Kitchen knife having extremely high initial sharpness and edge retention, and preparation method therefor

Abstract

The present disclosure provides a method for preparing a kitchen knife by using arc ion plating. A kitchen knife having extremely high initial sharpness and edge retention can be obtained therefrom. The method comprises: placing a kitchen knife body substrate having a blade in an arc ion plating chamber that is provided with an arc generation device, wherein surfaces at both sides of the blade are a first edge side surface and a second edge side surface, respectively; performing an ion etching treatment on the first edge side surface; using arc ion plating to deposit a bonding layer material on the first edge side surface which has been subjected to the ion etching treatment; and using arc ion plating to deposit a wear layer material on the deposited bonding layer material, or sequentially depositing one or more transition layer materials on the deposited bonding layer material and subsequently depositing a wear layer material, and not depositing any wear layer material on the second edge side surface, or removing the wear layer material after depositing same on the second edge side surface. The present disclosure further provides a wear-resistant kitchen knife having extremely high initial sharpness and edge retention.

Description

Kitchen knife with extremely high initial sharpness and sharpness retention and method for making the same

[0001] Cross-reference to Related Applications

[0002] This disclosure claims priority to Chinese Patent Application No. 202411319862.0, filed September 20, 2024, which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present disclosure relates to the field of kitchen knives, and more particularly, to a kitchen knife with extremely high initial sharpness and sharpness retention and a method for making the same. BACKGROUND

[0004] Kitchen knives are an indispensable tool in human daily life, which are used for manually cutting various food materials. An excellent kitchen knife should ideally possess multiple excellent properties including high sharpness, high wear resistance, high hardness, biological safety, high corrosion resistance, aesthetic appearance, high temperature resistance, and good oxidation resistance.

[0005] High sharpness is very important for a kitchen knife. The sharpness of the blade of a kitchen knife is directly related to the difficulty of cutting food materials. Low sharpness can result in some tough food materials such as animal fascia or plant fibers not being cut off. Lower sharpness also results in greater force and longer time required for cutting food materials each time. Since a kitchen knife is a tool operated by a common person manually, the strength and endurance of a common person are limited, and therefore a kitchen knife with low sharpness 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] Kitchen knives are tools that come into direct contact with food materials, and are also likely to come into contact with kitchen utensils such as cutting boards, stoves, sinks, etc. under high-temperature environments, and also frequently come into contact with the human body. Therefore, they need to be biologically safe for the human body, i.e. biological safety. They should not contain harmful substances that easily leach out or evaporate at room temperature or high temperature, nor should they contain substances that can decompose or synthesize into the above-mentioned harmful substances at high temperature. For biological safety, the provisions of the new national standard GB4806.9-2023 "Food safety national standard food contact metal materials and products" published in September 2023 must be met. In the new national standard, technical requirements for stainless steel products and other metal materials and products that come into direct contact with food are specified. The physicochemical indicators in the technical requirements specify the migration limits of impurity elements and alloy elements. Compared with the previous old version, in addition to arsenic, cadmium, lead as impurity elements, the migration limits of alloy elements such as aluminum, chromium, cobalt, manganese, etc. are also added. Since 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 a daily necessity, the appearance of the kitchen knife body should be beautiful. The importance of beauty is sometimes even more important than its cutting performance for the user.

[0011] The application environment of kitchen knives is likely to come into contact with high temperature intentionally or unintentionally, so they need to have high temperature resistance.

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

[0013] Current kitchen knives can be roughly divided into metal kitchen knives and ceramic kitchen knives based on the material, and the difference between the two is the base material of the knife body. In order to improve one or more of the above-mentioned performance, surface treatment or film coating can be performed on the surface of the knife body base material.

[0014] There are many film coating methods applied to the film coating of the cutting edge part of the kitchen knife to improve the performance of the kitchen knife. These methods mainly focus on magnetron sputtering, laser cladding, etc. Recently, arc ion plating has also been tried in kitchen knife film 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 by arc ion plating. It uses a conventional arc ion plating equipment to perform cathodic arc ion plating on the kitchen knife after pretreatment including pickling and ultrasonic cleaning, and deposits a titanium nitride film on the surface thereof. The kitchen knife obtained finally has a smooth, uniform, intact and dense metal luster surface coating, which increases the aesthetic appearance of the product. However, although the decorative deposition of hard titanium nitride film is achieved, the product produced by the method of the application does not have significant progress in aspects other than aesthetics, especially sharpness and wear resistance.

[0016] "Self-sharpening" or "self-sharpening" is a process used to enhance the durability of cutting tools. The basic principle is that by setting the hardness and wear resistance of different parts of the cutting tool blade differently, the softer parts wear faster and the harder parts wear slower in use, so as to control the blade to wear in a predetermined manner during use, in an attempt to make the cutting edge into a desired form, thereby affecting its cutting performance. Self-sharpening is greatly dependent on the specific coating structure and formation method, rather than just the material type. For example, Chinese patent application CN1642697A discloses that the same cobalt-based tungsten carbide coating can provide self-sharpening when a hard film is formed using a high-velocity oxygen flame (HVOF), but self-sharpening cannot be achieved when the hard film is deposited using plasma spraying. In fact, the formation of a coating that can provide self-sharpening depends on the specific properties of the coating, such as the coating bonding method, hardness, porosity and microstructure, etc. The Chinese application itself also proposes a self-sharpening structure, in which the cutting edge composed of a first material is coated on one side thereof with a coating that is harder than the first material, and the coating has a lamellar microstructure or a flaky microstructure substantially parallel to the coated side of the cutting edge. An example of the coating is a tungsten carbide coating formed by chemical vapor deposition (CVD) with a pre-activated carbon-containing gas, while a tungsten carbide coating formed by spraying does not have self-sharpening capability. As the product with the best cutting performance, the ICP range of a martensitic stainless steel blade coated on one side with the coating is between less than 50 mm and less than 100 mm after 3 cuts, and the TCC is between 1200 mm and about 1700 mm after 60 cuts.

[0017] There is a further need for a kitchen knife that is sharper and at the same time has other desired properties. SUMMARY

[0018] In one aspect, the present disclosure provides a method of preparing a kitchen knife using arc ion plating, the method comprising:

[0019] placing a kitchen knife blade substrate having a blade portion in an arc ion plating chamber provided with an arc generating device, the surfaces of two sides of the blade portion being a first blade side surface and a second blade side surface, respectively;

[0020] subjecting the first blade side surface to ion etching treatment;

[0021] depositing a bond layer material on the ion etching treated first blade side surface using arc ion plating; and

[0022] depositing a wear-resistant layer material on the deposited bond layer material using arc ion plating, or sequentially depositing one or more transition layer materials on the deposited bond layer material and then depositing a wear-resistant layer material, and

[0023] no deposition of the wear resistant layer material on the second blade side surface, or removal of the wear resistant layer material after deposition of the wear resistant layer material on the second blade side surface.

[0024] Preferably, the ion etching treatment of the first blade side surface comprises:

[0025] generating a plasma from a process gas fed into an arc ion plating chamber by using the arc generated by the arc generating device; and

[0026] etching the first blade side surface using the plasma.

[0027] Preferably, the conditions for etching the first blade side surface using the plasma are: the process gas is argon and hydrogen, the working temperature is 300-550°C, and the duration is 20-100 minutes.

[0028] Preferably, the ion etching treatment generates pits on the first blade side surface with a diameter of 0.01-0.05 microns, a depth of 0.01-0.05 microns, and a density of 10-100 pits per square micron.

[0029] Preferably, the kitchen knife body substrate with a blade portion is selected from martensitic stainless steel, die steel, and heat-resistant steel, and the surface roughness of the first blade side surface before the ion etching is 0.5-1 micron.

[0030] Preferably, the arc ion plating is multi-arc ion plating.

[0031] Preferably, the hardness of each layer gradually increases from the bonding layer to the wear resistant layer.

[0032] Preferably, the total thickness of the bonding layer material and the wear resistant layer material is 0.5-20 microns.

[0033] Preferably, after the method, the second blade side surface is bare.

[0034] Preferably, in the ion etching treatment of the first blade side surface and the deposition of the bonding layer material and the wear resistant layer material, a mask is used to shield the second blade side surface, so that the wear resistant layer material is not deposited on the second blade side surface.

[0035] Preferably, after the same treatment as the first blade side surface is performed on the second blade side surface, the wear resistant layer material is removed, so that the wear resistant layer material is removed after being deposited on the second blade side surface.

[0036] Preferably, the wear resistant layer material is removed by gradually increasing the fineness of the CNC sharpener grinding medium in the grinding process.

[0037] Preferably, the blade portion of the kitchen knife body substrate is formed by grinding with a CNC sharpener, and the removal of the wear resistant layer material is performed with the same CNC sharpener with the same machine settings.

[0038] Preferably, the bonding layer is TiAlN, the transition layer is TiAlSiN and TiSiN in turn from inside to outside, and the wear resistant layer is TiB2; or

[0039] the bonding layer is TiN, and the wear resistant layer is TiN; or

[0040] the bonding layer is CrAlN, and the wear resistant layer is CrAlBN; or

[0041] the bonding layer is TiAlN, and the wear resistant layer is TiAlN; or

[0042] the bonding layer is TiAlN, the transition layer is an alternating stack with a thickness of 2-8 times of TiAlSiN and TiAlN stacked alternately, and the wear resistant layer is TiSiN; or

[0043] the bonding layer is CrAlN, the transition layer is CrAlTiSiN, and the wear resistant layer is CrAlSiN; or

[0044] the bonding layer is CrAlN, the transition layer is CrAlTiSiN and TiSiN in turn from inside to outside, and the wear resistant layer is TiSiC; or

[0045] the bonding layer is CrN, and the wear resistant layer is CrNC.

[0046] Preferably, a decorative layer is formed on the second blade side surface, wherein the hardness of the decorative layer is lower than the hardness of the wear resistant layer.

[0047] Preferably, the decorative layer is TiN or CrN

[0048] In another aspect, the present disclosure provides a kitchen knife prepared according to the above method.

[0049] Preferably, the ICP of the kitchen knife is 170 millimeters or more, and the TCC of 60 cutting cycles is 2500 millimeters or more, measured according to EN ISO 8442-5.2005.

[0050] In yet another aspect, the present disclosure provides a kitchen knife, comprising:

[0051] a kitchen knife body substrate having a blade portion, the surfaces of the two sides of the blade portion being a first blade side surface and a second blade side surface respectively,

[0052] a bonding layer material on the first blade side surface of the kitchen knife body substrate, and

[0053] a wear resistant layer material on the bond layer material, or one or more transition layer materials sequentially on the bond layer material and a wear resistant layer material on the one or more transition layer materials,

[0054] wherein the hardness of each layer gradually increases from the bond layer to the wear resistant layer,

[0055] the second blade side surface is free of the wear resistant layer material,

[0056] wherein the kitchen knife has an ICP of 170 mm or more and a TCC of 60 cut cycles of 2500 mm or more, measured according to EN ISO 8442-5.2005.

[0057] Preferably,

[0058] the bond layer is TiAlN with a thickness of 0.5-10 micrometer, the transition layer is TiAlSiN with a thickness of 0.5-10 micrometer and TiSiN with a thickness of 0.5-10 micrometer, sequentially from the inside out, and the wear resistant layer is TiB2 with a thickness of 0.5-10 micrometer; or

[0059] the bond layer is TiN and the wear resistant layer is TiN with a total thickness of 0.5-10 micrometer; or

[0060] the bond layer is CrAlN with a thickness of 1-10 micrometer and the wear resistant layer is CrAlBN with a thickness of 3-20 micrometer; or

[0061] the bond layer is TiAlN and the wear resistant layer is TiAlN with a total thickness of 1-10 micrometer; or

[0062] the bond layer is TiAlN with a thickness of 0.5-10 micrometer, the transition layer is an alternating stack of TiAlSiN with a thickness of 0.1-1 micrometer and TiAlN with a thickness of 0.1-1 micrometer, stacked 2-8 times, and the wear resistant layer is TiSiN with a thickness of 0.2-10 micrometer; or

[0063] the bond layer is CrAlN with a thickness of 0.2-10 micrometer, the transition layer is CrAlTiSiN with a thickness of 0.1-10 micrometer, and the wear resistant layer is CrAlSiN with a thickness of 0.5-10 micrometer; or

[0064] the bond layer is CrAlN with a thickness of 1-10 micrometer, the transition layer is CrAlTiSiN with a thickness of 0.1-10 micrometer and TiSiN with a thickness of 0.5-10 micrometer, sequentially from the inside out, and the wear resistant layer is TiSiC with a thickness of 1-10 micrometer; or

[0065] The binding layer is CrN with a thickness of 1-10 microns, and the wear resistant layer is CrNC with a thickness of 1-10 microns.

[0066] Preferably, the binding layer material fills in the pits on the first blade side surface with a diameter of 0.01-0.05 microns, a depth of 0.01-0.05 microns, and a density of 10-100 per square microns. BRIEF DESCRIPTION OF DRAWINGS

[0067] Figure 1 shows a scanning electron micrograph of the surface of a knife body substrate after ion etching in one embodiment.

[0068] Figures 2-9 show cross-sectional scanning electron micrographs of the blade edge portion of a kitchen knife product that can be used to illustrate the structures of embodiments 1-8, respectively.

[0069] Figures 10a-10c show electron micrographs of the blade edge structure of one embodiment of the present disclosure.

[0070] Figure 11 shows a photograph of the appearance of a real knife body in which the wear resistant layer of the blade edge portion of the second blade side surface has been ground away and shows a bright reflection. DETAILED DESCRIPTION

[0071] The inventors of the present disclosure have discovered a method of making a kitchen knife with extremely high initial sharpness and sharpness retention. By the method of the present disclosure, a kitchen knife with super high initial sharpness and super high sharpness retention can be made. The kitchen knife made by the method of the present disclosure has excellent sharpness, with ICP and TCC measured according to EN ISO 8442-5.2005 far exceeding the pass level.

[0072] In one embodiment, the present disclosure provides a method of making a kitchen knife, the method comprising:

[0073] providing a kitchen knife body substrate having a blade portion in an arc ion plating chamber provided with an arc generating device, the surfaces of both sides of the blade portion being a first blade side surface and a second blade side surface, respectively;

[0074] subjecting the first blade side surface to an ion etching treatment;

[0075] depositing a binding layer material on the ion etching treated first blade side surface using arc ion plating; and

[0076] depositing a wear resistant layer material on the deposited binding layer material using arc ion plating, or sequentially depositing one or more transition layer materials on the deposited binding layer material and subsequently depositing a wear resistant layer material, and

[0077] The wear resistant layer material is not deposited on the second blade side surface, or is removed after being deposited on the second blade side surface.

[0078] The method of the present disclosure forms a kitchen knife, on one of the two blade side surfaces of which a binding layer material and a wear resistant layer material are deposited by arc ion plating, while on the other blade side surface the wear resistant layer material is absent. The kitchen knife surprisingly has very high initial sharpness and sharpness retention.

[0079] In this document, “first blade side surface” and “second blade side surface” are merely names for distinguishing the two different blade side surfaces.

[0080] The method of the present disclosure is based on the deposition of a hard film layer on a kitchen knife body substrate using arc ion plating.

[0081] Compared with some common material vapor deposition methods such as magnetron sputtering, arc ion plating has advantages in deposition uniformity and film layer density, and has been used in the deposition of hard film layers on machine tool cutters. However, due to the high requirements for equipment and process control, the cost of arc ion plating is also high, so it is rarely used in the field of kitchen knives.

[0082] Unlike machine tool cutters, the knife body and blade of a kitchen knife are usually much thinner, which puts higher requirements on the binding property of the hard film layer to the substrate when it is applied. The film layer made on a kitchen knife by conventional vapor deposition methods often has the problem of easy disintegration.

[0083] Although, as described in the background section, attempts have been made in the related art to use arc ion plating for titanium nitride plating in the field of kitchen knives, the technical effect to be achieved is only to increase the decoration. For example, the kitchen knife prepared according to the method of CN10965019A has a hard decorative film on the blade surface, but the film only slightly improves the surface hardness of the kitchen knife and does not significantly improve the performance of the kitchen knife, especially the sharpness. In addition, the binding property of the decorative film of the kitchen knife is not strong, and the decorative film is easy to fall off and has poor wear resistance. Due to the high cost of arc ion plating and the fact that it can only play a decorative plating role when used in kitchen knives, arc ion plating has not been widely used in the field of kitchen knives.

[0084] The method of the present disclosure uses arc ion plating combined with a special process to deposit surface materials on a kitchen knife, and after deposition, it can not only change the appearance of the kitchen knife, but also greatly change the sharpness and wear resistance of the kitchen knife. In particular, in combination with the structure that the hardness and wear resistance of the two blade side surfaces are different, a very high initial sharpness and sharpness retention can be obtained.

[0085] The method of the present disclosure employs arc ion plating for coating. Compared with products made by other common coating methods in the field of kitchen knives, such as magnetron sputtering, the products of the present disclosure made by arc ion plating achieve better sharpness and wear resistance. Without being bound by any theory, this can come from the synergistic effect of the material deposition mechanism of arc ion plating and the specific process of the present disclosure that matches it.

[0086] Compared with arc ion plating that directly deposits hard material on the substrate of the knife body, the arc ion plating process of the present disclosure has at least two characteristics, one is that a key ion etching step is added before the coating is implemented, and the other is that the ion etching step and the subsequent coating process are completed in the same arc ion plating chamber. It is extremely surprising that the inventors have previously found that a method with these characteristics can make the kitchen knives prepared have ultra-high sharpness, i.e., ultra-high initial sharpness and ultra-high sharpness durability, when used to prepare kitchen knives with a binding layer and a wear-resistant layer on both sides of the blade surface. The first three knives ICP of the finally obtained kitchen knives can be greater than 130 mm, even more than 150 mm, which is far ahead of the ICP level benchmark of "qualified" in the ISO standard (50 mm); and its 60-knife TCC can be greater than 1500 mm, which is far ahead of the TCC level benchmark of "qualified" in the ISO standard for both A-type and B-type kitchen knives (60 knives after 150 mm, or 200 knives after 1500 mm). The prepared kitchen knives also have extremely high wear resistance and can not be damaged or collapsed after a long time of use. In addition, the prepared kitchen knives have varied colors and are glossy and beautiful in appearance. On the basis of the above findings, the inventors further researched and more surprisingly found that the method of the present disclosure can prepare kitchen knives with a binding layer and a wear-resistant layer only on the first blade side surface, which are more excellent than the aforementioned kitchen knives in terms of initial sharpness and sharpness durability. The first three knives ICP of the finally obtained kitchen knives can be greater than 160 mm, even more than 170 mm, even more than 180 mm; and its 60-knife TCC can be greater than 2200 mm, even more than 2300 mm, even more than 2500 mm, even more than 2600 mm.

[0087] In the present disclosure, the ion etching performed before deposition refers to removing part of the material of the kitchen knife body substrate on the blade side surface of the blade part of the kitchen knife body substrate by means of ion bombardment, further forming a surface microstructure (also known as a surface substructure, which is a structure further produced on a basic smooth surface with low roughness) on the basis of the original surface of the substrate, such as a sub-micron surface microstructure. The surface microstructure can provide a suitable scale and activity of the underlying deposition space for the subsequent deposition of the film layer, and can improve the binding of the subsequent deposition film layer to the substrate.

[0088] The ion bombardment in the ion etching can be bombardment by ions in plasma form, or bombardment by ions in other forms, such as ion beam bombardment, etc. When plasma bombardment is used, the plasma can be plasma induced by arc discharge of the arc ion plating apparatus, or plasma induced by other forms, such as inductively coupled plasma generated by a coil, etc. Most preferably, the ion etching of the present disclosure uses ion bombardment by plasma induced by discharge between an arc cathode of the arc ion plating apparatus and an anode inside the vacuum chamber.

[0089] Generally, when depositing a film layer on a substrate, sometimes roughening treatment is attempted on the surface of the substrate to make some changes to the adhesion between the subsequently deposited film layer and the substrate. However, the effect of such changes is unpredictable, and the roughening can either improve the adhesion or reduce the adhesion. In particular, it has never been expected that roughening treatment on the surface of the body of a kitchen knife can produce the effect of the dramatic improvement of sharpness achieved by the kitchen knife of the present disclosure. The inventors have surprisingly found the correlation between the implementation of the ion etching step before arc ion plating and the great improvement of the sharpness of the kitchen knife. In fact, the surface of the substrate of the body of the kitchen knife also has a basic roughness before ion etching, but if ion etching is not performed and arc ion plating is directly performed, the kitchen knife cannot have the extremely high initial sharpness and sharpness retention.

[0090] Therefore, the great improvement of sharpness achieved by the kitchen knife of the present disclosure is not simply attributed to the improved adhesion due to the surface roughness caused by ion etching. Without being bound by any theory, it can also be related to five reasons. First, compared with other ways of changing the surface roughness, the rough surface microstructure formed by ion etching can also be able to optimize the force transmission and force distribution of the blade part due to its morphology and size, so as to not only make the deposited hard film layer not easy to fall off, but also effectively transmit and distribute the external force on the blade part to the knife body, so that the cutting is easier and the sharpness is improved. Second, the newly exposed surface microstructure formed on the surface of the knife body substrate by the ion etching step can have high activity for the subsequent film layer. Compared with the relatively inert rough surface, the high activity surface can further greatly enhance the firm adhesion of the subsequent deposited film layer, greatly improve the initial sharpness, sharpness retention and wear resistance. Third, the surface microstructure can induce the formation of a crystal phase of the subsequently deposited film layer that is beneficial to improving adhesion, sharpness or hardness, ultimately exhibiting excellent kitchen knife performance. Fourth, when the film layer formed by the method of the present disclosure is used as a relatively hard film layer for the structure with different hardness and wear resistance on the two blade side surfaces, due to the excellent adhesion and force transmission of the substrate to the adhesion layer and the wear-resistant layer, the wear-resistant layer can not only sufficiently extend and protrude from the substrate to form a sharper and sharper cutting edge than the case where the wear-resistant layer is on both sides, but also not easy to fall off or partially separate from the substrate to form micro serrations, achieving a cutting edge microstructure that can achieve excellent initial sharpness and sharpness retention. Fifth, the cutting edge formed by the method of the present disclosure can achieve self-sharpening during use, and the self-sharpening effect is particularly excellent, achieving excellent sharpness retention, which can be because the good adhesion and force transmission of the substrate to the coating are beneficial to the uniform wear of the substrate of the second blade side surface, thereby achieving consistent retention of the cutting edge morphology.

[0091] In the method of the present disclosure, the above-mentioned ion etching and subsequent deposition operations are carried out in the same chamber, which is an arc ion plating chamber (also referred to as a furnace) for carrying out arc ion plating. Without being bound by any theory, this feature helps the "fresh" surface microstructure formed during ion bombardment to be used as the basis for subsequent film layer deposition without being contaminated. If the ion etching treatment and arc ion plating are carried out in different chambers, environmental factors such as atmosphere and airborne dust during the transfer of the knife body substrate between different working chambers can cause contamination or even denaturation of the surface microstructure, thereby affecting the adhesion of the subsequent deposition and failing to achieve the best sharpness.

[0092] The kitchen knife as referred to in the present disclosure can also be called a kitchen tool, including a cutting tool used during the processing of food materials in a kitchen or other environment or a tool having the same function. A typical kitchen knife includes a kitchen knife body and a handle for gripping. The kitchen knife body has a blade for cutting food materials. Since its main function is food material cutting, the blade of the kitchen knife is thinner and sharper compared to industrial tools such as turning tools, milling tools, etc. The included angle between the surfaces on both sides of the blade can be any suitable included angle, for example, in the range of 12° to 36°, more preferably in the range of 16° to 30°, more preferably in the range of 20° to 24°. The kitchen knife of the present disclosure can be a Chinese kitchen knife or a Western kitchen knife, and in terms of main function can be, for example, a vegetable knife, 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.

[0093] The present disclosure uses arc ion plating to prepare a hard film on the surface of a kitchen knife. Arc ion plating is a well-known film plating technique. It takes the plated substrate as one electrode, such as an anode, and the plating film material target as the other electrode, such as a cathode. After applying a high voltage, an arc discharge is formed between the two electrodes, causing the target electrode to release plating film material through the arc discharge, and the plating film material to deposit onto the plated substrate under the action of the electric field. Gases in the atmosphere can also participate in plating after being ionized. When multiple electrodes are present, multiple arcs are generated simultaneously for plating, i.e., multi-arc ion plating.

[0094] Arc ion plating is carried out in an arc ion plating chamber. The arc ion plating chamber can be a reaction furnace and is usually equipped with a gas input device and a vacuum extraction system.

[0095] An arc generation device is provided in the arc ion plating chamber. As described below, it is preferred to use the arc generation device for ion etching.

[0096] The kitchen knife body substrate placed into the arc ion plating chamber is cleaned, which can also be called pre-furnace cleaning. Typical pre-furnace cleaning methods include multiple processes commonly used in the kitchen knife field to remove oil and dust from the body substrate. One advantageous final cleaning process is ultrasonic cleaning. By applying ultrasonic cleaning after removing oil and dust with other processes, the oil and impurities on the surface of the substrate can be substantially completely removed. After cleaning, the substrate is thoroughly dried.

[0097] The method of the present disclosure first places a kitchen knife blade substrate having a blade portion in an arc ion plating chamber. The material of the kitchen knife blade substrate provides the kitchen knife with the required bulk mechanical properties such as strength, rigidity, elasticity, toughness, etc. From the perspective of comprehensive performance, it is desirable for the kitchen knife blade substrate to have excellent mechanical properties and high corrosion resistance, and to be moderately priced. The material of the kitchen knife blade substrate can be a conventional metal-based kitchen knife body material, and metal-based materials that meet the above requirements can generally be used for the kitchen knife blade substrate of the present disclosure. Typical metal-based kitchen knife body materials include alloy steels and hard alloys (commonly known as tungsten steels), etc. Examples of alloy steels include stainless steels (such as martensitic stainless steels), die steels, heat-resistant steels, high-speed tool steels, etc. Martensitic stainless steels, die steels, and heat-resistant steels are particularly preferred due to their comprehensive performance. The model numbers of martensitic stainless steels suitable for use in the kitchen knife blade substrate of the present disclosure include, but are not limited to: 30Cr13, 40Cr13, 50Cr15MoV, 70Cr17MoV, 80Cr14MoV, 90Cr18MoV, AUS8, AUS10, VG10, M390, and 17-4PH. The model numbers of die steels suitable for use in the kitchen knife blade substrate of the present disclosure include, but are not limited to: SKD11, SKD61, Cr12MoV, DC53, and DAC55. The model numbers of heat-resistant steels suitable for use in the kitchen knife blade substrate of the present disclosure include, but are not limited to: 4Cr9Si2. The kitchen knife blade substrate can also be selected from suitable hard alloys and cermet. However, the kitchen knife blade substrate of the present disclosure does not use pure ceramic, because ceramic itself generally already has a high hardness without the need for plating, and the plasma etching step of the present disclosure is not suitable for ceramic substrates.

[0098] As the kitchen knife blade substrate, it already has the required shape of the final kitchen knife blade. The kitchen knife blade substrate is substantially plate-shaped, and at at least one side edge of the plate-shaped kitchen knife blade substrate, the two side surfaces of the plate intersect to form a blade portion. The included angle of the two side surfaces of the blade portion is important for the sharpness of the kitchen knife, and has been extensively studied in the related art. Generally, the included angle of the two side surfaces ranges from 12° to 36°, more preferably from 16° to 30°, and more preferably from 20° to 24°. If the included angle is too large, the sharpness is not enough. If the included angle is too small, it is too demanding on the process and material to achieve. Relative to the two side surfaces of the blade body, the two blade side surfaces of the cutting edge can both be inclined, or one is coplanar and the other is inclined. The first blade side surface can be either of the blade side surfaces. The blade side surfaces that are both inclined are more versatile for users of left-handed and right-handed knives.

[0099] At least one side surface, preferably both sides, of the blade portion of a kitchen knife body substrate provided in an arc ion plating chamber having a blade portion is smooth. The method of the present disclosure includes forming a microstructure on the first blade side surface for increasing the adhesion with the overlying wear resistant layer, and thus the initial surface condition is important. If the initial surface is not smooth enough, the microtopography formed by subsequent surface treatment is not easily controlled, which in turn affects the final product appearance and performance. The surface smoothness can be measured by the initial surface roughness. Typically, the first blade side surface of the initial kitchen knife body substrate has a roughness Ra of no more than 10 microns, for example, 0.5-10 microns, preferably 0.5-3 microns, for example, 0.5-1 microns.

[0100] When the kitchen knife body substrate having a blade portion is placed in the arc ion plating chamber, the surface of one or both sides of the blade portion is subjected to ion etching treatment. In the ion etching treatment, a plasma is formed in a process gas atmosphere, and ions in the plasma are made to bombard the substrate surface to remove a portion of the material of the substrate surface, thereby forming a surface microstructure.

[0101] Prior to the conventional arc ion plating operation, the substrate is sometimes also subjected to ion cleaning. This ion cleaning is sometimes inaccurately referred to as ion etching because it sometimes serves to remove impurities from the surface of the substrate. However, the purpose of this cleaning is generally limited to removing contamination and impurities from the surface of the substrate, rather than damaging the surface of the substrate and forming a new microstructure. In contrast, an ideal ion cleaning removes surface impurities without damaging the substrate. Therefore, the power of the ion bombardment is small and the duration is short. In contrast to this ion cleaning step, the ion etching step of the present disclosure is high in power and long in duration to achieve sufficient damage to the surface of the substrate and formation of a new microstructure. That is, the ion etching referred to in the present disclosure means that the ion bombardment is capable of causing sufficient damage to the substrate and achieving a new surface microstructure that is advantageous for achieving the object of the present disclosure. Ion cleaning that merely removes impurities from the surface of the substrate or unintentional slight damage to the substrate that accompanies it is not included in the ion etching referred to in the present disclosure. In contrast to the general ion cleaning in arc ion plating, the ion etching of the present disclosure is long in duration and high in bombardment power. Typically, the 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 sufficiently remove surface oxides that are not substantially affected by the conventional ion cleaning and form a microstructure on the fresh substrate surface on this basis.

[0102] After the surface microstructure is formed by ion etching to disrupt the surface of the substrate, a bond layer material, optionally a transition layer, and a wear resistant layer material are sequentially deposited. The wear resistant layer material is the outermost hard material that directly provides the surface properties of high hardness and high wear resistance. The wear resistant layer material is also typically a high temperature resistant material that can withstand high temperatures up to 1200-1300 °C. However, the wear resistant layer material in some cases does not have sufficiently good adhesion to the substrate, which is not conducive to achieving ultra-sharpness and wear resistance, so a bond layer and an optional transition layer are provided between the wear resistant layer and the substrate to achieve a gradual transition from the substrate to the wear resistant layer. Typically, the bond layer is adapted to be firmly bonded directly to the substrate and is of a different material than the wear resistant layer. However, if the wear resistant layer material is suitable for being firmly bonded directly to the substrate, the wear resistant layer material and the bond layer material can also be the same. Optionally, there can also be one or more transition layers between the bond layer and the wear resistant layer. The deposition of these film layers is all performed using conventional arc ion plating by selecting appropriate target materials, atmospheres, and process parameters in the arc ion plating chamber. A conventional target cleaning step can be performed before the arc ion plating officially starts.

[0103] The bond layer material is a material that has excellent adhesion to the substrate material of the kitchen knife body. Examples of the bond layer material include TiAlN material, TiN material, CrAlN material, CrN material, 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, B. The material of the transition layer is also a material containing elements selected from Ti, Al, Cr, Si, N, C, B, which has good adhesion to the materials on both sides. In principle, the coating formed by the bond layer material, the optional transition layer, and the wear resistant layer material gradually increases in hardness from the inside to the outside, which is conducive to the gradual change of the structure and stress, and achieves the desired final performance. The material selection that meets this gradually increasing hardness is preferred.

[0104] In the present disclosure, the metal-nonmetal compound film layer materials are represented in the way of elemental arrangement, and the stoichiometric ratio is not usually indicated after the elements. In other words, the representation method does not specify the stoichiometric ratio between the elements, but only focuses on showing the element types. For example, TiAlN represents a titanium aluminum nitride series material with various suitable element stoichiometric ratios, and CrAlNB represents a titanium aluminum nitride series material and a chromium aluminum nitrogen boride series material with various suitable element stoichiometric ratios. The present disclosure does not have a particularly strict limitation on the element stoichiometric ratio of the material, as long as it can provide high hardness, high wear resistance, and does not conflict with the spirit of the present disclosure. In other words, the present disclosure does not intend to improve the stoichiometric ratio of the film series material, or in other words, the improvement of the performance of the kitchen knife of the present disclosure is not based on the deliberate adjustment and improvement of the component ratio of the existing film series material. Therefore, various film series hard alloy materials commonly used in the knife field and corresponding commercially available alloy targets of various types and element ratios can be selected for film layer deposition. The only one that is particularly specified in the stoichiometric ratio is titanium diboride (TiB2) material, because it has particularly excellent performance as the outermost wear-resistant layer.

[0105] Preferably, the bonding layer (i.e. the layer formed directly on the substrate) is formed by using a high-current low-voltage mode of arc ion plating. The high-current low-voltage mode is a common working mode of the arc ion plating device. The reason why the present disclosure uses this working mode to deposit the bonding layer is to more effectively improve the bonding force between the vacuum ion plated film layer and the plated workpiece, to lay a better foundation for subsequent film layer deposition, and to more effectively improve the firmness between the film layer and the workpiece.

[0106] The thickness of the bonding layer at least completely fills the pores of the microstructure of the substrate surface, so that the substrate surface is completely covered and not exposed after deposition. On this basis, the bonding layer can be additionally deposited to a certain thickness to ensure coverage of the substrate and function of the bonding layer. The additional thickness can be preferably 1-10 microns. A too thick bonding layer can affect the performance of the composite coating, such as hardness, and increase the time-consuming and material cost.

[0107] The method of the present disclosure does not deposit the wear-resistant layer material on the second blade side surface, or removes the wear-resistant layer material after depositing it on the second blade side surface. The wear-resistant layer material can be deposited on the second blade side surface by setting a mask. After the same film layer is deposited on both sides, the coating on the second blade side surface can be removed by, for example, grinding or polishing. Since the bonding layer and the wear-resistant layer have good bonding and high wear resistance, it usually takes a certain amount of time to deposit the wear-resistant layer material and then remove it. In comparison, although the wear-resistant layer material can be prevented from being deposited by setting a mask to block the second blade side surface, the mask needs to completely cover the second blade side surface and completely expose the first blade side surface, so the precision of the mask setting is relatively high. Both processes have their own advantages and disadvantages.

[0108] The method of the present disclosure is based on arc ion plating deposition of the bonding layer and the wear-resistant layer material, improving the surface hardness and wear resistance of the kitchen knife body substrate, and by performing ion etching before arc ion plating and performing etching and plating in the same chamber, and setting the coating film on the first blade side surface and not setting the coating film on the second blade side surface, a kitchen knife with excellent sharpness is obtained.

[0109] Preferably, the ion etching treatment of the surfaces of the two sides of the blade portion comprises:

[0110] By using the arc discharge generated by the arc generation device, the process gas introduced into the arc ion plating chamber is formed into a plasma; and

[0111] The surface is etched using the plasma.

[0112] The arc discharge generated by using the arc generation device can make full use of the low-temperature plasma generated by the arc ion plating equipment. In the arc ion plating chamber, it is convenient to achieve arc discharge capable of generating plasma by adding an inert electrode. For example, one or more auxiliary inert cathodes can be provided, and a voltage is applied to the auxiliary cathode instead of the target cathode to generate arc discharge, thereby generating plasma from the process gas atmosphere for etching. Arc discharge can also be generated using the target cathode, for which a shielding plate is provided to shield the deposition of materials from the target to the substrate, but does not hinder the action of the plasma on the substrate. Compared with hot plasma or other separately arranged plasma generation devices, the plasma generated by arc discharge with the aid of arc ion plating equipment has less requirement for modification of the device, the plasma is formed quickly, the etching effect is better, and the etched substrate can be used for subsequent film deposition basically in situ. In the furnace, a plurality of kitchen knives can be processed at a time. The target cathode and the auxiliary inert cathode can be arranged appropriately according to the layout of the kitchen knives to be processed.

[0113] Preferably, the conditions for the plasma etching are that the process gas is argon and hydrogen, and the working temperature is 300-550°C. The advantage of selecting these process gases is that they do not cause adverse doping and contamination to the surface of the substrate, and can also be beneficial to form a highly active surface. Hydrogen helps to provide a reducing atmosphere to the surface to eliminate oxides, to ensure that the desired microstructure is obtained. A vacuum is maintained during the operation to maintain a low pressure in the chamber. The advantage of this working temperature range is that it does not cause adverse heat treatment effects to the tool body substrate. More preferably, the conditions for the plasma etching are that the temperature is 400-500°C, the total amount of argon introduced is 1000-2000ml, the total amount of hydrogen introduced is 500-1000ml, the etching current is 300-500A, and the etching time is 20-100 minutes. During the ion etching, a relatively large etching current is applied in order to generate an arc to form a plasma that enables the etching of the substrate. At this high current, high energy ions are generated that are sufficient to damage the surface of the substrate to form a microstructure, and long time bombardment is performed to complete the ion etching. In the present disclosure, an etching time of 20 minutes or more is generally necessary, for example 30 minutes or more, 40 minutes or more, or 60 minutes or more. Generally, an etching of 100 minutes is sufficient to form the desired surface microstructure. Further extending the etching time can reduce cost efficiency.

[0114] Preferably, the ion etching process forms pits on the substrate surface with a diameter of 0.01-0.05 microns and a depth of 0.01-0.05 microns. Microscopic analysis of the substrate surface after ion etching reveals that a large number of closely packed pits with a diameter of 0.01-0.05 microns and a depth of 0.01-0.05 microns are formed on the surface after ion etching compared to the surface without ion treatment or only with conventional plasma cleaning. The pits can be substantially circular, but can also not be circular. The diameter here refers to the largest 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 direction of the thickness of the blade body. The density of the micro-pits is reflected by the number of pits per unit area. Typically, the micro-pits are uniformly and densely formed on the entire surface, and the density per unit area can be about 10-100 per square micron, such as about 20-100, such as about 40-80. Without being bound by any theory, these micro-pits can be features of the aforementioned surface microstructure. On a surface with a roughness of less than 10 microns, for example 0.5-3 microns, the method including the step of further forming these micro-pits surprisingly results in ultra-high sharpness and wear resistance. This can be attributed to the ultra-high adhesion of the film layer to the blade substrate due to the previously described reasons, although there is no existing theory to suggest that it has a great impact on the subsequent deposited film layer. The inventors surprisingly found that when the blade side surface of the blade has the above-mentioned dense micro-pit microstructure or micro-topography, these pits can be used to deposit and possibly firmly bond the bonding layer material, and the wear-resistant layer material subsequently deposited on the bonding layer material has excellent mechanical performance in all directions with the kitchen knife blade substrate. The excellent mechanical performance allows the complex processes including extrusion, friction and other mechanical interactions between the surface of the kitchen knife and the material being cut to be fully smoothed and conducted to the kitchen knife blade substrate when the resulting kitchen knife is used for cutting, thereby minimizing the damage to the adhesion between the wear-resistant layer and the kitchen knife blade substrate, and greatly reducing the material damage to the surface of the wear-resistant layer. This results in a wear-resistant layer that does not disintegrate or damage even after multiple cuts, thereby obtaining a kitchen knife that not only has high initial sharpness, but also has high wear resistance and sharpness retention.

[0115] Without being bound by any theory, when the pit diameter is too large, the filling of the bonding layer material can not be uniform enough, resulting in insufficient adhesion in individual pits. When the pit diameter is too small, there can be pits that are not filled, resulting in insufficient overall adhesion. 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 thickness of the bonding layer, which can affect the properties such as hardness of the composite coating, and the excessively large depth can result in roughness of the surface of the finally formed coating.

[0116] The arrangement of the pits can be random, but is preferably honeycomb-like. Honeycomb-like means that the holes ion-blasted out of the surface are arranged in a uniform lattice like a honeycomb. The honeycomb-like arrangement of the pits is conducive to uniform conduction of internal stress.

[0117] As mentioned above, preferably, the material of the kitchen knife body substrate with the blade portion is martensitic steel, die steel, heat-resistant steel, cemented carbide, or other high-hardness metal material, and the surface roughness Ra of the blade side surface of the blade portion is 0.5-3 microns. The surface roughness is preferably 0.5-1 micron, which at least makes the finally formed blade surface look more glossy and beautiful.

[0118] Preferably, the arc ion plating is multi-arc ion plating. Preferably, multi-arc ion plating is used to perform multi-directional deposition plating in cooperation with target material electrodes at multiple different positions, which is conducive to forming a uniform and dense film layer on the entire knife body.

[0119] In addition to having ultra-high sharpness and wear resistance, the kitchen knife prepared by the method of the present disclosure also has excellent hardness, corrosion resistance, aesthetic appearance, biological safety, high temperature resistance, and oxidation resistance.

[0120] In one embodiment, the present disclosure provides a kitchen knife prepared according to the foregoing method, which has the above advantages.

[0121] In another embodiment, the present disclosure also provides a kitchen knife, which comprises:

[0122] a kitchen knife body substrate with a blade portion, the surfaces of the two sides of the blade portion are respectively a first blade side surface and a second blade side surface,

[0123] a bonding layer material on the first blade side surface of the kitchen knife body substrate, and

[0124] a wear-resistant layer material on the bonding layer material, or one or more transition layer materials in sequence on the bonding layer material and a wear-resistant layer material on the one or more transition layer materials,

[0125] wherein the hardness of each layer gradually increases from the bonding layer to the wear-resistant layer,

[0126] the second blade side surface is free of the wear-resistant layer material,

[0127] wherein the ICP of the kitchen knife measured according to EN ISO 8442-5.2005 is 170 millimeters or more, and the TCC of 60 cutting cycles is 2500 millimeters or more.

[0128] In the related art, there is no kitchen knife with the above structure and reaching the above sharpness. In a more preferred embodiment, the ICP can reach 180 mm or more, and the TCC can reach 2600 mm or more.

[0129] The aforementioned preferred parameters are all applicable to the kitchen knife.

[0130] Preferably, the total thickness of the bonding layer material and the wear-resistant layer material is 0.5-20 microns, more preferably 1-15 microns, more preferably 1.5-10 microns, more preferably 2.5 to 10 microns, and still more preferably 4-10 microns. Without being bound by any theory, a thicker total thickness is advantageous for ensuring the biological safety of the kitchen knife. Since the method of the present disclosure performs ion etching on the substrate, high-energy bombardment can cause impurity elements or alloy elements in the substrate to migrate to the surface formed by bombardment. Although the subsequent coating can prevent the adverse elements from coming into contact with food or the human body, if the coating is too thin, there is a possibility that micro-cracks will occur due to, for example, improper operation. At this time, if it continues to be used, the adverse elements can migrate out or seep out of the micro-cracks of the thin coating. Therefore, by making the coating have a larger thickness, the possibility of micro-cracks can be reduced to substantially zero, and even if it occurs, the thicker film layer thickness substantially prevents the seepage of adverse elements. In this way, the migration of impurity elements or alloy elements generated due to ion etching is limited, meeting the migration limit specified in the national standard GB4806.9-2023, and does not cause substantial harm to the human body. On the basis of ensuring safety, a thinner coating is advantageous for forming a sharper cutting edge.

[0131] After the method ends, the second blade side surface can be bare or a decorative layer can be formed thereon, wherein the hardness of the decorative layer is lower than the hardness of the wear-resistant layer. The bare surface is simpler to prepare, and the decorative layer can improve the aesthetics. Both are feasible as long as the hardness of the second blade side surface is lower than the hardness of the wear-resistant layer.

[0132] As mentioned above, for the bare second blade side surface, it can be that the second blade side surface is shielded using a mask when the first blade side surface is subjected to ion etching treatment and the bonding layer material and the wear-resistant layer material are deposited, so that the wear-resistant layer material is not deposited on the second blade side surface, or it can be that the second blade side surface is subjected to the same treatment as the first blade side surface, and after the wear-resistant layer material is deposited on the second blade side surface, it is removed.

[0133] Preferably, the wear resistant layer material is removed by grinding in a stepwise manner of increasing the fineness of the grinding medium. The grinding medium can be any material that can grind off the wear resistant layer, a preferred example is a grinding wheel. A material that can remove the wear resistant layer can naturally also remove the bonding layer. The stepwise manner of increasing the fineness of the grinding medium facilitates efficient and uniform removal of the wear resistant layer. In a preferred embodiment, the stepwise grinding is performed using grinding wheels with mesh sizes of 320 mesh, 600 mesh, 800 mesh, 1000 mesh and 1500 mesh in sequence, finally the wear resistant layer and the bonding layer can be completely removed and a smooth and beautiful second blade side surface is obtained.

[0134] The grinding process is preferably automated by a machine. In the kitchen knife industry, it is a common practice to rely on workers to manually sharpen the kitchen knives. However, for the kitchen knives of the present disclosure, the specific operation of removing the wear resistant layer, which is equivalent to a second sharpening, has a relatively obvious impact on the performance of the kitchen knives. If manual operation is used, due to the difficulty of grinding off the wear resistant layer, it is extremely easy to cause deformation of the cutting edge, affecting the cutting performance, especially the sharpness. Therefore, it is preferred to use an automated method to complete the grinding.

[0135] In the automated method, more preferably, the same numerical control sharpening machine (for example, a numerical control multifunctional sharpening machine) is used to form the blade part of the initial kitchen knife body substrate and to perform the final removal of the wear resistant layer and the bonding layer with the same machine settings. In other words, after the kitchen knife body substrate is sharpened, i.e., the blade part is formed, using a numerical control sharpening machine with a grinding medium such as a grinding wheel, the kitchen knife body substrate is removed from the numerical control sharpening machine and the arc ion plating method of the present disclosure is performed. During this process, the numerical control sharpening machine does not perform any other grinding operation. When the bonding layer and the wear resistant layer are deposited on both blade side surfaces of the kitchen knife body, the kitchen knife body is reinstalled into the numerical control sharpening machine, and the coating on the second blade side surface is ground off using the grinding wheel. In this way, the final blade part shape is closest to the initial state, and has the best cutting performance. Tests have shown that the kitchen knife made in this way can increase the TCC by several hundred millimeters after 60 knives, compared with a kitchen knife that is manually sharpened a second time under the same conditions.

[0136] The base material of the knife body is preferably stainless steel, more preferably martensitic stainless steel, die steel and heat-resistant steel. The included angle of the blade side surfaces is preferably 12°-36°, more preferably 16°-30°. The first blade side surface is smooth, with a basic roughness of no more than 10 microns, for example 0.5-10 microns, preferably 0.5-3 microns, for example 0.5-1 microns, not taking into account the dimples. The dimples are preferably distributed in a honeycomb pattern. The wear-resistant layer material is preferably a high-temperature-resistant material. Examples of the bonding layer material include TiAl materials, CrAl materials, TiSi materials and the like. The wear-resistant layer material is the outermost hard material, examples including hard materials comprising elements selected from Ti, Al, Cr, Si, N, C, B. The material of the transition layer is also a material comprising elements selected from Ti, Al, Cr, Si, N, C, B, which has good bonding properties with the materials on both sides thereof. In principle, the coating formed by the bonding layer material, optional transition layer and wear-resistant layer material has gradually increasing hardness from the inside to the outside.

[0137] The thickness of the bonding layer beyond the surface of the base material can be between 0.5 microns and 10 microns, preferably 1-10 microns. The preferred thickness of each film layer of the transition layer and the wear-resistant layer can generally be between 1 micron and 10 microns.

[0138] In addition, the total thickness of the deposited film layers (i.e. the total thickness of the bonding layer and the wear-resistant layer or, when a transition layer is present, the thickness of the transition layer in addition) can be up to 20 microns. Although the method of the present disclosure can also achieve a total thickness of more than 20 microns, further improvement in performance is not great and the risk of film disintegration increases. In many cases, a total thickness of 10 microns is sufficient for excellent sharpness and wear resistance, and film disintegration does not occur. In contrast, the film layer formed directly on the kitchen knife using arc ion plating is generally less than 3 microns in thickness, otherwise the film layer is prone to disintegration.

[0139] The kitchen knife having the same key structure as the kitchen knife produced by the production method of the present disclosure also has the same advantages when the production method other than the production method of the present disclosure is used.

[0140] There are a variety of film systems suitable for the present disclosure with respect to the bonding layer, transition layer and wear-resistant layer materials. The following are examples of some film systems.

[0141] In one embodiment, the bonding layer is TiAlN, the transition layer is TiAlSiN and TiSiN in turn from the inside to the outside, and the wear-resistant layer is TiB2. In one embodiment, their preferred thicknesses are 0.5-10 microns, 0.5-10 microns, 0.5-10 microns and 0.5-10 microns, respectively. The preferred total thickness is 2-20 microns, more preferably 4-10 microns.

[0142] In one embodiment, the binding layer is TiN and the wear resistant layer is TiN. In one embodiment, their preferred total thickness is 0.5-10 microns, more preferably 1-10 microns.

[0143] In one embodiment, the binding layer is CrAlN and the wear resistant layer is CrAlBN. In one embodiment, their preferred thicknesses are 1-10 microns and 2-20 microns, respectively. The preferred total thickness is 3-20 microns, more preferably 4-10 microns.

[0144] In one embodiment, the binding layer is TiAlN and the wear resistant layer is TiAlN. In one embodiment, their preferred total thickness is 1-10 microns, more preferably 3-10 microns.

[0145] In one embodiment, the binding 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 microns, 0.5-10 microns, and 0.2-10 microns, respectively, wherein the stack is preferably an alternating stack of 0.1-1 microns of TiAlSiN alternating with 0.1-1 microns of TiAlN for 2-8 times. In one embodiment, the preferred total thickness is 1-20 microns, more preferably 3-10 microns.

[0146] In one embodiment, the binding layer is CrAlN, the transition layer is CrAlTiSiN, and the wear resistant layer is CrAlTiSiN. In one embodiment, their preferred thicknesses are 0.2-10 microns, 0.1-10 microns, and 0.5-10 microns, respectively. The preferred total thickness is 1-20 microns, more preferably 3-10 microns.

[0147] In one embodiment, the binding layer is CrAlN, the transition layer is CrAlTiSiN and TiSiN in order from inner to outer, and the wear resistant layer is TiSiC. In one embodiment, their preferred thicknesses are 1-10 microns, 0.1-10 microns, 0.5-10 microns, and 1-10 microns, respectively. The preferred total thickness is 2.5-20 microns, more preferably 4-10 microns.

[0148] In one embodiment, the binding layer is CrN and the wear resistant layer is CrNC. Their preferred thicknesses are 1-10 microns and 1-10 microns, respectively. In one embodiment, the preferred total thickness is 2-20 microns, more preferably 4-10 microns.

[0149] In general, the total thickness of the film layers deposited by arc ion plating is preferably 0.5-20 microns, more preferably 1-15 microns, and more preferably 1.5-10 microns. If the ion etching step of the present disclosure is not used, the total thickness of the arc ion plating film of the corresponding film system is usually thinner, and in particular it is difficult to exceed 4 microns, otherwise film disintegration will easily occur. Even if the thickness is less than 4 microns, the adhesion of the film formed without the ion etching step of the present disclosure is much poorer, and the effect of significantly improving sharpness cannot be achieved.

[0150] In such a kitchen knife, the bonding layer material fills the pits on the surface with a diameter of 0.01-0.05 microns, a depth of 0.01-0.05 microns, and a density of 10-100 per square microns. These pits can be formed by ion etching in an arc ion plating chamber.

[0151] The present disclosure is further illustrated by the following examples. Unless otherwise specified, the target materials in the examples of the present disclosure are all conventional commercially available target materials, and the test methods are all conventional test methods in the art. The types of martensitic stainless steel are 50Cr15Mov, 70Cr17Mov, 80Cr14Mov, 90Cr18Mov, AUS10, VG10, M390, and 17-4PH; the types of die steel are Skd11, Skd61, Cr12Mov, DC53, DAC55, and 4Cr9Si2.

[0152] Specifically, an alloy target or an elemental target of the desired element is used. For the proportion of elements in the alloy target, the present disclosure is not particularly limited, and a conventional composition ratio of the alloy target used for arc ion plating can be used.

[0153] Specifically used target materials include commercially available TiAl targets, TiSi targets, CrAl targets, CrAlB targets, Ti targets, CrAlSi targets, and TiB2 targets, etc. Examples of the specific elemental composition of the target material include, but are not limited to: TiAl: 50:50, TiSi: 90:10, CrAl: 40:60, CrAlB: 20:70:10, CrAlSi: 40:50:10.

[0154] Preparation of a kitchen knife with a TiAlN-TiAlSiN-TiSiN-TiB2 film system according to Example 1

[0155] A kitchen knife was prepared by the following steps. The preparation was performed four times, and four products with the same film system were obtained. The specific process parameters for each preparation were selected from the ranges given below. Performance analysis and characterization were performed on the four products.

[0156] (1) The surface of the blade of the martensitic stainless steel base body is polished to a surface roughness of 0.5-3 microns by grinding with a grinding wheel using a numerical control multifunctional blade grinder (Guangdong San Guanshan Precision Machinery Co., Ltd., SGS-KR61), and then cleaned by ultrasonic waves.

[0157] (2) The cleaned kitchen knife base body is hung in an arc ion plating chamber and masked using a mask to shield one side of the blade surface from the bombardment and deposition of arc-generated substances.

[0158] (3) The arc ion plating chamber is evacuated to a pressure of 0.005-0.008 Pa, heated to 300-550°C, and supplied with a total of 1000-2000 ml of argon and a total of 500-1000 ml of hydrogen. An arc discharge is used to generate plasma, and the working current is 300-500 A. The hydrogen ions and argon ions in the generated plasma are accelerated under the action of an electric field to bombard the smooth surface of the kitchen knife base body and ion-etch the kitchen knife base body for a duration of 20-100 minutes to form a honeycomb-shaped micro-pit. Microscopic analysis shows that the pit diameter is 0.01-0.05 microns and the depth is about 0.01-0.05 microns. Figure 1 shows a scanning electron micrograph of the surface of the base body after ion etching, from which the densely arranged fine pits can be seen.

[0159] (4) N2 gas is supplied to maintain a pressure of 2-5 Pa. The arc of the TiAl target is turned on for multi-arc ion plating, and a TiAlN layer is deposited by a high-current low-voltage mode, with a current of 200-500 A, a deposition time of 20-50 minutes, and a deposition thickness of about 0.5-10 microns.

[0160] (5) N2 gas is maintained at a pressure of 2-5 Pa. The arc of the TiSi target is turned on for multi-arc ion plating, and a TiAlSiN layer is deposited. The current is 200-500 A, the deposition time is 30-50 minutes, and the deposition thickness is about 0.5-10 microns.

[0161] (6) N2 gas is maintained at a pressure of 2-5 Pa. The arc of the TiAl target is turned off, and a TiSiN layer is deposited. The current is 200-500 A, the deposition time is 30-70 minutes, and the deposition thickness is about 0.5-10 microns.

[0162] (7) N2 gas is turned off and Ar gas is supplied to maintain a pressure of 2-5 Pa. The arc of the TiSi target is turned off, and the arc of the TiB2 target is turned on for multi-arc ion plating to 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 microns.

[0163] (8) The obtained kitchen knife is removed from the arc ion plating chamber and installed back to the original numerical control multifunctional blade sharpening machine, and the blade side surface is gradually ground under the condition that the grinding angle is not changed by using abrasive wheels with mesh numbers of 320 mesh, 600 mesh, 800 mesh, 1000 mesh and 1500 mesh in sequence, so as to remove the wear-resistant layer and the bonding layer and form a second blade side surface. The blade side surface without grinding is a first blade side surface. The grinding time of each abrasive wheel is 1-20 seconds.

[0164] The bonding layer of the composite coating of the final first blade side surface is TiAlN, the transition layer is TiAlSiN and TiSiN from inside to outside, and the wear-resistant layer is TiB2. The obtained kitchen knife has extremely high initial sharpness and sharpness retention, and high hardness, low friction coefficient and oxidation resistance.

[0165] The Vickers hardness measurement is performed, and the result is HV3800-4200.

[0166] The friction coefficient VSNI is measured, and the result is 0.1-0.2.

[0167] The oxidation resistance temperature is measured, and the oxidation resistance temperature can reach 1000-1200°C.

[0168] The TCC (total of 60 knives) is measured according to EN ISO 8442-5, and the average result of four samples is more than 2560 mm.

[0169] The ICP (first three knives) is measured according to EN ISO 8442-5, and the average result of four samples is more than 185 mm.

[0170] The color of the obtained film layer on the first blade side surface is silver white, and the total thickness of the composite film layer of the bonding layer, the transition layer and the wear-resistant layer is about 2-20 microns. An electron micrograph that can be used to illustrate the structure of the knife body substrate, the bonding layer and the wear-resistant layer of such products is shown in FIG. 2. The electron micrograph is taken from a kitchen knife sample in the test in which the bonding layer and the wear-resistant layer are deposited on both sides of the blade edge (i.e. corresponding to the first and second blade side surfaces). The film layer structure thereof is not essentially different from the film layer structure of the present disclosure, and thus can be used to understand the film layer structure of the first blade side of the present disclosure. The same is true for the subsequent examples. In FIG. 2, the lowermost layer is the martensitic stainless steel substrate, followed by the bonding layer TiAlN layer, the transition layer TiAlSiN layer, the TiSiN layer, and the wear-resistant layer TiB2 layer, respectively. The same is true for subsequent FIGS. 3-9.

[0171] Preparation of a kitchen knife with a TiN film system in Example 2

[0172] A kitchen knife was prepared by the following steps. The preparation was performed four times to obtain four products of the same film system. The specific process parameters for each preparation were selected from the ranges given below. The four products were characterized by performance analysis.

[0173] The same steps (1) to (3) and (8) as in Example 1 were performed.

[0174] Before (8), (4) was performed by introducing N2 gas to keep the pressure at 2-5 Pa. The multi-arc ion plating was started, the arc of the Ti target was turned on, and the TiN layer was deposited by a high-current low-voltage mode, with a current of 200-500 A, a deposition time of 30-80 minutes, and a deposition thickness of about 0.5-10 microns. Thus, the bonding layer and the wear-resistant layer were directly formed and had the same material.

[0175] The bonding layer of the composite coating on the final first blade side surface was TiN, and the wear-resistant layer was also TiN. The obtained kitchen knife was tested to have super-high sharpness and high hardness, low friction coefficient, and oxidation resistance.

[0176] The Vickers hardness measurement was performed, and the result was HV 2300-2600.

[0177] The friction coefficient VSNI was measured, and the result was 0.3-0.5.

[0178] The oxidation resistance temperature was measured, and the oxidation resistance temperature could reach 500-700°C.

[0179] The TCC (total of 60 knives) was measured according to EN ISO 8442-5, and the average result for the four samples was more than 2520 mm.

[0180] The ICP (first three knives) was measured according to EN ISO 8442-5, and the average result for the four samples was more than 178 mm.

[0181] The obtained film layer was golden in color, the total thickness of the composite film layer of the bonding layer and the wear-resistant layer was about 0.5-10 microns, and an electron micrograph illustrating the structure of the knife body substrate, the bonding layer, and the wear-resistant layer of such a product is shown in Figure 3. In Figure 3, the lowermost layer is the martensitic stainless steel substrate, followed by the bonding layer TiN layer and the wear-resistant layer TiN layer, which have the same material and thus cannot be clearly distinguished in the micrograph.

[0182] Preparation of a kitchen knife with a CrAlN-CrAlBN film system according to Example 3

[0183] A kitchen knife was prepared by the following steps. The preparation was performed four times to obtain four products of the same film system. The specific process parameters for each preparation were selected from the ranges given below. The four products were characterized by performance analysis.

[0184] The same steps (1) to (3) and (8) as in Example 1 were performed.

[0185] Prior to (8), (4) was performed with N2 gas being introduced at a pressure of 2-5 Pa. The arc of the CrAl target was turned on to initiate multi-arc ion plating, and a CrAlN layer was deposited by a high-current, low-voltage mode, at a current of 200-500 A, for a deposition time of 20-50 minutes, and at a deposition thickness of about 1-10 microns.

[0186] (5) N2 gas was maintained at a pressure of 2-5 Pa. The arc of the CrAlB target was turned on to initiate arc ion plating, and a CrAlBN layer was deposited. The current was 200-500 A, the deposition time was 30-70 minutes, and the deposition thickness was about 0.5-10 microns.

[0187] (6) N2 gas was maintained at a pressure of 2-5 Pa. The arc of the CrAl target was turned off, and a CrAlBN layer was deposited. The current was 200-500 A, the deposition time was 30-70 minutes, and the deposition thickness was about 1-10 microns.

[0188] The final composite coating of the first blade side surface had a bonding layer of CrAlN and a wear resistant layer of CrAlBN. The resulting kitchen knife was tested to have super high sharpness and high hardness, low friction coefficient, and oxidation resistance.

[0189] Vickers hardness measurements were performed, and the results were HV 3800-4500.

[0190] The friction coefficient VSNI was measured, and the results were 0.3-0.5.

[0191] The oxidation resistance temperature was measured, and the oxidation resistance temperature was up to 900-1200 °C.

[0192] TCC (total of 60 knives) was measured according to EN ISO 8442-5, and the average results for four samples were 2550 mm or more.

[0193] ICP (first three knives) was measured according to EN ISO 8442-5, and the average results for four samples were 171 mm or more.

[0194] The color of the obtained film layer is gray, and the total thickness of the composite film layer of the bonding layer and the wear-resistant layer is about 3-20 microns. An electron micrograph showing the structure of the knife body substrate, bonding layer and wear-resistant layer of such a product is shown in FIG. 4. In FIG. 4, the lowermost layer is the martensitic stainless steel substrate, followed by the bonding layer CrAlN layer and the two sub-layers of the wear-resistant layer CrAlBN layer. Note that the wear-resistant layer CrAlBN is formed in steps (5) and (6), and since the CrAl target is not used in step (6) after it is used in step (5), the portion formed in step (5) has a slightly higher Al content than the portion formed in step (6) although the overall element amount is the same, and thus is shown as the uppermost distinguishable two sub-layers in FIG. 4.

[0195] Preparation of a kitchen knife with a TiAlN film system

[0196] A kitchen knife was prepared by the following steps. The preparation was carried out four times to obtain four products with the same film system. The specific process parameters for each preparation were selected from the ranges given below. Performance analysis characterization was carried out on the four products.

[0197] The same steps (1) to (3) and (8) as in Example 1 were carried out.

[0198] Before (8), (4) was carried out to introduce N2 gas to maintain a pressure of 2-5 Pa. The multi-arc ion plating was started, the arc of the TiAl target was turned on, and the TiAlN layer was deposited by a high-current low-voltage mode, with a current of 200-500 A, a deposition time of 40-90 minutes, and a deposition thickness of about 1-10 microns. Thus, the bonding layer and the wear-resistant layer were directly formed and had the same material.

[0199] The bonding layer of the composite coating on the final first blade side surface was TiAlN, and the wear-resistant layer was also TiAlN. The obtained kitchen knife was tested to have super-high sharpness and high hardness, low friction coefficient, and oxidation resistance.

[0200] Vickers hardness measurement was carried out, and the result was HV3800-4200.

[0201] The friction coefficient VSNI was measured, and the result was 0.3-0.5.

[0202] The oxidation resistance temperature was measured, and the oxidation resistance temperature could reach 900-1100°C.

[0203] TCC (total of 60 knives) was measured according to EN ISO 8442-5, and the average result of the four samples was 2510 mm or more.

[0204] ICP (first three knives) was measured according to EN ISO 8442-5, and the average result of the four samples was 172 mm or more.

[0205] The color of the obtained film layer is blue-black, and the total thickness of the composite film layer of the bonding layer and the wear-resistant layer is about 1-10 microns. An electron micrograph showing the structure of the blade substrate, bonding layer and wear-resistant layer of such a product is shown in Figure 5. In Figure 5, the lowermost layer is the martensitic stainless steel substrate, followed by the bonding layer TiAlN layer and the wear-resistant layer TiAlN layer. Since the two materials are the same, they cannot be clearly distinguished in the micrograph.

[0206] Preparation of a kitchen knife with TiAlN-TiAlSiN and TiAlN alternating stack-TiSiN film system of Example 5

[0207] A kitchen knife was prepared by the following steps. The preparation was carried out four times to obtain four products with the same film system. The specific process parameters of each preparation were selected from the ranges given below. Performance analysis and characterization were carried out on the four products.

[0208] The same steps (1) to (3) and (8) as in Example 1 were carried out.

[0209] Before (8), (4) was carried out to introduce N2 gas to maintain a pressure of 2-5 Pa. The multi-arc ion plating was turned on, the arc of the TiAl target was turned on, and the TiAlN layer was deposited by high-current low-voltage mode, with a current of 200-500 A, a deposition time of 30-80 minutes, and a deposition thickness of about 0.5-10 microns.

[0210] (5) N2 gas was maintained at a pressure of 2-5 Pa. The arc of the TiSi target was turned on to add multi-arc ion plating, and the TiAlSiN layer was deposited. The current was 200-500 A, the deposition time was 20-60 minutes, and the deposition thickness was about 0.1-1 micron.

[0211] The steps (4)-(5) were repeated five more times, and in the repeated step (4), the deposition thickness was changed to about 0.1-1 micron.

[0212] (6) N2 gas was maintained at a pressure of 2-5 Pa. The arc of the TiAl target was turned off, and the TiSiN layer was deposited. The current was 200-500 A, the deposition time was 30-70 minutes, and the deposition thickness was about 0.2-10 microns.

[0213] The bonding layer of the composite coating on the final first blade side surface was TiAlN, the transition layer was an alternating stack of TiAlSiN and TiAlN, and the wear-resistant layer was TiSiN. The obtained kitchen knife was tested to have super-high sharpness and high hardness, low friction coefficient, and oxidation resistance.

[0214] Vickers hardness measurement was carried out, and the result was HV3800-4200.

[0215] The friction coefficient VSNI was measured and the result was 0.1-0.2.

[0216] The oxidation resistance temperature was measured and the oxidation resistance temperature was up to 900-1100℃.

[0217] The TCC (60 cuts) was measured according to EN ISO 8442-5 and the average result of four samples was more than 2530mm.

[0218] The ICP (first three cuts) was measured according to EN ISO 8442-5 and the average result of four samples was more than 178mm.

[0219] The color of the obtained film layer was coffee color, and the total thickness of the combined film layer of the bonding layer and the wear-resistant layer was about 1-20 microns. An electron micrograph illustrating the structure of the knife body substrate, the bonding layer and the wear-resistant layer of such products is shown in Figure 6. In Figure 6, the lowermost layer is the martensitic stainless steel substrate, followed by the bonding layer TiAlN layer, the transition layer TiAlSiN and TiAlN alternating stack layer, and the wear-resistant layer TiSiN layer.

[0220] Preparation of a kitchen knife with CrAlN-CrAlTiSiN-CrAlSiN film system

[0221] The kitchen knife was prepared by the following steps. The preparation was carried out four times to obtain four products with the same film system. The specific process parameters of each preparation were selected from the ranges given below. Performance analysis and characterization were carried out on the four products.

[0222] The same steps (1) to (3) and (8) as in Example 1 were carried out.

[0223] Before (8), (4) N2 gas was introduced and the pressure was maintained at 2-5 Pa. The arc of the CrAl target was turned on to add multi-arc ion plating, and the CrAlN layer was deposited by high-current low-voltage mode, the current was 200-500 A, the deposition time was 30-70 minutes, and the deposition thickness was about 0.2-10 microns.

[0224] (5) N2 gas was maintained and the pressure was maintained at 2-5 Pa. The arc of the TiSi target was turned on to add multi-arc ion plating, and the CrAlTiSiN layer was deposited. The current was 200-500 A, the deposition time was 30-70 minutes, and the deposition thickness was about 0.1-10 microns.

[0225] (6) N2 gas was maintained and the pressure was maintained at 2-5 Pa. The arc of the TiSi target was turned off and the arc of the Si target was turned on to add multi-arc ion plating, and the CrAlSiN layer was deposited. The current was 200-500 A, the deposition time was 30-70 minutes, and the deposition thickness was about 0.5-10 microns.

[0226] The binding layer of the final first blade side surface composite coating is CrAlN, the transition layer is CrAlTiSiN, and the wear resistant layer is CrAlSiN. The resulting kitchen knife is tested to have super high sharpness and high hardness, low friction coefficient, and oxidation resistance.

[0227] Vickers hardness measurement is performed, and the result is HV3800-4000.

[0228] The friction coefficient VSNI is measured, and the result is 0.3-0.5.

[0229] The oxidation resistance temperature is measured, and the oxidation resistance temperature can reach 800-1100℃.

[0230] TCC (total of 60 knives) is measured according to EN ISO 8442-5, and the average result of four samples is 2520 mm or more.

[0231] ICP (first three knives) is measured according to EN ISO 8442-5, and the average result of four samples is 177 mm or more.

[0232] The resulting film layer color is bronze, and the total thickness of the composite film layer of the binding layer and the wear resistant layer is about 1-10 microns. An electron micrograph illustrating the structure of the knife body substrate, the binding layer, and the wear resistant layer of such a product is shown in FIG. 7. In FIG. 7, the lowermost layer is the martensitic stainless steel substrate, followed by the binding layer CrAlN layer, the transition layer CrAlTiSiN layer, and the wear resistant layer CrAlSiN layer, respectively.

[0233] Preparation of a kitchen knife with a CrAlN-CrAlTiSiN-TiSiN-TiSiC film system

[0234] A kitchen knife is prepared by the following steps. The preparation is performed four times to obtain four products with the same film system. The specific process parameters for each preparation are selected from the ranges given below. Performance analysis and characterization are performed on the four products.

[0235] The same steps (1) to (3) and (8) as in Example 1 are performed.

[0236] Before (8), (4) is performed to introduce N2 gas to maintain a pressure of 2-5 Pa. The multi-arc ion plating is turned on, the arc of the CrAl target is turned on, and the CrAlN layer is deposited by a high current and low voltage mode, with a current of 200-500 A, a deposition time of 40-90 minutes, and a deposition thickness of about 1-10 microns.

[0237] (5) Keep N2gas flowing, and maintain the pressure at 2-5 Pa. Turn on the multi-arc ion plating, and turn on the arc of the TiSi target to add multi-arc ion plating. Deposit a CrAlTiSiN layer, with a current of 200-500 A, a deposition time of 40-90 minutes, and a deposition thickness of about 0.1-10 microns.

[0238] (6) Keep N2gas flowing, and maintain the pressure at 2-5 Pa. Turn off the arc of the CrAl target, and deposit a TiSiN layer. The current is 200-500 A, the deposition time is 40-90 minutes, and the deposition thickness is about 0.5-10 microns.

[0239] (7) Turn off the N2gas, and turn on C2H2gas, and maintain the pressure at 2-5 Pa, and deposit a TiSiC layer. The current is 200-500 A, the deposition time is 40-90 minutes, and the deposition thickness is about 1-10 microns. The total amount of C2H2gas is 500-1000 ml.

[0240] The final composite coating of the first blade side surface has a bonding layer of CrAlN, a transition layer of CrAlTiSiN and TiSiN from inside to outside, and a wear-resistant layer of TiSiC. The obtained kitchen knife has super-high sharpness and high hardness, low friction coefficient, and oxidation resistance.

[0241] The Vickers hardness measurement results are HV3500-4000.

[0242] The friction coefficient VSNI measurement results are 0.1-0.3.

[0243] The oxidation resistance temperature is up to 1000-1100°C.

[0244] The TCC (total of 60 knives) is measured according to EN ISO 8442-5, and the average result of four samples is more than 2510 mm.

[0245] The ICP (first three knives) is measured according to EN ISO 8442-5, and the average result of four samples is more than 183 mm.

[0246] The obtained film layer is red-bronze in color, and the total thickness of the composite film layer of the bonding layer and the wear-resistant layer is about 3-20 microns. An electron micrograph illustrating the structure of the knife body substrate, the bonding layer, and the wear-resistant layer of such a product is shown in FIG. 8. In FIG. 8, the lowermost layer is the martensitic stainless steel substrate, followed by the bonding layer CrAl layer, the transition layer CrAlTiSiN layer, the TiSiN layer, and the wear-resistant layer TiSiC layer, respectively.

[0247] Preparation of a kitchen knife with a CrN-CrNC film system

[0248] A kitchen knife was prepared by the following steps. The preparation was performed four times to obtain four products of the same film system. The specific process parameters for each preparation were selected from the ranges given below. The four products were characterized by performance analysis.

[0249] The same steps (1) to (3) and (8) as in Example 1 were performed.

[0250] Prior to (8), (4) was performed to introduce N2 gas to maintain a pressure of 2-5 Pa. The arc of the Cr target was opened to start the multi-arc ion plating, and the CrN layer was deposited by a high-current low-voltage mode, with a current of 200-500 A, a deposition time of 40-80 minutes, and a deposition thickness of about 1-10 microns.

[0251] (5) was performed to introduce C2H2 gas to maintain a pressure of 2-5 Pa, and the CrNC layer was deposited. The current was 200-500 A, the deposition time was 40-90 minutes, and the deposition thickness was about 1-10 microns. The total amount of C2H2 gas flow was 500-1000 milliliters.

[0252] The final composite coating of the first blade side surface had a bonding layer of CrN and a wear-resistant layer of CrNC. The resulting kitchen knife was tested to have super-high sharpness and high hardness, low friction coefficient, and oxidation resistance.

[0253] Vickers hardness measurement was performed, with a result of HV 1500-2500.

[0254] The friction coefficient VSNI was measured, with a result of 0.1-0.2,

[0255] The oxidation resistance temperature was measured, with an oxidation resistance temperature of up to 500-700°C.

[0256] The wear resistance test cumulative cutting test (TCC) thickness was measured, with an average result of 2510 millimeters or more for the four samples.

[0257] The kitchen knife sharpness ICP three-knife test was performed, with an average result of 173 millimeters or more for the four samples.

[0258] The resulting film layer was black in color, with a total thickness of the composite film layer of the bonding layer and the wear-resistant layer of about 2-20 microns. An electron micrograph illustrating the structure of the knife body substrate, bonding layer, and wear-resistant layer of such a product is shown in FIG. 9. In FIG. 9, the lowermost layer is the martensitic stainless steel substrate, followed by the bonding layer CrN layer and the wear-resistant layer CrNC layer, respectively.

[0259] Preparation of a kitchen knife with a TiAlN-TiAlSiN-TiSiN-TiB2 film system

[0260] A kitchen knife was prepared by the following steps. The preparation was performed four times to obtain four products of the same film system. The specific process parameters for each preparation were selected from the ranges given below. The four products were characterized by performance analysis.

[0261] The same steps (1) to (7) as in Example 1 were performed, except that in step (1), after cleaning, the surface of the blade side was directly shielded as a mask using a copper foil jig installation shielding method, and after (7) instead of step (8) step (9) was performed:

[0262] (9) The copper foil was removed from the blade body substrate by disassembling the copper foil jig method to expose the second blade side surface.

[0263] Thus, a kitchen knife similar to Example 1 was obtained, which had a performance test result of 2500 mm or more.

[0264] Preparation of a kitchen knife having a decorative layer on the second blade side surface of Example 10

[0265] A kitchen knife was prepared by the following steps. The preparation was performed four times to obtain four products of the same film system. The specific process parameters for each preparation were selected from the ranges given below. The four products were characterized by performance analysis.

[0266] The same steps (1) to (8) as in Example 2 were performed, after which a decorative layer was formed on the exposed second blade side surface by a general arc ion plating or magnetron sputtering method to deposit TiN. The color of the decorative layer was gold.

[0267] The resulting decorative layer had a good appearance. It was tested that the hardness of the decorative layer material TiN on the second blade side surface was lower compared to the wear-resistant layer material TiN on the first blade side surface. Due to the low hardness, it did not affect self-sharpening in use despite the similar elemental composition of the coating. This lower hardness is attributed to the absence of the coating film method of the present disclosure.

[0268] The test results showed that the additional decorative layer did not affect the achievement of extremely high sharpness.

[0269] Comparative Example 1

[0270] A kitchen knife was prepared in a similar manner to Example 2, but without the ion etching step. After cleaning the blade body substrate of the kitchen knife with ultrasonic waves, it was subjected to 5 minutes of plasma cleaning in a separate plasma cleaning device, after which it was removed from the plasma cleaning device and transferred to an arc ion plating chamber. In this chamber, deposition of a TiN film was performed using arc ion plating, with a deposition thickness of less than 2 microns.

[0271] The resulting kitchen knife had a gold appearance. However, a portion of it developed cracks in the decorative film layer after being left for several days.

[0272] The remaining kitchen knives with decorative film plating but not chipped were subjected to sharpness test, and the sharpness level was far lower than that of the present disclosure.

[0273] In addition, comparison of the sharpness of the embodiments of the present disclosure with that of the example self-sharpening knife disclosed in CN1642697A shows that both the initial sharpness and the sharpness retention of the present disclosure are far higher than that of the self-sharpening knife. Without being bound by any theory, such high improvement in sharpness comes from the arc ion plating deposition method of the present disclosure and the ion etching step in cooperation therewith.

[0274] The results of the above embodiments all show that the method of the present disclosure can achieve kitchen knives with extremely excellent initial sharpness and sharpness retention, and these kitchen knives also have excellent wear resistance, excellent appearance, and sufficiently high high-temperature resistance and oxidation resistance. Comparison with the comparative examples shows that the method of the present disclosure can achieve unexpectedly large improvement in sharpness compared with arc ion plating without ion etching in the same chamber as the present disclosure.

[0275] Figs. 10a-10c show electron micrographs of the edge structure of one embodiment of the present disclosure. Among them, Fig. 10a shows the overall situation of the edge. Face 1 is the first blade side surface, on which there is a hard film layer deposited by arc ion plating. Face 2 corresponds to the second blade side surface, on which there is no coating. Fig. 10b shows an enlarged image of the boxed area of face 1, showing the coating formed on the first blade side surface by arc ion plating, and it can be seen that it includes a bonding layer and a wear-resistant layer (the coating is rotated to the top for easy observation). Fig. 10c shows an enlarged image of the boxed area of face 2, showing that no coating is formed on the second blade side surface.

[0276] Fig. 11 shows a photograph of the appearance of a real knife body, in which the wear-resistant layer of the edge portion of the second blade side surface (face 2) has been ground off and shows bright reflection, while the first blade side surface (face 1) remains as deposited.

[0277] Similar tests were also conducted on some other types of kitchen knife body substrates, and when the substrate is selected from other martensitic stainless steel, die steel, heat-resistant steel, hard alloy and metal ceramic, the method of the present disclosure can significantly improve the sharpness. However, for ceramic knife body substrates, the method of the present disclosure has no obvious effect. Examples of preferred substrates include martensitic stainless steel 30Cr13, 40Cr13, 50Cr15MoV, 70Cr17MoV, 80Cr14MoV, 90Cr18MoV, AUS8, AUS10, VG10, M390 and 17-4PH; die steel SKD 11, SKD 61, Cr12MoV, DC53 and DAC55; heat-resistant steel 4Cr9Si2. The most preferred martensitic stainless steel is 50Cr15MoV, 70Cr17MoV, 80Cr14MoV, 90Cr18MoV, AUS10, VG10, M390 and 17-4PH.

[0278] The above merely illustrates the specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present disclosure, which shall be covered within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.

Claims

1. A method of preparing a kitchen knife using arc ion plating, wherein, The method comprises: placing a kitchen knife body substrate having a blade portion in an arc ion plating chamber provided with an arc generating device, the surfaces on both sides of the blade portion being a first blade side surface and a second blade side surface respectively; subjecting the first blade side surface to ion etching treatment; depositing a bonding layer material on the first blade side surface subjected to ion etching treatment using arc ion plating; and depositing a wear-resistant layer material on the deposited bonding layer material using arc ion plating, or sequentially depositing one or more transition layer materials on the deposited bonding layer material and then depositing a wear-resistant layer material, and not depositing the wear-resistant layer material on the second blade side surface, or removing the wear-resistant layer material after it is deposited on the second blade side surface.

2. The method of claim 1, wherein, The ion etching treatment of the first blade side surface comprises: forming a plasma from a process gas introduced into the arc ion plating chamber by arc discharge generated using the arc generating device; and etching the first blade side surface using the plasma.

3. The method of claim 2, wherein, The conditions for etching the first blade side surface using the plasma are that the process gas is argon and hydrogen, the working temperature is 300-550°C, and the duration is 20-100 minutes.

4. The method of claim 1, wherein, The ion etching treatment generates pits on the first blade side surface with a diameter of 0.01-0.05 microns, a depth of 0.01-0.05 microns, and a density of 10-100 per square micron.

5. The method of claim 1, wherein, The kitchen knife body substrate having a blade portion is selected from martensitic stainless steel, die steel, and heat-resistant steel, and the surface roughness of the first blade side surface before the ion etching is 0.5-1 microns.

6. The method of claim 1, wherein, The arc ion plating is multi-arc ion plating.

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

8. The method of claim 1, wherein, The total thickness of the bonding layer material and the wear-resistant layer material is 0.5-20 microns.

9. The method of claim 1, wherein, After the method ends, the second blade side surface is bare.

10. The method of claim 9, wherein, In the ion etching treatment of the first blade side surface and the deposition of the bonding layer material and the wear-resistant layer material, a mask is used to shield the second blade side surface, so that the wear-resistant layer material is not deposited on the second blade side surface.

11. The method of claim 9, wherein, After the same treatment as the first blade side surface is performed on the second blade side surface, the wear-resistant layer material is removed, so that the wear-resistant layer material is removed after it is deposited on the second blade side surface.

12. The method of claim 11, wherein, The wear-resistant layer material is removed by grinding in a way of gradually increasing the fineness of the grinding medium.

13. The method of claim 12, wherein, The blade portion of the kitchen knife body substrate is formed by grinding with a numerical control blade opening machine, and the removal of the wear-resistant layer material is performed with the same numerical control blade opening machine using the same machine settings.

14. The method of claim 1, wherein, The bonding layer is TiAlN, the transition layer is TiAlSiN and TiSiN from inside to outside, and the wear-resistant layer is TiB2; or The bonding layer is TiN, and the wear-resistant layer is TiN; or The bonding layer is CrAlN, and the wear-resistant layer is CrAlBN; or The bonding layer is TiAlN, and the wear-resistant layer is TiAlN; or the bonding layer is TiAlN, the transition layer is an alternately stacked body of TiAlSiN and TiAlN alternately stacked 2-8 times in thickness, and the wear resistant layer is TiSiN; or the bonding layer is CrAlN, the transition layer is CrAlTiSiN, and the wear resistant layer is CrAlSiN; or the bonding layer is CrAlN, the transition layer is CrAlTiSiN and TiSiN from inside to outside, and the wear resistant layer is TiSiC; or the bonding layer is CrN, and the wear resistant layer is CrNC.

15. The method of claim 1, wherein, a decorative layer is formed on the second blade side surface, wherein the hardness of the decorative layer is lower than the hardness of the wear resistant layer.

16. The method of claim 15, wherein, the decorative layer is TiN or CrN 17. A kitchen knife prepared by the method according to any one of claims 1-16.

18. The kitchen knife of claim 17, wherein, The ICP of the kitchen knife is 170 mm or more, and the TCC for 60 cutting cycles is 2500 mm or more, measured according to EN ISO 8442-5.2005.

19. A kitchen knife, wherein, The kitchen knife comprises: a kitchen knife body substrate having a blade portion, the surfaces on both sides of the blade portion being a first blade side surface and a second blade side surface, respectively, a bonding layer material on the first blade side surface of the kitchen knife body substrate, and a wear resistant layer material on the bonding layer material, or one or more transition layer materials in sequence on the bonding layer material and a wear resistant layer material on the one or more transition layer materials, wherein the hardness of each layer gradually increases from the bonding layer to the wear resistant layer, the second blade side surface is free of the wear resistant layer material, wherein the ICP of the kitchen knife is 170 mm or more, and the TCC for 60 cutting cycles is 2500 mm or more, measured according to EN ISO 8442-5.2005.

20. The kitchen knife according to claim 19, wherein the bonding layer is TiAlN with a thickness of 0.5-10 microns, the transition layer is TiAlSiN with a thickness of 0.5-10 microns and TiSiN with a thickness of 0.5-10 microns from inside to outside, and the wear resistant layer is TiB2 with a thickness of 0.5-10 microns; or the bonding layer is TiN, and the wear resistant layer is TiN with a total thickness of 0.5-10 microns; or the bonding layer is CrAlN with a thickness of 1-10 microns, and the wear resistant layer is CrAlBN with a thickness of 3-20 microns; or the bonding layer is TiAlN, and the wear resistant layer is TiAlN with a total thickness of 1-10 microns; or the bonding layer is TiAlN with a thickness of 0.5-10 microns, the transition layer is an alternately stacked body of TiAlSiN with a thickness of 0.1-1 micron and TiAlN with a thickness of 0.1-1 micron alternately stacked 2-8 times, and the wear resistant layer is TiSiN with a thickness of 0.2-10 microns; or the bonding layer is CrAlN with a thickness of 0.2-10 microns, the transition layer is CrAlTiSiN with a thickness of 0.1-10 microns, and the wear resistant layer is CrAlSiN with a thickness of 0.5-10 microns; or the bonding layer is CrAlN with a thickness of 0.2-10 microns, the transition layer is CrAlTiSiN with a thickness of 0.1-10 microns, and the wear resistant layer is CrAlSiN with a thickness of 0.5-10 microns; or The binding layer is CrAlN with a thickness of 1-10 microns, the transition layer is sequentially CrAlTiSiN with a thickness of 0.1-10 microns and TiSiN with a thickness of 0.5-10 microns from inside to outside, and the wear-resistant layer is TiSiC with a thickness of 1-10 microns; or The binding layer is CrN with a thickness of 1-10 microns, and the wear-resistant layer is CrNC with a thickness of 1-10 microns.

21. The kitchen knife of claim 19, wherein, The binding layer material fills the pits on the first blade side surface, the pits have a diameter of 0.01-0.05 microns, a depth of 0.01-0.05 microns, and a density of 10-100 per square microns.

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