A high-wear-resistance composite coating, kitchen knife and preparation method thereof

Abstract

The application discloses a high-wear-resistance composite coating, a kitchen knife and a preparation method of the kitchen knife. The high-wear-resistance composite coating is formed on the surface of the base body of the kitchen knife through arc ion plating. The high-wear-resistance composite coating comprises a bonding layer, a wear-resistant layer and a sealing layer which are sequentially formed. A first gradient transition region is formed between the bonding layer and the wear-resistant layer, and a second gradient transition region is formed between the wear-resistant layer and the sealing layer. The wear-resistant layer is an AlCrTiZrSiN nitride structure formed by combining aluminum, chromium, titanium, zirconium, silicon and nitrogen. The wear-resistant layer comprises a nanocrystalline nitride phase and an amorphous silicon nitride phase. The application realizes the synergistic improvement of the high hardness, high wear resistance and high bonding strength of the surface of the kitchen knife by constructing a gradient composite coating structure and utilizing a nanocrystal-amorphous composite strengthening mechanism.

Description

Technical Field

[0001] This invention relates to the field of composite coating technology, and in particular to a high wear-resistant composite coating, a kitchen knife, and a method for preparing the same. Background Technology

[0002] Kitchen knives are cutting tools used in daily life and the catering industry for processing food such as cutting, slicing, and chopping. Kitchen knives are usually made of metal materials such as stainless steel and high carbon steel, and are manufactured through processes such as forging, heat treatment, and sharpening.

[0003] For high-quality kitchen knives, hardness, wear resistance, and food contact safety are important indicators for evaluating their quality. However, due to the inherent structural characteristics of the metal matrix material, it is difficult to simultaneously achieve high hardness and excellent wear resistance simply by optimizing the matrix material composition and traditional heat treatment processes.

[0004] To improve the performance of kitchen knives, current technologies typically employ methods such as increasing the alloying degree of the steel or using high-performance special steels as the knife base. However, high-alloy steels generally present challenges such as higher raw material costs, increased processing difficulty, and complex manufacturing processes, which limit the cost of kitchen knife products.

[0005] Therefore, there is a need to provide other technical approaches to improve the performance of kitchen knives while controlling production costs. Summary of the Invention

[0006] To address the technical problems existing in the prior art, the present invention aims to provide a high wear-resistant composite coating, a kitchen knife, and a method for preparing the same.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] In a first aspect, this application provides a high wear-resistant composite coating for use in cutting tools. The high wear-resistant composite coating is formed on the substrate surface of the cutting tool by arc ion plating.

[0009] The high wear-resistant composite coating includes a bonding layer, a wear-resistant layer and a sealing layer formed sequentially, with a first gradient transition region between the bonding layer and the wear-resistant layer, and a second gradient transition region between the wear-resistant layer and the sealing layer.

[0010] The wear-resistant layer is an AlCrTiZrSiN nitride structure formed by a combination of aluminum, chromium, titanium, zirconium, silicon and nitrogen. The wear-resistant layer includes a nanocrystalline nitride phase and an amorphous silicon nitride phase.

[0011] In one embodiment, the wear-resistant layer comprises the following elements by atomic percentage: 35%–45% nitrogen, 18%–22% aluminum, 15%–18% chromium, 10%–12% titanium, 8%–10% zirconium and 3%–5% silicon.

[0012] In one embodiment, the nanocrystalline nitride phase in the wear-resistant layer is a (AlCrTiZr)N nanocrystalline structure, and the amorphous silicon nitride phase is a SiNx amorphous structure; the amorphous silicon nitride phase is distributed in the grain boundary region of the nanocrystalline nitride phase.

[0013] In one embodiment, the bonding layer comprises, by atomic percentage, the following elements: 30%–35% aluminum, 22%–27% chromium, 15%–20% titanium, 10%–15% zirconium, and 5%–8% silicon.

[0014] In one embodiment, the nitrogen content in the first gradient transition region gradually increases along the direction away from the substrate surface of the tool, so that the bonding layer gradually changes from an AlCrTiZrSi structure to an AlCrTiZrSiN nitride structure.

[0015] In one embodiment, the sealing layer comprises the following elements by atomic percentage: 18%–22% aluminum, 15%–18% chromium, 10%–12% titanium, 8%–10% zirconium, 3%–5% silicon, 30%–35% nitrogen and 8%–15% oxygen.

[0016] In one embodiment, the oxygen content in the second gradient transition region gradually increases along the direction away from the tool and the nitrogen content gradually decreases along the direction away from the tool, so that the wear-resistant layer gradually changes from an AlCrTiZrSiN nitride structure to an AlCrTiZrSiON oxide nitride structure.

[0017] Secondly, this application provides a kitchen knife, the base surface of which is provided with a high wear-resistant composite coating as described in the first aspect.

[0018] In one embodiment, the thickness of the high wear-resistant composite coating is 3μm to 5μm. The high wear-resistant composite coating includes a bonding layer, a wear-resistant layer and a sealing layer formed sequentially. A first gradient transition region is formed between the bonding layer and the wear-resistant layer, and a second gradient transition region is formed between the wear-resistant layer and the sealing layer.

[0019] The bonding layer contains the following elements by atomic percentage: aluminum 30%–35%, chromium 22%–27%, titanium 15%–20%, zirconium 10%–15%, and silicon 5%–8%;

[0020] The wear-resistant layer contains the following elements by atomic percentage: nitrogen 35%–45%, aluminum 18%–22%, chromium 15%–18%, titanium 10%–12%, zirconium 8%–10%, and silicon 3%–5%;

[0021] The sealing layer contains the following elements by atomic percentage: 18%–22% aluminum, 15%–18% chromium, 10%–12% titanium, 8%–10% zirconium, 3%–5% silicon, 30%–35% nitrogen and 8%–15% oxygen.

[0022] Thirdly, this application provides a method for preparing a kitchen knife according to the second aspect, the method comprising:

[0023] Perform surface pretreatment on the blade substrate of the kitchen knife;

[0024] The pretreated tool substrate is placed in the vacuum chamber of the arc ion plating equipment, and an AlCrTiZrSi alloy target is used as the deposition target. Arc ion plating is performed in an inert gas environment to form a bonding layer on the surface of the tool substrate.

[0025] After the bonding layer is deposited, nitrogen gas is introduced into the vacuum chamber to allow nitrogen to gradually participate in the deposition process. The nitrogen content on the surface of the bonding layer is gradually increased by adjusting the nitrogen flow rate to form the first gradient transition region from AlCrTiZrSi structure to AlCrTiZrSiN structure. Then, the deposition continues to form the wear-resistant layer.

[0026] After the wear-resistant layer is deposited, oxygen is introduced into the vacuum chamber, and the ratio of nitrogen to oxygen is adjusted so that the oxygen content gradually increases in the direction away from the tool substrate surface, forming a second gradient transition region from AlCrTiZrSiN nitride structure to AlCrTiZrSiON oxide nitride structure; deposition continues to form a sealing layer.

[0027] After the sealing layer is deposited, the kitchen knife is cooled to obtain a kitchen knife with a highly wear-resistant composite coating on the surface.

[0028] Compared with the prior art, the present invention has at least the following beneficial effects:

[0029] This application provides a high-wear-resistant composite coating for cutting tools, which is formed on the substrate surface of the tool by arc ion plating. The high-wear-resistant composite coating includes a bonding layer, a wear-resistant layer, and a sealing layer formed sequentially. A first gradient transition region is formed between the bonding layer and the wear-resistant layer, and a second gradient transition region is formed between the wear-resistant layer and the sealing layer. The wear-resistant layer is an AlCrTiZrSiN nitride structure formed by a combination of aluminum, chromium, titanium, zirconium, silicon, and nitrogen, and includes a nanocrystalline nitride phase and an amorphous silicon nitride phase.

[0030] This application utilizes arc ion plating technology to form a highly wear-resistant composite coating on the surface of a knife substrate, comprising a bonding layer, a wear-resistant layer, and a sealing layer. A first gradient transition region and a second gradient transition region achieve a continuous transition between different functional layers. The bonding layer enhances the bonding strength between the coating and the substrate and alleviates interfacial stress. The wear-resistant layer, through the synergistic effect of multiple principal elements (aluminum, chromium, titanium, zirconium, silicon, and nitrogen), forms a composite structure of nanocrystalline nitride and amorphous silicon nitride phases, improving both the coating's hardness and wear resistance while enhancing its crack resistance. The sealing layer improves the density and corrosion resistance of the coating surface. This gradient composite structure design allows the kitchen knife to maintain high sharpness retention while improving its wear resistance, impact resistance, and long-term service stability. Attached Figure Description

[0031] Figure 1 This is a photograph of the actual coating sample.

[0032] Figure 2 The SEM image shows the cross-sectional morphology of the coating. Detailed Implementation

[0033] In this invention, numerical ranges are involved. Unless otherwise specified, the numerical ranges are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe features or characteristics, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are included.

[0034] This application provides a high wear-resistant composite coating for cutting tools. The high wear-resistant composite coating is formed on the surface of the tool substrate by an arc ion plating (AIP) process, which is used to improve the wear resistance, impact resistance and bonding stability between the coating and the substrate of the cutting tool during the cutting process.

[0035] In some embodiments, the knife base may be a stainless steel kitchen knife, a high-carbon steel kitchen knife, or other metal-based knives suitable for surface strengthening treatment.

[0036] The high wear-resistant composite coating in this embodiment of the invention includes a bonding layer, a wear-resistant layer, and a sealing layer formed sequentially on the surface of the tool substrate.

[0037] The bonding layer is disposed between the tool substrate and the wear-resistant layer to improve the interfacial bonding performance between the tool substrate and the wear-resistant layer, and to reduce the interfacial stress concentration problem caused by the difference in physical properties between the substrate material and the wear-resistant layer material. In some embodiments, the bonding layer may be a metal layer, a metal alloy layer, or a metal nitride layer that has good bonding performance with the tool substrate, such as at least one of Ti layer, Cr layer, Zr layer, TiN layer, and CrN layer.

[0038] The wear-resistant layer is disposed on the side of the bonding layer away from the tool substrate to provide primary wear protection. In some embodiments, the wear-resistant layer may be a hard coating material with high hardness, high thermal stability, and good oxidation resistance, such as transition metal nitrides, transition metal carbonitrides, transition metal borides, or multi-element composite nitrides or carbonitrides containing elements such as transition metal nitrides or transition metal carbonitrides.

[0039] A sealing layer is disposed on the side of the wear-resistant layer away from the tool substrate. It is used to seal the microporous structure on the surface of the wear-resistant layer, reduce the erosion of the wear-resistant layer by the external environmental medium, and improve the friction performance of the composite coating surface. In some embodiments, the sealing layer may be a highly dense metal nitride layer, carbide layer, carbonitride layer, or a composite functional layer containing low-friction components.

[0040] Furthermore, the present invention improves the performance matching relationship between different material layers by setting a gradient transition region between adjacent functional layers.

[0041] Specifically, a first gradient transition region is formed between the bonding layer and the wear-resistant layer. The constituent elements, crystal structure and mechanical properties of the first gradient transition region gradually change along the direction away from the tool substrate, so that there is no obvious material abrupt interface between the bonding layer and the wear-resistant layer, thereby reducing the residual stress at the interface and improving the bonding strength between the wear-resistant layer and the tool substrate.

[0042] In some embodiments, the first gradient transition region can be formed by gradually adjusting the target current, reactive gas ratio, or deposition parameters during the arc ion plating process, so that the main elements in the bonding layer gradually transition to the main elements in the wear-resistant layer. For example, when the bonding layer is a Ti layer and the wear-resistant layer is a TiAlN layer, the Ti layer can be gradually transitioned to the TiAlN wear-resistant layer by gradually increasing the Al content.

[0043] Furthermore, a second gradient transition region is formed between the wear-resistant layer and the sealing layer. The second gradient transition region is used to alleviate the interfacial stress caused by the difference in hardness, elastic modulus and thermal expansion coefficient between the wear-resistant layer and the sealing layer, thereby improving the bonding stability between the sealing layer and the wear-resistant layer.

[0044] In some specific examples, the second gradient transition region can be formed by gradually changing the proportions of metallic elements, non-metallic elements, and reactive gases during the deposition process, so that the crystal structure of the wear-resistant layer gradually transforms into a closed layer structure.

[0045] Furthermore, when the present invention prepares the above-mentioned high wear-resistant composite coating by arc ion plating, multiple targets can work together or different targets can be turned on in sequence to continuously deposit and form the bonding layer, wear-resistant layer, sealing layer and corresponding gradient transition region.

[0046] In some embodiments, the arc ion plating process includes: installing a pre-treated tool substrate in a coating equipment, evacuating the vacuum chamber and heating it to a preset temperature; then introducing an inert gas for ion cleaning; and after cleaning, sequentially depositing a bonding layer, a wear-resistant layer, and a sealing layer in an environment containing nitrogen, argon, or other reactive gases.

[0047] Through the above structural design, the high wear-resistant composite coating provided by the present invention adopts a multi-layer composite structure of "bonding layer - gradient transition region - wear-resistant layer - gradient transition region - sealing layer", which makes the coating interior form a continuously changing material system, avoiding stress concentration and peeling problems caused by obvious interfaces between different functional layers in the composite coating; at the same time, the wear-resistant layer provides high hardness and wear-resistant protection, and the sealing layer improves surface stability and friction performance, thereby improving the product performance of the cutting tool.

[0048] In one specific embodiment, the wear-resistant layer adopts an AlCrTiZrSiN nitride structure composed of aluminum (Al), chromium (Cr), titanium (Ti), zirconium (Zr), silicon (Si) and nitrogen (N), forming a nanocomposite structure with high hardness, high wear resistance and good thermal stability through the synergistic effect between the elements.

[0049] Specifically, the AlCrTiZrSiN wear-resistant layer includes a nanocrystalline nitride phase and an amorphous silicon nitride phase. The nanocrystalline nitride phase serves as the main load-bearing structure of the wear-resistant layer, providing the coating with high hardness and resistance to plastic deformation. The amorphous silicon nitride phase is distributed in the grain boundary region of the nanocrystalline nitride phase, which hinders the growth of nanocrystals and improves the internal structural stability of the coating.

[0050] In some embodiments, the nanocrystalline nitride phase is a (AlCrTiZr)N nanocrystalline structure, where aluminum, chromium, titanium, and zirconium elements coexist in the nitride lattice to form a multi-element solid solution nitride phase. Due to the different atomic sizes and electronic structures of Al, Cr, Ti, and Zr, the (AlCrTiZr)N nanocrystalline structure formed by multiple metal elements can produce a multi-element solid solution strengthening effect, increasing the degree of lattice distortion and thus enhancing the hardness and wear resistance of the wear-resistant layer.

[0051] Furthermore, the amorphous silicon nitride phase is a SiNx amorphous structure, wherein the SiNx amorphous structure is distributed in the grain boundary region of the (AlCrTiZr)N nanocrystalline structure, forming a nanocrystalline / amorphous composite structure.

[0052] In some specific examples, during the deposition of the AlCrTiZrSiN wear-resistant layer, silicon elements form an amorphous SiNx phase under the action of nitriding reaction. Since SiNx and (AlCrTiZr)N nanocrystalline structures have different crystal structures, the SiNx amorphous phase preferentially accumulates at the nanocrystalline grain boundary positions and coats the periphery of the nanocrystalline particles, thereby forming a nanocomposite structure composed of nanocrystalline nitride phase and amorphous silicon nitride phase.

[0053] Specifically, the SiNx amorphous phase can, on the one hand, suppress the abnormal growth of (AlCrTiZr)N nanocrystalline particles during the deposition process and high-temperature service, so that the wear-resistant layer maintains a nanoscale grain structure; on the other hand, the amorphous phase can fill grain boundary defects, reduce crack propagation along grain boundaries, and improve the toughness and impact resistance of the wear-resistant layer.

[0054] Furthermore, since the multi-component nitride nanocrystalline phase formed by AlCrTiZr elements has high bonding strength and thermal stability, while the SiNx amorphous phase has good structural stability, the AlCrTiZrSiN wear-resistant layer has both high hardness and high wear resistance through the synergistic effect between the nanocrystalline nitride phase and the amorphous silicon nitride phase.

[0055] Furthermore, the AlCrTiZrSiN wear-resistant layer can be formed by arc ion plating. During the deposition process, a multi-element alloy target containing Al, Cr, Ti, Zr, and Si elements can be used. Under a nitrogen-containing atmosphere, by adjusting the target composition, nitrogen flow rate, substrate bias voltage, deposition temperature, and deposition time, aluminum, chromium, titanium, and zirconium elements can form (AlCrTiZr)N nanocrystalline nitride phases, while silicon elements can form SiNx amorphous phases. During the deposition process, the SiNx amorphous phases are induced to segregate towards the nanocrystalline grain boundary regions.

[0056] In some specific examples, when the wear-resistant layer is subjected to frictional loads generated during the cutting process of a kitchen knife, the (AlCrTiZr)N nanocrystalline structure can withstand the main mechanical loads and reduce the wear of the material on the blade surface; at the same time, the SiNx amorphous structure distributed in the grain boundary region can alleviate local stress concentration through its own low shear resistance, reduce crack propagation along the grain boundary, thereby improving the impact resistance and spalling resistance of the wear-resistant layer.

[0057] Through the above structural design, when the AlCrTiZrSiN wear-resistant layer in this embodiment is applied to the surface of a kitchen knife, the (AlCrTiZr)N nanocrystalline structure provides high hardness and high wear resistance, while the SiNx amorphous structure improves the coating toughness and interface stability, enabling the kitchen knife to maintain high blade sharpness and service life during long-term food cutting.

[0058] In one specific embodiment, the wear-resistant layer has an AlCrTiZrSiN nitride structure, and the wear-resistant layer contains the following elements by atomic percentage: nitrogen (N) 35%–45%, aluminum (Al) 18%–22%, chromium (Cr) 15%–18%, titanium (Ti) 10%–12%, zirconium (Zr) 8%–10%, and silicon (Si) 3%–5%.

[0059] In some specific examples, the nitrogen content in the wear-resistant layer, by atomic percentage, can be 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, or 45%; the aluminum content can be 18%, 19%, 20%, 21%, or 22%; the chromium content can be 15%, 16%, 17%, or 18%; the titanium content can be 10%, 11%, or 12%; the zirconium content can be 8%, 9%, or 10%; and the silicon content can be 3%, 4%, or 5%.

[0060] In some specific examples, aluminum, chromium, titanium and zirconium elements in the wear-resistant layer jointly form (AlCrTiZr)N nanocrystalline nitride phase. Among them, Al, Cr, Ti and Zr elements enter the nitride lattice structure in a solid solution manner, which makes the formed nanocrystalline nitride phase have high lattice stability and hardness.

[0061] Furthermore, silicon and nitrogen combine to form SiNx amorphous silicon nitride phase, which is distributed in the grain boundary region of the (AlCrTiZr)N nanocrystalline structure. This grain boundary coating method restricts the growth of nanocrystals and reduces stress concentration caused by grain boundary defects.

[0062] In some embodiments, by controlling the silicon content in the wear-resistant layer to be 3% to 5%, the SiNx amorphous structure can be uniformly distributed between the (AlCrTiZr)N nanocrystalline phase, thereby ensuring the continuous load-bearing capacity of the nanocrystalline nitride phase while improving the density and crack propagation resistance of the wear-resistant layer.

[0063] Furthermore, when the aluminum content is controlled within the range of 18% to 22%, the oxidation resistance of the wear-resistant layer during service can be improved, and the formation of a stable oxide protective film can be promoted. When the chromium content is controlled within the range of 15% to 18%, the structural stability and corrosion resistance of the wear-resistant layer can be improved. When the titanium content is controlled within the range of 10% to 12%, it is beneficial to improve the formation stability of the nitride crystal phase and the coating hardness. When the zirconium content is controlled within the range of 8% to 10%, the toughness of the wear-resistant layer can be improved through lattice strengthening, reducing the risk of coating cracking caused by impact loads during the use of kitchen knives.

[0064] In some specific examples, when the wear-resistant layer is prepared by arc ion plating, AlCrTiZr composite targets and Si targets are used, and nitrogen gas is introduced as the reactant gas to allow Al, Cr, Ti, Zr, and Si elements to react with nitrogen to form an AlCrTiZrSiN composite nitride coating. By controlling the output power of each target and the nitrogen flow rate during the deposition process, the elemental ratio in the wear-resistant layer is controlled within the aforementioned range, thereby obtaining a nanocomposite structure containing (AlCrTiZr)N nanocrystalline phase and SiNx amorphous phase.

[0065] Through the above-mentioned elemental composition design, the AlCrTiZrSiN wear-resistant layer in this embodiment can have high hardness, high wear resistance and good toughness. Among them, the (AlCrTiZr)N nanocrystalline structure provides the main load-bearing and wear-resistant function, while the SiNx amorphous structure improves grain boundary stability and inhibits crack propagation, so that the high wear-resistant composite coating applied to the surface of the kitchen knife can maintain a good edge protection effect during long-term cutting.

[0066] Based on the above embodiments, this embodiment further describes the structural composition of the bonding layer and the first gradient transition region.

[0067] In one specific embodiment, a bonding layer is formed on the surface of the kitchen knife substrate to improve the bonding strength between the high-wear-resistant composite coating and the knife substrate. The bonding layer comprises, by atomic percentage, the following elements: aluminum (Al) 30%–35%, chromium (Cr) 22%–27%, titanium (Ti) 15%–20%, zirconium (Zr) 10%–15%, and silicon (Si) 5%–8%.

[0068] In some specific examples, the aluminum content in the bonding layer can be 30%, 31%, 32%, 33%, 34%, or 35% by atomic percentage; the chromium content can be 22%, 23%, 24%, 25%, 26%, or 27%; the titanium content can be 15%, 16%, 17%, 18%, 19%, or 20%; the zirconium content can be 10%, 11%, 12%, 13%, 14%, or 15%; and the silicon content can be 5%, 6%, 7%, or 8%.

[0069] In some specific examples, the bonding layer adopts an AlCrTiZrSi multi-metal structure, forming a good interface bond between the composite metal layer composed of elements such as aluminum, chromium, titanium, zirconium, and silicon and the surface of the kitchen knife substrate. Among them, elements such as Al, Cr, Ti, and Zr can improve the structural stability of the bonding layer itself, while Si can improve the density of the bonding layer, enabling the bonding layer to serve as a connecting buffer structure between the knife substrate and the upper wear-resistant layer.

[0070] Furthermore, the bonding layer is an AlCrTiZrSi multi-element alloy structure, primarily composed of solid-solution metallic phases formed by Al, Cr, Ti, Zr, and Si elements. Specifically, the Al, Cr, Ti, and Zr elements in the bonding layer exist in the metal lattice in a substitutional solid-solution form, forming a multi-element metallic solid-solution structure. Due to the different atomic radii and electronic structures of the various metallic elements, the co-solution of multiple elements can produce a lattice distortion effect, resulting in a stable solid-solution strengthening structure within the bonding layer and improving its mechanical strength.

[0071] In some specific examples, Ti and Zr elements in the bonding layer have high metallic bonding ability. Ti element can improve the interfacial bonding strength between the bonding layer and the kitchen knife substrate, and promote the formation of a stable transition interface. Zr element has a large atomic size, and its introduction can increase the degree of lattice distortion, hinder the propagation of interfacial defects, and improve the bonding layer's resistance to plastic deformation.

[0072] Furthermore, Cr can improve the structural density of the bonding layer and enhance the continuity of element diffusion between the bonding layer and the subsequent nitride wear-resistant layer; Al can regulate the crystal structure stability of the bonding layer and promote the continuous formation of AlCrTiZrSiN nitride structures during subsequent nitriding; Si can reduce grain size, improve the uniformity of the bonding layer structure, and improve the filling effect of defects within the bonding layer. Moreover, Si can exist as silicon-rich regions in some areas of the bonding layer and is distributed between metal grains to regulate grain boundary structure, reduce the number of grain boundary defects, and give the bonding layer better toughness and crack propagation resistance.

[0073] In some embodiments, a first gradient transition region is formed between the bonding layer and the wear-resistant layer. The first gradient transition region is used to realize the continuous transition from the AlCrTiZrSi metal structure to the AlCrTiZrSiN nitride structure.

[0074] Specifically, the nitrogen content in the first gradient transition region gradually increases in the direction away from the tool substrate surface, causing the AlCrTiZrSi structure in the bonding layer to gradually transform into an AlCrTiZrSiN nitride structure.

[0075] In some specific examples, on the side near the bonding layer, the nitrogen content in the first gradient transition region is low, and Al, Cr, Ti, Zr and Si elements mainly exist in the form of metal solid solution structures. As the deposition direction gradually moves away from the tool substrate surface, the proportion of nitrogen participating in the reaction gradually increases, allowing nitrogen elements to gradually enter the metal lattice and form metal nitride structures, eventually transitioning to the AlCrTiZrSiN nitride structure in the wear-resistant layer.

[0076] Furthermore, the first gradient transition region can be formed by gradually adjusting the proportion of reactive gases during the arc ion plating process. Specifically, in the deposition of the bonding layer stage, an AlCrTiZrSi alloy target is used as the source of metal elements to form an AlCrTiZrSi bonding layer under nitrogen-free conditions; subsequently, during the deposition of the first gradient transition region, the nitrogen flow rate is gradually increased, allowing nitrogen to gradually participate in the deposition reaction; when the nitrogen flow rate reaches the conditions for the deposition of the wear-resistant layer, a wear-resistant layer with a stable AlCrTiZrSiN nitride structure is formed.

[0077] In some embodiments, in the first gradient transition region, in addition to the nitrogen content gradually increasing, the crystal structure, hardness and elastic modulus of the coating also gradually change in the direction away from the tool substrate surface, so that a continuous performance gradient is formed between the bonding layer and the wear-resistant layer.

[0078] Furthermore, by setting a first gradient transition region, a distinct interface between the metal bonding layer and the hard nitride wear-resistant layer, as is common in traditional multi-layer coating structures, can be avoided. During the cutting process with a kitchen knife, when the blade is subjected to frictional loads and localized impact loads, the first gradient transition region can absorb and alleviate the mechanical stress generated at the interface, improving the connection stability between the wear-resistant layer and the bonding layer, and reducing the risk of peeling or cracking of the wear-resistant layer.

[0079] Based on the above embodiments, this embodiment further describes the structural composition of the sealing layer and the second gradient transition region.

[0080] In some embodiments, a sealing layer is formed on the side of the wear-resistant layer away from the tool substrate to improve the surface stability, oxidation resistance, and tribological properties of the high-wear-resistant composite coating during service. The sealing layer comprises, by atomic percentage, the following elements: aluminum (Al) 18%–22%, chromium (Cr) 15%–18%, titanium (Ti) 10%–12%, zirconium (Zr) 8%–10%, silicon (Si) 3%–5%, nitrogen (N) 30%–35%, and oxygen (O) 8%–15%.

[0081] In some specific examples, the aluminum content in the enclosed layer can be 18%, 19%, 20%, 21%, or 22% by atomic percentage; the chromium content can be 15%, 16%, 17%, or 18%; the titanium content can be 10%, 11%, or 12%; the zirconium content can be 8%, 9%, or 10%; the silicon content can be 3%, 4%, or 5%; the nitrogen content can be 30%, 31%, 32%, 33%, 34%, or 35%; and the oxygen content can be 8%, 9%, 10%, 11%, 12%, 13%, 14%, or 15%.

[0082] In some specific examples, the sealing layer adopts an AlCrTiZrSiON oxynitride structure, wherein the main phases in the sealing layer include (AlCrTiZr)ON oxynitride nanocrystalline phase and Si-ON amorphous phase. Specifically, aluminum, chromium, titanium, and zirconium elements combine with nitrogen and oxygen elements to form the (AlCrTiZr)ON oxynitride nanocrystalline structure, and silicon elements combine with nitrogen and oxygen elements to form the Si-ON amorphous structure. The Si-ON amorphous structure is distributed in the grain boundary region of the (AlCrTiZr)ON nanocrystalline structure.

[0083] Among them, the Si-ON amorphous structure can be expressed as SiOxNy amorphous phase, silicon-rich oxynitride amorphous phase, or composite amorphous phase containing a small amount of SiNx structural units.

[0084] Furthermore, the oxygen element in the sealing layer can improve the chemical stability of the coating surface, reducing the possibility of oxidation and corrosion of the coating surface during long-term contact of the kitchen knife with water, salt, and acidic or alkaline materials; at the same time, the introduction of an appropriate amount of oxygen element can improve the wetting properties of the sealing layer surface, giving the kitchen knife better surface contact performance when cutting food.

[0085] Specifically, the main phases in the sealing layer include metal oxynitride nanocrystalline phases and silicon-based oxynitride amorphous phases. Among them, aluminum, chromium, titanium, and zirconium elements combine with nitrogen and oxygen elements to form (AlCrTiZr)ON oxynitride nanocrystalline structures, while silicon elements combine with nitrogen and oxygen elements to form Si-ON amorphous structures. The Si-ON amorphous structures can manifest as SiNx, SiOxNy, or silicon-rich oxynitride amorphous phases.

[0086] In some specific examples, the (AlCrTiZr)ON oxynitride nanocrystalline structure is a composite crystal structure formed by the solid solution of multiple elements, Al, Cr, Ti, and Zr, within an oxynitride lattice. The inter-elemental lattice distortion between Al, Cr, Ti, and Zr results in solid solution strengthening of the oxynitride lattice, thereby improving the structural stability and resistance to plastic deformation of the encapsulated layer.

[0087] Furthermore, due to the introduction of oxygen, some oxygen atoms enter the nitride lattice positions, forming an oxynitride structure with oxygen substitution characteristics, which improves the chemical stability of the sealing layer surface. Oxygen can reduce the active adsorption of moisture, acidic substances, and salt ions from the external environment on the coating surface, thereby improving the corrosion resistance of the kitchen knife in humid environments and under complex food contact conditions.

[0088] In some embodiments, the SiOxNy amorphous structure formed by silicon is distributed in the grain boundary region of the (AlCrTiZr)ON nanocrystalline structure.

[0089] Specifically, the SiOxNy amorphous structure can fill the grain boundary gaps between nanocrystals, forming a grain boundary coating structure. On the one hand, the amorphous silicon oxynitride phase can limit the further growth of (AlCrTiZr)ON nanocrystals, keeping the sealing layer with a fine-grained structure; on the other hand, the amorphous phase can alleviate stress concentration in the grain boundary region, hinder crack propagation along the grain boundary, and improve the crack resistance of the sealing layer.

[0090] In some embodiments, a second gradient transition region is formed between the sealing layer and the wear-resistant layer. The second gradient transition region is used to realize the continuous transformation of the AlCrTiZrSiN nitride structure to the AlCrTiZrSiON oxynitride structure.

[0091] Specifically, the oxygen content in the second gradient transition region gradually increases in the direction away from the tool substrate surface, while the nitrogen content gradually decreases in the direction away from the tool substrate surface, causing the wear-resistant layer to gradually transform from an AlCrTiZrSiN nitride structure to an AlCrTiZrSiON oxynitride structure.

[0092] In some specific examples, on the side near the wear-resistant layer, the oxygen content in the second gradient transition region is low and the nitrogen content is high, and its structural composition is close to the AlCrTiZrSiN nitride structure. As the deposition direction gradually moves away from the surface of the wear-resistant layer, oxygen gradually participates in the deposition reaction, the oxygen content gradually increases, and the nitrogen participation ratio gradually decreases, causing the coating structure to gradually transform into the AlCrTiZrSiON oxynitride structure, eventually forming a sealing layer.

[0093] Furthermore, the second gradient transition region can be formed by gradually adjusting the reaction atmosphere during the arc ion plating process. Specifically, after the wear-resistant layer is deposited, the proportion of nitrogen introduced is gradually reduced, while the proportion of oxygen or oxygen-containing reactive gases is gradually increased, allowing oxygen to gradually enter the coating structure and forming a second gradient transition region with a compositional gradient.

[0094] In some embodiments, the second gradient transition region not only exhibits a gradient change in elemental composition, but also a continuous change in the internal crystal structure, hardness, and surface energy of the coating. Specifically, the side closer to the wear-resistant layer maintains a higher proportion of nitride structure to ensure good bonding stability between the second gradient transition region and the wear-resistant layer; the side closer to the sealing layer gradually forms an oxynitride structure to improve the density and environmental stability of the sealing layer.

[0095] Furthermore, by setting a second gradient transition region, large interfacial stresses can be avoided between the AlCrTiZrSiN nitride wear-resistant layer and the AlCrTiZrSiON oxynitride sealing layer due to abrupt changes in elemental composition. During high-speed cutting or long-term friction use of the kitchen knife, the second gradient transition region can buffer the transfer of surface loads and reduce the risk of cracking and peeling of the sealing layer.

[0096] Through the above structural design, the sealing layer in this embodiment adopts an AlCrTiZrSiON oxynitride structure, and the continuous transition between the wear-resistant layer and the sealing layer is achieved through the second gradient transition region, so that the high wear-resistant composite coating has excellent wear resistance, surface stability and interfacial bonding performance at the same time, thereby improving the service life of the kitchen knife during long-term cutting.

[0097] In some embodiments, the high wear-resistant composite coating for kitchen knife surfaces provided in this application employs a multi-layer gradient composite structure: an AlCrTiZrSi bonding layer—a first gradient transition region—an AlCrTiZrSiN wear-resistant layer—a second gradient transition region—an AlCrTiZrSiON sealing layer. The functional layers are not simply stacked together; rather, a continuous gradient structure is formed by gradually varying elemental content, resulting in a gradual change in material composition, crystal structure, and mechanical properties from the knife substrate towards the outer surface of the entire composite coating.

[0098] This application also provides a kitchen knife, the base surface of which is provided with the aforementioned high wear-resistant composite coating.

[0099] In some embodiments, the knife body may be made of stainless steel, such as martensitic stainless steel, chromium-molybdenum-vanadium stainless steel, or other metal materials suitable for manufacturing kitchen knives. After stamping, forging, heat treatment, grinding, and surface cleaning, a highly wear-resistant composite coating is formed on the surface of the knife body to improve the wear resistance of the blade edge area and its ability to maintain sharpness over long-term use.

[0100] In one specific implementation, the thickness of the high wear-resistant composite coating is 3μm to 5μm. The high wear-resistant composite coating is formed on the surface of the kitchen knife substrate by an arc ion plating process, and includes a bonding layer, a wear-resistant layer and a sealing layer formed sequentially. A first gradient transition region is formed between the bonding layer and the wear-resistant layer, and a second gradient transition region is formed between the wear-resistant layer and the sealing layer.

[0101] In some specific examples, the total thickness of the high-wear-resistant composite coating can be 3μm, 3.5μm, 4μm, 4.5μm, or 5μm. By controlling the coating thickness, the high-wear-resistant composite coating can improve the coating's ability to protect the substrate surface while ensuring the sharpness of the tool's cutting edge.

[0102] Specifically, a bonding layer is disposed between the kitchen knife substrate and the wear-resistant layer to improve the bonding strength between the coating and the substrate. By atomic percentage, the bonding layer contains the following elements: aluminum (Al) 30%–35%, chromium (Cr) 22%–27%, titanium (Ti) 15%–20%, zirconium (Zr) 10%–15%, and silicon (Si) 5%–8%.

[0103] In some specific examples, the bonding layer adopts an AlCrTiZrSi multi-metal structure, which can form a strong bond between the metal elements and the metal atoms on the surface of the kitchen knife substrate. At the same time, it serves as a buffer structure between the substrate and the hard wear-resistant layer, reducing the interfacial stress caused by the difference in material systems.

[0104] The wear-resistant layer is located on the side of the bonding layer away from the knife body, providing primary wear resistance. By atomic percentage, the wear-resistant layer contains the following elements: nitrogen (N) 35%–45%, aluminum (Al) 18%–22%, chromium (Cr) 15%–18%, titanium (Ti) 10%–12%, zirconium (Zr) 8%–10%, and silicon (Si) 3%–5%.

[0105] In some embodiments, the wear-resistant layer adopts an AlCrTiZrSiN nitride structure, the main phases of which include (AlCrTiZr)N nanocrystalline phase and SiNx amorphous phase. The (AlCrTiZr)N nanocrystalline phase provides high hardness and wear resistance, while the SiNx amorphous phase is distributed in the nanocrystalline grain boundary region, which helps to limit grain growth and improve coating toughness, thereby enhancing the wear resistance of the kitchen knife during long-term cutting.

[0106] The sealing layer is located on the side of the wear-resistant layer away from the knife substrate, and is used to improve the stability, oxidation resistance, and adaptability of the coating surface to the service environment. By atomic percentage, the sealing layer contains the following elements: aluminum (Al) 18%–22%, chromium (Cr) 15%–18%, titanium (Ti) 10%–12%, zirconium (Zr) 8%–10%, silicon (Si) 3%–5%, nitrogen (N) 30%–35%, and oxygen (O) 8%–15%.

[0107] In some specific examples, the sealing layer adopts an AlCrTiZrSiON oxynitride structure, whose main phases include (AlCrTiZr)ON oxynitride nanocrystalline phase and Si-ON amorphous phase. The (AlCrTiZr)ON oxynitride nanocrystalline phase improves the structural stability and oxidation resistance of the sealing layer, while the Si-ON amorphous phase is distributed in the grain boundary regions of the nanocrystalline structure, improving the compactness of the sealing layer and reducing the possibility of crack propagation along the grain boundaries.

[0108] In one specific embodiment, a high-abrasion-resistant composite coating is formed on the surface of a kitchen knife substrate. The total thickness of the high-abrasion-resistant composite coating is 4.2 μm, comprising a bonding layer, a first gradient transition region, an abrasion-resistant layer, a second gradient transition region, and a sealing layer formed sequentially. Specifically, the bonding layer has a thickness of 0.5 μm, the first gradient transition region has a thickness of 0.3 μm, the abrasion-resistant layer has a thickness of 2.5 μm, the second gradient transition region has a thickness of 0.3 μm, and the sealing layer has a thickness of 0.6 μm.

[0109] In this application embodiment, the present application also provides a method for preparing the above-mentioned kitchen knife, the preparation method comprising:

[0110] Step 1: Perform surface pretreatment on the knife body.

[0111] In some embodiments, the tool substrate may be made of stainless steel. Before coating deposition, the tool substrate is first mechanically polished to reduce the surface roughness and improve the uniformity of the subsequent coating; then, it is ultrasonically cleaned with an organic solvent to remove oil, grinding residues, and adsorbed impurities from the surface of the tool substrate.

[0112] In some specific examples, the polished tool substrate is ultrasonically cleaned sequentially with acetone and anhydrous ethanol for 5 to 20 minutes, respectively. After cleaning, the residual liquid on the surface is removed by hot air drying or vacuum drying.

[0113] Furthermore, the pretreated tool substrate is loaded into the workpiece gantry of the arc ion plating equipment, and the vacuum chamber is evacuated to achieve a background vacuum level of 1.0 × 10⁻⁶. -2 Pa ~ 1.0 × 10 -3 Pa, and heat the tool base to 300℃~550℃.

[0114] In some embodiments, an ion bombardment cleaning step is included before the formal deposition of the coating on the tool substrate.

[0115] Specifically, argon gas is introduced into the vacuum chamber to maintain the chamber pressure at 0.1 Pa to 1.5 Pa. The bias voltage of the tool substrate is adjusted to -100 V to -600 V. The surface of the tool substrate is bombarded with argon ions by arc-enhanced glow discharge or ion source to remove the oxide layer and adsorbed impurities on the surface of the tool substrate, thereby improving the bonding strength between the subsequent coating and the substrate.

[0116] Step 2: Place the pretreated tool substrate in the vacuum chamber of the arc ion plating equipment, use AlCrTiZrSi alloy target as the deposition target, and perform arc ion plating deposition in an inert gas environment to form a bonding layer on the surface of the tool substrate.

[0117] Specifically, the tool substrate after ion bombardment treatment is held in the vacuum chamber of an arc ion plating equipment, and an AlCrTiZrSi alloy target is used as the deposition target to perform arc ion plating deposition in an inert gas environment.

[0118] In some specific examples, the inert gas is argon, the pressure in the vacuum chamber during deposition is controlled at 0.5 Pa to 3 Pa, the bias voltage of the tool substrate is controlled at -20 V to -200 V, and the current of the AlCrTiZrSi alloy target is controlled at 100 A to 200 A.

[0119] In this step, the deposition time is controlled to achieve a bonding layer thickness of 0.5 μm. This bonding layer primarily consists of an AlCrTiZrSi multi-metal structure, which enhances the bonding strength between the subsequent nitride wear-resistant layer and the tool substrate.

[0120] Step 3: After the bonding layer is deposited, nitrogen gas is introduced into the vacuum chamber to allow nitrogen to gradually participate in the deposition process. The nitrogen content on the surface of the bonding layer is gradually increased by adjusting the nitrogen flow rate to form the first gradient transition region from AlCrTiZrSi structure to AlCrTiZrSiN structure. Then, the deposition continues to form the wear-resistant layer.

[0121] After the bonding layer is deposited, nitrogen gas is gradually introduced into the vacuum chamber to allow nitrogen to participate in the deposition process.

[0122] Specifically, by continuously adjusting the nitrogen flow rate, the nitrogen concentration in the deposition area is gradually increased, causing the material structure on the surface of the bonding layer to gradually transform from an AlCrTiZrSi metallic structure to an AlCrTiZrSiN nitride structure, thereby forming the first gradient transition region.

[0123] In some specific examples, the thickness of the first gradient transition region is controlled to be 0.3 μm. By controlling the nitrogen flow rate, the nitrogen content in the first gradient transition region gradually increases in the direction away from the tool substrate surface, thus avoiding a significant compositional interface between the bonding layer and the wear-resistant layer.

[0124] Furthermore, after the first gradient transition region is formed, an arc ion plating deposition is performed while maintaining a nitrogen environment to form a wear-resistant layer on the side of the first gradient transition region away from the tool substrate.

[0125] In some embodiments, during the wear-resistant layer deposition process, the nitrogen pressure in the vacuum chamber is controlled to be 1 Pa to 5 Pa, the bias voltage of the tool substrate is controlled to be -20 V to -200 V, and the current of the AlCrTiZrSi alloy target is controlled to be 100 A to 200 A.

[0126] By controlling the deposition time, the wear-resistant layer thickness can be achieved to 2.5 μm.

[0127] In this step, the wear-resistant layer forms an AlCrTiZrSiN nitride structure, in which the (AlCrTiZr)N nanocrystalline phase serves as the main hard phase, and the SiNx amorphous phase is distributed in the grain boundary region of the nanocrystalline phase. Through the strengthening effect of nanocrystalline phase and the toughening effect of amorphous phase, the hardness, wear resistance and crack propagation resistance of the wear-resistant layer are improved.

[0128] Step 4: After the wear-resistant layer is deposited, oxygen is introduced into the vacuum chamber, and the ratio of nitrogen to oxygen is adjusted so that the oxygen content gradually increases in the direction away from the tool substrate surface, forming a second gradient transition region from AlCrTiZrSiN nitride structure to AlCrTiZrSiON nitride structure; continue deposition to form a sealing layer.

[0129] After the wear-resistant layer is deposited, oxygen is gradually introduced into the vacuum chamber, while the ratio of nitrogen to oxygen is adjusted simultaneously. Specifically, by gradually increasing the oxygen flow rate, oxygen gradually participates in the deposition process, and the material structure on the surface of the wear-resistant layer gradually transforms from an AlCrTiZrSiN nitride structure to an AlCrTiZrSiON oxynitride structure, thereby forming a second gradient transition region.

[0130] In some specific examples, the thickness of the second gradient transition region is controlled to be 0.3 μm. During the formation of the second gradient transition region, the oxygen content gradually increases in the direction away from the tool substrate surface, while the nitrogen content gradually decreases, resulting in a continuous change in the coating composition.

[0131] Furthermore, after the second gradient transition region is formed, arc ion plating deposition continues to form a sealing layer. In some embodiments, during the sealing layer deposition process, the pressure of the oxygen and nitrogen mixed atmosphere is controlled at 1 Pa to 5 Pa, and the tool substrate bias voltage is controlled at -20 V to -150 V. By controlling the deposition time, the sealing layer thickness reaches 0.6 μm.

[0132] In this step, the sealing layer forms an AlCrTiZrSiON oxynitride structure, including a (AlCrTiZr)ON oxynitride nanocrystalline phase and a Si-ON amorphous phase. The oxynitride nanocrystalline phase enhances the oxidation resistance of the sealing layer, while the Si-ON amorphous phase fills the grain boundary regions, increasing the density of the sealing layer and reducing the possibility of external moisture, salt, and corrosive media diffusing into the coating.

[0133] Step 5: After completing the sealing layer deposition, the kitchen knife is cooled to obtain a kitchen knife with a highly wear-resistant composite coating on its surface. Specifically, after completing the sealing layer deposition, the target power is turned off, and the kitchen knife is allowed to cool naturally in the vacuum chamber. When the temperature of the knife substrate drops below 100°C, the kitchen knife is removed from the vacuum chamber, resulting in a kitchen knife with a highly wear-resistant composite coating on its surface.

[0134] Based on the above embodiments, this embodiment further describes the AlCrTiZrSi multi-element alloy target used in the arc ion plating process. The AlCrTiZrSi multi-element alloy target is prepared by vacuum melting, powder metallurgy, or hot isostatic pressing, resulting in a uniformly distributed multi-element alloy structure of aluminum, chromium, titanium, zirconium, and silicon within the target. The purity of the AlCrTiZrSi multi-element alloy target is not less than 99.5%, preferably not less than 99.9%.

[0135] In one specific embodiment, the AlCrTiZrSi multi-element alloy target is composed of aluminum (Al), chromium (Cr), titanium (Ti), zirconium (Zr), and silicon (Si). By atomic percentage, the AlCrTiZrSi multi-element alloy target contains the following elements: aluminum (Al) 30%–35%, chromium (Cr) 22%–27%, titanium (Ti) 15%–20%, zirconium (Zr) 10%–15%, and silicon (Si) 5%–8%.

[0136] In some embodiments, by adjusting the proportions of each element in the AlCrTiZrSi multi-element alloy target, the deposited bonding layer can have mechanical properties that are well matched with the kitchen knife substrate, and provide a continuous source of elements for the subsequent formation of the AlCrTiZrSiN wear-resistant layer.

[0137] Example 1

[0138] This embodiment provides a kitchen knife with a highly wear-resistant composite coating on its surface.

[0139] In this embodiment, the knife substrate is made of 9Cr18MoV stainless steel. Before coating the knife substrate, surface pretreatment is performed. The mechanically polished knife substrate is then ultrasonically cleaned with acetone and anhydrous ethanol to remove oil and adsorbed impurities from its surface. The ultrasonic cleaning time is 15 minutes. After cleaning, the substrate is dried with hot air and then placed in the vacuum chamber of an arc ion plating apparatus.

[0140] Subsequently, the vacuum chamber was evacuated to achieve a background vacuum level of 5.0 × 10⁻⁶. -3 The pressure is below Pa, and the temperature of the vacuum chamber is increased to 450°C.

[0141] Argon gas was introduced into the vacuum chamber to maintain the chamber pressure at 0.5 Pa, and the bias voltage of the kitchen knife substrate was adjusted to -250 V. The surface of the kitchen knife substrate was cleaned by argon ion bombardment for 40 minutes to remove the oxide layer on the surface of the kitchen knife substrate and improve the bonding strength between the subsequent coating and the kitchen knife substrate.

[0142] After pretreatment, an AlCrTiZrSi multi-element alloy target was used as the deposition target, and arc ion plating was performed in an argon atmosphere. The arc target current was 160A, the bias voltage of the kitchen knife substrate was -120V, and the deposition time was 20 minutes, forming a bonding layer on the surface of the kitchen knife substrate. The AlCrTiZrSi multi-element alloy target contained the following elements: aluminum (Al) 35%, chromium (Cr) 25%, titanium (Ti) 18%, zirconium (Zr) 14%, and silicon (Si) 8%.

[0143] Subsequently, the nitrogen flow rate is gradually increased within the vacuum chamber, allowing nitrogen to gradually participate in the deposition process. By adjusting the nitrogen flow rate, the nitrogen content on the bonding layer surface gradually increases away from the knife substrate, thus forming the first gradient transition region from the AlCrTiZrSi structure to the AlCrTiZrSiN structure. Further increasing the nitrogen flow rate, arc ion plating deposition continues under a nitrogen atmosphere to form the AlCrTiZrSiN wear-resistant layer.

[0144] The nitrogen flow rate was gradually increased from 0 sccm to 80 sccm over a period of 15 minutes. During the deposition of the wear-resistant layer, the nitrogen pressure was maintained at 3.0 Pa, the arc target current was 170 A, the bias voltage of the kitchen knife substrate was -130 V, and the deposition time was 50 minutes.

[0145] After the wear-resistant layer deposition is completed, the nitrogen flow rate is gradually reduced while oxygen is introduced into the vacuum chamber. This allows oxygen to gradually participate in the deposition process, and the oxygen-to-nitrogen ratio is controlled to gradually increase the oxygen content and decrease the nitrogen content on the wear-resistant layer surface. This forms a second gradient transition region from an AlCrTiZrSiN nitride structure to an AlCrTiZrSiON oxynitride structure. Specifically, the oxygen flow rate is gradually increased from 0 sccm to 30 sccm, while the nitrogen flow rate is decreased from 80 sccm to 50 sccm.

[0146] During the deposition of the sealed layer, the vacuum chamber pressure was maintained at 2.5 Pa, the total flow rate of oxygen and nitrogen was kept stable, the arc target current was 150 A, the bias voltage of the kitchen knife substrate was -100 V, and the deposition time was 20 min.

[0147] Continue deposition to form a sealing layer. After the sealing layer deposition is complete, allow the kitchen knife to cool naturally to below 100°C in a vacuum chamber, then remove the kitchen knife to obtain a kitchen knife with a highly wear-resistant composite coating on the surface.

[0148] Example 2

[0149] This embodiment provides a kitchen knife with a highly wear-resistant composite coating on its surface.

[0150] The main difference between this embodiment and Embodiment 1 lies in adjusting the deposition process parameters during the arc ion plating process, resulting in a more stable nanocrystalline / amorphous composite structure in the wear-resistant layer. In this embodiment, the kitchen knife substrate still uses 9Cr18MoV stainless steel.

[0151] The polished kitchen knife substrate was ultrasonically cleaned with acetone and alcohol for 20 minutes each, dried, and then placed into an arc ion plating apparatus. A vacuum of 4.0 × 10⁻⁶ was applied. -3The pressure was kept below Pa, and the temperature of the vacuum chamber was increased to 500℃. Argon gas was introduced to maintain the chamber pressure at 0.6 Pa. The substrate bias voltage was adjusted to -300V, and the kitchen knife substrate was subjected to argon ion bombardment cleaning for 35 minutes.

[0152] Subsequently, an AlCrTiZrSi alloy target was used to deposit the bonding layer in an argon atmosphere. During the deposition process, the target current was 180A, the substrate bias voltage was -150V, and the deposition time was 25min.

[0153] The nitrogen ratio was then gradually increased to create a first gradient transition region between the bonding layer and the wear-resistant layer. Nitrogen was continued to be introduced, and the wear-resistant layer was deposited under the following conditions: nitrogen pressure 3.8 Pa, arc target current 190 A, and substrate bias voltage -170 V, for a deposition time of 70 min. After the wear-resistant layer deposition was completed, a second gradient transition region was created by adjusting the nitrogen and oxygen ratio, and a sealing layer was further deposited.

[0154] Example 3

[0155] This embodiment provides a kitchen knife with a highly wear-resistant composite coating on its surface.

[0156] Compared with Example 1, the main difference in this embodiment is that the gas ratio during the deposition process of the wear-resistant layer and the sealing layer is adjusted, so that the wear-resistant layer forms an AlCrTiZrSiN nanocrystalline / amorphous composite structure with high density, and the sealing layer forms an AlCrTiZrSiON oxynitride structure with high oxygen content.

[0157] After the bonding layer deposition is completed, nitrogen gas is gradually introduced into the vacuum chamber through a mass flow controller, so that nitrogen element gradually participates in the deposition process. The nitrogen gas flow rate is controlled to make the nitrogen element content on the surface of the bonding layer gradually increase in the direction away from the kitchen knife substrate, thereby forming the first gradient transition region from AlCrTiZrSi structure to AlCrTiZrSiN structure.

[0158] Specifically, the nitrogen flow rate was gradually increased from 0 sccm to 100 sccm, with the adjustment time controlled at 25 min, to create a continuous gradient change in nitrogen concentration along the coating thickness direction. After the formation of the first gradient transition region was completed, arc ion plating deposition was continued under high nitrogen ratio conditions to form an AlCrTiZrSiN wear-resistant layer.

[0159] During the wear-resistant layer deposition process, the vacuum chamber pressure was maintained at 4.2 Pa, the nitrogen flow rate was maintained at 100 sccm, the arc target current was set to 200 A, the kitchen knife substrate bias voltage was set to -160 V, and the deposition time was 60 min.

[0160] Specifically, the oxygen flow rate was gradually increased from 0 sccm to 40 sccm, while the nitrogen flow rate was gradually decreased from 100 sccm to 60 sccm, with the adjustment time controlled at 25 min. This caused the oxygen content to gradually increase and the nitrogen content to gradually decrease along the direction away from the surface of the kitchen knife substrate, thereby forming a second gradient transition region from the AlCrTiZrSiN nitride structure to the AlCrTiZrSiON oxynitride structure.

[0161] After forming the second gradient transition region, arc ion plating deposition continues under a nitrogen-oxygen mixed atmosphere to form a sealing layer.

[0162] During the deposition of the sealed layer, the vacuum chamber pressure was maintained at 3.0 Pa, the oxygen flow rate was maintained at 40 sccm, the nitrogen flow rate was maintained at 60 sccm, the total flow rate of oxygen and nitrogen was kept stable, the arc target current was set to 150 A, the bias voltage of the kitchen knife substrate was set to -110 V, and the deposition time was 30 min.

[0163] Performance Testing and Results Analysis

[0164] (1) Coating cross-sectional morphology and thickness test

[0165] The cross-sectional morphology of the high wear-resistant composite coatings prepared in Examples 1-3 was observed using field emission scanning electron microscopy (FE-SEM), and the elemental distribution characteristics inside the coatings were analyzed by cross-sectional energy dispersive spectroscopy. During the testing process, the kitchen knives prepared in Examples 1-3 were cross-sectionally prepared along the direction perpendicular to the blade edge. After mechanical grinding, polishing, and ion beam finishing, the cross-sectional morphology of the coatings was observed.

[0166] Test results show that:

[0167] Since the high wear-resistant composite coating in this application adopts a gradient transition structure, it is not possible to directly distinguish the geometric boundaries of each functional area by a single cross-sectional morphology. Instead, it is necessary to analyze different functional areas by combining the element depth distribution.

[0168] The high-wear-resistant composite coating prepared in Example 1 continuously covered the surface of the kitchen knife substrate. The coating and the knife substrate were tightly bonded, and no obvious pores, through cracks, or interface peeling defects were observed in the cross-section. Measurements using cross-sectional SEM images showed that the overall thickness of the high-wear-resistant composite coating in this example was approximately 4.10 μm.

[0169] The high-wear-resistant composite coating prepared in Example 2 exhibits uniform overall coverage. Cross-sectional observation shows that the coating's internal structure is continuous and dense, with no obvious delamination or peeling. Cross-sectional SEM measurements revealed that the overall thickness of the high-wear-resistant composite coating in this example is approximately 4.60 μm.

[0170] The high wear-resistant composite coating prepared in Example 3 has an overall thickness of approximately 4.80 μm. Cross-sectional morphology shows that the coating exhibits good adhesion to the kitchen knife substrate, with a more uniform and dense internal structure and continuous gradient transition regions, which helps reduce stress concentration between different structural areas.

[0171] Furthermore, to verify the internal gradient structure characteristics of the high-wear-resistant composite coating, EDS elemental line scan analysis was performed on the cross-sections of the coatings prepared in Examples 1-3. The test results showed that along the direction away from the surface of the kitchen knife substrate:

[0172] In the region near the tool substrate, Al, Cr, Ti, Zr, and Si elements maintain high contents, while nitrogen content is low, exhibiting characteristics of an AlCrTiZrSi bonding layer. As the detection position moves further away from the tool substrate surface, the nitrogen content gradually increases, forming a gradient region transitioning from an AlCrTiZrSi structure to an AlCrTiZrSiN structure. In the central region of the coating, the nitrogen content remains stable, forming an AlCrTiZrSiN wear-resistant layer. Continuing detection towards the coating surface, the oxygen content gradually increases while the nitrogen content gradually decreases, forming a gradient region transitioning from AlCrTiZrSiN to AlCrTiZrSiON, ultimately forming an oxynitride sealing layer.

[0173] The above results indicate that the high wear-resistant composite coating prepared in this application has a continuous elemental gradient distribution, which can realize the structural gradient between the bonding layer, the wear-resistant layer and the sealing layer, thereby improving the overall bonding performance and service stability of the coating.

[0174] (2) Elemental composition analysis of the modulation layer

[0175] Since the thickness of the high wear-resistant composite coating in Examples 1 to 3 is at the micrometer scale, and the thickness of the first gradient transition region and the second gradient transition region is relatively small, it is difficult to accurately obtain the elemental composition of the local area by directly using conventional EDS testing.

[0176] Therefore, in order to obtain the true elemental composition of each coating region, this application uses a single-layer film calibration method for component analysis. Specifically, under the same deposition conditions as the kitchen knife substrate, using the same test substrate as the kitchen knife substrate material, and following the arc ion plating process parameters corresponding to Examples 1 to 3, a bonding layer single-layer film, a wear-resistant layer single-layer film, and a sealing layer single-layer film with a thickness greater than 2 μm were deposited separately.

[0177] Subsequently, the obtained monolayer film was quantitatively analyzed using an energy dispersive spectroscopy (EDS) instrument, and the elemental composition inside the coating was analyzed in combination with the results of X-ray photoelectron spectroscopy (XPS) depth profiling (the content of each element was normalized according to atomic percentage, in at.%, and the sum of the contents of each element was 100%).

[0178]

[0179] (3) Coating mechanical property testing

[0180] To evaluate the mechanical properties of the high wear-resistant composite coatings prepared in Examples 1-3, the coatings were tested respectively.

[0181] (a) Nanoindentation test

[0182] The mechanical properties of the high wear-resistant composite coatings obtained in Examples 1-3 were tested using a nanoindenter.

[0183] During the testing process, a Berkovich diamond indenter was used for loading tests. To avoid the influence of the tool substrate hardness on the test results, the maximum indentation depth was controlled to not exceed 10% of the total thickness of the high-wear-resistant composite coating. In this embodiment, the maximum indentation depth was set to 300 nm, the loading rate was 20 mN / min, the holding time was 10 s, and 10 areas were randomly selected from each sample for testing, with the average value taken as the final test result.

[0184] The nanohardness and elastic modulus obtained from the tests are shown in the table below.

[0185] Sample Nanohardness HIT (GPa) Elastic modulus EIT (GPa) Example 1 28.6 318.4 Example 2 30.1 326.7 Example 3 31.4 334.2

[0186] The test results above show that the high wear-resistant composite coatings obtained in Examples 1 to 3 all have high nano-hardness and suitable elastic modulus, indicating that the formed AlCrTiZrSiN wear-resistant layer can effectively improve the resistance to plastic deformation of the kitchen knife surface.

[0187] In Example 1, an AlCrTiZrSiN wear-resistant layer and an AlCrTiZrSiON sealing layer are formed in the coating. The solid solution strengthening effect is generated by the nitride or oxynitride structure formed by multiple elements such as aluminum, chromium, titanium and zirconium. At the same time, the amorphous silicon nitride or silicon oxynitride phase formed by silicon is distributed in the grain boundary region of the nanocrystal, which can inhibit the further growth of nanocrystals and strengthen the grain boundary region. Therefore, it has high nanohardness.

[0188] Example 2 adjusts the deposition conditions such as nitrogen atmosphere, target current, and substrate bias during the arc ion plating process to make the AlCrTiZrSiN wear-resistant layer have a denser nanocrystalline / amorphous composite structure, thereby further reducing the internal porosity and micro-defects of the coating and improving the interfacial bonding between the nanocrystalline and amorphous phases. Therefore, its nanohardness and elastic modulus are higher than those of Example 1.

[0189] Example 3 further improves the densification degree during the wear-resistant layer deposition process, and by adjusting the ratio of nitrogen and oxygen, the sealing layer has a high oxygen content, so that a relatively stable AlCrTiZrSiON oxynitride structure is formed on the coating surface. At the same time, the silicon-based oxynitride amorphous phase forms grain boundary coating on the nanocrystalline phase, thereby further improving the coating's ability to resist local plastic deformation and crack initiation. Therefore, it exhibits the highest nanohardness and elastic modulus.

[0190] It should be noted that, based on the test results of the AlCrSiON system, its nanohardness is approximately in the range of 12.6 to 17.87 GPa. However, the coating of this application introduces Al, Cr, Ti, Zr multi-element nitride nanocrystalline phases and Si-based amorphous phases, and adopts a gradient transition structure. Therefore, it is reasonable to design the target hardness of the coating of this application to be in the range of approximately 28 to 32 GPa.

[0191] (4) Membrane-substrate bonding strength test

[0192] The bonding performance between the high wear-resistant composite coatings obtained in Examples 1 to 3 and the 9Cr18MoV tool substrate was tested using the scratch test method. A continuous load scratch tester was used, with a diamond conical indenter used to scratch the coating surface. By simultaneously recording the frictional force, acoustic emission signals, and changes in the morphology of the scratched area during the scratching process, the critical load corresponding to the initial failure of the coating was determined.

[0193] During the specific testing process, a diamond conical indenter with a radius of 200 μm was used. The initial load was set to 5 N, the final load to 80 N, the loading rate to 10 N / min, and the scratch length to 5 mm. After the test, the morphology of the scratched area was observed using a scanning electron microscope. The critical load Lc corresponding to the first occurrence of cracking, local peeling, or failure of the film-substrate interface in the coating was determined by combining the acoustic emission signal and the location of the abrupt change in the friction coefficient.

[0194] For each embodiment, three different locations were selected for scratch testing, and the average value of the test results was taken as the critical bonding load of that embodiment.

[0195] The test results are shown in the table below.

[0196] Sample Example 1 Example 2 Example 3 Critical bonding load Lc / N 46.8 50.7 53.6

[0197] The test results show that the high wear-resistant composite coatings obtained in Examples 1 to 3 all have good film-substrate bonding performance. This is because the bonding layer adopts an AlCrTiZrSi structure, which has a good compositional and structural transition relationship with the 9Cr18MoV tool substrate. At the same time, the bonding layer and the wear-resistant layer do not form an abrupt interface, but rather the nitrogen content gradually increases through the first gradient transition region, causing the coating to gradually transform from an AlCrTiZrSi structure to an AlCrTiZrSiN nitride structure, thereby reducing the interfacial stress concentration between the hard wear-resistant layer and the tool substrate.

[0198] In addition, a second gradient transition region is set between the wear-resistant layer and the sealing layer, so that the nitrogen content gradually decreases and the oxygen content gradually increases, and the AlCrTiZrSiN nitride structure gradually transforms into the AlCrTiZrSiON oxynitride structure. Therefore, it can reduce the interfacial stress between the sealing layer and the wear-resistant layer caused by the difference in crystal structure and chemical composition.

[0199] In Example 2, the density of the wear-resistant layer was improved, which reduced the porosity and defects inside the coating. In Example 3, the structural density of the wear-resistant layer and the sealing layer was further improved. Therefore, Examples 2 and 3 exhibited higher critical bonding loads.

[0200] (5) Tribological and wear performance test

[0201] The high wear-resistant composite coatings obtained in Examples 1 to 3 were tested using a ball-disc friction and wear tester to evaluate their wear resistance under continuous sliding friction conditions.

[0202] During the test, Al2O3 ceramic balls were used as the grinding material with a diameter of 6 mm; the test load was set to 5 N, the sliding speed was set to 100 mm / s, the sliding distance was set to 1000 m, and the test environment was room temperature air environment.

[0203] Before testing, the kitchen knife samples obtained in each embodiment were cleaned and dried, and a flat area on the coating surface was selected as the friction and wear test area. During the test, the change curve of the friction coefficient with the sliding distance was continuously recorded. After the test, a three-dimensional white light interferometer was used to scan the three-dimensional morphology of the wear track to obtain the wear track width, depth, and wear cross-sectional profile, and the coating wear rate was calculated based on the wear volume. The wear rate was calculated according to the following formula: W=V / (F×L), where W is the wear rate, in mm³ / (N·m); V is the wear volume, in mm³; F is the normal load, in N; and L is the sliding distance, in m.

[0204] For each embodiment, parallel friction and wear tests were conducted at at least three different locations, and the average value was taken as the final test result. The test results are shown in the table below.

[0205] Sample Average coefficient of friction <![CDATA[Wear rate / (×10 -7 mm³ / Nm)]]> Maximum wear depth / μm Example 1 0.43 2.86 0.82 Example 2 0.40 2.17 0.67 Example 3 0.38 1.74 0.55

[0206] The test results show that the high wear-resistant composite coatings obtained in Examples 1 to 3 all have low coefficients of friction and low wear rates, which can effectively reduce the loss of coating material caused by friction during long-term cutting of kitchen knives.

[0207] Among them, the (AlCrTiZr)N nanocrystalline phase in the AlCrTiZrSiN wear-resistant layer has high hardness and can bear the main load generated during friction; the SiNx amorphous phase distributed in the nanocrystalline grain boundary region can inhibit the growth of nanocrystals and reduce the stress concentration in the grain boundary region, thereby reducing the possibility of crack propagation along the grain boundary during friction.

[0208] In Example 2, because the wear-resistant layer has a denser nanocrystalline / amorphous composite structure, the internal pores and micro-defects of the coating are reduced, which reduces the possibility of abrasive particles entering the interior of the coating during the grinding process. Therefore, the coefficient of friction and wear rate are both lower than those in Example 1.

[0209] In Example 3, the density of the AlCrTiZrSiN wear-resistant layer was further improved, and an AlCrTiZrSiON sealing layer with a high oxygen content was formed on the outermost side of the coating. The (AlCrTiZr)ON nanocrystalline structure and the Si-ON amorphous structure in the sealing layer together form a dense surface protective structure, which can reduce the penetration of external media into the wear-resistant layer during friction. At the same time, the structural stress between the sealing layer and the wear-resistant layer is reduced through the second gradient transition region, thus exhibiting the lowest coefficient of friction and wear rate.

[0210] The reference document uses Al2O3 ceramic balls, 6mm ball diameter, 5N load, 100mm / s sliding speed and 1000m sliding distance to evaluate the ball-disc friction and wear of hard coatings. This application adopts the same test system to ensure comparability between different embodiments.

[0211] Based on the above test results, the high-wear-resistant composite coatings obtained in Examples 1 to 3 all exhibited high nano-hardness, good film-substrate adhesion, and low friction and wear rates. Among them, Example 3 showed the best overall performance, with a nano-hardness of 31.4 GPa, a critical bonding load of 53.6 N, an average friction coefficient reduced to 0.38, and a wear rate reduced to 1.74 × 10⁻⁶. -7mm³ / (N·m). This indicates that by setting a first gradient transition region between the kitchen knife substrate and the AlCrTiZrSiN wear-resistant layer, and a second gradient transition region between the AlCrTiZrSiN wear-resistant layer and the AlCrTiZrSiON sealing layer, while utilizing the composite structure formed by the nanocrystalline nitride phase and the silicon-based amorphous phase, it is possible to improve the coating hardness while simultaneously improving the film-substrate bonding performance and friction and wear resistance, thereby enhancing the durability of the kitchen knife coating during long-term cutting use.

[0212] The above embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of protection of the present invention. For those skilled in the art, it will be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high wear-resistant composite coating applied to cutting tools, characterized in that, The high wear-resistant composite coating is formed on the substrate surface of the cutting tool by arc ion plating; The high wear-resistant composite coating includes a bonding layer, a wear-resistant layer and a sealing layer formed sequentially, wherein a first gradient transition region is formed between the bonding layer and the wear-resistant layer, and a second gradient transition region is formed between the wear-resistant layer and the sealing layer. The wear-resistant layer is an AlCrTiZrSiN nitride structure formed by a combination of aluminum, chromium, titanium, zirconium, silicon and nitrogen, and the wear-resistant layer includes a nanocrystalline nitride phase and an amorphous silicon nitride phase.

2. The high wear-resistant composite coating according to claim 1, characterized in that, The wear-resistant layer contains the following elements by atomic percentage: 35%–45% nitrogen, 18%–22% aluminum, 15%–18% chromium, 10%–12% titanium, 8%–10% zirconium and 3%–5% silicon.

3. The high wear-resistant composite coating according to claim 2, characterized in that, The nanocrystalline nitride phase in the wear-resistant layer has a (AlCrTiZr)N nanocrystalline structure, and the amorphous silicon nitride phase has a SiNx amorphous structure; the amorphous silicon nitride phase is distributed in the grain boundary region of the nanocrystalline nitride phase.

4. The high wear-resistant composite coating according to claim 1, characterized in that, The bonding layer comprises the following elements by atomic percentage: 30%–35% aluminum, 22%–27% chromium, 15%–20% titanium, 10%–15% zirconium, and 5%–8% silicon.

5. The high wear-resistant composite coating according to claim 4, characterized in that, The nitrogen content in the first gradient transition region gradually increases along the direction away from the substrate surface of the tool, causing the bonding layer to gradually transform from an AlCrTiZrSi structure to an AlCrTiZrSiN nitride structure.

6. The high wear-resistant composite coating according to claim 1, characterized in that, The sealing layer contains the following elements by atomic percentage: 18%–22% aluminum, 15%–18% chromium, 10%–12% titanium, 8%–10% zirconium, 3%–5% silicon, 30%–35% nitrogen and 8%–15% oxygen.

7. The high wear-resistant composite coating according to claim 6, characterized in that, The oxygen content in the second gradient transition region gradually increases along the direction away from the substrate surface of the tool, while the nitrogen content gradually decreases along the direction away from the substrate surface of the tool, so that the wear-resistant layer gradually changes from an AlCrTiZrSiN nitride structure to an AlCrTiZrSiON nitride structure.

8. A kitchen knife, characterized in that, The base surface of the kitchen knife is provided with a high wear-resistant composite coating as described in any one of claims 1 to 7.

9. A kitchen knife according to claim 8, characterized in that, The thickness of the high wear-resistant composite coating is 3μm to 5μm. The high wear-resistant composite coating includes a bonding layer, a wear-resistant layer and a sealing layer formed sequentially. A first gradient transition region is formed between the bonding layer and the wear-resistant layer, and a second gradient transition region is formed between the wear-resistant layer and the sealing layer. The bonding layer comprises the following elements by atomic percentage: 30%–35% aluminum, 22%–27% chromium, 15%–20% titanium, 10%–15% zirconium, and 5%–8% silicon; The wear-resistant layer comprises, by atomic percentage, the following elements: nitrogen 35%–45%, aluminum 18%–22%, chromium 15%–18%, titanium 10%–12%, zirconium 8%–10%, and silicon 3%–5%; The sealing layer contains the following elements by atomic percentage: 18%–22% aluminum, 15%–18% chromium, 10%–12% titanium, 8%–10% zirconium, 3%–5% silicon, 30%–35% nitrogen and 8%–15% oxygen.

10. A method for preparing the kitchen knife according to claim 9, characterized in that, The preparation method includes: Perform surface pretreatment on the blade substrate of the kitchen knife; The pretreated tool substrate is placed in the vacuum chamber of an arc ion plating equipment, and an AlCrTiZrSi alloy target is used as the deposition target. Arc ion plating is performed in an inert gas environment to form a bonding layer on the surface of the tool substrate. After the bonding layer is deposited, nitrogen gas is introduced into the vacuum chamber to allow nitrogen to gradually participate in the deposition process. The nitrogen content on the surface of the bonding layer is gradually increased by adjusting the nitrogen flow rate to form a first gradient transition region from the AlCrTiZrSi structure to the AlCrTiZrSiN structure. Then, the deposition continues to form a wear-resistant layer. After the wear-resistant layer is deposited, oxygen is introduced into the vacuum chamber, and the ratio of nitrogen to oxygen is adjusted so that the oxygen content gradually increases in the direction away from the tool substrate surface, forming a second gradient transition region from AlCrTiZrSiN nitride structure to AlCrTiZrSiON nitride structure; deposition continues to form a sealing layer. After the sealing layer deposition is completed, the kitchen knife is cooled to obtain a kitchen knife with a highly wear-resistant composite coating on the surface.

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