Hard coating with continuous gradient transition layer and applications
Patent Information
- Application Number
- CN202611182223.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-08-05
- Publication Date
- 2026-09-29
AI Technical Summary
[0004]TiN涂层在含钽碳氮化钛基金属陶瓷基体上因化学相容性差和热膨胀系数不匹配，从而导致结合力弱、易剥落，且其硬度较低，耐磨性不足，刀具寿命短等种种问题
[0031]本发明可以增强硬质层与基体的结合强度。在Ta为第二陶瓷相，Co为粘结相的支撑下，近表层的(Ti,Ta)N硬质纳米复合层与基体之间形成了平滑的成分过渡和应力缓释区，避免了因硬质层与基体直接接触而导致的结构突变和界面应力集中，使高硬度耐磨层得以牢固附着。
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Figure CN122833435A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of tool coating technology, and more specifically to a hard coating with a continuous gradient transition layer and its application. Background Technology
[0002] With the emergence of new materials such as high-temperature alloys, titanium alloys, and ultra-high-strength steel, the market has placed higher demands on the machining performance of cermet cutting tools. To improve the wear resistance, anti-adhesion properties, and service life of cutting tools, physical vapor deposition (PVD) technology is often used to prepare hard coatings on the tool surface. Common systems include TiN, TiCN, and TiAlN.
[0003] In actual service, high interfacial bonding strength between the coating and the substrate is a prerequisite for the effective performance of tool coatings. Poor bonding, even with extremely high coating hardness, can easily lead to premature spalling under the thermal-mechanical stress of cutting, causing instantaneous tool failure. This is especially true when machining difficult-to-machine materials such as high-temperature alloys and titanium alloys, where the interface is subjected to severe thermal mismatch stress and chip impact. A strong metallurgical bond effectively prevents crack initiation and propagation, ensuring stable coating service. Furthermore, the coating surface must possess excellent wear resistance. Only through the synergy of these two factors can the coating achieve functional matching from the inside out, providing reliable support for strong interfacial bonding, while high surface wear resistance contributes to a long cutting life. Therefore, designing gradient coatings that enrich bonding elements inward to enhance bonding strength and optimize hard phases outward to improve wear resistance has become an effective way to overcome the performance bottlenecks of existing tool coatings. Summary of the Invention
[0004] TiN coatings on tantalum-containing titanium carbonitride-based cermet substrates suffer from poor chemical compatibility and mismatched coefficients of thermal expansion, resulting in weak adhesion, easy peeling, low hardness, insufficient wear resistance, and short tool life. To address these issues, this invention provides a hard coating with a continuous gradient transition layer. Specifically, to address the weak adhesion between the TiN hard layer and the Ta-containing substrate, a Co-based layer is constructed between the TiN hard layer and the substrate. 0.15 Ti x Ta y The transition layer increases the bonding strength between the Ta-containing matrix and the TiN hard layer, thereby improving tool life.
[0005] The technical solution of this invention is a hard coating with a continuous gradient transition layer, comprising a continuous gradient transition layer and a hard layer, wherein the continuous gradient transition layer is composed of Co. 0.15 Ti x Ta yAs the distance from the substrate increases, the x-value continuously changes from 0.55 to 0.85, and the y-value continuously changes from 0.3 to 0, with x + y = 0.85; the hard layer is TiN. Cobalt is the binder phase of WC-Co hard alloy and cermet. Cobalt doping in the transition layer is beneficial for the formation of bonds between the transition layer and the substrate material surface at the start of deposition, thus improving deposition efficiency.
[0006] The substrate of the hard coating with a continuous gradient transition layer is any one of titanium carbonitride cermet, tungsten cobalt cemented carbide, or tantalum titanium carbonitride-based cermet, preferably tantalum titanium carbonitride-based cermet.
[0007] The thickness of the continuous gradient transition layer is 0.5-1.5 μm, and the thickness of the hard layer is 1-2 μm.
[0008] The continuous gradient transition layer is attached to the substrate and is located between the substrate and the hard layer, which is attached to the continuous gradient transition layer.
[0009] Compared to the other two matrices (titanium carbonitride cermets and tungsten-cobalt cemented carbide), tantalum-containing titanium carbonitride cermets possess extremely high melting points for tantalum carbides / nitrides (TaC melting point approximately 3880℃). When dissolved into the Ti(C,N) lattice, they significantly improve the high-temperature stability of the hard phase. During steel cutting, chips experience intense friction with the rake face, leading to element diffusion. The tantalum-containing hard phase effectively blocks iron diffusion into the tool, significantly reducing crater formation—a crucial improvement over tantalum-free cermets. The addition of tantalum promotes the formation of a denser composite oxide film, hindering oxygen infiltration and making the tool more oxidation-resistant at high temperatures, extending its service life in high-temperature environments. Furthermore, using tantalum-containing titanium carbonitride cermets not only improves fracture toughness but also enhances resistance to thermal shock, making the tool less prone to chipping and hot cracking during intermittent cutting or when coolant is applied.
[0010] The present invention uses tantalum-containing titanium carbonitride-based cermet as the matrix, which, while maintaining high hardness and wear resistance, can also greatly improve high-temperature strength, resistance to diffusion wear and toughness, so that the tool exhibits longer life and better reliability under high-speed, high-temperature and harsh working conditions.
[0011] The method for preparing the above-mentioned hard coating with a continuous gradient transition layer includes the following steps:
[0012] Before the continuous gradient transition layer is fabricated, the substrate is subjected to ion etching.
[0013] Preparation of continuous gradient transition layer: under argon atmosphere, with Co 0.15 Ti 0.85 and Co 0.15 Ta 0.85For magnetron sputtering targets, to Co 0.15 Ti 0.85 A constant current is applied to the target material, and the bias voltage is gradually increased to direct the Co... 0.15 Ta 0.85 A constant current is passed through the target material, and the bias voltage gradually decreases. A continuous gradient transition layer is prepared on the substrate surface by magnetron sputtering and physical vapor deposition.
[0014] Hard layer preparation: Under a nitrogen atmosphere, using high-purity titanium (99.99%) as the target material, a constant current and a constant bias voltage are applied, and a hard layer is prepared on the substrate surface by physical vapor deposition through magnetron sputtering.
[0015] Before the continuous gradient transition layer is fabricated, the substrate undergoes ion etching treatment. Specifically, the substrate is placed in a vacuum chamber and evacuated to a vacuum level of 5 × 10⁻⁶. -4 The temperature is increased to 500℃, and argon gas is introduced into the vacuum chamber at a flow rate of 50 sccm. The bias voltage is maintained at -180V, and the substrate surface is bombarded with ions for 0.5-1h.
[0016] During the fabrication of the continuous gradient transition layer, Co 0.15 Ti 0.85 A constant current of 80A is applied to the target material, and the bias voltage is increased from -60V to -100V at a rate of 0.5-1V / min, while maintaining a constant voltage; Co 0.15 Ta 0.85 A constant current of 80A is applied to the target material, with an initial bias voltage of -40V, which is adjusted to 0V at a rate of 0.5-1V / min. During the preparation process, the argon gas flow rate is maintained at 50-60 sccm; the magnetron sputtering time is 1-2 hours. This invention targets Co... 0.15 Ta 0.85 The target material uses an initial bias voltage of -40V because this voltage value is relatively mild, ensuring a stable and controllable Ta deposition rate. This allows for the formation of a Ta-rich transition layer without causing thermal damage to the sensitive metal-ceramic substrate or excessive interfacial mixing due to excessive energy. An initial bias voltage of -50V would result in an excessively high initial Ta content, leading to an overly Ta-rich coating. This could conflict with the total Ti supply from the Ti target, causing the total metal element content to deviate from the design. Furthermore, this high-Ta layer would have low hardness and potentially different friction coefficients, weakening the cutting edge's load-bearing capacity. An initial bias voltage of -30V would result in insufficient initial Ta content, failing to fully utilize Ta's affinity for the substrate, thus reducing the bonding strength between the transition layer and the substrate. Simultaneously, the relatively high Ti content near the substrate could trigger harmful phase reactions at the interface (e.g., excessive Ti reacting with carbon and nitrogen in the substrate to form a brittle phase).
[0017] This invention targets Co 0.15 Ti 0.85The target bias voltage is selected from -60V to -100V because the initial bias voltage is chosen to be -60V, in order to match Co. 0.15 Ta 0.85 The initial bias voltage of the target is -40V, which ensures high lattice matching and good wettability between the bottom-layer product and the tantalum-containing cermet matrix, allowing for the formation of epitaxial or semi-coherent interfaces, thereby enhancing adhesion. With the development of Co... 0.15 Ti 0.85 The target bias voltage is increased slowly, and the Ti supply increases linearly, gradually filling the compositional gap left by the reduction in Ta, ensuring x+y≡0.85. This gradual increase process avoids abrupt changes in lattice constant and thermal expansion coefficient caused by abrupt compositional changes, transforming thermal stress and intrinsic stress into a broad and gentle gradient region, resulting in excellent coating toughness. Finally, a high sputtering power can be provided at -100V and a constant current of 80A, enabling the pure Co-Ti coating on the surface to grow densely at a relatively fast rate. At the same time, this voltage is not too high, avoiding target overheating, droplet sputtering, and compositional mismatch caused by severe backsputtering due to excessive power density.
[0018] If Co 0.15 Ta 0.85 If the initial bias voltage of the target is too low (e.g., -30V), the initial Ti content will be too low and the Ta content will be too high (exceeding 30%). Although the coating with excessive Ta content has good adhesion to the substrate, its hardness may be low, and the compositional difference with the subsequent gradient layers will increase, which will also create new mismatch interfaces.
[0019] If the initial Ti content is too high (>55%), Ta will be relatively insufficient. This will lead to abrupt changes in composition and structure between the transition layer and the Ta-rich matrix, causing it to lose its "bridging" function, resulting in a sharp increase in interfacial stress and making it easy for cracks to initiate and propagate at the interface.
[0020] In the process of preparing the continuous gradient transition layer in this invention, the argon flow rate is controlled at 60 sccm because the vacuum chamber pumping system stabilizes the chamber pressure within a suitable sputtering range (0.3 ~ 0.8 Pa) through a throttling valve. The 60 sccm inlet flow rate precisely maintains this dynamic balance; at this pressure, the mean free path of the gas molecules is moderate. This ensures sufficient argon ion concentration in front of each target to maintain a stable constant current discharge of 80 A, while preventing excessive coupling of plasmas between the two targets due to excessive pressure. Excessive argon flow rate leads to a sharp drop in deposition rate, uncontrolled composition, porous coating structure, performance degradation, unstable discharge, and target abnormalities, among other problems. Insufficient argon flow rate results in excessively low chamber pressure, making it difficult to maintain insufficiently ionized plasma, or even causing it to "extinguish." Under low pressure, sputtered atoms and reflected argon ions bombard the substrate with extremely high kinetic energy with almost no collisions, leading to severe backsputtering and substrate damage.
[0021] This invention uses Co 0.15 Ti 0.85 and Co 0.15 Ta 0.85 This is because the cobalt content of the two targets is precisely consistent, both being 15 at.%. This means that throughout the entire gradient change process, regardless of how the Ti / Ta ratio gradually changes from 0.55 / 0.30 to 0.85 / 0, the total supply of Co atoms reaching the substrate remains constant.
[0022] By simply adjusting the sputtering rates of the two targets linearly (one increasing and one decreasing), a gradient layer with absolutely constant Co content and only continuously varying Ti / Ta ratio can be perfectly achieved, simplifying the process.
[0023] If the Co content in the target material is too low, the coating will become hard and brittle, and its fracture toughness will drop sharply. If the Co content is too high, the coating will become excessively "soft," losing its core function as a hard coating, and its wear resistance will decrease exponentially.
[0024] During the preparation of the hard layer, a 120A current is applied to the high-purity titanium target, maintaining a -100V bias voltage, and the magnetron sputtering time is 2-4 hours; during the preparation process, the nitrogen flow rate is maintained at 500 sccm. The purity of the high-purity titanium target is greater than or equal to 99.99%.
[0025] During the preparation of the continuous gradient transition layer and the hard layer, the substrate maintains both revolution and rotation, with a revolution speed of 5-10 rpm and a rotation speed of 10-30 rpm.
[0026] The hard coating with a continuous gradient transition layer designed and prepared in this invention has applications including its application on cutting tools.
[0027] The principle of this invention is as follows:
[0028] By introducing Co 0.15 Ti x Ta y A compositional gradient transition layer is used to connect the tantalum-containing metal ceramic matrix and the hard layer. By utilizing the continuous gradient change of Ti and Ta elements, the composition ratio of the tantalum-containing ceramic phase at the interface is controlled, thereby improving chemical compatibility, enhancing bonding force, and mitigating defects and stress concentration caused by lattice mismatch and differences in thermal expansion coefficients.
[0029] Co with specific Ti and Ta contents respectively 0.15 Ti 0.85 and Co 0.15 Ta 0.85By applying a bias voltage that enhances and attenuates the target material, the ratio of Ti and Ta elements in the transition layer can be controlled, thereby achieving the purpose of preparing a transition layer with a continuous gradient.
[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0031] This invention can enhance the bonding strength between the hard layer and the substrate. With Ta as the second ceramic phase and Co as the binder phase, a smooth compositional transition and stress relief zone are formed between the near-surface (Ti,Ta)N hard nanocomposite layer and the substrate, avoiding structural abrupt changes and interfacial stress concentration caused by direct contact between the hard layer and the substrate, thus enabling the high-hardness wear-resistant layer to adhere firmly.
[0032] Tool life is significantly extended. Thanks to the synergistic effect of high interfacial bonding strength and high surface wear resistance, the coating is not easy to peel off under high temperature and high stress cutting conditions, and can resist wear for a long time. This effectively delays tool tip dulling and coating failure, and greatly improves the tool life and machining stability when machining high-requirement materials such as high-temperature alloys and titanium alloys. Attached Figure Description
[0033] Figure 1 This is a photograph of the product obtained in Example 2 after being tested by cutting SCM440 steel;
[0034] Figure 2 This is a photograph of the product obtained in Comparative Example 1 after being tested by cutting SCM440 steel.
[0035] Figure 3 This is a photograph of the product obtained in Comparative Example 5 after being tested by cutting SCM440 steel. Detailed Implementation
[0036] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.
[0037] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.
[0038] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.
[0039] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.
[0040] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.
[0041] The coating was prepared using a tantalum titanium carbonitride-based cermet cutting tool (model SNMN150408) as the tool substrate. The specific process after necessary cleaning and drying of the tool surface is as follows:
[0042] Example 1
[0043] (1) Ion etching: mounting Co 0.15 Ti 0.85 Co 0.15 Ta 0.85 High-purity titanium target material. The tool substrate was placed in a vacuum chamber and evacuated to 5 × 10⁻⁶. -4 The temperature is increased to 500℃, and argon gas is introduced into the vacuum chamber at a flow rate of 60 sccm, maintaining a bias voltage of -180V to attract Ar gas. + The substrate surface is bombarded with ions to etch the tool surface for 1 hour.
[0044] (2) Preparation of continuous gradient transition layer: Maintaining the argon flow rate at 50 sccm, the argon gas is introduced into the Co layer. 0.15 Ti 0.85 The target material is supplied with a current of 80A and a bias voltage of -60V. The bias voltage is increased at a rate of 0.75V / min until it reaches a constant -100V. Simultaneously, a current is applied to the Co... 0.15 Ta 0.85 The target material was fed with a current of 80A and an initial bias voltage of -40V. The bias voltage was reduced at a decay rate of 0.75V / min until it reached 0V, forming a continuous gradient transition layer. The magnetron sputtering time was 1h to obtain a continuous gradient transition layer with a thickness of 1μm.
[0045] (3) Hard layer preparation: After turning off the current in step (2), nitrogen gas of 500 sccm is continuously introduced into the vacuum chamber, and then a current of 120A is continuously introduced into the high-purity titanium target to maintain a bias voltage of -100V. The magnetron sputtering time is 4h to form a TiN hard layer with a thickness of 2μm.
[0046] Comparative Example 1
[0047] Co is used in ion etching and continuous gradient transition layer fabrication. 0.1 Ti 0.9 Co 0.1 Ta 0.9 Apart from the target material, the other preparation process parameters are the same as in Example 1.
[0048] Comparative Example 2
[0049] Except for the use of argon gas with a flow rate of 40 sccm in ion etching and the preparation of the continuous gradient transition layer, the target material composition and other preparation process parameters are the same as in Example 1.
[0050] Comparative Example 3
[0051] Except for the ion etching time of 0.5 h, the etching process was carried out on Co. 0.15 Ti 0.85 The target material is supplied with a current of 80A, and the bias voltage is constant at -100V, directed towards Co. 0.15 Ta 0.85 The current applied to the target was 80A, the initial bias voltage was -40V, and the bias voltage was reduced to 0V at a decay rate of 1.5V / min. The target composition and other preparation process parameters were the same as in Example 1.
[0052] Comparative Example 4
[0053] Except for the ion etching time of 2.5 h, the etching process was carried out on Co. 0.15 Ti 0.85 A constant current of 80A is applied to the target, and the bias voltage is increased at a rate of 1.5V / min from -60V to -100V and maintained constant; Co 0.15 Ta 0.85 Except for the target material being supplied with a constant current of 80A and the bias voltage being kept constant at -40V, the target material composition and other preparation process parameters are the same as in Example 1.
[0054] Comparative Example 5
[0055] Except to Co 0.15 Ti 0.85 The target is supplied with a current of 80A and a bias voltage of -60V. The bias voltage is increased at a rate of 1.5V / min until it reaches a constant -100V. Simultaneously, a current of 80A is applied to the Co target. 0.15 Ta 0.85The current applied to the target was 80A, the initial bias voltage was -40V, and the bias voltage was reduced at a decay rate of 1.5V / min until the bias voltage was 0V. The target composition and other preparation process parameters were the same as in Example 1.
[0056] Comparative Example 6
[0057] Except for the magnetron sputtering time of 8 hours during the preparation of the hard layer, which forms a TiN hard layer with a thickness of about 3 μm, the target material composition and other preparation process parameters are the same as in Example 1.
[0058] Comparative Example 7
[0059] All other conditions are the same as in Example 1, except that:
[0060] (2) Preparation of continuous gradient transition layer: Maintaining the argon flow rate at 45 sccm, the argon gas flow rate was increased to Co 0.15 Ti 0.85 The target material is supplied with a current of 80A and a bias voltage of -60V. The bias voltage is increased at a rate of 0.75V / min until it reaches a constant -100V. Simultaneously, a current is applied to the Co... 0.15 Ta 0.85 The target material was fed with a current of 80A and an initial bias voltage of -50V. The bias voltage was reduced at a decay rate of 0.75V / min until it reached 0V, forming a continuous gradient transition layer. The continuous gradient transition layer was obtained by magnetron sputtering for 1 hour.
[0061] Comparative Example 8
[0062] All other conditions are the same as in Example 1, except that:
[0063] (2) Preparation of continuous gradient transition layer: Maintaining the argon flow rate at 50 sccm, the argon gas is introduced into the Co layer. 0.15 Ti 0.85 The target material is supplied with a current of 80A and a bias voltage of -30V. The bias voltage is increased at a rate of 0.75V / min until it reaches a constant -100V. Simultaneously, a current of 80A is applied to the Co target. 0.15 Ta 0.85 The target material was fed with a current of 80A and an initial bias voltage of -50V. The bias voltage was reduced at a decay rate of 0.75V / min until it reached 0V, forming a continuous gradient transition layer. The continuous gradient transition layer was obtained by magnetron sputtering for 1 hour.
[0064] Example 2
[0065] (1) Ion etching: mounting Co 0.15 Ti 0.85 Co 0.15 Ta 0.85 High-purity titanium target material. The tool substrate was placed in a vacuum chamber and evacuated to 5 × 10⁻⁶. -4The temperature is increased to 500℃, and argon gas is introduced into the vacuum chamber at a flow rate of 60 sccm, maintaining a bias voltage of -180V to attract Ar gas. + The substrate surface is bombarded with ions to etch the tool surface for 0.5 hours.
[0066] (2) Preparation of continuous gradient transition layer: Maintaining the argon flow rate at 50 sccm, the argon gas is introduced into the Co layer. 0.15 Ti 0.85 The target material is supplied with a current of 80A and a bias voltage of -60V. The bias voltage is increased at a rate of 0.5V / min until it reaches a constant -100V. Simultaneously, a current of 80A is applied to the Co target. 0.15 Ta 0.85 The target material was fed with a current of 80A and an initial bias voltage of -40V. The bias voltage was reduced at a decay rate of 0.5V / min until it reached 0V, forming a continuous gradient transition layer. The magnetron sputtering time was 1.5h, and a continuous gradient transition layer with a thickness of 1.5μm was obtained.
[0067] (3) Hard layer preparation: After turning off the current in step (2), nitrogen gas of 500 sccm is continuously introduced into the vacuum chamber, and then a current of 120A is continuously introduced into the high-purity titanium target to maintain a bias voltage of -100V. The magnetron sputtering time is 3h to form a TiN hard layer with a thickness of 1μm.
[0068] Example 3
[0069] (1) Ion etching: mounting Co 0.15 Ti 0.85 Co 0.15 Ta 0.85 High-purity titanium target material. The tool substrate was placed in a vacuum chamber and evacuated to 5 × 10⁻⁶. -4 The temperature is increased to 500℃, and argon gas is introduced into the vacuum chamber at a flow rate of 50 sccm. A bias voltage of -180V is maintained to attract Ar gas. + The substrate surface is bombarded with ions to etch the tool surface for 0.5 hours.
[0070] (2) Preparation of continuous gradient transition layer: Maintaining the argon flow rate at 50 sccm, the argon gas is introduced into the Co layer. 0.15 Ti 0.85 The target is supplied with a current of 80A and a bias voltage of -60V. The bias voltage is increased at a rate of 1.5V / min until it reaches a constant -100V. Simultaneously, a current of 80A is applied to the Co target. 0.15 Ta 0.85 The target was fed with a current of 80A and an initial bias voltage of -40V. The bias voltage was reduced at a decay rate of 1.5V / min until it reached 0V, forming a continuous gradient transition layer. The magnetron sputtering time was 1h to obtain a continuous gradient transition layer with a thickness of 1μm.
[0071] (3) Hard layer preparation: After turning off the current in step (2), nitrogen gas of 500 sccm is continuously introduced into the vacuum chamber, and then a current of 120A is continuously introduced into the high-purity titanium target to maintain a bias voltage of -100V. The magnetron sputtering time is 4h to form a TiN hard layer with a thickness of 2μm.
[0072] Cutting tests were conducted on the coated cutting tools obtained in Examples 1-3 and Comparative Examples 1-8. The specific process is as follows:
[0073] Tool model: SNMN150408
[0074] Material to be cut: SCM440 steel (SCM440 steel is a chromium-molybdenum alloy steel, possessing excellent properties such as high strength, high hardenability, excellent resistance to temper brittleness, and good toughness. Its performance is comprehensively superior to S45C steel. When the performance of S45C steel is insufficient for demanding working conditions, SCM440 steel is usually the first-line alternative. The SCM440 steel used in this patent is in a quenched and tempered state (after heat treatment), with a hardness of 300 HB).
[0075] Material shape to be cut: 150mm × Φ80mm
[0076] Cutting speed: 350m / min
[0077] Feed: 0.25mm / rev
[0078] Depth of cut: 1.0mm
[0079] Coolant: None
[0080] The experimental results are shown in Table 1;
[0081] Table 1
[0082]
[0083] Cutting tests were conducted on the coated cutting tools obtained in Examples 1-3 and Comparative Examples 1-2. The specific process is as follows:
[0084] Tool model: SNMN150408
[0085] Material to be cut: S45C steel (heat-treated product, hardness 220HB)
[0086] Material shape to be cut: 150mm × Φ80mm
[0087] Cutting speed: 350m / min
[0088] Feed: 0.25mm / rev
[0089] Depth of cut: 1.0mm
[0090] Coolant: None
[0091] The experimental results are shown in Table 2;
[0092] Table 2
[0093]
[0094] The coated cutting tool obtained by this invention has superior cutting performance compared to similar products, including patent CN113652661A.
Claims
1. A hard coating having a continuous gradient transition layer, characterized in that, It includes a continuous gradient transition layer and a hard layer, wherein the continuous gradient transition layer is composed of Co. 0.15 Ti x Ta y As the distance from the substrate increases, the x value changes continuously from 0.55 to 0.85, and the y value changes continuously from 0.3 to 0, x+y=0.85; the hard layer is TiN; the continuous gradient transition layer is attached to the substrate and located between the substrate and the hard layer, the hard layer is attached to the continuous gradient transition layer, and the substrate is a tantalum-containing metal ceramic substrate.
2. The hard coating with a continuous gradient transition layer according to claim 1, characterized in that, The thickness of the continuous gradient transition layer is 0.5-1.5 μm, and the thickness of the hard layer is 1-2 μm.
3. The hard coating with a continuous gradient transition layer according to claim 1, characterized in that, The substrate is a tantalum-containing titanium carbonitride-based metal ceramic substrate.
4. A method for preparing a hard coating having a continuous gradient transition layer according to any one of claims 1-3, characterized in that, Includes the following steps: Preparation of continuous gradient transition layer: under argon atmosphere, with Co 0.15 Ti 0.85 and Co 0.15 Ta 0.85 For magnetron sputtering targets, to Co 0.15 Ti 0.85 A constant current is applied to the target material, and the bias voltage is gradually increased to direct the Co... 0.15 Ta 0.85 A constant current is passed through the target material, and the bias voltage gradually decreases. A continuous gradient transition layer is prepared on the substrate surface by magnetron sputtering and physical vapor deposition. Hard layer preparation: Under a nitrogen atmosphere, a high-purity titanium target is used as the target material, and a constant current and constant bias voltage are applied to prepare a hard layer on the substrate surface by magnetron sputtering physical vapor deposition.
5. The method for preparing a hard coating with a continuous gradient transition layer according to claim 4, characterized in that, During the fabrication of the continuous gradient transition layer, Co 0.15 Ti 0.85 A constant current of 80A is applied to the target, and the bias voltage is increased at a rate of 0.5-1V / min from -60V to -100V and maintained constant; Co 0.15 Ta 0.85 A constant current of 80A is applied to the target material, with an initial bias voltage of -40V. The bias voltage is reduced to 0V at a decay rate of 0.5-1V / min. During the preparation process, the argon gas flow rate is maintained at 60sccm. The magnetron sputtering time is 1-2h.
6. The method for preparing a hard coating with a continuous gradient transition layer according to claim 4, characterized in that, During the preparation of the hard layer, a 120A current is passed through the high-purity titanium target, a -100V bias voltage is maintained, and the magnetron sputtering time is 2-4 hours; during the preparation process, the nitrogen flow rate is maintained at 500 sccm.
7. The method for preparing a hard coating having a continuous gradient transition layer according to any one of claims 4-6, characterized in that, Before the continuous gradient transition layer is fabricated, the substrate is subjected to ion etching.
8. The method for preparing a hard coating with a continuous gradient transition layer according to claim 7, characterized in that, The ion etching step specifically includes: placing the substrate in a vacuum chamber and evacuating the vacuum to 5×10⁻⁶. -4 The temperature is increased to 500℃, and argon gas is introduced into the vacuum chamber at a flow rate of 50 sccm. The bias voltage is maintained at -180V, and the substrate surface is bombarded with ions for 0.5-1h.
9. The application of a hard coating having a continuous gradient transition layer according to any one of claims 1-3 in tool coatings.
10. A cutting tool, characterized in that, The surface coating is the hard coating with a continuous gradient transition layer as described in any one of claims 1-3.