups IVB, VB, and VIB of the periodic table. The average grain size of the conductive nanoparticles is smaller than the average grain size of the diamond phase, and the conductive nanoparticles are non-uniformly distributed in the thickness direction of the wear-resistant conductive layer, with a higher concentration in the region closer to the gradient transition layer than in the region farther from the gradient transition layer.
[0026] In this embodiment, the nitrogen / carbon / carbonitrides of group IVB, VB, and VIB metals (such as TiN, VC, WC, etc.) are hard conductive ceramics with high hardness and good conductivity. Compared with traditional cutting tools that use pure metals as the conductive phase, which have problems such as insufficient hardness and easy oxidation, the first sublayer can ensure that the conductivity itself also has excellent wear resistance and chemical stability, thus forming a strong bond with the diamond matrix.
[0027] The average grain size of the conductive nanoparticles is smaller than that of the diamond phase, allowing them to embed themselves in the interstices of diamond grains or distribute at grain boundaries during growth (i.e., chemical deposition) without disrupting the continuity of the diamond phase. This fine-particle embedding within a coarse matrix microstructure forms an effective conductive circuit while maximizing the mechanical integrity and ultra-high hardness of the continuous diamond phase as the primary supporting framework. The particle concentration decreases from the inside out, utilizing a high concentration of particles near the interface to ensure the conductive network remains robust and uninterrupted even under surface wear. Lowering the particle concentration at the outer surface allows for the deposition of more diamond, thus maintaining the cutting sharpness and wear resistance of the cutting tool.
[0028] In some embodiments, the average grain size of the diamond phase is 0.5 μm to 3 μm, ensuring that the grains are sufficiently large to exhibit the intrinsic property of diamond's extremely high hardness, thereby providing excellent bulk wear resistance; while avoiding excessive grain growth that could lead to deterioration of surface roughness or increased brittleness. The average grain size of the conductive nanoparticles is 20 nm to 100 nm, enabling them to embed into diamond grain boundaries or defect locations without disrupting the integrity of the diamond grains, thus introducing conductivity while minimizing the disruption and weakening of the mechanical properties of the continuous diamond phase.
[0029] In some embodiments, the first sublayer is made of TiC, TiN, CrN, or WC, forming a strong chemical bond with the substrate to achieve firm anchoring, while its excellent mechanical properties also provide solid support for the entire coating. The second sublayer is doped with one or more of Si, B, Ti, and Cr to regulate the growth behavior and internal stress of the diamond lattice, achieving a smooth transition in lattice and thermodynamic properties from the first sublayer to the top pure diamond phase.
[0030] See Figure 2 This application also provides a method for manufacturing a diamond cutting tool, comprising: S21, in the reaction chamber of a single chemical vapor deposition apparatus, sequentially depositing a gradient transition layer and a wear-resistant conductive layer on the surface of the tool substrate, wherein the deposition step of the wear-resistant conductive layer includes: S211, a diamond growth source, a conductive nanoparticle formation source, and a reactive gas are simultaneously introduced into the reaction chamber. A pulsed bias field is applied to the tool substrate, and the energy parameters of the pulsed bias field are adjusted to control the activity of conductive nanoparticles generated by the in-situ reaction between the conductive nanoparticle formation source and the reactive gas within the diamond growth source, so that the conductive nanoparticles self-assemble in-situ from the gradient transition layer interface to the tool surface to form a three-dimensional conductive network.
[0031] In this embodiment, during the deposition of the wear-resistant conductive layer, the raw material gases that form the diamond phase and the conductive phase are simultaneously introduced into the reaction chamber, allowing the diamond and conductive nanoparticles to compete for growth and intertwine on the substrate surface. A pulsed bias voltage creates a periodically varying strong electric field on the substrate surface to actively control the energy and direction of the charged particles in the gas phase. By adjusting energy parameters such as the amplitude, frequency, and duty cycle of the bias voltage, the energy transport, implantation depth, and distribution density of the conductive nanoparticles can be precisely controlled, thereby achieving controllable deposition of the conductive nanoparticles. The in-situ reaction involves the conductive nanoparticles (such as TiN) being generated in-situ within the reaction chamber using their precursors (TiCl4 and N2). The in-situ self-assembly involves the conductive nanoparticles spontaneously connecting and assembling into a three-dimensional network under the guidance of the pulsed bias voltage field and the pressure from diamond growth during the deposition process. This ensures that the conductive network and the diamond matrix co-grow and are tightly bonded, forming a mechanically robust and electrically interconnected integrated structure.
[0032] In some embodiments, the pulsed bias field is controlled as follows: a first pulsed bias condition is applied during a first time period of the deposition stage, the first pulsed bias condition including a first negative bias amplitude of -150V to -300V and a first duty cycle of 40% to 70%; a second pulsed bias condition is applied during a second time period of the deposition stage, the second pulsed bias condition including a second negative bias amplitude of -50V to -140V and a second duty cycle of 20% to 50%, wherein the second negative bias amplitude is less than the first negative bias amplitude, and the second duty cycle is not greater than the first duty cycle; the first pulsed bias condition and the second pulsed bias condition decay over time.
[0033] In this embodiment, a higher negative bias and duty cycle are used in the first time period to subject the substrate surface to strong and dense ion bombardment. This imparts extremely high kinetic energy to the conductive nanoparticles precipitated from the gas phase, enabling them to forcefully embed into the interstitial spaces or grain boundaries of the growing diamond lattice and to form a local pinning effect at the interface. This ensures that the network possesses high density and strong bonding characteristics in the root region near the gradient transition layer, laying a solid and tightly interconnected foundation for the entire conductive system. Simultaneously, the strong ion bombardment promotes the formation of a finer and denser microcrystalline diamond structure, providing more grain boundary embedding sites for the conductive nanoparticles.
[0034] The second time period employs a lower negative bias and duty cycle to reduce the intensity and frequency of ion bombardment. This allows for continued, gentle deposition based on the stable network framework established in the first time period. This approach facilitates the continuous epitaxial growth of high-quality diamond phases, maintaining the coating's excellent overall wear resistance. It also allows subsequent conductive nanoparticles to primarily connect and fill the existing network framework through surface diffusion and self-assembly, extending towards the surface and widening the conductive pathways without causing destructive deep implantation. Simultaneously, the reduced ion bombardment environment is more conducive to the full epitaxial growth of diamond grains, enabling diamond to preferentially grow along specific crystal orientations under gentler conditions. This results in a continuous microcrystalline diamond phase with larger grain size and higher crystal quality, thereby endowing the tool surface with higher macroscopic hardness and excellent wear resistance.
[0035] The first and second pulse bias conditions are not fixed values, but linearly varying values that decay over time. This allows the conductive nanoparticles to form a gradient network from the inside (high density, deep implantation) to the outside (low density, shallow distribution), and the diamond to form a gradient continuous phase from the inside (fine grains, dense) to the outside (coarse grains, high hardness). This achieves a smooth transition in density of the conductive nanoparticles from the inside to the outside and a smooth transition in size of the diamond from the inside to the outside, avoiding sudden changes in process parameters that could lead to internal stress and discontinuities or defective interfaces in the coating.
[0036] In some embodiments, the diamond growth source gas is a mixture of hydrogen and methane, wherein methane accounts for 1% to 5% of the total volume of the mixture; the conductive nanoparticle formation source is the vapor of at least one metal compound selected from titanium tetrachloride, chromium hexacarbonyl, molybdenum hexacarbonyl, and trimethylaluminum; and the reaction gas is nitrogen or acetylene.
[0037] In this embodiment, hydrogen gas generates a large number of active hydrogen atoms under high temperature or plasma action, which react with hydrocarbon groups produced by methane decomposition, promoting the deposition of diamond phase on the substrate surface, and hydrogen atoms can strongly etch the non-diamond carbon phase generated at the same time, thus achieving in-situ purification.
[0038] Titanium tetrachloride, chromium hexacarbonyl, molybdenum hexacarbonyl, and trimethylaluminum possess sufficiently high vapor pressures at the operating temperature and pressure of the reaction chamber, enabling stable transport and easy decomposition in a plasma environment to release target metal atoms (Ti, Cr, Mo, Al) as building blocks for conductive nanoparticles. The reaction gas reacts with the decomposed active metal building blocks in the gas phase or on the surface to directly generate the desired hard conductive ceramic phase with a specific chemical composition. Nitrogen is used to synthesize nitride nanoparticles (such as TiN and CrN) with the active metal building blocks, and acetylene is used to synthesize carbide nanoparticles (such as TiC, CrN ... ).
[0039] In some embodiments, the deposition step of the gradient transition layer includes: In a halide or organometallic precursor atmosphere containing titanium, chromium or tungsten, a first sublayer composed of carbides, nitrides or carbonitrides is deposited on the surface of the tool substrate; While maintaining the diamond growth atmosphere, silane, borane, or phosphine are simultaneously introduced as dopants, and the flow rate of the dopants is reduced in a stepwise manner until a preset value is reached, forming a second sublayer in which the concentration of doped elements continuously decreases from the inside to the outside.
[0040] In this embodiment, the first sublayer solves the fundamental problem of the adhesion between the coating and the substrate through strong chemical bonding. The second sublayer reduces the amount of dopant in a stepwise manner to control the concentration distribution of dopant elements in the diamond layer growth direction, so that it continuously decreases from the bottom layer to the top layer. The purity, grain size and crystal integrity of the diamond phase gradually approach the pure diamond layer at the top, achieving a smooth transition in the coefficient of thermal expansion and elastic modulus.
[0041] As an example, and not a limitation, the first sub-layer: As a precursor, in A Ti(C,N) layer with a thickness of approximately 0.8 μm was deposited in the atmosphere. Second sublayer: maintaining the diamond growth atmosphere ( ), synchronous input (diluted in) (The text abruptly shifts to a different topic) The boron-doped graded diamond layer was formed by stepping its flow rate from 15 sccm to 1 sccm within 30 minutes using a mass flow controller, resulting in a layer approximately 1.5 μm thick. The wear-resistant conductive layer was then introduced into a single-filament CVD reaction chamber, simultaneously with the diamond growth source (…). (methane concentration 3%) and conductive phase precursor ( Steam and A pulsed bias voltage was applied to the drill bit. For the first 40 minutes (the first time period), a bias voltage of -200V and a duty cycle of 60% were applied. For the next 80 minutes (the second time period), a bias voltage of -100V and a duty cycle of 30% were applied. A composite layer with a thickness of approximately 5 μm was deposited.
[0042] Continuous drilling tests were conducted on PCB (copper-clad laminate) boards using a CNC drilling machine. Traditional TiN metal-coated drill bits exhibited unstable electrical signals and depth control deviations exceeding ±5μm after approximately 15,000 drilling cycles due to surface TiN wear. In contrast, the drill bit in this embodiment maintained stable contact signal triggering after 60,000 drilling cycles, with hole depth control accuracy remaining within ±2μm. Furthermore, SEM observation of the used drill bit revealed no coating peeling or flaking.
[0043] See Figure 3 The present application illustrates a cutting method using a diamond cutting tool, comprising the following steps: S31, electrically connect the tool body of the diamond cutting tool to the signal output terminal of the monitoring circuit, and electrically connect the conductive area on the workpiece to the signal return terminal of the monitoring circuit; S32, drive the diamond cutting tool to cut the workpiece, and continuously acquire real-time loop electrical signals through the monitoring circuit during the cutting process; S33, based on the real-time loop electrical signal, determine the working state or machining position of the diamond cutting tool and execute control operations.
[0044] In this embodiment, step S31 connects the tool substrate to the monitoring circuit and uses the conductive area on the workpiece as the other pole of the loop, forming a complete current path. When the tool cuts the workpiece in step S32, the wear-resistant conductive layer on its cutting edge will contact the workpiece. Due to the presence of a continuous three-dimensional conductive network inside the coating, the current can stably pass through the tool coating, contact point, and conductive area of the workpiece to form a loop. Any change in state during the cutting process will immediately trigger a corresponding change in the real-time loop electrical signals such as resistance, capacitance, or current in the electrical monitoring loop, such as the moment the tool contacts the workpiece, abnormal chipping or abnormal peeling of the coating, and changes in contact resistance due to normal wear. The monitoring circuit and control system in step S33 can non-contactly and in real-time determine the precise contact position of the tool (for depth determination), whether breakage has occurred (safety warning), or wear state (life management) by analyzing the characteristics of these electrical signals (such as threshold, abrupt change, and trend), and automatically trigger control operations such as setting zero point, stopping feed, or issuing tool change prompts.
[0045] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above descriptions are merely specific embodiments of this application and are not intended to limit the scope of protection of this application. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application for those skilled in the art.
Claims
1. A diamond cutting tool, characterized in that, The tool includes a tool substrate, a gradient transition layer, and a wear-resistant conductive layer deposited on the gradient transition layer; the gradient transition layer includes a first sub-layer and a second sub-layer sequentially from the surface of the tool substrate outward, wherein the first sub-layer is a carbide or nitride compatible with the tool substrate, and the second sub-layer is a graded-doped diamond. The wear-resistant conductive layer comprises a continuous diamond phase and conductive nanoparticles, wherein the conductive nanoparticles are interconnected in the diamond phase to form a three-dimensional conductive network extending from the gradient transition layer interface to the tool surface.
2. The diamond cutting tool as described in claim 1, characterized in that, The conductive nanoparticles form conductive paths in at least two directions in the wear-resistant conductive layer, including a normal direction from the gradient transition layer interface to the tool surface, and at least one transverse direction perpendicular to the normal direction.
3. The diamond cutting tool as described in claim 1, characterized in that, The conductive nanoparticles are selected from nitride nanocrystals, carbide nanocrystals, or carbonitride nanocrystals of metals in Groups IVB, VB, and VIB of the periodic table. The average grain size of the conductive nanoparticles is smaller than the average grain size of the diamond phase, and the conductive nanoparticles are non-uniformly distributed in the thickness direction of the wear-resistant conductive layer, with a higher concentration in the region closer to the gradient transition layer than in the region farther away from the gradient transition layer.
4. The diamond cutting tool as described in claim 3, characterized in that, The average grain size of the diamond phase is 0.5μm to 3μm, and the average grain size of the conductive nanoparticles is 20nm to 100nm.
5. The diamond cutting tool as described in claim 1, characterized in that, The first sublayer is made of TiC, TiN, CrN or WC, and the second sublayer is doped with one or more of Si, B, Ti and Cr.
6. A method for manufacturing a diamond cutting tool as described in any one of claims 1 to 5, characterized in that, include: In the reaction chamber of a single chemical vapor deposition apparatus, a gradient transition layer and a wear-resistant conductive layer are sequentially deposited on the surface of a tool substrate, wherein the deposition step of the wear-resistant conductive layer includes: A diamond growth source, a conductive nanoparticle formation source, and a reactive gas are simultaneously introduced into the reaction chamber. A pulsed bias field is applied to the tool substrate, and the energy parameters of the pulsed bias field are adjusted to control the activity of conductive nanoparticles generated by the in-situ reaction between the conductive nanoparticle formation source and the reactive gas within the diamond growth source. This allows the conductive nanoparticles to self-assemble in situ from the gradient transition layer interface to the tool surface to form a three-dimensional conductive network.
7. The manufacturing method as described in claim 6, characterized in that, The pulse bias field control mode is as follows: during the first time period of the deposition stage, a first pulse bias condition is applied, which includes a first negative bias amplitude of -150V to -300V and a first duty cycle of 40% to 70%; during the second time period of the deposition stage, a second pulse bias condition is applied, which includes a second negative bias amplitude of -50V to -140V and a second duty cycle of 20% to 50%, wherein the second negative bias amplitude is less than the first negative bias amplitude, and the second duty cycle is not greater than the first duty cycle; The first pulse bias condition and the second pulse bias condition decay over time.
8. The manufacturing method as described in claim 6, characterized in that, The diamond growth source gas is a mixture of hydrogen and methane, wherein methane accounts for 1% to 5% of the total volume of the mixture; the conductive nanoparticle formation source is the vapor of at least one metal compound selected from titanium tetrachloride, chromium hexacarbonyl, molybdenum hexacarbonyl, and trimethylaluminum; the reaction gas is nitrogen or acetylene.
9. The manufacturing method as described in claim 6, characterized in that, The deposition steps of the gradient transition layer include: In a halide or organometallic precursor atmosphere containing titanium, chromium or tungsten, a first sublayer composed of carbides, nitrides or carbonitrides is deposited on the surface of the tool substrate; While maintaining the diamond growth atmosphere, silane, borane, or phosphine are simultaneously introduced as dopants, and the flow rate of the dopants is reduced in a stepwise manner until a preset value is reached, forming a second sublayer in which the concentration of doped elements continuously decreases from the inside to the outside.
10. A cutting method using a diamond cutting tool as described in any one of claims 1 to 5, characterized in that, Includes the following steps: The tool body of the diamond cutting tool is electrically connected to the signal output terminal of the monitoring circuit, and the conductive area on the workpiece is electrically connected to the signal return terminal of the monitoring circuit. The diamond cutting tool is driven to cut the workpiece, and during the cutting process, the monitoring circuit continuously acquires real-time loop electrical signals. Based on the real-time loop electrical signal, the working state or machining position of the diamond cutting tool is determined, and control operations are executed.