A wear-resistant and high-temperature-resistant composite coating band saw blade and a preparation method and application thereof

Abstract

This invention relates to a wear-resistant and high-temperature resistant composite coated band saw blade, its preparation method and application. Through the synergistic optimization of the three-layer coating structure and composite deposition process, it fundamentally breaks through the bottleneck of the existing technology and has the following advantages: (1) Gradient transition layer: Through the composition gradient design of TiN / AlTiN / HfN, the difference in thermal expansion coefficient between the matrix and the core layer is matched, significantly improving the interfacial bonding force and effectively alleviating the thermal stress concentration during high-temperature sawing; (2) Superhard core layer: PcBN is used as the wear-resistant skeleton, HfC is used as the toughening phase, graphene is used as the interfacial reinforcement phase, and Ti-Cr-Ni alloy is used as the bonding phase to achieve the multi-effect synergy of "superhard + toughening + high-temperature oxidation resistance"; (3) Self-lubricating surface layer: The composite coating is used as a friction reduction barrier to reduce the friction coefficient to below 0.12, while isolating oxygen penetration and further improving the high-temperature oxidation resistance of the coating.

Description

Technical Field

[0001] This invention belongs to the field of metal processing tool preparation technology, and relates to a wear-resistant and high-temperature resistant composite coated band saw blade, its preparation method and application. Background Technology

[0002] Band saw blades are core tools for metal blanking and profile cutting, and their performance directly determines the processing efficiency and manufacturing cost of difficult-to-machine materials. Currently, the domestic high-end band saw blade market is dominated by Hunan Taijia New Material Technology Co., Ltd., whose products cover three major series: bimetallic, cemented carbide, and high-speed steel, and its market share ranks among the top in the industry.

[0003] In existing technologies, Taijia Co., Ltd.'s core coating technologies are mainly divided into three categories: First, single coating systems based on WC-Co, WC-Co-Cr, WC-Ni, or WC-CrC-Ni, with a total coating thickness of 3μm~20μm. The high-temperature hardness of this type of coating is only maintained at around 2000HV, and it will oxidize rapidly above 600℃, leading to a sharp decrease in wear resistance; Second, the periodic multilayer structure of CrN bonding layer + CrN / AlCrN alternating functional layer + AlCrN top layer disclosed in CN113584438A, with a modulation period of 5nm~50nm and a modulation ratio of 1:1~1:4 in the CrN / AlCrN functional layer, which can balance hardness and toughness to a certain extent, but at high temperatures above 600℃, the hardness of AlCrN will drop sharply to below 2000HV, and it cannot withstand the instantaneous high temperature (usually exceeding 800℃) during high-speed sawing of high-temperature alloys; Third, the structure disclosed in CN117758206A... Alternating coating systems are mainly optimized for processing non-ferrous metals such as aluminum alloys. However, they lack sufficient chemical inertness for ferrous metals and do not solve the problem of chip adhesion during high-temperature alloy sawing.

[0004] Furthermore, existing coatings generally suffer from the drawback of not being able to balance toughness and wear resistance: hard coatings (such as AlCrN) have high hardness but are brittle and prone to chipping under impact loads; tough coatings (such as WC-Co) lack wear resistance and are prone to chip adhesion and rapid wear. For example, when an aerospace component supplier used ordinary AlTiN coated saw blades to saw Inconel 718, the saw blade had to be replaced after sawing every 3 to 5 bars with a diameter of 50mm, with each blade change taking up to 15 minutes. This not only directly reduced production efficiency but also caused fluctuations in the end face accuracy of the workpiece due to frequent blade changes, increasing the cost of subsequent finishing.

[0005] To address the aforementioned issues and overcome the limitations of traditional coating materials and processes, and to construct a synergistic system of "ultra-hard core layer + gradient transition layer + self-lubricating surface layer," the simultaneous improvement of high-temperature stability, ultra-hard wear resistance, and impact toughness can be achieved through the functional complementarity of multiphase materials and stress optimization of gradient structures. Summary of the Invention

[0006] In view of this, one objective of the present invention is to provide a wear-resistant and high-temperature resistant composite coated band saw blade; a second objective of the present invention is to provide a method for preparing a wear-resistant and high-temperature resistant composite coated band saw blade; and a third objective of the present invention is to provide an application of a wear-resistant and high-temperature resistant composite coated band saw blade in metal material processing.

[0007] To achieve the above objectives, the present invention provides the following technical solution: 1. A wear-resistant and high-temperature resistant composite coated band saw blade, the band saw blade comprising a band saw blade substrate and a composite coating deposited on the tooth surface of the band saw blade substrate; The composite coating consists of a gradient transition layer, an ultra-hard core layer, and a self-lubricating surface layer from the inside out. The gradient transition layer is composed of a TiN layer, an AlTiN layer, and an HfN layer that are in direct contact with the band saw blade substrate; The superhard core layer uses cubic boron nitride (PcBN) micro powder as the superhard framework, hafnium carbide (HfC) particles as the toughening phase, graphene nanosheets as the interface reinforcement phase, and Ti-Cr-Ni alloy as the binder phase. The self-lubricating surface layer is doped. Diamond carbon (DLC).

[0008] Preferably, the total thickness of the composite coating is 2.5~6.5μm; The total thickness of the gradient transition layer is 1.5~3.5μm, and the interfacial bonding force is ≥85N; The thickness of the TiN or AlTiN layer in the gradient transition layer is 0.5~1μm, and the thickness of the HfN layer is 0.5~1.5μm.

[0009] Preferably, the thickness of the ultrahard core layer is 0.5~2μm and the microhardness is ≥3500HV; The cubic boron nitride (PcBN) in the superhard core layer accounts for 60-70% of the total mass of the superhard core layer, the hafnium carbide (HfC) accounts for 15-20% of the total mass of the superhard core layer, the graphene nanosheets are doped at 0.2-0.5 wt%, and the Ti-Cr-Ni alloy accounts for 10-15% of the total mass of the superhard core layer.

[0010] Preferably, the coefficient of friction of the self-lubricating surface layer is ≤0.12; In the self-lubricating surface layer The doping amount is 5~8wt%; The thickness of the self-lubricating surface layer is 0.5~1μm.

[0011] Preferably, the tooth tip material of the band saw blade base is high-speed steel, and the backing material is spring steel; The hardness of the tooth tip is 65~70HRC, and the hardness of the tooth back is 47~53HRC.

[0012] 2. The preparation method of the above-mentioned wear-resistant and high-temperature resistant composite coated band saw blade, the preparation method comprising the following steps: (1) Preparation of gradient transition layer: TiN material, AlTiN material and HfN material are sequentially deposited on the pretreated band saw blade substrate by arc ion plating; (2) Preparation of superhard core layer: The superhard core layer can be obtained by using a magnetron sputtering-arc ion plating composite method, with PcBN-HfC composite target and Ti-Cr-Ni alloy target as target materials, and graphene nanosheets are introduced in situ for doping. After vacuuming, the superhard core layer can be obtained by deposition. (3) Preparation of self-lubricating surface layer: using magnetron sputtering, with DLC target and Target co-deposition; (4) Post-treatment: Temper the material treated in step (4) in a vacuum environment at 200~300℃ to obtain wear-resistant and high-temperature resistant composite coated band saw blade.

[0013] Preferably, in step (1), the pretreatment method is as follows: the band saw blade substrate is subjected to acetone ultrasonic cleaning and argon ion etching in sequence. The argon ion etching power is 500W and the time is 20min. The bias voltage of the argon ion etching is -800V and the argon flow rate is 50~100sccm. In step (1), the deposition temperature is 350~400℃, and the vacuum degree is... Pa, deposition rate 1.5 μm / h.

[0014] Preferably, in step (2), the magnetron sputtering power is 2000W and the target current of the arc ion plating is 150~200A in the magnetron sputtering-arc ion plating composite method.

[0015] Preferably, in step (2), the deposition temperature is 450~500℃ and the time is 8h.

[0016] Preferably, in step (3), the argon flow rate is 20-60 sccm and the acetylene flow rate is 5-15 sccm in the magnetron sputtering method.

[0017] Preferably, in step (3), the deposition temperature is 200~250℃.

[0018] Preferably, in step (4), the tempering time is 2 hours.

[0019] 3. Application of the above-mentioned wear-resistant and high-temperature resistant composite coated band saw blades in metal material processing.

[0020] Preferably, the metal material is any one of high-temperature alloy, titanium alloy, or mold steel.

[0021] The beneficial effects of the present invention are as follows: The present invention discloses a wear-resistant and high-temperature resistant composite coated band saw blade, which adopts the composite design concept of "gradient stress relief + superhard phase synergy + self-lubricating friction reduction". Through the synergistic optimization of the three-layer coating structure and composite deposition process, it fundamentally breaks through the bottleneck of the existing technology. The wear-resistant and high-temperature resistant composite coated band saw blade of the present invention has the following advantages: (1) Gradient transition layer: Through the composition gradient design of TiN / AlTiN / HfN, the difference in thermal expansion coefficient between the matrix and the core layer is matched, significantly improving the interface bonding force and effectively relieving the thermal stress concentration during high-temperature sawing; (2) Superhard core layer: PcBN (currently known superhard material with hardness second only to diamond) is used as the wear-resistant skeleton, HfC (one of the materials with the highest melting point among metal carbides) is used as the toughening phase, graphene is used as the interface reinforcement phase, and Ti-Cr-Ni alloy is used as the bonding phase, realizing the multi-effect synergy of "superhard + toughening + high-temperature oxidation resistance"; (3) Self-lubricating surface layer: The composite coating acts as a friction-reducing barrier, lowering the coefficient of friction to below 0.12 while also preventing oxygen penetration, further enhancing the coating's high-temperature oxidation resistance.

[0022] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein: Figure 1 The metallographic structure of the wear-resistant and high-temperature resistant composite coating on the tip of the band saw blade prepared in Example 1; Figure 2 The coating thickness of the wear-resistant and high-temperature resistant composite coated band saw blade prepared in Example 1 was approximately 6~10μm, as determined by the ball milling thickness measurement method. Figure 3 The results show the test results of the adhesion of the wear-resistant and high-temperature resistant composite coating on the tooth tip of the band saw blade prepared in Example 1. Detailed Implementation

[0024] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0025] Example 1 The specific method for preparing wear-resistant and high-temperature-resistant composite coated band saw blades is as follows: 1. Pretreatment of band saw blade substrate: (1) Cleaning: First, the M42 bimetal band saw blade (tooth tip hardness 69HRC) is ultrasonically cleaned with acetone and ethanol for 15 minutes each to remove surface oil, dust and other impurities; then rinsed with deionized water and dried for later use (this step can effectively prevent impurities from affecting the adhesion of the coating); (2) Sandblasting roughening: 300~400 mesh white corundum sand is used to sandblast the tooth tip area at a pressure of 0.2~0.3MPa to make the surface roughness of the tooth tip reach Ra0.8~1 .2μm (The purpose of roughening is to increase the contact area between the coating and the substrate, and at the same time form an "anchoring effect" to enhance the mechanical bonding force of the coating); (3) Argon ion etching: Put the substrate into the vacuum chamber, introduce argon gas (flow rate 50~100sccm), apply 500W power and -800V bias voltage, and perform argon ion etching for 20min (this step can remove the oxide film and residual impurities on the surface of the substrate, so that the surface of the substrate is in an active state, further enhancing the bonding strength of the coating), and the pretreated band saw blade substrate can be obtained.

[0026] 2. Preparation of the gradient transition layer: This is achieved using arc ion plating (temperature 350℃, vacuum level...). (Pa, deposition rate of 1.5 μm / h) TiN material, AlTiN material and HfN material are sequentially deposited on the surface of the pretreated band saw blade substrate to form a composite coating with a total thickness of 1.5 μm and an interfacial bonding force of 92 N on the saw tooth surface of the pretreated band saw blade substrate. The coating includes a TiN layer (thickness of 0.5 μm), an AlTiN layer (thickness of 0.5 μm) and an HfN layer (thickness of 0.5 μm) that are in direct contact with the band saw blade substrate.

[0027] 3. Preparation of the ultrahard core layer: A magnetron sputtering-arc ion plating composite method was adopted (temperature 450℃, magnetron sputtering power 2000W, arc target current 180A). PcBN-HfC composite target and Ti-Cr-Ni alloy target were used as target materials. Graphene nanosheets were simultaneously introduced for in-situ doping. The mass of PcBN was 65wt%, HfC was 18wt%, graphene was 0.3wt%, and Ti-Cr-Ni alloy was 16.7wt%. An ultrahard core layer with a thickness of 0.5μm and a microhardness of 3800HV was formed on the surface of the composite coating prepared above.

[0028] 4. Preparation of self-lubricating surface layer: A magnetron sputtering method was used (temperature 230℃, argon flow rate 40 sccm, acetylene flow rate 10 sccm), with a DLC target and... Target co-deposition, in which The doping amount is 6wt%, and a self-lubricating surface layer with a thickness of 0.5μm and a friction coefficient of 0.11 is formed on the surface of the superhard core layer prepared above.

[0029] 5. Post-processing: Temper the material processed in step (4) in a vacuum environment at 200℃ for 2 hours to obtain a wear-resistant and high-temperature resistant composite coated band saw blade.

[0030] Figure 1 The metallographic structure of the wear-resistant and high-temperature-resistant composite coating on the tip portion of the band saw blade teeth prepared in Example 1 is shown below. Figure 1 As can be seen, the thickness of the wear-resistant and high-temperature resistant composite coating on the tip of the band saw blade prepared in Example 1 is approximately 2–5 μm.

[0031] The coating thickness of the wear-resistant and high-temperature-resistant composite coated band saw blade prepared in Example 1 was tested using the ball milling thickness measurement method, and the results are as follows: Figure 2 As shown in the figure, it can be seen that the coating thickness of the wear-resistant and high-temperature resistant composite coated band saw blade prepared in Example 1 is about 2 to 5 μm.

[0032] The adhesion of the wear-resistant and high-temperature-resistant composite coating on the tooth tip of the band saw blade prepared in Example 1 was tested, and the results are as follows: Figure 3 As shown, it can be seen that the wear-resistant and high-temperature resistant composite coating of the band saw blade tooth tip prepared in Example 1 has good adhesion, with most of it at HF2-3 level.

[0033] Eight samples of the wear-resistant and high-temperature resistant composite coated band saw blades prepared in Example 1 were taken, and the tooth / back hardness values ​​of the coating were tested. The results are shown in Table 1.

[0034] Table 1. Test values ​​of tooth / back hardness of the wear-resistant and high-temperature resistant composite coating band saw blade prepared in Example 1.

[0035] Eight samples of the wear-resistant and high-temperature resistant composite coated band saw blades prepared in Example 1 were taken, and the tensile strength of the coating was tested. The results are shown in Table 2.

[0036] Table 2. Tensile strength test of the wear-resistant and high-temperature resistant composite coating on the band saw blade prepared in Example 1.

[0037] Eight samples of the wear-resistant and high-temperature resistant composite coated band saw blades prepared in Example 1 were taken and their wear resistance was tested. The results are shown in Table 3.

[0038] Table 3. Wear resistance test results of the wear-resistant and high-temperature resistant composite coated band saw blade prepared in Example 1.

[0039] Eight samples of the wear-resistant and high-temperature resistant composite coated band saw blades prepared in Example 1 were taken and their hardness and saw number were tested. The results are shown in Table 4.

[0040] Table 4. Hardness and sawing number tests of the wear-resistant and high-temperature resistant composite coated band saw blade prepared in Example 1.

[0041] The wear-resistant and high-temperature resistant composite coated band saw blade prepared in Example 1 above was subjected to a high-temperature hardness test, and it could maintain 3200 HV at 800℃.

[0042] The sawing life of the wear-resistant and high-temperature resistant composite coated band saw blade prepared in Example 1 was tested. The test results showed that the blade could cut 15 Inconel 718 bars with a diameter of 100mm, which is more than twice that of traditional AlTiN coated band saw blades.

[0043] The surface quality of the wear-resistant and high-temperature resistant composite coated band saw blade prepared in Example 1 was tested. The test results were as follows: the temperature of the cutting zone was controlled below 750℃, the surface roughness of the workpiece end face was Ra=1.2μm, and there were no obvious chips or chipping phenomena.

[0044] Example 2 The specific method for preparing wear-resistant and high-temperature-resistant composite coated band saw blades is as follows: 1. Band saw blade substrate pretreatment: (1) Cleaning: First, the M51 bimetal band saw blade (tooth tip hardness 70HRC) is ultrasonically cleaned with acetone and ethanol for 15 minutes each to remove surface oil, dust and other impurities; then rinsed with deionized water and dried for later use (this step can effectively avoid impurities affecting the coating adhesion); (2) Sandblasting roughening: 80~120 mesh white corundum sand is used to sandblast the tooth tip area with a pressure of 0.2~0.3MPa to make the tooth tip surface roughness reach Ra0.8~1.2μm (the purpose of roughening is to increase the contact area between the coating and the substrate, and at the same time form an "anchoring effect" to improve the mechanical adhesion of the coating); (3) Argon ion etching: The substrate is placed in a vacuum chamber, argon gas (flow rate 50~100sccm) is introduced, and 500W power and -800V are applied. Apply a bias voltage and perform argon ion etching for 20 minutes (this step removes the oxide film and residual impurities on the substrate surface, keeping the substrate surface in an active state and further improving the bonding strength of the coating) to obtain the pretreated band saw blade substrate.

[0045] 2. Preparation of the gradient transition layer: This is achieved using arc ion plating (temperature 360℃, vacuum level...). (Pa, deposition rate of 1.5 μm / h) TiN material, AlTiN material and HfN material are sequentially deposited on the pretreated band saw blade substrate surface to form a composite coating with a total thickness of 2 μm and an interfacial bonding force of 88 N on the saw tooth surface of the pretreated band saw blade substrate. This coating includes a TiN layer (thickness of 0.5 μm), an AlTiN layer (thickness of 0.5 μm) and an HfN layer (thickness of 1 μm) that are in direct contact with the band saw blade substrate.

[0046] 3. Preparation of the superhard core layer: A magnetron sputtering-arc ion plating composite method was adopted (temperature 460℃, magnetron sputtering power 1800W, arc target current 160A). PcBN-HfC composite target and Ti-Cr-Ni alloy target were used as target materials. Graphene nanosheets were simultaneously introduced for in-situ doping. The mass of PcBN was 62wt%, HfC was 16wt%, graphene was 0.25wt%, and Ti-Cr-Ni alloy was 21.75wt%. A superhard core layer with a thickness of 1μm and a microhardness of 3600HV was formed on the surface of the composite coating prepared above.

[0047] 4. Preparation of self-lubricating surface layer: A magnetron sputtering method was used (temperature 220℃, argon flow rate 40 sccm, acetylene flow rate 10 sccm), with a DLC target and... Target co-deposition, in which The doping amount is 7wt%, and a self-lubricating surface layer with a thickness of 1μm and a friction coefficient of 0.105 is formed on the surface of the superhard core layer prepared above.

[0048] 5. Post-treatment: The material with the self-lubricating surface layer prepared above is tempered in a vacuum environment at 200℃ for 2 hours to obtain a wear-resistant and high-temperature resistant composite coated band saw blade.

[0049] The wear-resistant and high-temperature resistant composite coated band saw blade prepared in Example 2 above was subjected to a high-temperature hardness test, and it could maintain 3100 HV at 800℃.

[0050] The sawing life of the wear-resistant and high-temperature resistant composite coated band saw blade prepared in Example 2 was tested. The test results showed that when sawing 300×400mm H13 mold steel square material, the linear speed was 30m / min and the feed speed was 20mm / min. The life was 75% longer than that of the Taijia WC-Co coated saw blade.

[0051] The wear-resistant and high-temperature resistant composite coated band saw blade prepared in Example 2 was tested for its anti-chipping performance. The test results showed that there was no chipping after 10 consecutive sawing operations, and the coating was intact.

[0052] Example 3 The specific method for preparing wear-resistant and high-temperature-resistant composite coated band saw blades is as follows: 1. Band saw blade substrate pretreatment: (1) Cleaning: First, the M42 bimetal band saw blade (tooth tip hardness 69HRC) is ultrasonically cleaned with acetone and ethanol for 15 minutes each to remove surface oil, dust and other impurities; then rinsed with deionized water and dried for later use (this step can effectively avoid impurities affecting the coating adhesion); (2) Sandblasting roughening: 80~120 mesh white corundum sand is used to sandblast the tooth tip area with a pressure of 0.2~0.3MPa to make the tooth tip surface roughness reach Ra0.8~1.2μm (the purpose of roughening is to increase the contact area between the coating and the substrate, and at the same time form an "anchoring effect" to improve the mechanical adhesion of the coating); (3) Argon ion etching: The substrate is placed in a vacuum chamber, argon gas (flow rate 50~100sccm) is introduced, and 500W power and -800V are applied. Apply a bias voltage and perform argon ion etching for 20 minutes (this step removes the oxide film and residual impurities on the substrate surface, keeping the substrate surface in an active state and further improving the bonding strength of the coating) to obtain the pretreated band saw blade substrate.

[0053] 2. Preparation of the gradient transition layer: This is achieved using arc ion plating (temperature 350℃, vacuum level...). (a. Deposition rate of 1.5 μm / h) TiN material, AlTiN material and HfN material are sequentially deposited on the pretreated band saw blade substrate surface to form a composite coating with a total thickness of 2.5 μm and an interfacial bonding force of 92 N on the saw tooth surface of the pretreated band saw blade substrate. This coating includes a TiN layer (thickness of 0.6 μm), an AlTiN layer (thickness of 0.7 μm) and an HfN layer (thickness of 1.2 μm) that are in direct contact with the band saw blade substrate.

[0054] 3. Preparation of the ultrahard core layer: A magnetron sputtering-arc ion plating composite method was adopted (temperature 450℃, magnetron sputtering power 2000W, arc target current 150A). PcBN-HfC composite target and Ti-Cr-Ni alloy target were used as target materials. Graphene nanosheets were simultaneously introduced for in-situ doping. The mass of PcBN was 65wt%, HfC was 18wt%, graphene was 0.3wt%, and Ti-Cr-Ni alloy was 16.7wt%. An ultrahard core layer with a thickness of 1.1μm and a microhardness of 3800HV was formed on the surface of the composite coating prepared above.

[0055] 4. Preparation of a self-lubricating surface layer: A magnetron sputtering method was used (temperature 230℃, argon flow rate 20 sccm, acetylene flow rate 5 sccm) to co-deposit a DLC target and a MoS2 target (deposition temperature 200℃). The doping amount is 6wt%, and a self-lubricating surface layer with a thickness of 1.1μm and a friction coefficient of 0.11 is formed on the surface of the superhard core layer prepared above.

[0056] 5. Post-processing: Temper the material processed in step (4) in a vacuum environment at 250℃ for 2 hours to obtain a wear-resistant and high-temperature resistant composite coated band saw blade.

[0057] Example 4 The specific method for preparing wear-resistant and high-temperature-resistant composite coated band saw blades is as follows: 1. Band saw blade substrate pretreatment: (1) Cleaning: First, the M42 bimetal band saw blade (tooth tip hardness 69HRC) is ultrasonically cleaned with acetone and ethanol for 15 minutes each to remove surface oil, dust and other impurities; then rinsed with deionized water and dried for later use (this step can effectively avoid impurities affecting the coating adhesion); (2) Sandblasting roughening: 80~120 mesh white corundum sand is used to sandblast the tooth tip area with a pressure of 0.2~0.3MPa to make the tooth tip surface roughness reach Ra0.8~1.2μm (the purpose of roughening is to increase the contact area between the coating and the substrate, and at the same time form an "anchoring effect" to improve the mechanical adhesion of the coating); (3) Argon ion etching: The substrate is placed in a vacuum chamber, argon gas (flow rate 50~100sccm) is introduced, and 500W power and -800V are applied. Apply a bias voltage and perform argon ion etching for 20 minutes (this step removes the oxide film and residual impurities on the substrate surface, keeping the substrate surface in an active state and further improving the bonding strength of the coating) to obtain the pretreated band saw blade substrate.

[0058] 2. Preparation of gradient transition layer: TiN, AlTiN and HfN materials are sequentially deposited on the pretreated band saw blade substrate using an arc ion plating method (temperature 400℃, vacuum degree 5×10⁻³Pa, deposition rate 1.5μm / h). A composite coating with a total thickness of 3.5μm and an interfacial bonding force of 92N is formed on the saw tooth surface of the pretreated band saw blade substrate. This coating includes a TiN layer (thickness 1μm), an AlTiN layer (thickness 1μm) and an HfN layer (thickness 1.5μm) that are in direct contact with the band saw blade substrate.

[0059] 3. Preparation of the superhard core layer: A magnetron sputtering-arc ion plating composite method was adopted (temperature 500℃, magnetron sputtering power 2000W, arc target current 200A). PcBN-HfC composite target and Ti-Cr-Ni alloy target were used as target materials. Graphene nanosheets were simultaneously introduced for in-situ doping. The mass of PcBN was 65wt%, HfC was 18wt%, graphene was 0.3wt%, and Ti-Cr-Ni alloy was 16.7wt%. A superhard core layer with a thickness of 2μm and a microhardness of 3800HV was formed on the surface of the composite coating prepared above.

[0060] 4. Preparation of a self-lubricating surface layer: A magnetron sputtering method was used (temperature 230℃, argon flow rate 60 sccm, acetylene flow rate 15 sccm) to co-deposit a DLC target and a MoS2 target (deposition temperature 250℃). The doping amount is 6wt%, and a self-lubricating surface layer with a thickness of 1μm and a friction coefficient of 0.11 is formed on the surface of the superhard core layer prepared above.

[0061] 5. Post-processing: Temper the material processed in step (4) in a vacuum environment at 300℃ for 2 hours to obtain a wear-resistant and high-temperature resistant composite coated band saw blade.

[0062] Similarly, the wear-resistant and high-temperature resistant composite coated band saw blades prepared in Examples 3 and 4 were subjected to relevant performance tests (coating tooth / back hardness value, coating tensile strength, wear resistance, hardness, and sawing count). The results also showed that the wear-resistant and high-temperature resistant composite coated band saw blades prepared according to the preparation method of the present invention can indeed improve high-temperature hardness, increase friction coefficient, increase sawing life, strengthen interfacial bonding, and increase impact toughness.

[0063] To verify the performance advantages of this invention, the national standard T / CSTM 00646.2-2021 (high temperature friction coefficient test), GB / T 12444-2021 (impact toughness test) and industry standard JB / T 10230-2013 (sawing life test) were used to conduct comparative tests with existing products. All tests were conducted under the same working conditions to ensure the comparability of the data. The test results are as follows: (1) High temperature hardness at 800℃: The wear-resistant and high temperature-resistant composite coated band saw blade prepared by this invention has a hardness of 3000~3200HV, while the existing band saw blade has a hardness of 1800~2000HV. After the improvement of this invention, the hardness is increased by about 50%; (2) Friction coefficient: The wear-resistant and high temperature-resistant composite coated band saw blade prepared by this invention has a friction coefficient of 0.11~0.12, while the existing band saw blade has a friction coefficient of 0.40~0.65. After the improvement of this invention, the friction coefficient is increased by 7%. 0%; (3) Cutting life (Inconel718, diameter 110mm): The wear-resistant and high-temperature resistant composite coated band saw blade prepared by the present invention is 100-120 cut, while the existing band saw blade is 70-90 cut. After the improvement of the present invention, its improvement range is about 10-70%; (4) Interface bonding force: The wear-resistant and high-temperature resistant composite coated band saw blade prepared by the present invention is ≥85N, while the existing band saw blade is 50-60N. After the improvement of the present invention, its improvement range is about 40%; Therefore, the wear-resistant and high-temperature resistant composite coated band saw blade prepared by the present invention is significantly better than the existing technology in terms of core indicators such as hardness, friction coefficient and cutting life.

[0064] In summary, the wear-resistant and high-temperature resistant composite coated band saw blade disclosed in this invention has an ultra-hard core layer as the main wear-resistant unit of the coating. The material selection is based on "high-temperature stability, ultra-high hardness, and impact toughness" as the core indicators. The functions and proportions of each component have been optimized through multiple rounds of experiments, and the following results have been obtained: (1) Cubic boron nitride (PcBN): As an ultra-hard skeleton phase, it accounts for 60%~70% of the mass of the core layer, and micro powder with a particle size of 1~3μm is selected. The microhardness of PcBN can reach 3500~4500HV, and the thermal stability is as high as 1200℃. Its chemical inertness to iron group metals is far superior to that of diamond. This means that when sawing high-temperature alloys, PcBN will not react chemically with iron elements like diamond, and can maintain more stable cutting performance. More importantly, PcBN has a thermal conductivity that is 2 to 3 times that of cemented carbide, which can quickly dissipate heat from the cutting zone and prevent the tooth tip from softening due to excessive temperature; (2) Hafnium carbide (HfC): As a toughening phase, it accounts for 15% to 20% of the core layer mass and uses 0.5 to 1 μm particles. HfC has a melting point as high as 3890℃, which is the highest among all metal carbides. It can still maintain a hardness of 3800 HV above 800℃, and its fracture toughness is about 15% higher than that of PcBN. In addition, the interface bonding energy between HfC and steel is significantly higher than that of traditional carbides, which can effectively suppress chip adhesion. This is crucial for solving the "sticking" problem when sawing high-temperature alloys; (3) Graphene nanosheets: As an interface reinforcement phase, the doping amount is 0.2 to 0.5 wt%. Graphene possesses extremely low interlaminar shear strength and a friction coefficient of only 0.05–0.1, making it an ideal solid lubricant phase. It can form a transfer film on the contact surface between the tooth tip and the workpiece, transforming sliding friction into interlaminar friction and significantly reducing cutting resistance. Simultaneously, graphene has a high thermal conductivity. It is more than 5 times that of copper, which can quickly dissipate cutting heat and reduce the temperature of the tooth tip. More importantly, the "bridging effect" of graphene can effectively inhibit crack propagation: when microcracks are generated inside the coating, the graphene sheets will block the extension path of the cracks, and even absorb the crack energy through their own deformation, thereby improving the impact toughness of the coating; (4) Ti-Cr-Ni alloy: as a binder phase, it accounts for 10%~15% of the mass of the core layer, with a mass ratio of Ti:Cr:Ni=4:3:3. Among them, Ti can react with the oxide on the surface of the substrate to form a strong chemical bonding interface, which significantly improves the bonding force between the coating and the substrate; Cr can form a dense layer at high temperature. The oxide film effectively blocks oxygen from penetrating into the coating, delaying the oxidation failure of the superhard phase; Ni element can improve the toughness of the binder phase, preventing the coating from peeling off due to excessive brittleness.

Claims

1. A wear-resistant and high-temperature resistant composite coated band saw blade, characterized in that, The band saw blade includes a band saw blade substrate and a composite coating deposited on the tooth surface of the band saw blade substrate; The composite coating consists of a gradient transition layer, an ultra-hard core layer, and a self-lubricating surface layer from the inside out. The gradient transition layer is composed of a TiN layer, an AlTiN layer, and an HfN layer that are in direct contact with the band saw blade substrate; The superhard core layer uses cubic boron nitride micro powder as the superhard framework, hafnium carbide particles as the toughening phase, graphene nanosheets as the interface reinforcement phase, and Ti-Cr-Ni alloy as the binder phase. The self-lubricating surface layer is doped. Diamond carbon.

2. The wear-resistant and high-temperature resistant composite coated band saw blade according to claim 1, characterized in that, The total thickness of the composite coating is 2.5~6.5μm; The total thickness of the gradient transition layer is 1.5~3.5μm, and the interfacial bonding force is ≥85N; The thickness of the TiN or AlTiN layer in the gradient transition layer is 0.5~1μm, and the thickness of the HfN layer is 0.5~1.5μm.

3. The wear-resistant and high-temperature resistant composite coated band saw blade according to claim 1, characterized in that, The thickness of the ultrahard core layer is 0.5~2μm, and the microhardness is ≥3500HV; The cubic boron nitride in the superhard core layer accounts for 60-70% of the total mass of the superhard core layer, the hafnium carbide accounts for 15-20% of the total mass of the superhard core layer, the graphene nanosheets are doped with 0.2-0.5 wt%, and the Ti-Cr-Ni alloy accounts for 10-15% of the total mass of the superhard core layer.

4. The wear-resistant and high-temperature resistant composite coated band saw blade according to claim 1, characterized in that, The coefficient of friction of the self-lubricating surface layer is ≤0.12; In the self-lubricating surface layer The doping amount is 5~8wt%; The thickness of the self-lubricating surface layer is 0.5~1μm.

5. The wear-resistant and high-temperature resistant composite coated band saw blade according to claim 1, characterized in that, The tooth tip material of the band saw blade base is high-speed steel, and the tooth back material is spring steel; The hardness of the tooth tip is 65~70HRC, and the hardness of the tooth back is 47~53HRC.

6. The method for preparing the wear-resistant and high-temperature resistant composite coated band saw blade according to any one of claims 1 to 5, characterized in that, The preparation method includes the following steps: (1) Preparation of gradient transition layer: TiN material, AlTiN material and HfN material are sequentially deposited on the pretreated band saw blade substrate by arc ion plating; (2) Preparation of superhard core layer: The magnetron sputtering-arc ion plating composite method is adopted, with PcBN-HfC composite target and Ti-Cr-Ni alloy target as target materials, and graphene nanosheets are introduced in situ for doping. After vacuuming, ion plating is performed, and the superhard core layer can be obtained by deposition. (3) Preparation of self-lubricating surface layer: using magnetron sputtering, with a DLC target and A self-lubricating surface layer was prepared by target co-deposition; (4) Post-treatment: The wear-resistant and high-temperature resistant composite coated band saw blade can be prepared by tempering the material treated in step (4) in a vacuum environment at 200~300℃.

7. The preparation method according to claim 6, characterized in that, In step (1), the pretreatment method is as follows: the band saw blade substrate is subjected to acetone ultrasonic cleaning and argon ion etching in sequence. The argon ion etching power is 500W and the time is 20min. The bias voltage of the argon ion etching is -800V and the argon flow rate is 50~100sccm. In step (1), the deposition temperature is 350~400℃, and the vacuum degree is... Pa, deposition rate 1.5 μm / h.

8. The preparation method according to claim 6, characterized in that, In step (2), the magnetron sputtering power is 2000W and the target current of the arc ion plating is 150~200A in the magnetron sputtering-arc ion plating composite method. In step (2), the deposition temperature is 450~500℃ and the time is 8h; In step (3), the argon flow rate is 20-60 sccm and the acetylene flow rate is 5-15 sccm in the magnetron sputtering method; In step (3), the deposition temperature is 200~250℃; In step (4), the tempering time is 2 hours.

9. The application of the wear-resistant and high-temperature resistant composite coated band saw blade according to any one of claims 1 to 5 in the processing of metal materials.

10. The application according to claim 9, characterized in that, The metal material is any one of high-temperature alloy, titanium alloy, or mold steel.

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