Kitchen knife having ultra-high sharpness and manufacturing method therefor

Abstract

The present invention provides a method for manufacturing a kitchen knife by arc ion plating, by which a kitchen knife having ultra-high sharpness can be obtained. The method comprises: placing, in an arc ion plating chamber provided with an arc generation device, a kitchen knife body substrate having a blade portion, and performing ion etching treatment on surfaces of two sides of the blade portion; depositing a bonding layer material on the ion-etched surfaces by means of arc ion plating; and depositing a wear-resistant layer material on the deposited bonding layer material by means of arc ion plating, or sequentially depositing one or more transition layer materials on the deposited bonding layer material and subsequently depositing the wear-resistant layer material. The present invention further provides a wear-resistant kitchen knife having ultra-high initial sharpness and ultra-high sharpness retention.

Description

Kitchen knives with extremely high sharpness and their manufacturing method

[0001] Cross-reference to related applications

[0002] This disclosure claims priority to Chinese Patent Application No. 202411216365.8, filed on August 30, 2024, which is incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure relates to the field of kitchen knives, and more specifically, to kitchen knives with extremely high sharpness and methods for their preparation. Background Technology

[0004] Kitchen knives are an indispensable tool in daily life, used for hand-cutting various ingredients. An excellent kitchen knife should ideally possess a range of superior properties, including high sharpness, high wear resistance, high hardness, high corrosion resistance, aesthetic appeal, high-temperature resistance, and good oxidation resistance.

[0005] High sharpness is crucial for kitchen knives. The sharpness of a kitchen knife's blade is directly related to the difficulty of cutting food. Low sharpness means that some tough ingredients, such as animal tendons or plant fibers, cannot be cut. Lower sharpness also means that more force is required and the cutting time is longer each time food is cut. Since kitchen knives are tools operated by hand, and the average person has limited strength and endurance, a low-sharp knife is very disadvantageous to the user.

[0006] Currently, the most commonly used indicators for measuring the sharpness of kitchen knives include initial sharpness and sharpness retention. Initial sharpness refers to the initial sharpness of a newly manufactured kitchen knife when it is first used. Sharpness retention refers to the ability of a kitchen knife to maintain its sharpness after multiple cuts. Ideally, kitchen knives should possess both high initial sharpness and high sharpness retention, as this reduces the need for frequent sharpening or replacement, saving time and costs. These can be measured according to the European international standard EN ISO 8442-5.2005 (Materials and articles in contact with food – Knives and concave cutlery – Part 5: Test specifications for sharpness and edge retention of knives). In this standard, the performance parameter used to evaluate initial sharpness is initial cutting performance (ICP), and the performance parameter used to evaluate sharpness retention is total card cut (TCC), which is related to cutting edge retention (CER). ICP is characterized by the total depth of the first three cuts when cutting a standard stack of cardboard with a newly manufactured knife. TCC (Total Cutting Capacity) is characterized by the cumulative depth of cuts made by a knife after cutting a stack of standard paper. Here, one "cut" represents one cutting cycle in the test. The standard recommends that each cutting cycle be performed with a load of 50 N, a cutting length of 40 mm, and a cutting speed of 50 mm / s. Kitchen knives are classified into two types, A and B, based on whether the blade is designed to be resharpened during actual use. For type A kitchen knives, the passing standard is an ICP (Integrated Cutting Capacity) of 50 mm and a TCC (Total Cutting Capacity) of 150 mm after 60 cuts. For type B kitchen knives, the passing standard is an ICP of 50 mm and a TCC of 1500 mm after 200 cuts.

[0007] Kitchen knives should also be highly abrasion-resistant relative to the food being processed and the utensils supporting the food (such as cutting boards). Knives with low abrasion resistance will wear down more easily during repeated cutting of food, becoming dull or even failing. The appearance of a kitchen knife with poor abrasion resistance will also deteriorate easily due to wear.

[0008] The blade of a kitchen knife should also have sufficient hardness to prevent damage such as blade breakage when encountering hard materials.

[0009] Because kitchen knives are used to handle various biological substances and come into contact with various liquids and seasonings, they also need to have high corrosion resistance.

[0010] As an everyday item, a kitchen knife should have an attractive appearance. Sometimes, aesthetics are just as important to users as its cutting performance.

[0011] Kitchen knives are often exposed to high temperatures, whether intentionally or unintentionally, so they need to be heat-resistant.

[0012] For metal kitchen knives, they should also have good oxidation resistance to prevent rusting.

[0013] Kitchen knives can be broadly categorized by material into metal knives and ceramic knives, the difference being the base material of the blade. To improve one or more of the aforementioned performance characteristics, surface treatments or coatings can be applied to the surface of the blade's base material.

[0014] Several coating methods have been applied to the blade of kitchen knives to improve their performance. These methods mainly focus on processes such as magnetron sputtering and laser cladding. Recently, arc ion plating has also begun to be explored in kitchen knife coating.

[0015] Chinese invention patent application CN10965019A discloses a process for forming a titanium nitride hard decorative coating on the surface of a martensitic stainless steel kitchen knife using arc ion plating. It employs conventional arc ion plating equipment to perform cathodic arc ion plating on the kitchen knife after pretreatment including pickling and ultrasonic cleaning, depositing a thin film of titanium nitride on its surface. The resulting kitchen knife has a smooth, uniform, and dense metallic luster coating, enhancing the product's aesthetics. However, despite achieving the decorative deposition of a hard titanium nitride film, the product produced by this method does not show significant improvement in aspects other than aesthetics, particularly in sharpness and wear resistance.

[0016] There is a need for further development of kitchen knives that are sharper and also possess other desirable properties. Summary of the Invention

[0017] In one aspect, this disclosure provides a method for preparing a kitchen knife using arc ion plating, the method comprising:

[0018] A kitchen knife blade substrate with a cutting edge is placed in an arc ion plating chamber equipped with an arc generation device.

[0019] The surfaces on both sides of the cutting edge are subjected to ion etching treatment;

[0020] A bonding layer material is deposited on the ion-etched surface using arc ion plating; and

[0021] The wear-resistant layer material can be deposited on the deposited bonding layer material using arc ion plating, or one or more transition layer materials can be deposited sequentially on the deposited bonding layer material followed by the deposition of the wear-resistant layer material.

[0022] Preferably, the ion etching treatment of the surfaces on both sides of the cutting edge includes:

[0023] The arc discharge generated by the arc generating device causes the process gas introduced into the arc ion plating chamber to form plasma; and

[0024] The surface is etched using the plasma.

[0025] Preferably, the conditions for etching the surface using the plasma are: the process gas is argon and hydrogen, the operating temperature is 300-550℃, and the duration is 20-100 minutes.

[0026] Preferably, the ion etching process generates pits on the surface with a diameter of 0.01-0.05 micrometers, a depth of 0.01-0.05 micrometers, and a density of 10-100 pits per square micrometer.

[0027] Preferably, the substrate of the kitchen knife body with the blade is selected from martensitic stainless steel, mold steel and heat-resistant steel, and the surface roughness of the two sides of the blade is 0.5-1 micrometer before the ion etching.

[0028] Preferably, the arc ion plating is multi-arc ion plating.

[0029] Preferably, the hardness of each layer gradually increases from the bonding layer to the wear-resistant layer.

[0030] Preferably, the bonding layer is TiAlN, the transition layer consists of TiAlSiN and TiSiN from the inside out, and the wear-resistant layer is TiB2.

[0031] Preferably, the bonding layer is TiN and the wear-resistant layer is TiN.

[0032] Preferably, the bonding layer is CrAlN and the wear-resistant layer is CrAlBN.

[0033] Preferably, the bonding layer is TiAlN and the wear-resistant layer is TiAlN.

[0034] Preferably, the bonding layer is TiAlN, the transition layer is an alternating stack of TiAlSiN and TiAlN, and the wear-resistant layer is TiSiN.

[0035] Preferably, the bonding layer is CrAlN, the transition layer is CrAlTiSiN, and the wear-resistant layer is CrAlSiN.

[0036] Preferably, the bonding layer is CrAlN, the transition layer consists of CrAlTiSiN and TiSiN from the inside out, and the wear-resistant layer is TiSiC.

[0037] Preferably, the bonding layer is CrN and the wear-resistant layer is CrNC.

[0038] In another aspect, this disclosure provides a kitchen knife prepared according to the above method.

[0039] Preferably, the kitchen knife has an ICP of 130 mm or more as measured according to EN ISO 8442-5.2005, and a TCC of 1500 mm or more after 60 cutting cycles.

[0040] In another aspect, this disclosure provides a kitchen knife, said kitchen knife comprising:

[0041] Kitchen knife body base material with blade,

[0042] The bonding layer material on both sides of the blade portion of the kitchen knife body substrate, and

[0043] A wear-resistant layer material on the bonding layer material, or one or more transition layer materials on the bonding layer material followed by a wear-resistant layer material on the one or more transition layer materials.

[0044] From the bonding layer to the wear-resistant layer, the hardness of each layer gradually increases.

[0045] The kitchen knife described herein has an ICP of 130 mm or more as measured according to EN ISO 8442-5.2005, and a TCC of 1500 mm or more after 60 cutting cycles.

[0046] Preferably,

[0047] The bonding layer is TiAlN with a thickness of 0.5-10 micrometers; the transition layer consists of TiAlSiN and TiSiN with thicknesses of 0.5-10 micrometers, respectively, from the inside out; and the wear-resistant layer is TiB2 with a thickness of 0.5-10 micrometers.

[0048] The bonding layer is TiN, the wear-resistant layer is TiN, and the total thickness is 0.5-10 micrometers; or

[0049] The bonding layer is CrAlN with a thickness of 1-10 micrometers, and the wear-resistant layer is CrAlBN with a thickness of 3-20 micrometers; or

[0050] The bonding layer is TiAlN, the wear-resistant layer is TiAlN, and the total thickness is 1-10 micrometers; or

[0051] The bonding layer is TiAlN with a thickness of 0.5-10 micrometers; the transition layer is an alternating stack of TiAlSiN and TiAlN with a thickness of 0.1-1 micrometers, stacked 2-8 times; and the wear-resistant layer is TiSiN with a thickness of 0.2-10 micrometers.

[0052] The bonding layer is CrAlN with a thickness of 0.2-10 micrometers, the transition layer is CrAlTiSiN with a thickness of 0.1-10 micrometers, and the wear-resistant layer is CrAlSiN with a thickness of 0.5-10 micrometers; or

[0053] The bonding layer is CrAlN with a thickness of 1-10 micrometers, the transition layer consists of CrAlTiSiN with a thickness of 0.1-10 micrometers and TiSiN with a thickness of 0.5-10 micrometers from the inside out, and the wear-resistant layer is TiSiC with a thickness of 1-10 micrometers; or

[0054] The bonding layer is CrN with a thickness of 1-10 micrometers, and the wear-resistant layer is CrNC with a thickness of 1-10 micrometers.

[0055] Preferably, the bonding layer material fills the surface with pits having a diameter of 0.01-0.05 micrometers, a depth of 0.01-0.05 micrometers, and a density of 10-100 pits per square micrometer. Attached Figure Description

[0056] Figure 1 shows a scanning electron microscope image of the blade substrate surface after ion etching in one embodiment.

[0057] Figures 2-9 show cross-sectional scanning electron micrographs of the blade portion of the kitchen knife products of Examples 1-8, respectively. Detailed Implementation

[0058] The inventors of this disclosure have discovered a method for preparing kitchen knives with extremely high sharpness. Using this method, kitchen knives with extremely high initial sharpness and extremely high sharpness retention can be obtained. The kitchen knives produced by this method have excellent sharpness, with ICP and TCC measurements according to EN ISO 8442-5.2005 far exceeding acceptable levels.

[0059] In one embodiment, this disclosure provides a method for preparing a kitchen knife, the method comprising:

[0060] A kitchen knife body substrate with a blade is provided in an arc ion plating chamber equipped with an arc generation device.

[0061] The surfaces on both sides of the cutting edge are subjected to ion etching treatment;

[0062] A bonding layer material is deposited on the ion-etched surface using arc ion plating; and

[0063] The wear-resistant layer material can be deposited on the deposited bonding layer material using arc ion plating, or one or more transition layer materials can be deposited sequentially on the deposited bonding layer material followed by the deposition of the wear-resistant layer material.

[0064] The method disclosed herein is based on the deposition of a hard film layer on a kitchen knife blade substrate using arc ion plating.

[0065] Compared to some common material vapor deposition methods such as magnetron sputtering, arc ion plating has advantages in deposition uniformity and film density, and has been used in the industrial cutting tool field for depositing hard films on machine tool tools. However, due to the high requirements for equipment and process control, as well as the high cost, arc ion plating is rarely used in the kitchen knife industry.

[0066] Unlike machine tool cutters, kitchen knives typically have much thinner blades and cutting edges, which places higher demands on the adhesion between the hard film layer and the substrate during application. Films fabricated on kitchen knives using conventional vapor deposition methods often suffer from easy disintegration.

[0067] Although, as described in the background section, related technologies have begun to explore the use of arc ion plating for titanium nitride coating in the field of kitchen knives, the desired technical effect is merely to enhance aesthetics. For example, while kitchen knives prepared according to the method in CN10965019A have a hard decorative film added to the blade surface, this film, besides improving appearance, only slightly increases the surface hardness of the knife and does not significantly improve its performance, especially its sharpness. Furthermore, the decorative film on these knives has poor adhesion, is prone to peeling, and exhibits poor wear resistance. Due to the high cost of arc ion plating and its purely decorative function when used on kitchen knives, it has not been widely adopted in the kitchen knife industry.

[0068] The method disclosed herein uses arc ion plating combined with a special process to deposit surface materials on kitchen knives. After deposition, it can not only change the appearance of the kitchen knife, but also greatly improve its sharpness and wear resistance.

[0069] The method disclosed herein employs arc ion plating for coating. Compared to products produced by other common coating methods in the kitchen knife industry, such as magnetron sputtering, the products produced by arc ion plating as disclosed herein achieve better sharpness and wear resistance. This is not dependent on any theory, but likely stems from the synergistic effect of the material deposition mechanism of arc ion plating and the specific processes matched with it in this disclosure.

[0070] Compared to arc ion plating, which directly deposits hard materials onto the knife substrate, the process disclosed herein has at least two advantages: first, it adds a crucial ion etching step before coating; second, this ion etching step and the subsequent coating process are completed in the same arc ion plating chamber. Surprisingly, the inventors discovered that this method, with its unique characteristics, can produce kitchen knives with exceptionally high sharpness, including both exceptional initial sharpness and exceptional sharpness durability. The resulting kitchen knife exhibits an ICP (Initial Cutting Capacity) greater than 130 mm, even exceeding 150 mm, significantly surpassing the ISO standard's "acceptable" ICP level benchmark (50 mm); and its TCC (Total Cutting Capacity) after 60 cuts exceeds 1500 mm, significantly exceeding both the ISO standard's "acceptable" TCC level benchmarks for Type A and Type B kitchen knives (150 mm after 60 cuts, or 1500 mm after 200 cuts). The resulting kitchen knives also possess extremely high wear resistance, and the coating will not be damaged or collapse even after prolonged use. Furthermore, the knives come in a variety of colors and have a glossy finish, making them aesthetically pleasing.

[0071] In this disclosure, ion etching prior to deposition refers to the removal of a portion of the material from the surfaces of both sides of the blade portion of a kitchen knife substrate by means of ion bombardment. This further forms surface microstructures (also known as surface substructures, which are structures further generated on a previously smooth surface with low roughness) on the substrate surface, for example, submicron-scale surface microstructures. These surface microstructures may provide a base deposition space with appropriate scale and activity for subsequent film deposition and can improve the adhesion between the subsequent film deposition layer and the substrate.

[0072] Ion bombardment in ion etching can be generated by ions in plasma form or by ions in other forms, such as ion beam bombardment. When plasma bombardment is used, the plasma can be plasma induced by the arc discharge of an arc ion plating device or plasma induced by other forms, such as inductively coupled plasma generated by coils. Most preferably, the ion etching of this disclosure uses plasma induced by the discharge between the arc cathode and the anode inside the vacuum chamber of an arc ion plating device for ion bombardment.

[0073] Generally, when depositing a film on a substrate, it is sometimes attempted to roughen the substrate surface to alter the adhesion between the subsequently deposited film and the substrate. However, the effect of this alteration is unpredictable; roughening may improve or decrease adhesion. In particular, it was never expected that roughening the surface of a kitchen knife would produce the dramatically improved sharpness achieved by the kitchen knife of this disclosure. This disclosure unexpectedly discovers a correlation between performing an ion etching step before arc ion plating and a significant improvement in the sharpness of the kitchen knife. In fact, the surface of the kitchen knife substrate already has basic roughness before ion etching, but without ion etching, directly performing arc ion plating cannot yield a kitchen knife with ultra-high sharpness.

[0074] Therefore, the significant improvement in sharpness achieved by the kitchen knife disclosed herein is not simply attributed to improved adhesion due to surface unevenness caused by ion etching. Without relying on any theory, it may also be related to three other reasons. First, compared to other methods of altering surface roughness, the uneven surface microstructures formed by ion etching may, due to their morphology and size, optimize force transmission and distribution at the cutting edge. This not only makes the deposited hard film layer less prone to detachment but also effectively transmits and distributes external forces on the blade body, making cutting easier and improving sharpness. Second, the newly exposed surface microstructures formed on the surface of the knife substrate by the ion etching step may be highly active for subsequent film layers. Compared to a relatively inert rough surface, this highly active surface may further significantly enhance the strong adhesion of the subsequently deposited film layer, greatly improving initial sharpness, sharpness retention, and wear resistance. Third, this surface microstructure may induce the formation of crystalline phases in the subsequently deposited film layer that are beneficial to improving adhesion, sharpness, or hardness, ultimately resulting in excellent kitchen knife performance.

[0075] In the method disclosed herein, the aforementioned ion etching and subsequent deposition operations are performed in the same chamber, which is the arc ion plating chamber (also referred to as a furnace) for performing arc ion plating. This characteristic, independent of any theory, helps ensure that the "fresh" surface microstructures formed during ion bombardment can be used as a basis for subsequent film deposition without contamination. If the ion etching and arc ion plating are performed in different chambers, environmental factors such as atmospheric and airborne dust may contaminate or even denature the surface microstructures during the transfer of the blade substrate between different working chambers, thus affecting the adhesion of subsequent depositions and preventing the achievement of optimal sharpness.

[0076] The kitchen knife as described in this disclosure may also be referred to as a kitchen knife, including cutting knives or knives with the same function used during food preparation in a kitchen or other environment. A typical kitchen knife includes a blade and a handle for gripping. The blade has an edge for cutting food. Because its primary function is food cutting, the edge of a kitchen knife is thinner and sharper than that of industrial knives such as lathe tools and milling cutters. The included angle between the two surfaces of the edge can be any suitable angle, for example, in the range of 12° to 36°. The kitchen knife of this disclosure can be a Chinese kitchen knife or a Western kitchen knife, and in terms of its primary function, it can be, for example, a cleaver, a bone-chopping knife, a fruit knife, a chef's knife, a steak knife, a bread knife, a fish knife, a dagger, a survival knife, etc.

[0077] This disclosure describes the preparation of a hard film on the surface of a kitchen knife using arc ion plating. Arc ion plating is a well-known coating technology. It uses the substrate to be coated as one electrode (e.g., anode) and a target material for the coating as another electrode (e.g., cathode). When a high voltage is applied, an arc discharge is formed between the two electrodes, causing the target electrode to release the coating material through the arc discharge. The coating material is then deposited onto the substrate under the influence of the electric field. Ionized gases in the atmosphere can also participate in the coating process. When multiple electrodes are present, multiple arcs are generated simultaneously for coating, which is known as multi-arc ion plating.

[0078] Arc ion plating is carried out in an arc ion plating chamber. The arc ion plating chamber can be a reactor and is usually equipped with a gas input device and a vacuum extraction system.

[0079] An arc generation device is installed in the arc ion plating chamber. As described below, using an arc generation device for ion etching is preferred.

[0080] The kitchen knife substrate placed in the arc ion plating chamber has been cleaned, a process also known as pre-furnace cleaning. Typical pre-furnace cleaning methods include multiple degreasing and dust removal processes common in the kitchen knife industry. An advantageous final cleaning process is ultrasonic cleaning; by applying ultrasonic cleaning after other degreasing and dust removal processes, grease and impurities on the substrate surface can be almost completely removed. After cleaning, the substrate is thoroughly dried.

[0081] The method disclosed herein first places a kitchen knife body substrate with a blade in an arc ion plating chamber. The material of the kitchen knife body substrate provides the kitchen knife with the required bulk mechanical properties such as strength, rigidity, elasticity, and toughness. From a comprehensive performance perspective, it is desirable for the kitchen knife body substrate to possess excellent mechanical properties and high corrosion resistance, while maintaining a moderate cost. The material of the kitchen knife body substrate can be a conventional metal-based kitchen knife body material, and metal-based materials meeting the above requirements are generally suitable for the kitchen knife body substrate of this disclosure. Typical metal-based kitchen knife body materials include alloy steel and cemented carbide (commonly known as tungsten steel). Examples of alloy steel include stainless steel (such as martensitic stainless steel), die steel, heat-resistant steel, and high-speed tool steel. Martensitic stainless steel, die steel, and heat-resistant steel are particularly preferred due to their comprehensive performance. Suitable martensitic stainless steel grades for the kitchen knife body substrate of this disclosure include, but are not limited to: 30Cr13, 40Cr13, 50Cr15MoV, 70Cr17MoV, 80Cr14MoV, 90Cr18MoV, AUS8, AUS10, VG10, M390, and 17-4PH. Suitable mold steel grades for the kitchen knife body substrate of this disclosure include, but are not limited to: SKD11, SKD61, Cr12MoV, DC53, and DAC55. Suitable heat-resistant steel grades for the kitchen knife body substrate of this disclosure include, but are not limited to: 4Cr9Si2. Suitable cemented carbide and cermet can also be used as the kitchen knife body substrate. However, pure ceramic is not used as the kitchen knife body substrate of this disclosure because ceramic itself usually has high hardness and does not require coating, and the plasma etching step of this disclosure has poor applicability to ceramic substrates.

[0082] As the base material for the kitchen knife body, it already possesses the required shape for the final knife body. The base material is essentially plate-shaped, and at at least one side edge of the plate-shaped base material, the two sides of the plate intersect to form the blade. The included angle between the two surfaces of the blade is important for the sharpness of the kitchen knife, and this has been extensively studied in related technologies. Typically, the included angle ranges from 12° to 36°, more preferably from 16° to 30°. An angle that is too large results in insufficient sharpness. An angle that is too small places overly stringent requirements on the manufacturing process and materials.

[0083] The surfaces on both sides of the blade of the kitchen knife body substrate, provided to the arc ion plating chamber, are smooth. The method of this disclosure includes forming microstructures on these two surfaces to increase adhesion to the covering wear-resistant layer; therefore, the initial surface condition is important. If the initial surface is not smooth enough, the micromorphology formed by subsequent surface treatments is difficult to control, thus affecting the final product appearance and performance. Surface smoothness can be measured by the initial surface roughness. Typically, the initial surface roughness Ra of the two sides of the kitchen knife body substrate does not exceed 10 micrometers, for example, 0.5-10 micrometers, preferably 0.5-3 micrometers, for example, 0.5-1 micrometers.

[0084] After placing a kitchen knife substrate with a blade in an arc ion plating chamber, the surfaces on both sides of the blade are subjected to ion etching. In the ion etching process, plasma is formed in a process gas atmosphere, and ions in the plasma bombard the substrate surface, removing a portion of the material and thus forming a surface microstructure.

[0085] Before conventional arc ion plating, the substrate is sometimes ion-cleaned. Because this process sometimes removes surface impurities, it is sometimes inaccurately referred to as ion etching. However, the purpose of this cleaning is usually limited to removing contaminants and impurities from the substrate surface, rather than damaging the substrate surface and forming new microstructures. Ideally, ion cleaning removes surface impurities without damaging the substrate. Therefore, it uses lower power and shorter duration ion bombardment. Compared to this ion cleaning step, the ion etching step of this disclosure has higher power and longer duration to achieve sufficient damage to the substrate surface and form new microstructures. That is, ion etching as used in this disclosure refers to ion bombardment that can sufficiently damage the substrate and achieve new surface microstructures beneficial to the purpose of this disclosure. Ion cleaning that only removes surface impurities or the accompanying unintentional minor damage to the substrate is not included in the scope of ion etching as used in this disclosure. Compared to general ion cleaning in arc ion plating, the ion etching of this disclosure has a longer duration and higher bombardment power. Typically, ion etching lasts for 20 minutes or more, preferably 30 minutes or more, more preferably 40 minutes or more, such as up to 1 hour. Such ion etching can effectively remove any surface oxides that may be present and are essentially unaffected by conventional ion cleaning, thereby forming microstructures on the fresh substrate surface.

[0086] After forming a surface microstructure through ion etching that disrupts the substrate surface, a bonding layer material, an optional transition layer, and a wear-resistant layer material are deposited sequentially. The wear-resistant layer material is the outermost hard material, directly providing surface properties such as high hardness and high wear resistance. The wear-resistant layer material is typically also a high-temperature resistant material, capable of withstanding temperatures up to 1200-1300°C. However, in some cases, the adhesion between the wear-resistant layer material and the substrate is not optimal, hindering the achievement of ultra-high sharpness and wear resistance. Therefore, a bonding layer and an optional transition layer are placed between the wear-resistant layer and the substrate to achieve a gradual transition from the substrate to the wear-resistant layer. Typically, the bonding layer is suitable for direct and strong bonding with the substrate and is made of a different material than the wear-resistant layer. However, if the wear-resistant layer material is suitable for direct and strong bonding with the substrate, the wear-resistant layer material and the bonding layer material can be the same. Optionally, one or more transition layers can be placed between the bonding layer and the wear-resistant layer. The deposition of these films is performed using conventional arc ion plating, achieved by selecting appropriate target materials, atmospheres, and process parameters within the arc ion plating chamber. Before the formal coating process of arc ion plating begins, a routine target cleaning step can be performed.

[0087] The bonding layer material is a material with excellent adhesion to the base material of the knife body. Examples of bonding layer materials include TiAlN, TiN, CrAlN, and CrN. The wear-resistant layer material is the outermost hard material, and examples include hard materials containing elements selected from Ti, Al, Cr, Si, N, C, and B. The transition layer material is also a material containing elements selected from Ti, Al, Cr, Si, N, C, and B, and has good adhesion to the materials on both sides. In principle, the coating formed by the bonding layer material, optional transition layer, and wear-resistant layer material should have a gradually increasing hardness from the inside out, which is beneficial for the gradual change in structure and stress, and achieves the desired final performance. Material selection that conforms to this gradual increase in hardness is preferred.

[0088] In this disclosure, metal-nonmetal compound film materials are generally represented by an arrangement of elements, and stoichiometric ratios are typically not specified after the elements. In other words, this representation does not specify the stoichiometric ratios between elements, but only focuses on showing the types of elements. For example, TiAlN represents titanium aluminum nitride materials with various suitable element stoichiometric ratios, and CrAlNB represents titanium aluminum nitride materials with various suitable element stoichiometric ratios and chromium aluminum nitride boron nitride materials. This disclosure does not impose particularly strict limitations on the element stoichiometric ratios of the materials, as long as they provide high hardness, high wear resistance, and do not conflict with the spirit of this disclosure. In other words, this disclosure is not intended to improve the stoichiometric ratios of film materials, or in other words, the improvement in the performance of the kitchen knife disclosed in this disclosure is not based on the deliberate adjustment and improvement of the component ratios of existing film materials. Therefore, various cemented carbide materials commonly used in the knife industry and corresponding commercially available alloy targets of various types and element ratios can be selected for film deposition. The only material specifically specified by stoichiometry is titanium diboride (TiB2), because it has particularly excellent performance as the outermost wear-resistant layer.

[0089] Preferably, the bonding layer (i.e., the layer formed directly on the substrate) is formed by arc ion plating in a high-current, low-voltage mode. The high-current, low-voltage mode is a common operating mode for arc ion plating apparatuses. This disclosure uses this operating mode to deposit the bonding layer because it more effectively improves the adhesion between the vacuum ion-plated film and the workpiece, providing a better foundation for subsequent film deposition and more effectively enhancing the bond strength between the film and the workpiece.

[0090] The bonding layer should be thick enough to completely fill the pores of the microstructure on the substrate surface, ensuring that the substrate surface is fully covered and not exposed after deposition. Further bonding layer thickness can be deposited to ensure continued coverage of the substrate and to maintain the bonding layer's functionality. This additional thickness is preferably 1-10 micrometers. Excessive bonding layer thickness may affect the hardness and other properties of the composite coating and increase time and material costs.

[0091] The method disclosed herein improves the surface hardness and wear resistance of the kitchen knife substrate by depositing a bonding layer and a wear-resistant layer material through arc ion plating. Furthermore, by performing ion etching before arc ion plating and performing etching and coating in the same chamber, a kitchen knife with excellent sharpness is obtained.

[0092] Preferably, the ion etching treatment of the surfaces on both sides of the cutting edge includes:

[0093] The arc discharge generated by the arc generating device causes the process gas introduced into the arc ion plating chamber to form plasma; and

[0094] The surface is etched using the plasma.

[0095] The arc discharge generated using the aforementioned arc generating device can fully utilize the low-temperature plasma produced by the arc ion plating equipment. In the arc ion plating chamber, it is convenient to achieve an arc discharge capable of generating plasma by adding inert electrodes. For example, one or more auxiliary inert cathodes can be provided, and a voltage can be applied to the auxiliary cathodes instead of the target cathode to generate an arc discharge, thereby generating plasma from the process gas atmosphere for etching. Alternatively, a target cathode can be used to generate the arc discharge, requiring a shielding plate to block material deposition from the target to the substrate, but without hindering the plasma's effect on the substrate. Compared to thermal plasma or other separately installed plasma generating devices, the plasma generated by arc discharge using the arc ion plating equipment requires less modification to the device, generates plasma quickly, achieves better etching results, and the etched substrate can be used almost in situ for subsequent film deposition. Multiple kitchen knives can typically be processed simultaneously in the furnace. The target cathode and auxiliary inert cathode can be appropriately arranged according to the layout of the kitchen knives being processed.

[0096] Preferably, the plasma etching conditions are: the process gases are argon and hydrogen, and the operating temperature is 300-550°C. The advantage of choosing these process gases is that they do not cause adverse doping and contamination to the substrate surface, and may also facilitate the formation of a highly active surface. Hydrogen helps to provide a reducing atmosphere to the surface to eliminate oxides, ensuring the desired microstructure is obtained. A vacuum is maintained during operation to keep the chamber at a low pressure. This operating temperature range has the advantage of not causing adverse heat treatment effects on the substrate. More preferably, the plasma etching conditions are: a temperature of 400-500°C, a total argon flow rate of 1000-2000 ml, a total hydrogen flow rate of 500-1000 ml, an etching current of 300-500 A, and an etching time of 20-100 minutes. During ion etching, the etching current applied to generate an arc capable of forming a plasma that can etch the substrate is quite large. Under this high current, high-energy ions sufficient to destroy the microstructure formed on the substrate surface are generated, and prolonged bombardment completes the ion etching. In this disclosure, etching times of 20 minutes or more are typically required, such as 30 minutes or more, 40 minutes or more, or 60 minutes or more. Generally, 100 minutes of etching is sufficient to form the desired surface microstructure. Further extending the etching time may reduce cost efficiency.

[0097] Preferably, the ion etching process forms pits with a diameter of 0.01-0.05 micrometers and a depth of 0.01-0.05 micrometers on the substrate surface. Microscopic analysis of the substrate surface after ion etching reveals that, compared to surfaces without ion treatment or those only subjected to conventional plasma cleaning, the ion-etched surface of this disclosure exhibits a large number of densely packed micropits with a diameter of 0.01-0.05 micrometers and a depth of 0.01-0.05 micrometers. The pits can be substantially circular, but may not be circular. The diameter here refers to the maximum dimension of the upper edge of the pit. The depth of the pit refers to the distance from the bottom of the pit to the upper edge in the thickness direction of the cutting edge. The density of the micropits is represented by the number of pits per unit area. Typically, the micropits are formed uniformly and densely across the entire surface, with a density of approximately 10-100, 20-100, or 40-80 per square micrometer. Without relying on any theory, these micropits can be characteristic of the aforementioned surface microstructure. On surfaces with a roughness of less than 10 micrometers, such as 0.5-3 micrometers, the method, including the step of further forming these micro-pits, unexpectedly resulted in extremely high sharpness and wear resistance. This may be attributed to the extremely high adhesion between the film and the blade substrate caused by the three reasons mentioned above, although no existing theory suggests that it would have a significant impact on subsequent film deposition. The inventors unexpectedly discovered that when the surfaces on both sides of the blade have the aforementioned dense micro-pit microstructure or micro-morphology, these pits can be used to deposit a bonding layer material and may allow the bonding layer material to bond firmly to it, resulting in excellent mechanical properties in all directions for the wear-resistant layer material subsequently deposited on the bonding layer material and the knife body substrate. This excellent mechanical property performance allows the complex mechanical interactions between the knife surface and the material being cut, including compression and friction, to be sufficiently smoothed and transmitted to the knife body substrate when cutting with the resulting knife, thereby minimizing the damage to the adhesion between the wear-resistant layer and the knife body substrate, and greatly reducing material damage to the surface of the wear-resistant layer. This results in a wear-resistant layer that does not disintegrate or break down even after multiple cuts, thus producing a kitchen knife that not only has high initial sharpness but also high wear resistance and sharpness retention.

[0098] Without relying on any theory, when the pit diameter is too large, the filling of the bonding layer material may not be uniform enough, resulting in insufficient bonding strength in individual pits. When the pit diameter is too small, there may be unfilled pits, leading to insufficient overall bonding strength. When the depth is too small, it provides insufficient constraint to the bonding layer in the direction parallel to the surface, affecting the wear resistance of the coating. When the depth is too large, it increases the required bonding layer thickness, which may affect the hardness and other properties of the composite coating, and excessive depth may lead to roughness and unevenness on the final coating surface.

[0099] The arrangement of the pits can be random, but a honeycomb pattern is preferred. A honeycomb pattern refers to the uniform lattice arrangement of the pores created by surface ion bombardment, resembling a honeycomb. This honeycomb-like pit arrangement facilitates the uniform transmission of internal stress.

[0100] As described above, preferably, the material of the knife body substrate with the blade is a high-hardness metal material such as martensitic steel, die steel, heat-resistant steel, or cemented carbide, and the surface roughness Ra of the two sides of the blade is 0.5-3 micrometers. The surface roughness is preferably 0.5-1 micrometer, which at least makes the final blade surface appear more glossy, smooth, and aesthetically pleasing.

[0101] Preferably, the arc ion plating is multi-arc ion plating. Using multi-arc ion plating in conjunction with multiple target electrodes at different locations for multi-directional deposition helps to form a uniform and dense film layer across the entire blade body.

[0102] In addition to having extremely high sharpness and wear resistance, the kitchen knife prepared by the method disclosed herein also has excellent hardness, corrosion resistance, aesthetics, high temperature resistance and oxidation resistance.

[0103] In one embodiment, this disclosure provides a kitchen knife prepared according to the aforementioned method, which has the above-mentioned advantages.

[0104] In another embodiment, this disclosure also provides a kitchen knife, the kitchen knife comprising:

[0105] Kitchen knife body base material with blade,

[0106] The bonding layer material on both sides of the blade portion of the kitchen knife body substrate, and

[0107] A wear-resistant layer material on the bonding layer material, or one or more transition layer materials on the bonding layer material followed by a wear-resistant layer material on the one or more transition layer materials.

[0108] From the bonding layer to the wear-resistant layer, the hardness of each layer gradually increases.

[0109] The kitchen knife described herein has an ICP of 130 mm or more as measured according to EN ISO 8442-5.2005, and a TCC of 1500 mm or more after 60 cutting cycles.

[0110] In the relevant technologies, there is currently no kitchen knife with the above-mentioned structure and sharpness.

[0111] The aforementioned preferred parameters all apply to this kitchen knife.

[0112] The base material of the kitchen knife body is preferably stainless steel, more preferably martensitic stainless steel, die steel, and heat-resistant steel. The included angle between the two surfaces of the blade is preferably 12°-36°, more preferably 16°-30°. Ignoring pits, the two surfaces of the blade are smooth, with a basic roughness not exceeding 10 micrometers, for example, 0.5-10 micrometers, preferably 0.5-3 micrometers, for example, 0.5-1 micrometer. The pits are preferably distributed in a honeycomb pattern. The wear-resistant layer material is preferably a high-temperature resistant material. Examples of bonding layer materials include TiAl, CrAl, TiSi, etc. The wear-resistant layer material is the outermost hard material, examples of which include hard materials containing elements selected from Ti, Al, Cr, Si, N, C, and B. The transition layer material is also a material containing elements selected from Ti, Al, Cr, Si, N, C, and B, and has good bonding with the materials on both sides. In principle, the coating formed by the bonding layer material, optional transition layer, and wear-resistant layer material gradually increases in hardness from the inside to the outside.

[0113] The thickness of the bonding layer extending beyond the substrate surface can be between 0.5 micrometers and 10 micrometers, preferably 1-10 micrometers. The preferred thickness of each film layer in the transition layer and the wear-resistant layer is typically between 1 micrometer and 10 micrometers.

[0114] Furthermore, the total thickness of the deposited film (i.e., the total thickness of the bonding layer and the wear-resistant layer, or, if a transition layer is present, the thickness of the transition layer) can be up to 20 micrometers. While the method of this disclosure can also achieve a total thickness of more than 20 micrometers, the further improvement in performance is minimal, and the risk of film collapse increases. In many cases, a total thickness of 10 micrometers is sufficient for excellent sharpness and wear resistance without film collapse. The preferred minimum value of the total thickness is generally related to the total number of film layers of different materials. Typically, the total thickness can be greater than 3 micrometers, more preferably greater than 4 micrometers, and even more preferably greater than 5 micrometers. In contrast, the thickness of a film formed directly on a kitchen knife using arc ion plating is typically less than 3 micrometers, otherwise the film is prone to collapse.

[0115] Kitchen knives with the same key structure as those prepared by methods other than those disclosed herein will also have the same advantages.

[0116] Regarding the bonding layer, transition layer, and wear-resistant layer materials, there are various membrane systems suitable for this disclosure. The following are some examples of membrane systems.

[0117] In one embodiment, the bonding layer is TiAlN, the transition layer consists of TiAlSiN and TiSiN from the inside out, and the wear-resistant layer is TiB2. Their preferred thicknesses are 0.5-10 micrometers, 0.5-10 micrometers, 0.5-10 micrometers, and 0.5-10 micrometers, respectively. The preferred total thickness is 2-20 micrometers, more preferably 4-10 micrometers.

[0118] In one embodiment, the bonding layer is TiN, and the wear-resistant layer is TiN. Their preferred total thickness is 0.5-10 micrometers, more preferably 1-10 micrometers.

[0119] In one embodiment, the bonding layer is CrAlN and the wear-resistant layer is CrAlBN. Their preferred thicknesses are 1-10 micrometers and 2-20 micrometers, respectively. The preferred total thickness is 3-20 micrometers, more preferably 4-10 micrometers.

[0120] In one embodiment, the bonding layer is TiAlN, and the wear-resistant layer is TiAlN. Their preferred total thickness is 1-10 micrometers, more preferably 3-10 micrometers.

[0121] In one embodiment, the bonding layer is TiAlN, the transition layer is an alternating stack of TiAlSiN and TiAlN, and the wear-resistant layer is TiSiN. Their preferred thicknesses are 0.5-10 micrometers, 0.5-10 micrometers, and 0.2-10 micrometers, respectively, wherein the stack is preferably an alternating stack of 0.1-1 micrometer thick TiAlSiN and 0.1-1 micrometer thick TiAlN, stacked 2-8 times. The preferred total thickness is 1-20 micrometers, more preferably 3-10 micrometers.

[0122] In one embodiment, the bonding layer is CrAlN, the transition layer is CrAlTiSiN, and the wear-resistant layer is CrAlTiSiN. Their preferred thicknesses are 0.2-10 micrometers, 0.1-10 micrometers, and 0.5-10 micrometers, respectively. The preferred total thickness is 1-20 micrometers, more preferably 3-10 micrometers.

[0123] In one embodiment, the bonding layer is CrAlN, the transition layers are CrAlTiSiN and TiSiN from the inside out, and the wear-resistant layer is TiSiC. Their preferred thicknesses are 1-10 micrometers, 0.1-10 micrometers, 0.5-10 micrometers, and 1-10 micrometers, respectively. The preferred total thickness is 2.5-20 micrometers, more preferably 4-10 micrometers.

[0124] In one embodiment, the bonding layer is CrN and the wear-resistant layer is CrNC. Their preferred thicknesses are 1-10 micrometers and 1-10 micrometers, respectively. The preferred total thickness is 2-20 micrometers, more preferably 4-10 micrometers.

[0125] Generally speaking, the total thickness of the film deposited by arc ion plating is preferably 3 micrometers or more, and more preferably 4 micrometers or more. If the ion etching step of this disclosure is not used, the total thickness of the arc ion plating film of the corresponding film system is usually thin, especially difficult to exceed 4 micrometers, otherwise film collapse will easily occur.

[0126] In such a kitchen knife, a bonding layer material fills the surface with pits having a diameter of 0.01-0.05 micrometers, a depth of 0.01-0.05 micrometers, and a density of 10-100 pits per square micrometer. These pits can be formed by ion etching in an arc ion plating chamber.

[0127] The present disclosure is further illustrated by the following examples. Unless otherwise specified, the targets used in the examples of this disclosure are all commercially available targets, and the testing methods are all conventional testing methods in the art. The martensitic stainless steels are 50Cr15Mov, 70Cr17Mov, 80Cr14Mov, 90Cr18Mov, AUS10, VG10, M390, and 17-4PH; the die steels are Skd11, Skd61, Cr12Mov, DC53, DAC55, and 4Cr9Si2.

[0128] Specifically, an alloy target or elemental target containing the desired elements is used. This disclosure does not specifically limit the elemental ratio in the alloy target; alloy targets with conventional composition ratios used for arc ion plating can be used.

[0129] Specific target materials used include commercially available TiAl, TiSi, CrAl, CrAlB, Ti, CrAlSi, and TiB2 targets. Examples of specific elemental compositions of target materials include, but are not limited to: TiAl: 50:50, TiSi: 90:10, CrAl: 40:60, CrAlB: 20:70:10, and CrAlSi: 40:50:10.

[0130] Example 1: Preparation of a kitchen knife with a TiAlN-TiAlSiN-TiSiN-TiB2 film system

[0131] The kitchen knife was prepared using the following steps. The preparation was performed four times, resulting in four products with the same film system. The specific process parameters for each preparation were selected from the ranges given below. The performance of the four products was characterized by analysis.

[0132] (1) Polish the surfaces on both sides of the cutting edge of the martensitic stainless steel base knife body to a surface roughness of 0.5-3 micrometers, and then clean it with ultrasonic waves.

[0133] (2) The cleaned kitchen knife body substrate is sent into the arc ion plating chamber and suspended.

[0134] (3) Evacuate the arc ion plating chamber to 0.005-0.008 Pa. Heat to 300-550℃ and introduce 1000-2000 ml of argon and 500-1000 ml of hydrogen. Use arc discharge to generate plasma with a working current of 300-500 A. Accelerate the hydrogen and argon ions in the plasma under the action of an electric field to bombard the smooth surface of the kitchen knife substrate, performing ion etching on the substrate for 20-100 minutes, forming honeycomb-like micro-pits. Microscopic analysis shows that the pit diameter is 0.01-0.05 μm and the depth is approximately 0.01-0.05 μm. Figure 1 shows a scanning electron microscope image of the knife substrate surface after ion etching, which shows the densely arranged fine pits.

[0135] (4) Introduce N2 gas and maintain the pressure at 2-5 Pa. Turn on the arc of the TiAl target to start multi-arc ion plating. Deposit the TiAlN layer in a high current and low voltage mode. The current is 200-500 A, the deposition time is 20-50 minutes, and the deposition thickness is about 0.5-10 micrometers.

[0136] (5) Maintain the flow of N2 gas and keep the pressure at 2-5 Pa. Turn on the arc of the TiSi target to perform multi-arc ion plating and deposit the TiAlSiN layer. The current is 200-500 A, the deposition time is 30-50 minutes, and the deposition thickness is about 0.5-10 micrometers.

[0137] (6) Maintain the flow of N2 gas and keep the pressure at 2-5 Pa. Turn off the arc on the TiAl target and deposit the TiSiN layer. The current is 200-500 A, the deposition time is 30-70 minutes, and the deposition thickness is about 0.5-10 micrometers.

[0138] (7) Turn off the N2 gas and introduce Ar gas, maintaining a pressure of 2-5 Pa. Turn off the arc on the TiSi target and turn on the arc on the TiB2 target to perform multi-arc ion plating and deposit a TiB2 layer. The current is 200-500 A, the deposition time is 30-70 minutes, and the deposition thickness is about 0.5-10 micrometers.

[0139] The final composite coating uses TiAlN as the bonding layer, TiAlSiN and TiSiN as the transition layers from the inside out, and TiB2 as the wear-resistant layer. The resulting kitchen knife, after testing, exhibits ultra-high sharpness, high hardness, low coefficient of friction, and oxidation resistance.

[0140] Vickers hardness was measured, and the result was HV3800-4200.

[0141] The friction coefficient VSNI was measured and the result was 0.1-0.2.

[0142] The antioxidant temperature can be measured, and the antioxidant temperature can reach 1000-1200℃.

[0143] The TCC was measured according to EN ISO 8442-5 (60 cuts in total), and the average result for the four samples was over 2100 mm.

[0144] ICP was measured according to EN ISO 8442-5 (first three cuts), and the average result for the four samples was over 150 mm.

[0145] The resulting film is silvery-white in color, and the total thickness of the composite film consisting of the bonding layer, transition layer, and wear-resistant layer is approximately 2-20 micrometers. An electron micrograph of a cross-section of a product is shown in Figure 2. In Figure 2, the bottom layer is a martensitic stainless steel substrate, followed by the bonding layer TiAlN, the transition layer TiAlSiN, the TiSiN layer, and the wear-resistant layer TiB2.

[0146] Example 2: Preparation of a kitchen knife with a TiN film system

[0147] The kitchen knife was prepared using the following steps. The preparation was performed four times, resulting in four products with the same film system. The specific process parameters for each preparation were selected from the ranges given below. The performance of the four products was characterized by analysis.

[0148] Perform the same steps (1) to (3) as in Example 1.

[0149] (4) Introduce N2 gas and maintain a pressure of 2-5 Pa. Start multi-arc ion plating, turn on the arc of the Ti target to start multi-arc ion plating, and deposit the TiN layer through a high current and low voltage mode. The current is 200-500 A, the deposition time is 30-80 minutes, and the deposition thickness is about 0.5-10 micrometers. This directly forms a bonding layer and a wear-resistant layer, and both are made of the same material.

[0150] The final composite coating uses TiN as both the bonding layer and the wear-resistant layer. The resulting kitchen knife, after testing, exhibits extremely high sharpness, high hardness, low coefficient of friction, and oxidation resistance.

[0151] Vickers hardness was measured, and the result was HV2300-2600.

[0152] The friction coefficient VSNI was measured and the result was 0.3-0.5.

[0153] The antioxidant temperature can be measured, and the antioxidant temperature can reach 500-700℃.

[0154] The TCC (60 cuts in total) was measured according to EN ISO 8442-5, and the average result for the four samples was over 1900 mm.

[0155] ICP was measured according to EN ISO 8442-5 (first three cuts), and the average result for the four samples was over 150 mm.

[0156] The resulting film is gold in color, and the total thickness of the composite film of the bonding layer and the wear-resistant layer is approximately 0.5-10 micrometers, as shown in Figure 3. In Figure 3, the bottom layer is a martensitic stainless steel substrate, followed by the bonding layer TiN layer and the wear-resistant layer TiN layer. Since the two layers are made of the same material, they cannot be clearly distinguished in the microscopic image.

[0157] Example 3: Preparation of a kitchen knife with a CrAlN-CrAlBN film system

[0158] The kitchen knife was prepared using the following steps. The preparation was performed four times, resulting in four products with the same film system. The specific process parameters for each preparation were selected from the ranges given below. The performance of the four products was characterized by analysis.

[0159] Perform the same steps (1) to (3) as in Example 1.

[0160] (4) Introduce N2 gas and maintain the pressure at 2-5 Pa. Turn on the arc of the CrAl target to start multi-arc ion plating. Deposit the CrAlN layer in a high current and low voltage mode. The current is 200-500 A, the deposition time is 20-50 minutes, and the deposition thickness is about 1-10 micrometers.

[0161] (5) Maintain the flow of N2 gas and keep the pressure at 2-5 Pa. Turn on the arc of the CrAlB target to perform arc ion plating and deposit the CrAlBN layer. The current is 200-500 A, the deposition time is 30-70 minutes, and the deposition thickness is about 0.5-10 micrometers.

[0162] (6) Maintain the flow of N2 gas and keep the pressure at 2-5 Pa. Turn off the arc on the CrAl target and deposit the CrAlBN layer. The current is 200-500 A, the deposition time is 30-70 minutes, and the deposition thickness is about 1-10 micrometers.

[0163] The final composite coating uses CrAlN as the bonding layer and CrAlBN as the wear-resistant layer. The resulting kitchen knife, after testing, exhibits extremely high sharpness, high hardness, low coefficient of friction, and oxidation resistance.

[0164] Vickers hardness was measured, and the result was HV3800-4500.

[0165] The friction coefficient VSNI was measured and the result was 0.3-0.5.

[0166] The antioxidant temperature can be measured and can reach 900-1200℃.

[0167] The TCC (60 cuts in total) was measured according to EN ISO 8442-5, and the average result for the four samples was above 2150 mm.

[0168] ICP (first three cuts) was measured according to EN ISO 8442-5, and the average result for the four samples was over 145 mm.

[0169] The resulting film is gray in color, and the total thickness of the composite film of the bonding layer and the wear-resistant layer is about 3-20 micrometers, as shown in Figure 4. In Figure 4, the bottom layer is a martensitic stainless steel substrate, followed by two sublayers: the bonding layer CrAlN and the wear-resistant layer CrAlBN. Note that the wear-resistant layer CrAlBN is formed in steps (5) and (6), and because a CrAl target is used in step (5) but not in step (6), the part formed in step (5) has a slightly higher Al content than the part formed in step (6), although the overall elemental amount is the same. Therefore, it is shown as the two distinguishable sublayers at the top in Figure 4.

[0170] Example 4: Preparation of a kitchen knife with a TiAlN film system

[0171] The kitchen knife was prepared using the following steps. The preparation was performed four times, resulting in four products with the same film system. The specific process parameters for each preparation were selected from the ranges given below. The performance of the four products was characterized by analysis.

[0172] Perform the same steps (1) to (3) as in Example 1.

[0173] (4) Introduce N2 gas and maintain a pressure of 2-5 Pa. Start multi-arc ion plating, turn on the arc of the TiAl target to start multi-arc ion plating, and deposit the TiAlN layer through a high current and low voltage mode. The current is 200-500 A, the deposition time is 40-90 minutes, and the deposition thickness is about 1-10 micrometers. This directly forms a bonding layer and a wear-resistant layer, and both are made of the same material.

[0174] The final composite coating uses TiAlN as both the bonding layer and the wear-resistant layer. The resulting kitchen knife, after testing, exhibits extremely high sharpness, high hardness, low coefficient of friction, and oxidation resistance.

[0175] Vickers hardness was measured, and the result was HV3800-4200.

[0176] The friction coefficient VSNI was measured and the result was 0.3-0.5.

[0177] The antioxidant temperature can be measured and can reach 900-1100℃.

[0178] The TCC (60 cuts in total) was measured according to EN ISO 8442-5, and the average result for the four samples was over 1880 mm.

[0179] ICP was measured according to EN ISO 8442-5 (first three cuts), and the average result for the four samples was over 150 mm.

[0180] The resulting film is bluish-black in color, and the total thickness of the composite film of the bonding layer and the wear-resistant layer is approximately 1-10 micrometers, as shown in Figure 5. In Figure 5, the bottom layer is a martensitic stainless steel substrate, followed by the bonding layer TiAlN and the wear-resistant layer TiAlN. Since the two layers are made of the same material, they cannot be clearly distinguished in the microscopic image.

[0181] Example 5: Preparation of a kitchen knife with an alternating stack of TiAlN-TiAlSiN and TiAlN-TiSiN films.

[0182] The kitchen knife was prepared using the following steps. The preparation was performed four times, resulting in four products with the same film system. The specific process parameters for each preparation were selected from the ranges given below. The performance of the four products was characterized by analysis.

[0183] Perform the same steps (1) to (3) as in Example 1.

[0184] (4) Introduce N2 gas and maintain the pressure at 2-5 Pa. Start multi-arc ion plating and turn on the arc of the TiAl target. Deposit the TiAlN layer in a high current and low voltage mode. The current is 200-500 A, the deposition time is 30-80 minutes, and the deposition thickness is about 0.5-10 micrometers.

[0185] (5) Maintain the flow of N2 gas and keep the pressure at 2-5 Pa. Turn on the arc of the TiSi target to perform multi-arc ion plating and deposit the TiAlSiN layer. The current is 200-500 A, the deposition time is 20-60 minutes, and the deposition thickness is about 0.1-1 micrometer.

[0186] Then repeat steps (4)-(5) five times, in which the deposition thickness becomes about 0.1-1 micrometers during the repeated step (4).

[0187] (6) Maintain the flow of N2 gas and keep the pressure at 2-5 Pa. Turn off the arc on the TiAl target and deposit the TiSiN layer. The current is 200-500 A, the deposition time is 30-70 minutes, and the deposition thickness is about 0.2-10 micrometers.

[0188] The final composite coating consists of a TiAlN bonding layer, an alternating stack of TiAlSiN and TiAlN transition layers, and a TiSiN wear-resistant layer. The resulting kitchen knife, after testing, exhibits ultra-high sharpness, high hardness, low coefficient of friction, and oxidation resistance.

[0189] Vickers hardness was measured, and the result was HV3800-4200.

[0190] The friction coefficient VSNI was measured and the result was 0.1-0.2.

[0191] The antioxidant temperature can be measured and can reach 900-1100℃.

[0192] TCC was measured according to EN ISO 8442-5 (60 cuts in total), and the average result for the four samples was over 2000 mm.

[0193] ICP was measured according to EN ISO 8442-5 (first three cuts), and the average result for the four samples was over 150 mm.

[0194] The resulting film is coffee-colored, and the total thickness of the composite film, consisting of the bonding layer and the wear-resistant layer, is approximately 1-20 micrometers, as shown in Figure 6. In Figure 6, the bottom layer is a martensitic stainless steel substrate, followed by a bonding layer (TiAlN), a transition layer consisting of alternating stacks of TiAlSiN and TiAlN, and a wear-resistant layer (TiSiN).

[0195] Example 6: Preparation of a kitchen knife with a CrAlN-CrAlTiSiN-CrAlSiN film system

[0196] The kitchen knife was prepared using the following steps. The preparation was performed four times, resulting in four products with the same film system. The specific process parameters for each preparation were selected from the ranges given below. The performance of the four products was characterized by analysis.

[0197] Perform the same steps (1) to (3) as in Example 1.

[0198] (4) Introduce N2 gas and maintain the pressure at 2-5 Pa. Turn on the arc of the CrAl target to start multi-arc ion plating. Deposit the CrAlN layer in a high current and low voltage mode. The current is 200-500 A, the deposition time is 30-70 minutes, and the deposition thickness is about 0.2-10 micrometers.

[0199] (5) Maintain the flow of N2 gas and keep the pressure at 2-5 Pa. Turn on the arc of the TiSi target to perform multi-arc ion plating and deposit a CrAlTiSiN layer. The current is 200-500 A, the deposition time is 30-70 minutes, and the deposition thickness is about 0.1-10 micrometers.

[0200] (6) Maintain the flow of N2 gas and keep the pressure at 2-5 Pa. Turn off the arc on the TiSi target and turn on the arc on the Si target to perform multi-arc ion plating to deposit a CrAlSiN layer. The current is 200-500 A, the deposition time is 30-70 minutes, and the deposition thickness is about 0.5-10 micrometers.

[0201] The final composite coating consists of a bonding layer of CrAlN, a transition layer of CrAlTiSiN, and a wear-resistant layer of CrAlSiN. The resulting kitchen knife, after testing, exhibits extremely high sharpness, high hardness, low coefficient of friction, and oxidation resistance.

[0202] Vickers hardness was measured, and the result was HV3800-4000.

[0203] The friction coefficient VSNI was measured and the result was 0.3-0.5.

[0204] The antioxidant temperature can be measured and can reach 800-1100℃.

[0205] The TCC (60 cuts in total) was measured according to EN ISO 8442-5, and the average result for the four samples was above 2150 mm.

[0206] ICP was measured according to EN ISO 8442-5 (first three cuts), and the average result for the four samples was over 140 mm.

[0207] The resulting film is bronze in color, and the total thickness of the composite film, consisting of the bonding layer and the wear-resistant layer, is approximately 1-10 micrometers, as shown in Figure 7. In Figure 7, the bottom layer is a martensitic stainless steel substrate, followed by the bonding layer CrAlN, the transition layer CrAlTiSiN, and the wear-resistant layer CrAlSiN.

[0208] Example 7: Preparation of a kitchen knife with a CrAlN-CrAlTiSiN-TiSiN-TiSiC film system

[0209] The kitchen knife was prepared using the following steps. The preparation was performed four times, resulting in four products with the same film system. The specific process parameters for each preparation were selected from the ranges given below. The performance of the four products was characterized by analysis.

[0210] Perform the same steps (1) to (3) as in Example 1.

[0211] (4) Introduce N2 gas and maintain the pressure at 2-5 Pa. Start multi-arc ion plating and turn on the arc of the CrAl target. Deposit the CrAlN layer in a high current and low voltage mode. The current is 200-500 A, the deposition time is 40-90 minutes, and the deposition thickness is about 1-10 micrometers.

[0212] (5) Keep the N2 gas flowing through and maintain the pressure at 2-5 Pa. Start the multi-arc ion plating process, turn on the arc of the TiSi target to start the multi-arc ion plating process, deposit the CrAlTiSiN layer, the current is 200-500A, the deposition time is 40-90 minutes, and the deposition thickness is about 0.1-10 micrometers.

[0213] (6) Maintain the flow of N2 gas and keep the pressure at 2-5 Pa. Turn off the arc on the CrAl target and deposit the TiSiN layer. The current is 200-500 A, the deposition time is 40-90 minutes, and the deposition thickness is about 0.5-10 micrometers.

[0214] (7) Turn off the N2 gas and introduce C2H2 gas, maintaining a pressure of 2-5 Pa, to deposit the TiSiC layer. The current is 200-500 A, the deposition time is 40-90 minutes, and the deposition thickness is about 1-10 micrometers. The total amount of C2H2 gas is 500-1000 ml.

[0215] The final composite coating uses CrAlN as the bonding layer, CrAlTiSiN and TiSiN as transition layers from the inside out, and TiSiC as the wear-resistant layer. The resulting kitchen knife, after testing, exhibits ultra-high sharpness, high hardness, low coefficient of friction, and oxidation resistance.

[0216] Vickers hardness was measured, and the result was HV3500-4000.

[0217] The friction coefficient VSNI was measured, and the results were 0.1-0.3.

[0218] The antioxidant temperature can be measured, and the antioxidant temperature can reach 1000-1100℃.

[0219] The TCC was measured according to EN ISO 8442-5 (60 cuts in total), and the average result for the four samples was over 2100 mm.

[0220] ICP was measured according to EN ISO 8442-5 (first three cuts), and the average result for the four samples was over 150 mm.

[0221] The resulting film is copper-red in color, and the total thickness of the composite film of the bonding layer and the wear-resistant layer is approximately 3-20 micrometers, as shown in Figure 8. In Figure 8, the bottom layer is a martensitic stainless steel substrate, followed by the bonding layer CrAl, the transition layer CrAlTiSiN, the TiSiN layer, and the wear-resistant layer TiSiC.

[0222] Example 8: Preparation of a kitchen knife with a CrN-CrNC film system

[0223] The kitchen knife was prepared using the following steps. The preparation was performed four times, resulting in four products with the same film system. The specific process parameters for each preparation were selected from the ranges given below. The performance of the four products was characterized by analysis.

[0224] Perform the same steps (1) to (3) as in Example 1.

[0225] (4) Introduce N2 gas and maintain the pressure at 2-5 Pa. Turn on the arc of the Cr target to start multi-arc ion plating. Deposit the CrN layer in a high current and low voltage mode. The current is 200-500 A, the deposition time is 40-80 minutes, and the deposition thickness is about 1-10 micrometers.

[0226] (5) Introduce C2H2 gas and maintain a pressure of 2-5 Pa to deposit a CrNC layer. The current is 200-500 A, the deposition time is 40-90 minutes, and the deposition thickness is about 1-10 micrometers. The total flow rate of C2H2 gas is 500-1000 ml.

[0227] The final composite coating uses CrN as the bonding layer and CrNC as the wear-resistant layer. The resulting kitchen knife, after testing, exhibits extremely high sharpness, high hardness, low coefficient of friction, and oxidation resistance.

[0228] Vickers hardness was measured, and the result was HV1500-2500.

[0229] The friction coefficient VSNI was measured, and the result was 0.1-0.2.

[0230] The antioxidant temperature can be measured, and the antioxidant temperature can reach 500-700℃.

[0231] The abrasion resistance test cumulative cut test (TCC) thickness of the four samples resulted in an average of over 1650 mm.

[0232] The sharpness of kitchen knives was tested using the ICP three-knife test, and the average result of the four samples was over 145 mm.

[0233] The resulting film is black in color, and the total thickness of the composite film of the bonding layer and the wear-resistant layer is approximately 2-20 micrometers, as shown in Figure 9. In Figure 9, the bottom layer is a martensitic stainless steel substrate, followed by the bonding layer CrN and the wear-resistant layer CrNC.

[0234] Comparative Example 1

[0235] The kitchen knife was prepared in a manner similar to that of Example 2, but without the ion etching step. After ultrasonically cleaning the knife body substrate, it was subjected to 5 minutes of plasma cleaning in a separate plasma cleaning device. It was then removed from the plasma cleaning device and transferred to an arc ion plating chamber. In this chamber, a TiN film was deposited using arc ion plating, with a deposition thickness of less than 2 micrometers.

[0236] The resulting kitchen knives had a golden appearance. However, after a few days, the decorative coating on some of them began to crack.

[0237] The remaining kitchen knives with decorative coating but without cracks and those without decorative coating were compared in terms of sharpness. The ICP of both was about 90 mm, and the TCC after 60 cuts was about 350-400 mm, with no obvious difference.

[0238] The results of the above embodiments all demonstrate that the method of this disclosure can produce kitchen knives with extremely excellent initial sharpness and sharpness retention, as well as excellent wear resistance, superior appearance, and sufficiently high high-temperature resistance and oxidation resistance. Comparison with comparative examples shows that the method of this disclosure achieves a surprisingly significant improvement in sharpness compared to arc ion plating, which does not involve ion etching in the same chamber as in this disclosure.

[0239] Similar tests were conducted on other types of kitchen knife blade substrates, and the method disclosed herein significantly improved sharpness when other martensitic stainless steel, die steel, heat-resistant steel, cemented carbide, and cermet were used as substrates. However, the method disclosed herein had no significant effect on ceramic blade substrates. Examples of preferred substrates include martensitic stainless steels 30Cr13, 40Cr13, 50Cr15MoV, 70Cr17MoV, 80Cr14MoV, 90Cr18MoV, AUS8, AUS10, VG10, M390, and 17-4PH; die steels SKD 11, SKD 61, Cr12MoV, DC53, and DAC55; and heat-resistant steel 4Cr9Si2. The most preferred martensitic stainless steels are 50Cr15MoV, 70Cr17MoV, 80Cr14MoV, 90Cr18MoV, AUS10, VG10, M390, and 17-4PH.

[0240] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A method for preparing kitchen knives using arc ion plating, wherein, The method includes: A kitchen knife blade substrate with a cutting edge is placed in an arc ion plating chamber equipped with an arc generation device. The surfaces on both sides of the cutting edge are subjected to ion etching treatment; A bonding layer material is deposited on the ion-etched surface using arc ion plating; and The wear-resistant layer material can be deposited on the deposited bonding layer material using arc ion plating, or one or more transition layer materials can be deposited sequentially on the deposited bonding layer material followed by the deposition of the wear-resistant layer material.

2. The method according to claim 1, wherein, The ion etching process performed on the surfaces of both sides of the cutting edge includes: The arc discharge generated by the arc generating device causes the process gas introduced into the arc ion plating chamber to form plasma; and The surface is etched using the plasma.

3. The method according to claim 2, wherein, The conditions for etching the surface using the plasma are: the process gases are argon and hydrogen, the operating temperature is 300-550℃, and the duration is 20-100 minutes.

4. The method according to claim 1, wherein, The ion etching process generates pits on the surface with a diameter of 0.01-0.05 micrometers, a depth of 0.01-0.05 micrometers, and a density of 10-100 pits per square micrometer.

5. The method according to claim 1, wherein, The knife body substrate with the blade is selected from martensitic stainless steel, mold steel and heat-resistant steel, and the surface roughness of the two sides of the blade is 0.5-1 micrometer before the ion etching.

6. The method according to claim 1, wherein, The arc ion plating is a multi-arc ion plating.

7. The method according to claim 1, wherein, From the bonding layer to the wear-resistant layer, the hardness of each layer gradually increases.

8. The method according to claim 1, wherein, The bonding layer is TiAlN, the transition layer consists of TiAlSiN and TiSiN from the inside out, and the wear-resistant layer is TiB2.

9. The method according to claim 1, wherein, The bonding layer is TiN, and the wear-resistant layer is TiN.

10. The method according to claim 1, wherein, The bonding layer is CrAlN, and the wear-resistant layer is CrAlBN.

11. The method according to claim 1, wherein, The bonding layer is TiAlN, and the wear-resistant layer is TiAlN.

12. The method according to claim 1, wherein, The bonding layer is TiAlN, the transition layer is an alternating stack of TiAlSiN and TiAlN, and the wear-resistant layer is TiSiN.

13. The method according to claim 1, wherein, The bonding layer is CrAlN, the transition layer is CrAlTiSiN, and the wear-resistant layer is CrAlSiN.

14. The method according to claim 1, wherein, The bonding layer is CrAlN, the transition layers are CrAlTiSiN and TiSiN from the inside out, and the wear-resistant layer is TiSiC.

15. The method according to claim 1, wherein, The bonding layer is CrN, and the wear-resistant layer is CrNC.

16. A kitchen knife prepared by the method according to any one of claims 1-15.

17. The kitchen knife according to claim 16, wherein, The kitchen knife, measured according to EN ISO 8442-5.2005, has an ICP of 130 mm or more and a TCC of 1500 mm or more after 60 cutting cycles.

18. A kitchen knife, wherein, The kitchen knife includes: Kitchen knife body base material with blade, The bonding layer material on both sides of the blade portion of the kitchen knife body substrate, and A wear-resistant layer material on the bonding layer material, or one or more transition layer materials on the bonding layer material followed by a wear-resistant layer material on the one or more transition layer materials. From the bonding layer to the wear-resistant layer, the hardness of each layer gradually increases. The kitchen knife described herein has an ICP of 130 mm or more as measured according to EN ISO 8442-5.2005, and a TCC of 1500 mm or more after 60 cutting cycles.

19. The kitchen knife according to claim 18, wherein, The bonding layer is TiAlN with a thickness of 0.5-10 micrometers; the transition layer consists of TiAlSiN and TiSiN with thicknesses of 0.5-10 micrometers, respectively, from the inside out; and the wear-resistant layer is TiB2 with a thickness of 0.5-10 micrometers. The bonding layer is TiN, the wear-resistant layer is TiN, and the total thickness is 0.5-10 micrometers; or The bonding layer is CrAlN with a thickness of 1-10 micrometers, and the wear-resistant layer is CrAlBN with a thickness of 3-20 micrometers; or The bonding layer is TiAlN, the wear-resistant layer is TiAlN, and the total thickness is 1-10 micrometers; or The bonding layer is TiAlN with a thickness of 0.5-10 micrometers; the transition layer is an alternating stack of TiAlSiN and TiAlN with a thickness of 0.1-1 micrometers, stacked 2-8 times; and the wear-resistant layer is TiSiN with a thickness of 0.2-10 micrometers. The bonding layer is CrAlN with a thickness of 0.2-10 micrometers, the transition layer is CrAlTiSiN with a thickness of 0.1-10 micrometers, and the wear-resistant layer is CrAlSiN with a thickness of 0.5-10 micrometers; or The bonding layer is CrAlN with a thickness of 1-10 micrometers, the transition layer consists of CrAlTiSiN with a thickness of 0.1-10 micrometers and TiSiN with a thickness of 0.5-10 micrometers from the inside out, and the wear-resistant layer is TiSiC with a thickness of 1-10 micrometers; or The bonding layer is CrN with a thickness of 1-10 micrometers, and the wear-resistant layer is CrNC with a thickness of 1-10 micrometers.

20. The kitchen knife according to claim 18, wherein, The bonding layer material fills the surface with pits having a diameter of 0.01-0.05 micrometers, a depth of 0.01-0.05 micrometers, and a density of 10-100 pits per square micrometer.

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